Papers by Sagadevan Mundree
Biofuels from food processing wastes
Current Opinion in Biotechnology, 2016
Food processing industry generates substantial high organic wastes along with high energy uses. T... more Food processing industry generates substantial high organic wastes along with high energy uses. The recovery of food processing wastes as renewable energy sources represents a sustainable option for the substitution of fossil energy, contributing to the transition of food sector towards a low-carbon economy. This article reviews the latest research progress on biofuel production using food processing wastes. While extensive work on laboratory and pilot-scale biosystems for energy production has been reported, this work presents a review of advances in metabolic pathways, key technical issues and bioengineering outcomes in biofuel production from food processing wastes. Research challenges and further prospects associated with the knowledge advances and technology development of biofuel production are discussed.
Fuels and Chemicals from Lignocellulosic Biomass
Solar Power as an Energy Source, 2013
Novel Determinants of Salinity Tolerance
Plant Tolerance to Abiotic Stresses in Agriculture: Role of Genetic Engineering, 2000
ABSTRACT
Oecologia, 1993
The effects of waterlogging and salinity on morphological and physiological responses in the mars... more The effects of waterlogging and salinity on morphological and physiological responses in the marsh grass Sporobolus virginicus (L.) Kunth were investigated in a 4 • 2 factorial experiment. Plants were subjected to four salinity levels (0, 100, 200 and 400 mol m -3 NaC1) and two soil inundation conditions (drained and flooded) for 42 days. Flooding at 0 tool m -3 NaC1 caused initiation of adventitious surface roots, increased internal aeration and plant height, induced alcohol dehydrogenase activity (ADH), and decreased belowground biomass and the number ofculms per plant. Salinity increase from 0 to 400 tool m-3 NaC1 under drained conditions increased leaf and root proline concentrations and decreased photosynthesis, aboveground biomass, number of culms per plant and number of internodes per culm. Concurrent waterlogging and salinity induced ADH activity and adventitious surface roots but decreased plant height and aboveground biomass. Internal air space increased with waterlogging from 0 to 100 tool m -3 NaC1 but further increases in salinity to 400 tool m-3 reduced air space. Combined waterlogging and salinity stresses, however, had no effect on photosynthesis or on the concentrations of proline in leaves or roots. These results are discussed in relation to the widespread colonization by S. virginicus of a wide range of coastal environments varying in soil salinity and in the frequency and intensity of waterlogging.
Planta, Oct 1, 2002
A cDNA corresponding to 1-Cys peroxiredoxin, an evolutionarily conserved thiol-specific antioxida... more A cDNA corresponding to 1-Cys peroxiredoxin, an evolutionarily conserved thiol-specific antioxidant enzyme, was isolated from Xerophyta viscosa Baker, a resurrection plant indigenous to Southern Africa and belonging to the family Velloziaceae. The cDNA, designated XvPer1, contains an open reading frame that encodes a polypeptide of 219 residues with a predicted molecular weight of 24.2 kDa. The XvPer1 polypeptide shows significant sequence identity (approx. 70%) to other recently identified plant 1-Cys peroxiredoxins and relatively high levels of sequence similarity (approx. 40%) to non-plant 1-Cys peroxiredoxins. The XvPer1 cDNA contains a putative polyadenylation site. As for all 1-Cys peroxiredoxins identified to date, the amino acid sequence proposed to constitute the active site of the enzyme, PVCTTE, is highly conserved in XvPer1. It also contains a putative bipartite nuclear localization signal. Southern blot analysis revealed that there is a single copy of XvPer1 in the X. viscosa genome. All angiosperm 1-Cys peroxiredoxins described to date are seed-specific and absent in vegetative tissues even under stress conditions; therefore, XvPer1 is unique in that it is expressed in the vegetative tissues of X. viscosa. The XvPer1 transcript was absent in fully hydrated X. viscosa tissue but levels increased in tissues subjected to abiotic stresses such as dehydration, heat (42°C), high light intensity (1,500 lmol photons m -2 s -1 ) and when treated with abscisic acid (100 lM ABA) and sodium chloride (100 mM NaCl). Western blot analyses correlated with the patterns of expression of XvPer1 transcripts under different stress conditions. Immunofluorescence analyses revealed that XvPer1 is localized in the nucleus of dehydrated X. viscosa leaf cells. These results suggest that XvPer1 is a stress-inducible gene, which may function to protect nucleic acids within the nucleus against oxidative injury.
Zeitschrift Fur Naturforschung C, 2005
In this study, photochemical and antioxidant responses of the monocotyledonous resurrection plant... more In this study, photochemical and antioxidant responses of the monocotyledonous resurrection plant Xerophyta viscosa Baker and the crab grass Digitaria sanguinalis L. under water deficit were investigated as a function of time. Water deficit was imposed by withholding irrigation for 21 d. Gas exchange and chlorophyll a fluorescence analyses indicated that the dehydration treatment caused photoinhibition in both species. The reduction in the photosynthesis rate in both species during water deficit probably contributed to the decline in the photochemical efficiency of PSII and electron transport rate. However, the stomatal conductance of both species did not change during treatment whereas the intercellular CO 2 pressure increased after 10 d of water deficit treatment. These observations could be related to nonstomatal limitations. The increasing net transpiration rate of both species may have contributed to leaf cooling because of water limitations. Prolonged water deficit resulted in photosynthetic pigment chlorophyll (a + b) and carotenoids content loss in only D. sanguinalis. Both species especially D. sanguinalis had increased the level of anthocyanin after 15 d of treatment, possibly to prevent the damaging effect of photooxidation. The total SOD activity of D. sanguinalis was significantly different from X. viscosa during the treatment. The total peroxidase activity in D. sanguinalis was significantly higher than in X. viscosa. X. viscosa acclimated to water deficit with no ultimate apparent oxidative damage due to endogenous protective mechanisms of resurrection. In case of D. sanguinalis, water deficit induced considerable stress and possibly caused some oxidative damage, despite the upregulation of protection mechanisms.
Molecular and biochemical characterisation of a novel type II peroxiredoxin (XvPrx2) from the resurrection plant Xerophyta viscosa
Functional Plant Biology, 2016
Trehalose Accumulation Triggers Autophagy during Plant Desiccation
PLOS Genetics, 2015
Global climate change, increasingly erratic weather and a burgeoning global population are signif... more Global climate change, increasingly erratic weather and a burgeoning global population are significant threats to the sustainability of future crop production. There is an urgent need for the development of robust measures that enable crops to withstand the uncertainty of climate change whilst still producing maximum yields. Resurrection plants possess the unique ability to withstand desiccation for prolonged periods, can be restored upon watering and represent great potential for the development of stress tolerant crops. Here, we describe the remarkable stress characteristics of Tripogon loliiformis, an uncharacterised resurrection grass and close relative of the economically important cereals, rice, sorghum, and maize. We show that T. loliiformis survives extreme environmental stress by implementing autophagy to prevent Programmed Cell Death. Notably, we identified a novel role for trehalose in the regulation of autophagy in T.loliiformis. Transcriptome, Gas Chromatography Mass Spectrometry, immunoblotting and confocal microscopy analyses directly linked the accumulation of trehalose with the onset of autophagy in dehydrating and desiccated T. loliiformis shoots. These results were supported in vitro with the observation of autophagosomes in trehalose treated T. loliiformis leaves; autophagosomes were not detected in untreated samples. Presumably, once induced, autophagy promotes desiccation tolerance in T.loliiformis, by removal of cellular toxins to suppress programmed cell death and the recycling of nutrients to delay the onset of senescence. These findings illustrate how resurrection plants manipulate sugar metabolism to promote desiccation tolerance and may provide candidate genes that are potentially useful for the development of stress tolerant crops.
An aldose reductase homolog from the resurrection plant Xerophyta viscosa Baker
Planta, 2000
An aldose reductase homologue (ALDRXV4) was cloned from the resurrection plant Xerophyta viscosa ... more An aldose reductase homologue (ALDRXV4) was cloned from the resurrection plant Xerophyta viscosa Baker using complementation by functional sufficiency in Escherichia coli. A cDNA library constructed from X. viscosa leaves dehydrated to 85%, 37% and 5% relative water contents (RWC) was converted into an infective phagemid library. Escherichia coli (sr1::Tn10) cells transformed with ds-pBluescript phagemids were selected on minimal medium plates supplemented with 1 mM isopropyl beta-D-thiogalactopyranoside and 1.25 M sorbitol. Nine cDNA clones that conferred tolerance to the osmotically stressed E. coli cells were selected. The phagemid from one clone contained the ALDRXV4 insert. The E. coli cells expressing ALDRXV4 were capable of tolerating the osmotic stress, whereas control cultures were not. The ALDRXV4 insert contained an open reading frame that can code for 319 amino acids, and the predicted protein had a calculated Mr of 35,667. Amino acid sequence comparisons revealed significant similarity to several aldose reductases, with the highest similarity to aldose reductase proteins from Hordeum vulgare, Bromus inermis and Avena fatua, in the order of 66%, 65% and 65% respectively. Northern blot analysis revealed that ALDRXV4 was expressed only under dehydration conditions in X. viscosa leaves. Western blot analysis detected a protein of 36 kDa under dehydration conditions only. Aldose reductase activity levels in X. viscosa leaves increased as the leaf RWC decreased, whereas there was no significant change in aldose reductase activity in Sporobolus stafianus as the leaf RWC decreased.
Journal of Plant Biochemistry and Biotechnology, 2005
L-myo-inositol 1-phosphate synthase (EC 5.5.1.4 ; MIPS ) , an evolutionarily conserved enzyme-pro... more L-myo-inositol 1-phosphate synthase (EC 5.5.1.4 ; MIPS ) , an evolutionarily conserved enzyme-protein, catalyses the first and rate limiting step of inositol biosynthesis. Inositol and its derivatives play important roles in biological kingdom like growth regulation, membrane biogenesis, signal transduction and also acts as an osmolyte or osmoprotectant in abiotic stress tolerance. Here we report the cloning, sequencing and the characterization of the INO1 gene from Xerophyta viscosa (XINO1), a monocotyledonous resurrection plant. Nucleotide sequences of XINO1 show striking homology (70-99%) with a number of INO1 genes from plant sources particularly with the monocots. The gene is functionally identified through genetic complementation using a yeast inositol auxotrophic strain FY250. The gene is expressed in E. coli BL21, recombinant protein purified to homogeneity, biochemically characterized and compared with Oryza INO1 (RINO1) gene product. The XINO1 gene product is catalytically active in a broader range of lower temperature (between 10-40 0 C) than the RINO1 gene-product. This is the first report of MIPS gene from any resurrection plant.
Isolation and characterisation of a novel dehydration-induced Grp94 homologue from the resurrection plant Xerophyta viscosa
South African Journal of Botany, 2004
ABSTRACT This study demonstrates that the putative ER-located Hsp90, XVGrp94, is upregulated unde... more ABSTRACT This study demonstrates that the putative ER-located Hsp90, XVGrp94, is upregulated under conditions of stress, and is the first report of such upregulation in response to desiccation stress. XVGrp94 was identified by differential screening of a cDNA library from a dehydrated resurrection plant Xerophyta viscosa Baker. Sequence analysis revealed that the cDNA potentially encoded a protein of 812 amino acids with a calculated molecular weight of 92.83kDa. Amino acid sequence comparisons revealed significant homology to several Grp94s from plants with the highest similarity to Grp94 from Oryza sativa (82.74%), Catharanthus roseus (81.97%), Hordeum vulgare (80.10%) and Arabidopsis thaliana (77.45%). The sequence contains the Hsp90 protein family signature, NKDIFL, a putative eukaryotic secretory signal, and the endoplasmic reticulum targeting and retention signal, KDEL. Residues that interact with ATP within the N-terminal domain of Hsp90s are conserved in the N-domain of the putative XVGrp94, indicating that it is potentially capable of ATP binding and hydrolysis. Southern blot analysis confirmed the presence of the XVGrp94 gene within the X. viscosa genome and the results suggest the possibility of homologues. Western blot analysis showed that the XVGrp94 expression increased significantly in response to heat and dehydration, and slightly in response to high salinity. No response was seen in response to high light, cold treatment or exogenous ABA (abscisic acid) application.
The 90-kDa family of heat shock proteins are major molecular chaperones found in bacteria, mammal... more The 90-kDa family of heat shock proteins are major molecular chaperones found in bacteria, mammals, yeast and plants with high degree of conservation. The cytosolic Hsp90 and the endoplasmic reticulum-located Grp94 (94-kDa glucose regulated protein) are the best-characterised representatives. Hsp90 appears to have an important role in the folding and activation of proteins involved in signal transduction and control of the cell cycle, whereas Grp94 has been implicated in the correct folding and assembly of proteins passing through the ER. Until recently the mechanism of action of this important group of proteins was one of the least well understood of the molecular chaperones, but significant progress has been made in understanding its biochemistry. Dissection of the functional domains of the protein has revealed the mechanism of action as well as the importance of conformational transitions for its activity. This review seeks to provide an overview of current knowledge of the struc...
A molecular physiological review of vegetative desiccation tolerance in the resurrection plant Xerophyta viscosa (Baker)
Planta, 2015
Provides a first comprehensive review of integrated physiological and molecular aspects of desicc... more Provides a first comprehensive review of integrated physiological and molecular aspects of desiccation tolerance Xerophyta viscosa . A synopsis of biotechnological studies being undertaken to improve drought tolerance in maize is given. Xerophyta viscosa (Baker) is a monocotyledonous resurrection plant from the family Vellociacea that occurs in summer-rainfall areas of South Africa, Lesotho and Swaziland. It inhabits rocky terrain in exposed grasslands and frequently experiences periods of water deficit. Being a resurrection plant it tolerates the loss of 95 % of total cellular water, regaining full metabolic competency within 3 days of rehydration. In this paper, we review some of the molecular and physiological adaptations that occur during various stages of dehydration of X. viscosa, these being functionally grouped into early and late responses, which might be relevant to the attainment of desiccation tolerance. During early drying (to 55 % RWC) photosynthesis is shut down, there is increased presence and activity of housekeeping antioxidants and a redirection of metabolism to the increased formation of sucrose and raffinose family oligosaccharides. Other metabolic shifts suggest water replacement in vacuoles proposed to facilitate mechanical stabilization. Some regulatory processes observed include increased presence of a linker histone H1 variant, a Type 2C protein phosphatase, a calmodulin- and an ERD15-like protein. During the late stages of drying (to 10 % RWC) there was increased expression of several proteins involved in signal transduction, and retroelements speculated to be instrumental in gene silencing. There was induction of antioxidants not typically found in desiccation-sensitive systems, classical stress-associated proteins (HSP and LEAs), proteins involved in structural stabilization and those associated with changes in various metabolite pools during drying. Metabolites accumulated in this stage are proposed, inter alia, to facilitate subcellular stabilization by vitrification process which can include glass- and ionic liquid formation.
Frontiers in Plant Science, 2015
Environmental factors contribute to over 70% of crop yield losses worldwide. Of these drought and... more Environmental factors contribute to over 70% of crop yield losses worldwide. Of these drought and salinity are the most significant causes of crop yield reduction. Rice is an important staple crop that feeds more than half of the world's population. However among the agronomically important cereals rice is the most sensitive to salinity. In the present study we show that exogenous expression of anti-apoptotic genes from diverse origins, AtBAG4 (Arabidopsis), Hsp70 (Citrus tristeza virus) and p35 (Baculovirus), significantly improves salinity tolerance in rice at the whole plant level. Physiological, biochemical and agronomical analyses of transgenic rice expressing each of the anti-apoptotic genes subjected to salinity treatment demonstrated traits associated with tolerant varieties including, improved photosynthesis, membrane integrity, ion and ROS maintenance systems, growth rate, and yield components. Moreover, FTIR analysis showed that the chemical composition of salinity-treated transgenic plants is reminiscent of non-treated, unstressed controls. In contrast, wild type and vector control plants displayed hallmark features of stress, including pectin degradation upon subjection to salinity treatment. Interestingly, despite their diverse origins, transgenic plants expressing the anti-apoptotic genes assessed in this study displayed similar physiological and biochemical characteristics during salinity treatment thus providing further evidence that cell death pathways are conserved across broad evolutionary kingdoms. Our results reveal that anti-apoptotic genes facilitate maintenance of metabolic activity at the whole plant level to create favorable conditions for cellular survival. It is these conditions that are crucial and conducive to the plants ability to tolerate/adapt to extreme environments.
Current and Future Applications of Genetically Modified Crops, 2006
The Use of African Indigenous Genes in the Development of Transgenic Maize Tolerant to Drought and Resistant to Maize Streak Virus
Science Policy Reports, 2014
Zeitschrift für Naturforschung C, 2005
In this study, photochemical and antioxidant responses of the monocotyledonous resurrection plant... more In this study, photochemical and antioxidant responses of the monocotyledonous resurrection plant Xerophyta viscosa Baker and the crab grass Digitaria sanguinalis L. under water deficit were investigated as a function of time. Water deficit was imposed by withholding irrigation for 21 d. Gas exchange and chlorophyll a fluorescence analyses indicated that the dehydration treatment caused photoinhibition in both species. The reduction in the photosynthesis rate in both species during water deficit probably contributed to the decline in the photochemical efficiency of PSII and electron transport rate. However, the stomatal conductance of both species did not change during treatment whereas the intercellular CO 2 pressure increased after 10 d of water deficit treatment. These observations could be related to nonstomatal limitations. The increasing net transpiration rate of both species may have contributed to leaf cooling because of water limitations. Prolonged water deficit resulted in photosynthetic pigment chlorophyll (a + b) and carotenoids content loss in only D. sanguinalis. Both species especially D. sanguinalis had increased the level of anthocyanin after 15 d of treatment, possibly to prevent the damaging effect of photooxidation. The total SOD activity of D. sanguinalis was significantly different from X. viscosa during the treatment. The total peroxidase activity in D. sanguinalis was significantly higher than in X. viscosa. X. viscosa acclimated to water deficit with no ultimate apparent oxidative damage due to endogenous protective mechanisms of resurrection. In case of D. sanguinalis, water deficit induced considerable stress and possibly caused some oxidative damage, despite the upregulation of protection mechanisms.
XvSap1, a Desiccation Tolerance Associated Gene with Potential for Crop Improvement
Plant Desiccation Tolerance, 2007
... Chapter 10. XvSap1, a Desiccation Tolerance Associated Gene with Potential for Crop Improveme... more ... Chapter 10. XvSap1, a Desiccation Tolerance Associated Gene with Potential for Crop Improvement. Matthew A. Jenks PhD 1 ,; Andrew J. Wood PhD 2. Revel Iyer,; Sagadevan Govindasamy Mundree,; Mohamed Suhail Rafudeen,; Jennifer Ann Thomson. ...
The development of genetically modified maize for abiotic stress tolerance
South African Journal of Botany, 2007
An aldose reductase homolog from the resurrection plant Xerophyta viscosa Baker
Planta, 2000
An aldose reductase homologue (ALDRXV4) was cloned from the resurrection plant Xerophyta viscosa ... more An aldose reductase homologue (ALDRXV4) was cloned from the resurrection plant Xerophyta viscosa Baker using complementation by functional sufficiency in Escherichia coli. A cDNA library constructed from X. viscosa leaves dehydrated to 85%, 37% and 5% relative water contents (RWC) was converted into an infective phagemid library. Escherichia coli (sr1::Tn10) cells transformed with ds-pBluescript phagemids were selected on minimal medium plates supplemented with 1 mM isopropyl beta-D-thiogalactopyranoside and 1.25 M sorbitol. Nine cDNA clones that conferred tolerance to the osmotically stressed E. coli cells were selected. The phagemid from one clone contained the ALDRXV4 insert. The E. coli cells expressing ALDRXV4 were capable of tolerating the osmotic stress, whereas control cultures were not. The ALDRXV4 insert contained an open reading frame that can code for 319 amino acids, and the predicted protein had a calculated Mr of 35,667. Amino acid sequence comparisons revealed significant similarity to several aldose reductases, with the highest similarity to aldose reductase proteins from Hordeum vulgare, Bromus inermis and Avena fatua, in the order of 66%, 65% and 65% respectively. Northern blot analysis revealed that ALDRXV4 was expressed only under dehydration conditions in X. viscosa leaves. Western blot analysis detected a protein of 36 kDa under dehydration conditions only. Aldose reductase activity levels in X. viscosa leaves increased as the leaf RWC decreased, whereas there was no significant change in aldose reductase activity in Sporobolus stafianus as the leaf RWC decreased.
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Papers by Sagadevan Mundree