PLANT PROTEINS

Reversible phosphorylation of thylakoid light harvesting proteins is a mechanism to compensate for unbalanced excitation of PSI vs PSII under limiting light. In monocots, an additional phosphorylation event on the PSII antenna CP29 occurs upon exposure to excess light, enhancing resistance to light stress. Different from the case of the major LHCII antenna complex, the STN7 kinase and its related PPH1 phosphatase were proven not to be involved in CP29 phosphorylation, indicating that a different set of enzymes act in the high-light response. Here, we analyze a rice stn8 mutant in which both PSII core proteins and CP29 phosphorylation are suppressed in high light, implying that STN8 is the kinase catalyzing this reaction. In order to identify the phosphatase involved, we produced a recombinant enzyme encoded by the rice ortholog of AtPBCP, antagonist of AtSTN8, which catalyzes the dephosphorylation of PSII core proteins. The recombinant protein was active in dephosphorylating P-CP29....

PsbS is a 22-kDa Photosystem (PS) II protein involved in non-photochemical quenching (NPQ) of chlorophyll fluorescence. Rice (Oryza sativa L.) has two PsbS genes, PsbS1 and PsbS2. However, only inactivation of PsbS1, through a knockout (PsbS1-KO) or in RNAi transgenic plants, results in plants deficient in qE, the energy-dependent component of NPQ. In studies presented here, under fluctuating high light, growth of young seedlings lacking PsbS is retarded, and PSII in detached leaves of the mutants is more sensitive to photoinhibitory illumination compared with the wild type. Using both histochemical and fluorescent probes, we determined the levels of reactive oxygen species, including singlet oxygen, superoxide, and hydrogen peroxide, in leaves and thylakoids. The PsbS-deficient plants generated more superoxide and hydrogen peroxide in their chloroplasts. PSII complexes isolated from them produced more superoxide compared with the wild type, and PSII-driven superoxide production was...

Potato tuber dormancy is the last phase of tuber existence helping to maintain tubers as organs of vegetative reproduction under non-favorable growth environments. Tubers of potato (Solanum tuberosum L.) are dormant and will not sprout. As the time of postharvest storage is prolonged, dormancy of tuber is broken and sprout growth commences. Dormancy breaking and beginning of sprout growth of potato tuber is complemented by several biochemical changes, most of which are critical to the nutritional and processing qualities of potatoes. Environmental, physiological and hormonal control mechanisms have been proposed to play a significant role in tuber dormancy regulation. In this review, the environmental and endogenous factors responsible for tuberization have been reviewed and discussed. Furthermore, numerous biochemical and physiological processes principal to enhanced tuberization under the influence of environmental and endogenous factors are discussed in detail.

The aim of this study was to characterise the molecular mechanisms of transcriptional regulation of Differentially Expressed Genes (DEGs) in rice coleoptiles under anoxia by identifying motifs that are common in the promoter region of co-regulated genes. Un-changed DEGs (<2 fold and >-2), up-regulated DEGs (≥2 fold) and down-regulated DEGs (≤-2 fold) were separated in three different data sets. Their gene promoters were extracted from eukaryotic promoter database. Statistically significant consensus promoter motifs were detected by in silico method. A significant variation in the number of promoter motifs, consensus promoter motif and their sequences between UR-DEGs and DR-DEGs were detected that might be responsible for their related expression.

Novel approaches for the control of agriculturally damaging nematodes are sorely needed. Endoparasitic nematodes complete their life cycle within the root vascular cylinder, inducing specialized feeding cells: giant cells for root-knot nematodes and syncytia for cyst nematodes. Both nematodes hijack parts of the transduction cascades involved in developmental processes, or partially mimic the plant responses to other interactions with microorganisms, but molecular evidence of their differences and commonalities is still under investigation. Transcriptomics has been used to describe global expression profiles of their interaction with Arabidopsis, generating vast lists of differentially expressed genes. Although these results are available in public databases and publications, the information is scattered and difficult to handle. Here, we present a rapid, visual, user-friendly and easy to handle spreadsheet tool, called NEMATIC (NEMatode-Arabidopsis Transcriptomic Interaction Compendium; ). It combines existing transcriptomic data for the interaction between Arabidopsis and plant-endoparasitic nematodes with data from different transcriptomic analyses regarding hormone and cell cycle regulation, development, different plant tissues, cell types and various biotic stresses. NEMATIC facilitates efficient in silico studies on plant-nematode biology, allowing rapid crosscomparisons with complex datasets and obtaining customized gene selections through sequential comparative and filtering steps. It includes gene functional classification and links to utilities from several databases. This data-mining spreadsheet will be valuable for the understanding of the molecular bases subjacent to feeding site formation by comparison with other plant systems, and for the selection of genes as potential tools for biotechnological control of nematodes, as demonstrated in the experimentally confirmed examples provided.

Leaves and glumes act as lateral organs and have essential effects on photosynthesis and seed morphology, thus affecting yield.  However, the molecular mechanisms controlling their polarity development in rice still need further study.  Here, we isolated a polarity defect of lateral organs 1 (pdl1) mutant in rice, which exhibits twisted/filamentous-shaped leaves and cracked/filamentous-shaped lemmas caused by defects in polarity development.  PDL1 encodes a SUPPRESSOR OF GENE SILENCING 3 protein localized in the cytoplasmic granules.  PDL1 is expressed in the shoot apical meristem, inflorescence meristem, floral meristem, and lateral organs including leaves and floral organs.  PDL1 is involved in the synthesis of tasiR-ARF, which may subsequently modulate the expression of OsARFs.  Meanwhile, the expression levels of abaxial miR165/166 and the adaxial identity genes OSHBs were respectively increased and reduced significantly.  The results of this study clarify the molecular mechanism by which PDL1-mediated tasiR-ARF synthesis regulates the lateral organ polarity development in rice.

Pear (Pyrus communis) is an economically important fruit crop. Drops in yield and even losses of whole plantations are caused by diseases, most importantly fire blight which is triggered by the bacterial pathogen Erwinia amylovora. In response to the infection, biphenyls and dibenzofurans are formed as phytoalexins, biosynthesis of which is initiated by biphenyl synthase (BIS). Two PcBIS transcripts were cloned from fire blight-infected leaves and the encoded enzymes were characterized regarding substrate specificities and kinetic parameters. Expression of PcBIS1 and PcBIS2 was studied in three pear cultivars after inoculation with E. amylovora. Both PcBIS1 and PcBIS2 were expressed in &#39;Harrow Sweet&#39;, while only PcBIS2 transcripts were detected in &#39;Alexander Lucas&#39; and &#39;Conference&#39;. Expression of the PcBIS genes was observed in both leaves and the transition zone of the stem; however, biphenyls and dibenzofurans were only detected in stems. The maximum phytoa...

In plants, prenylation of metabolites is widely distributed to generate compounds with efficient defense potential and distinct pharmacological activities profitable to human health. Prenylated compounds are formed by members of the prenyltransferase (PT) superfamily, which catalyze the addition of prenyl moieties to a variety of acceptor molecules. Cell cultures of Hypericum calycinum respond to elicitor treatment with the accumulation of the prenylated xanthone hyperxanthone E. A cDNA encoding a membrane-bound PT (HcPT) was isolated from a subtracted cDNA library and transcript preparations of H. calycinum. An increase in the HcPT transcript level preceded hyperxanthone E accumulation in cell cultures of H. calycinum treated with elicitor. The HcPT cDNA was functionally characterized by expression in baculovirus-infected insect cells. The recombinant enzyme catalyzed biosynthesis of 1,3,6,7-tetrahydroxy-8-prenylxanthone through regiospecific C-8 prenylation of

Upon pathogen attack, fruit trees such as apple (Malus spp.) and pear (Pyrus spp.) accumulate biphenyl and dibenzofuran phytoalexins, with aucuparin as a major biphenyl compound. 4-Hydroxylation of the biphenyl scaffold, formed by biphenyl synthase (BIS), is catalyzed by a cytochrome P450 (CYP). The biphenyl 4-hydroxylase (B4H) coding sequence of rowan (Sorbus aucuparia) was isolated and functionally expressed in yeast (Saccharomyces cerevisiae). SaB4H was named CYP736A107. No catalytic function of CYP736 was known previously. SaB4H exhibited absolute specificity for 3-hydroxy-5-methoxybiphenyl. In rowan cell cultures treated with elicitor from the scab fungus, transient increases in the SaB4H, SaBIS, and phenylalanine ammonia lyase transcript levels preceded phytoalexin accumulation. Transient expression of a carboxyl-terminal reporter gene construct directed SaB4H to the endoplasmic reticulum. A construct lacking the amino-terminal leader and transmembrane domain caused cytoplasmic localization. Functional B4H coding sequences were also isolated from two apple (Malus 3 domestica) cultivars. The MdB4Hs were named CYP736A163. When stems of cv Golden Delicious were infected with the fire blight bacterium, highest MdB4H transcript levels were observed in the transition zone. In a phylogenetic tree, the three B4Hs were closest to coniferaldehyde 5-hydroxylases involved in lignin biosynthesis, suggesting a common ancestor. Coniferaldehyde and related compounds were not converted by SaB4H.

Oleosomes, with their unique structural proteins, the oleosins, are known to be useful in cosmetics and other emulsion applications. A procedure to fractionate intact oleosomes to produce soybean oil without the use of organic solvents was investigated. Process parameters, enzyme treatment, filtration, cell lysis, and centrifugation, were studied. Successive extractions of the residue, eliminating the filtration step, pressurization, or ultrasonication of soybean flour prior to enzyme treatment and enzyme treatment on the residue, were the key steps. A mixture of Multifect Pectinase FE, Cellulase A, and Multifect CX 13L in equal proportion gave 36.42-63.23% of the total soybean oil from oleosomes, respectively, for 45 and 180 s of blending time, compared to the conventional method with lower yields (34.24 and 28.65%, respectively, for 45 and 180 s of blending time). Three successive extractions of the residue increased the oil yield to a maximum of 84.65% of the total soybean oil recovered in intact oleosomes. The percentage of lipid in the supernatant fraction decreased to a minimum value of 0.33% with the use of the enzymes at a 3% dosage. The results are considered to be useful for developing large-scale and efficient extraction of oleosomes from soybean.

Cell expansion is an increase in cell size and thus plays an essential role in plant growth and development. Phytohormones and the primary plant cell wall play major roles in the complex process of cell expansion. In shoot tissues, cell expansion requires the auxin receptor AUXIN BINDING PROTEIN1 (ABP1), but the mechanism by which ABP1 affects expansion remains unknown. We analyzed the effect of functional inactivation of ABP1 on transcriptomic changes in dark-grown hypocotyls and investigated the consequences of gene expression on cell wall composition and cell expansion. Molecular and genetic evidence indicates that ABP1 affects the expression of a broad range of cell wall–related genes, especially cell wall remodeling genes, mainly via an SCFTIR/AFB-dependent pathway. ABP1 also functions in the modulation of hemicellulose xyloglucan structure. Furthermore, fucosidase-mediated defucosylation of xyloglucan, but not biosynthesis of nonfucosylated xyloglucan, rescued dark-grown hypoc...

The interaction amongst papain-like cysteine-proteases (PLCP) and their substrates and inhibitors, such as cystatins, can be perceived as part of the molecular battlefield in plantpathogen interaction. In cacao, four cystatins were identified and characterized by our group. We identified 448 proteases in cacao genome, whereof 134 were cysteine-proteases. We expressed in Escherichia coli a PLCP from cacao, named TcCYSPR04. Immunoblottings with anti-TcCYSPR04 exhibited protein increases during leaf development. Additional isoforms of TcCYSPR04 appeared in senescent leaves and cacao tissues infected by Moniliophthora perniciosa during the transition from the biotrophic to the saprophytic phase. TcCYSPR04 was induced in the apoplastic fluid of Catongo and TSH1188 cacao genotypes, susceptible and resistant to M. perniciosa, respectively, but greater intensity and additional isoforms were observed in TSH1188. The fungal protein MpNEP induced PLCP isoform expression in tobacco leaves, according to the cross reaction with anti-TcCYSPR04. Several protein isoforms were detected at 72 hours after treatment with MpNEP. We captured an active PLCP from cacao tissues, using a recombinant cacao cystatin immobilized in CNBr-Sepharose. Mass spectrometry showed that this protein corresponds to TcCYSPR04. A homology modeling was obtained for both proteins. In order to become active, TcCYSPR04 needs to lose its inhibitory domain. Molecular docking showed the physical-chemical complementarities of the interaction between the cacao enzyme and its inhibitor. We propose that TcCYSPR04 and its interactions with cacao cystatins are involved in the senescence and necrosis events related to witches' broom symptoms. This molecular interaction may be the target for future interventions to control witches' broom disease.

Plant proteins extracted with traditional method are generally of lower quality, with a less favorable amino acid profile as compared to animal protein. This review explores effective protein extraction methods to enhance plant protein functionality. Moreover, animal protein is associated with high risk of cardiovascular disease and other disease. This review will highlight the impact of plant protein over animal protein on cardiovascular disease and other health Issues.

Main conclusion Salt stress is limiting barley growth, development, and production. Transcription factors (TFs) play a critical role in plant responses to salt stress by modulating gene expression Abstract Salinity stress increases over time due to climate change. It represents a major constraint to barley growth, development, and yield. Enhancing salt tolerance to withstand salt stress is crucial for ensuring global food security. We discussed transcription factors (TFs) that play a key role in responding to salt stress by modulating downstream genes and facilitating alterations in physiological and biochemical pathways. TF families strongly associated with the bZIP, DREB, NAC, bHLH, MYB, ERF, and WRKY are particularly involved in regulating ion homeostasis, osmotic adjustment, and signaling under stressful conditions. These discoveries establish a platform for generating salt-tolerant barley genotypes utilizing modern biotechnological methods. CRISPR/Cas and virus-induced gene silencing (VIGS) are broadly used tools to investigate gene function by knocking out or silencing target genes under salt stress. Furthermore, integrating the existing knowledge and foundations of TFs could yield sustainable, salt-resistant barley genotypes for agriculture. Multi-omics and bioinformatics have accelerated the identification of salt-responsive genes and TFs. The review recorded the recent progress in the molecular mechanisms of salinity tolerance in barley and indicates the potential of biotechnology for improving salt tolerance in barley varieties.

Mechanisms regulating legume root nodule development are still poorly understood, and very few regulatory genes have been cloned and characterized. Here, we describe EFD (for ethylene response factor required for nodule differentiation), a gene that is upregulated during nodulation in Medicago truncatula. The EFD transcription factor belongs to the ethylene response factor (ERF) group V, which contains ERN1, 2, and 3, three ERFs involved in Nod factor signaling. The role of EFD in the regulation of nodulation was examined through the characterization of a null deletion mutant (efd-1), RNA interference, and overexpression studies. These studies revealed that EFD is a negative regulator of root nodulation and infection by Rhizobium and that EFD is required for the formation of functional nitrogen-fixing nodules. EFD appears to be involved in the plant and bacteroid differentiation processes taking place beneath the nodule meristem. We also showed that EFD activated Mt RR4, a cytokinin...

The PA1b (Pea Albumin 1, subunit b) peptide is an entomotoxin extract from Legume seeds with lethal activity on several insect pests, such as mosquitoes, some aphids and cereal weevils. This 37 amino-acid cysteine-rich peptide has been, until now, obtained by biochemical purification or chemical synthesis. In this paper, we present our results for the transient production of the peptide in Nicotiana benthamiana by agro-infiltration, with a yield of about 35 mg/g of fresh leaves and maximum production 8 days after infiltration. PA1b is part of the PA1 gene which, after post-translational modifications, encodes two peptides (PA1b and PA1a). We show that transforming tobacco with the PA1b cDNA alone does not result in production of the toxin and, in fact, the entire cDNA is necessary, raising the question of the role of PA1a. We constructed a PA1-cassette, allowing for the quick ''cut/paste'' of different PA1b mutants within a conserved PA1 cDNA. This cassette enabled us to produce the six isoforms of PA1b which exist in pea seeds. Biological tests revealed that all the isoforms display similar activity, with the exception of one which is inactive. The lack of activity in this isoform led us to conclude that the amphiphilic nature of the peptide is necessary for activity. The possible applications of this expression system for other cysteine-rich biomolecules are discussed.

PA1b (for pea albumin 1 subunit b) is a plant bioinsecticide lethal to several pests that are important in agriculture or human health. PA1b belongs to the inhibitory cystine knot family or knottin family. Originating from a plant (the garden pea) commonly eaten by humans without any known toxic or allergic effects, PA1b is a candidate for transgenic applications and is one of the most promising biopesticides for pest control. Using whole-cell patch-clamp techniques on Sf9 PA1b-sensitive lepidopteran insect cells, we discovered that PA1b reversibly blocked ramp membrane currents in a dose-dependent manner (EC 50 ‫؍‬ 0.52 M). PA1b had the same effect as bafilomycin, a specific inhibitor of the vacuolar proton pump (V-type H ؉ -AT-Pase), and the PA1b-sensitive current depended on the internal proton concentration. Biochemical assays on purified V-AT-Pase from the lepidopteran model Manduca sexta showed that PA1b inhibited the V 1 V 0 -type H ؉ -ATPase holoenzyme activity (IC 50 ϳ 70 nM) by interacting with the membrane-bound V 0 part of the V-ATPase. V-ATPase is a complex protein that has been studied increasingly because of its numerous physiological roles. In the midgut of insects, V-ATPase activity is essential for energizing nutrient absorption, and the results reported in this work explain the entomotoxic properties of PA1b. Targeting V-ATPase is a promising means of combating insect pests, and PA1b represents the first peptidic V-ATPase inhibitor. The search for V-ATPase inhibitors is currently of great importance because it has been demonstrated that V-ATPase plays a role in so many physiological processes.

The pea (Pisum sativum L.) is one of the most significant legumes in the world. This species is rich in proteins, vitamins, minerals and bioactive compounds that benefit human health. Although the symbiosis between atmospheric nitrogenfixing bacteria (Rhizobium) and legume plants is well known, farmers apply nitrogen fertilizers to pea crops. It should be noted that imbalances due to excess nitrogen in plants cause population increases of insect pests. The aim of the study was to evaluate the effect of three levels of nitrogen [(N0= unfertilized, 0 Kg N ha-1), (N1= medium level, 30 Kg N ha-1), (N2= High level, 60 Kg N ha-1)] and two infestation status (control and herbivory) on pea plants (dry weight) and its influence on the aphid Acyrthosiphon pisum. Our results indicate that high levels of nitrogen significantly increased the biomass of the aerial parts and its pods, unlike to others. However, root nodule biomass decreased significantly by increasing nitrogen. On the other hand, the aphid population was higher in plants at medium nitrogen level, in contrast to the rest. Whereas, A. pisum was mainly attracted to leaflets from plants over-fertilized (N2). Thus, the excess of nitrogen promoted the growth of pea plants, increasing the attraction and reproduction of the aphid A. pisum, due to the greater availability of food. However, the Rhizobium-legume interaction was inhibited by nitrogen applied. Therefore, further studies of the effect of inorganic nitrogen fertilization on symbiotic bacteria and plant defenses are required, to develop suitable minimum fertilization programs for crops, avoiding the loss of inputs, increases in pest populations, and inhibition of growth-promoting microorganisms, within the context of clean and sustainable agriculture.

Bitter gourd (Momordica charantia L.) is a nutritious vegetable crop of Asian origin, used as a medicinal herb in Indian and Chinese traditional medicine. Molecular breeding in bitter gourd is in its infancy, due to limited molecular resources, particularly on functional markers for traits such as gynoecy. We performed de novo transcriptome sequencing of bitter gourd using Illumina next-generation sequencer, from root, flower buds, stem and leaf samples of gynoecious line (Gy323) and a monoecious line (DRAR1). A total of 65,540 transcripts for Gy323 and 61,490 for DRAR1 were obtained. Comparisons revealed SNP and SSR variations between these lines and, identification of gene classes. Based on available transcripts we identified 80 WRKY transcription factors, several reported in responses to biotic and abiotic stresses; 56 ARF genes which play a pivotal role in auxin-regulated gene expression and development. The data presented will be useful in both functions studies and breeding programs in bitter gourd.

Nearly all programmed and plastic plant growth responses are at least partially regulated by auxins, such as indole-3-acetic acid (IAA). Although vectorial, long distance auxin transport is essential to its regulatory function, all auxin responses are ultimately localized in individual target cells. As a consequence, cellular auxin concentrations are tightly regulated via coordinated biosynthesis, transport, conjugation, and oxidation. The primary auxin oxidative product across species is 2-oxindole-3-acetic acid (oxIAA), followed by glucose and amino acid conjugation to oxIAA. Recently, the enzymes catalyzing the oxidative reaction were characterized in Arabidopsis thaliana. DIOXYGENASE OF AUXIN OXIDATION (DAO) comprises a small subfamily of the 2-oxoglutarate and Fe(II) [2-OG Fe(II)] dependent dioxygenase superfamily. Biochemical and genetic studies have revealed critical physiological functions of DAO during plant growth and development. Thus far, DAO has been identified in three...

Conversion of non-grain biomass into liquid fuel is a sustainable approach to energy demands as global population increases. Previously, we showed that iron can act as a catalyst to enhance the degradation of lignocellulosic biomass for biofuel production. However, direct addition of iron catalysts to biomass pre-treatment is diffusion-limited, would increase the cost and complexity of biorefinery unit operations, and may have deleterious environmental impacts. Here, we show a new strategy for in planta accumulation of iron throughout the volume of the cell wall where iron acts as a catalyst in the deconstruction of lignocellulosic biomass. We engineered CBM-IBP fusion polypeptides composed of a carbohydrate-binding module family 11 (CBM11) and an iron binding peptide (IBP) for secretion into Arabidopsis and rice cell walls. CBM-IBP transformed Arabidopsis and rice plants show significant increases in iron accumulation and biomass conversion compared to respective controls. Further,...

While seed or foliar application of thiourea (TU) has the potential to modulate plant growth, studies reporting such bioregulatory role(s) of root-applied TU are limited. Here we report the growth regulation by root-applied TU in nine maize (Zea mays L.) varieties grown using sand culture. Thirty day old plants were treated with 0-1.25 mM TU levels dissolved in nutrient solution, and the data recorded 20 days later. The parameters studied were symptoms of TU toxicity, growth and photosynthetic pigment contents. Results revealed that 0.25 mM TU promoted the growth of all varieties; 0.50 mM did so in some, while 0.75-1.25 mM TU was inhibitory to all varieties. Higher TU levels (1.00-1.25 mM) produced more intensive toxicity symptoms such as yellowing of leaves, and browning and constriction of roots but with significant varietal differences; Pak-Afgoi showed the lowest while EV-20 had the highest incidence of symptoms. Lowest TU level (0.25 mM) increased the photosynthetic pigments in all the varieties, while higher levels (1.00-1.25) reduced chlorophyll (Chl) b and carotenoids (Car) contents and increased Chl:Car ratio more legibly in the sensitive varieties. There were no correlations of toxicity symptoms with growth and leaf pigments contents at 0.25 mM TU but these correlations were negative for shoot weight, number and area of leaves and Chl b, Car and Chl:Car ratio of leaves at 1.25 mM (toxic) level of TU. Likewise, root dry weight of maize varieties was negatively correlated with root constriction and root browning. Results suggest that higher levels of TU had pronounced influence on the root functions leading to reduced dry weight. From the current results we believe that TU has a definitive growth bioregulatory activity as it improved photosynthetic pigments contents at lower level (0.25 mM) but deteriorated them at higher levels (0.75-1.25 mM). Substantial varietal differences suggested that TU effects are genetically-related in maize. Possible physiological basis of the current observations are discussed.

Pepino mosaic virus (PepMV, Fig. ) may infect several Solanaceae, tomato, pepper, potato, weeds. Although infection can be symptomless the damage caused by the virus was reported to be up to 90 % of collapsed plants. At the moment the virus can only be controlled by comprehensive disinfection and care in the greenhouse. Our goal was to find out if biological agents can confine the virus. Three endophytic fungi were tested: -Piriformospora indica (Fig. ). All plants inoculated and tested so far responded with an enhanced growth of shoot and root. It induced resistance in barley against Fusarium spp. and Blumeria graminis. -Pythium oligandrum (Fig. ). The oomycete, a soil born fungus, induced systemic resistance in tomato leaves against Botrytis cinerea. -Pythium aphanidermatum (Fig. ). An important pathogen in soilless systems, causing root rot. When pre-inoculated before PepMV a delayed infection and distribution of the virus up to eight weeks was found.

Los efectos del cambio climático sobre la biodiversidad ocurren a diferentes niveles de organización (organismos, especies y ecosistemas). La vegetación se encuentra relacionada directamente con el clima, por lo que se espera que el calentamiento global altere la distribución de los tipos de vegetación para el futuro cercano. Usando un enfoque de envoltura bioclimática, los tipos de vegetación de Chile fueron modelados y proyectados usando escenarios del IPCC para el año 2080. Los resultados presentan diferentes transiciones entre los tipos de vegetación, en relación a su distribución latitudinal y altitudinal actual. Entre los cambios principales, se identifica el avance altitudinal de la vegetación alpina, la expansión hacia el sur del desierto absoluto y del matorral desértico sobre el bosque esclerófilo. Se esperan cambios en la representación relativa de las áreas protegidas dentro de los diferentes tipos de vegetación de Chile. Las limitaciones del ejercicio de modelación son discutidas junto a la necesidad de mejorar el conocimiento científico sobre procesos biológicos claves como dispersión y polinización. Palabras clave: Cambio climático, Modelos de envoltura bioclimática, tipos de vegetación, MAXENT, PRECIS.

Mature pollen represents an extremely resistant quiescent structure surrounded by a tough cell wall. After its hydration on stigma papillary cells, pollen tube growth starts rapidly. Massive metabolic changes are likely to be accompanied by changes in protein phosphorylation. Protein phosphorylation belongs among the most rapid post-translational modifications. To date, only Arabidopsis thaliana and tobacco (Nicotiana tabacum) mature pollen have been subjected to phosphoproteomic studies in order to identify the phosphoproteins present. In the present mini-review, Arabidopsis and tobacco datasets were compared with each other. The representation of the O-phosphorylated amino acids was compared between these two datasets, and the putative pollen-specific or pollen-abundant phosphopeptides were highlighted. Finally, the phosphorylation sites common for both Arabidopsis and tobacco phosphoproteins are listed as well as the phosphorylation motifs identified.

Background: As in animals, cell-cell communication plays a pivotal role in male-female recognition during plant sexual reproduction. Prelaid peptides secreted from the female reproductive tissues guide pollen tubes towards ovules for fertilization. However, the elaborate mechanisms for this dialogue have remained elusive, particularly from the male perspective. Results: We performed genome-wide quantitative liquid chromatography-tandem mass spectrometry analysis of a pistil-stimulated pollen tube secretome and identified 801 pollen tube-secreted proteins. Interestingly, in silico analysis reveals that the pollen tube secretome is dominated by proteins that are secreted unconventionally, representing 57 % of the total secretome. In support, we show that an unconventionally secreted protein, translationally controlled tumor protein, is secreted to the apoplast. Remarkably, we discovered that this protein could be secreted by infiltrating through the initial phases of the conventional secretory pathway and could reach the apoplast via exosomes, as demonstrated by co-localization with Oleisin1 exosome marker. We demonstrate that translationally controlled tumor protein-knockdown Arabidopsis thaliana plants produce pollen tubes that navigate poorly to the target ovule and that the mutant allele is poorly transmitted through the male. Further, we show that regulators of the endoplasmic reticulum-trans-Golgi network protein secretory pathway control secretion of Nicotiana tabacum Pollen tube-secreted cysteine-rich protein 2 and Lorelei-like GPI-anchor protein 3 and that a regulator of endoplasmic reticulum-trans-Golgi protein translocation is essential for pollen tube growth, pollen tube guidance and ovule-targeting competence. Conclusions: This work, the first study on the pollen tube secretome, identifies novel genome-wide pollen tube-secreted proteins with potential functions in pollen tube guidance towards ovules for sexual reproduction. Functional analysis highlights a potential mechanism for unconventional secretion of pollen tube proteins and reveals likely regulators of conventional pollen tube protein secretion. The association of pollen tube-secreted proteins with marker proteins shown to be secreted via exosomes in other species suggests exosome secretion is a possible mechanism for cell-cell communication between the pollen tube and female reproductive cells.

I hereby declare that I completed this master thesis independently under the guidance of RNDr. David Honys, Ph.D., and RNDr. Věra Čapková, CSc. It documents my own work if not explicitly otherwise mentioned. I have properly acknowledged and cited all sources used. The thesis is not subject of any other defending procedure.

Abscisic acid (ABA) is a plant hormone which plays an important role in seed development and dormancy and in plant response to environmental stresses. An ABA-deficient mutant of Nicotiana plumbaginifolia, aba2, was isolated by transposon tagging using the maize Activator transposon. The aba2 mutant exhibits precocious seed germination and a severe wilty pheno- type. The mutant is impaired in the first step of the ABA biosynthesis pathway, the zeaxanthin epoxidation reaction. ABA2 cDNA is able to complement N.plumbaginifolia aba2 and Arabidopsis thaliana aba mutations indicating that these mutants are homologous. ABA2 cDNA encodes a chloroplast-imported protein of 72.5 kDa, sharing similarities with different monooxigenases and oxidases of bacterial origin and having an ADP-binding fold and an FAD-binding domain. ABA2 protein, produced in Escherichia coli, exhibits in vitro zeaxanthin epoxidase activity. This is the first report of the isolation of a gene of the ABA biosynthetic pathway. The molecular identification of ABA2 opens the possibility to study the regulation of ABA biosyn- thesis and its cellular location. Keywords: abscisic acid/Arabidopsis thaliana/carotenoid/ Nicotiana plumbaginifolialtransposable element

Hevea brasiliensis trees produce natural rubber latex that can be transformed into dry natural rubber (NR). This biopolymer displays very specific properties unequalled so far by synthetic rubbers produced from fossil carbon sources. Nevertheless, NR also comes with disadvantages including the variability of its properties, and a dynamic of structuration during storage, usually called “storage hardening” [1-3] the mechanisms of which are still not fully understood. Some results from “RUBBex”, an on-going international project supported by French National Research Agency (ANR) will be presented. One of the objectives of this project is to identify and locate the main biochemical components of latex that drive NR quality consistency and the ability of raw NR structure to evolve during storage. Fresh Hevea latex is able to segregate into four fractions by centrifugation: the cream, the skim, the C-serum and the bottom fraction (made mainly of lutoids) [4-7]. Each fraction was analyzed ...

WRKY transcription factors in plants regulate diverse biological functions including abiotic and biotic stress responses, growth and development, embryogenesis and many other physiological processes. Indica and japonica genotypes of rice were identified to have 111 and 113 WRKY genes respectively in their genomes. Reports on the involvement of some of the WRKY genes in rice disease resistance covering the major diseases like blast and bacterial blight indicate the possibilities of further exploring these genes for the production of disease resistant varieties. In this review, we summarize the research progress on the function of WRKY transcription factors in rice disease resistance and discuss their relative importance for further exploration. The review will help researchers in choosing the candidate WRKY genes for characterization and evaluation in transgenic strategies for disease resistance development in rice.

WRKY transcription factor (TF) family regulates many functions in plant growth and development and also during biotic and abiotic stress. In this study, 101 WRKY TF gene models in indica and japonica rice were used to conduct evolutionary analysis, gene structure analysis, and motif composition. Co-expression analysis was carried out first by selecting the differentially expressing genes that showed a significant change in response to the pathogens from Rice Oligonucleotide Array Database (ROAD). About 82 genes showed responses to infection by Magnaporthe oryzae or Xanthomonas oryzae pv. oryzae. Co-expression gene network was constructed using direct neighborhood and context associated inbuilt mode in RiceNetv2 tool. Only 41 genes showed interaction with 2299 non-WRKY genes. Variations exist in the structure and evolution of WRKY genes among indica and japonica genotypes which have important implications in their differential roles including disease resistance. WRKY genes mediate a complex networking and co-express along with other WRKY and non-WRKY genes to mediate resistance against fungal and bacterial pathogens in rice.

Birch allergy (BA) is a common pollinosis. Bet v 1, Bet v 2, and Bet v 4 are birch allergen molecules. Oral allergic syndrome (OAS) is frequently associated with BA. Previously, it has been reported that there is a gradient of birch allergen sensitization profile across Europe. Thus, this study aimed to investigate the birch sensitization profile, including OAS, across Italy. This retrospective study considered a series of 854 patients (391 males, mean age 35.9 years, range 18-93): 196 patients were recruited in Genoa, 188 in Northern Italy, 359 in Central Italy, and 111 in Southern Italy. Serum IgE to Bet v 1, Bet v 2, and Bet v 4 were assessed. OAS was analysed. Considering the geographical path Genoa-North-Center-South Italy, Bet v 1 sensitization significantly (p&lt;0.0001) decreased from Genoa (95.41%) to Southern Italy (58.56%). Bet v 2 sensitization significantly (p&lt;0.0001) increased from Genoa (6.12%) to Southern Italy (52.25%). Also Bet v 4 significantly (p=0.0002) incre...

Cypress pollen represents the primary cause of respiratory allergies in Mediterranean areas. Patients allergic to Cupressus sempervirens pollen (Cups) (CPA) can be discriminated on the basis of the immunoglobulin E (IgE) binding to a basic 14 kDa protein (BP14) or to high-molecular-weight (HMW) glycoproteins only. Specific IgE repertoires of two differentially exposed CPA cohorts, French and Italian, were investigated using an IgE microarray system (some known major allergens from several allergenic sources) and individual IgE immunoblotting (IB) of whole Cups pollen extract separated by SDS-PAGE (all allergens from one allergenic source: cypress pollen). The prevalence of sensitization to BP14 was higher in French (37 %) than in Italian patients (17 %) and major differences were observed in IgE reactivities to lipid transfer proteins (LTPs). Thirty percent of the Italian CPA (4 % in the French group) had specific IgE against the Parietaria pollen LTP, independently of IB subgroups....

Antioxidant activities of canola protein hydrolysates (CPHs) and peptide fractions preparedusing five proteases and ultrafiltration membranes (1, 3, 5, & 10 kDa) were investigated. CPHs hadsimilar and adequate quantities of essential amino acids. The effective concentration that scavenged50% (EC50) of the ABTS*+ was greatest for the <1 kDa pancreatin fraction at 10.1 μg/ml. CPHs andpeptide fractions scavenged DPPH*+ with most of the EC50 values being <1.0 mg/ml. Scavenging ofsuperoxide radical ...

Cassava (Manihot esculenta Crantz) is a major world crop, whose storage roots provide food for over 800 million throughout the humid tropics. Despite many advantages as a crop, the development of cassava is seriously constrained by the rapid post-harvest physiological deterioration (PPD) of its roots that occurs within 24-72 h of harvest, rendering the roots unpalatable and unmarketable. PPD limits cassava&#39;s marketing possibilities in countries that are undergoing increased development and urbanisation due to growing distances between farms and consumers. The inevitable wounding of the roots caused by harvesting triggers an oxidative burst that spreads throughout the cassava root, together with the accumulation of secondary metabolites including phenolic compounds, of which the coumarin scopoletin (7-hydroxy-6-methoxy-2H-1-benzopyran-2-one) is the most abundant. Scopoletin oxidation yields a blue-black colour, which suggests its involvement in the discoloration observed during P...

The present study in a two-year experiment investigated the influence of drought and sowing time on protein composition, antinutrients, and mineral contents of wheat whole meal of two genotypes differing in their water requirements. Different thermal conditions prevailing during the grain filling period under different sowing time generated a large effect on the amount of total soluble proteins. Late sown conditions offered higher protein content accompanied by increased albumin-globulin but decreased glutenin content. Fe content was increased to 20-23%; however, tannin decreased to 18-35% under early sown rain-fed conditions as compared to irrigated timely sown conditions in both the genotypes. Activity of trypsin inhibitor was decreased under rain-fed conditions in both genotypes. This study inferred that variable sowing times and irrigation practices can be used for inducing variation in different wheat whole meal quality characteristics. Lower temperature prevailing under early ...

In most eukaryotes, centromere is determined by the presence of the centromere-specific histone variant CenH3. Two types of chromosome morphology are generally recognized with respect to centromere organization. Monocentric chromosomes possess a single CenH3-containing domain in primary constriction, whereas holocentric chromosomes lack the primary constriction and display dispersed distribution of CenH3. Recently, metapolycentric chromosomes have been reported in Pisum sativum, representing an intermediate type of centromere organization characterized by multiple CenH3-containing domains distributed across large parts of chromosomes that still form a single constriction. In this work, we show that this type of centromere is also found in other Pisum and closely related Lathyrus species, whereas Vicia and Lens genera, which belong to the same legume tribe Fabeae, possess only monocentric chromosomes. We observed extensive variability in the size of primary constriction and the arran...

menaquinone. Deletion mutants have reduced oxygen consumption rates and electron transport efficiency, although membrane integrity, cellular ATP levels and rates of ATP synthesis are unaltered as are bacterial growth rates. However, in vitro infection studies using J774A.1 cells and the M. tuberculosis Rv0561c deletion mutant demonstrated that the mutant is unable to survive in macrophage-like cells. Thus, Rv0561c represents a novel, contextually essential enzyme that is a potential drug target in M. tuberculosis. Funded by NIH/NIAID grant # AI049151.

To understand the biochemical events that control the generation of superoxide, the effect of inhibiting the respiratory complexes III and IV (C‐III and C‐IV) and alternative oxidase (AOX) on the rate of superoxide production was analyzed in mitochondria from maize seedlings. To increase superoxide production, it was required to inhibit C‐III or C‐IV by at least 30% or 50%, respectively. Below this inhibition threshold, AOX exerted the highest degree of control on superoxide production, whereas above it, the highest degree of control was exerted by C‐IV. The contribution of C‐III to control superoxide production became significant when AOX activity was modulated.

Chemically labile ester linkages can be introduced into lignin by incorporation of monolignol conjugates, which are synthesized in planta by acyltransferases that use a coenzyme A (CoA) thioester donor and a nucleophilic monolignol alcohol acceptor. The presence of these esters facilitates processing and aids in the valorization of renewable biomass feedstocks. However, the effectiveness of this strategy is potentially limited by the low steady-state levels of aromatic acid thioester donors in plants. As part of an effort to overcome this, aromatic acid CoA ligases involved in microbial aromatic degradation were identified and screened against a broad panel of substituted cinnamic and benzoic acids involved in plant lignification. Functional fingerprinting of this ligase library identified four robust, highly active enzymes capable of facile, rapid, and high-yield synthesis of aromatic acid CoA thioesters under mild aqueous reaction conditions mimicking in planta activity.

Galactinol synthase (GolS) catalyzes the first and rate limiting step of Raffinose Family Oligosaccharide (RFO) biosynthetic pathway, which is a highly specialized metabolic event in plants. Increased accumulation of galactinol and RFOs in seeds have been reported in few plant species, however their precise role in seed vigor and longevity remain elusive. In present study, we have shown that galactinol synthase activity as well as galactinol and raffinose content progressively increase as seed development proceeds and become highly abundant in pod and mature dry seeds, which gradually decline as seed germination progresses in chickpea (Cicer arietinum). Furthermore, artificial aging also stimulates galactinol synthase activity and consequent galactinol and raffinose accumulation in seed. Molecular analysis revealed that GolS in chickpea are encoded by two divergent genes (CaGolS1 and CaGolS2) which potentially encode five CaGolS isoforms through alternative splicing. Biochemical ana...

PROTEIN l-ISOASPARTYL O-METHYLTRANSFERASE (PIMT) is a protein-repairing enzyme involved in seed vigor and longevity. However, the regulation of PIMT isoforms during seed development and the mechanism of PIMT-mediated improvement of seed vigor and longevity are largely unknown. In this study in rice (Oryza sativa), we demonstrate the dynamics and correlation of isoaspartyl (isoAsp)-repairing demands and PIMT activity, and their implications, during seed development, germination and aging, through biochemical, molecular and genetic studies. Molecular and biochemical analyses revealed that rice possesses various biochemically active and inactive PIMT isoforms. Transcript and western blot analyses clearly showed the seed development stage and tissue-specific accumulation of active isoforms. Immunolocalization studies revealed distinct isoform expression in embryo and aleurone layers. Further analyses of transgenic lines for each OsPIMT isoform revealed a clear role in the restriction of...

We propose a network structure-based model for heterosis, and investigate it relying on metabolite profiles from Arabidopsis. A simple feed-forward two-layer network model (the Steinbuch matrix) is used in our conceptual approach. It allows for directly relating structural network properties with biological function. Interpreting heterosis as increased adaptability, our model predicts that the biological networks involved show increasing connectivity of regulatory interactions. A detailed analysis of metabolite profile data reveals that the increasing-connectivity prediction is true for graphical Gaussian models in our data from early development. This mirrors properties of observed heterotic Arabidopsis phenotypes. Furthermore, the model predicts a limit for increasing hybrid vigor with increasing heterozygosity—a known phenomenon in the literature. Copyright © 2009 Sandra Andorf et al. This is an open access article distributed under the Creative Commons Attribution License, which...

and in particular Mr. R. Berry, are thanked for allowing me the use of their High Performance Liquid Chromatogram. Thanks are also extended to the members of the technical staff of the University of Natal for their assistance in a variety of ways. I should like to express my gratitude to my parents for their guidance and support throughout my years of study. My sincere thanks also go to my wife Julia for her companionship and enthusiastic support throughout the course of this undertaking.