Fungal interactions-Mycorrhiza

Living organisms establish complex networks of mutualistic and antagonistic interactions in nature, which impact strongly on their own survival and on the stability of the whole population. Fungi, in particular, can shape natural as well as man-managed ecosystems due to their ubiquitous occurrence and the range of interactions they establish with plants, animals and other microbes. This review describes some examples of mutualistic and antagonistic fungal interactions that are of particular interest for their ecological role, or because they can be exploited by man to improve plant health and/or productivity in sustainable agriculture and forestry.

Living organisms establish complex networks of mutualistic and antagonistic interactions in nature, which impact strongly on their own survival and on the stability of the whole population. Fungi, in particular, can shape natural as well as man-managed ecosystems due to their ubiquitous occurrence and the range of interactions they establish with plants, animals and other microbes. This review describes some examples of mutualistic and antagonistic fungal interactions that are of particular interest for their ecological role, or because they can be exploited by man to improve plant health and/or productivity in sustainable agriculture and forestry.

Mitochondrial genomes (mt-genomes) are characterized by a distinct codon usage and their autonomous replication. Mt-genomes encode highly conserved genes (mt-genes), like proteins involved in electron transport and oxidative phosphorylation but they also carry highly variable regions that are in part responsible for their high plasticity. The degree of conservation of their genes is such that they allow the establishment of phylogenetic relationships even across distantly related species. Here, we describe the mechanisms that generate changes along mt-genomes, which play key roles at enlarging the ability of fungi to adapt to changing environments. Within mt-genomes of fungal pathogens, there are dispensable as well as indispensable genes for survival, virulence and/or pathogenicity. We also describe the different complexes or mechanisms targeted by fungicides, thus addressing a relevant issue regarding disease management. Despite the controversial origin and evolution of fungal mt-genomes, the intrinsic mechanisms and molecular biology involved in their evolution will help to understand, at the molecular level, the strategies for fungal disease management.

Trichoderma arundinaceum IBT 40837 (Ta37) and Botrytis cinerea produce the sesquiterpenes harzianum A (HA) and botrydial (BOT), respectively, and also the polyketides aspinolides and botcinins (Botcs), respectively. We analysed the role of BOT and Botcs in the Ta37-B. cinerea interaction, including the transcriptomic changes in the genes involved in HA (tri) and ergosterol biosynthesis, as well as changes in the level of HA and squaleneergosterol. We found that, when confronted with B. cinerea, the tri biosynthetic genes were up-regulated in all dual cultures analysed, but at higher levels when Ta37 was confronted with the BOT non-producer mutant bcbot2D. The production of HA was also higher in the interaction area with this mutant. In Ta37-bcbot2D confrontation experiments, the expression of the hmgR gene, encoding the 3-hydroxy-3-methylglutaryl coenzyme A reductase, which is the first enzyme of the terpene biosynthetic pathway, was also up-regulated, resulting in an increase in squalene production compared with the confrontation with B. cinerea B05.10. Botcs had an up-regulatory effect on the tri biosynthetic genes, with BotcA having a stronger effect than BotcB. The results indicate that the interaction between Ta37 and B. cinerea exerts a stimulatory effect on the expression of the tri biosynthetic genes, which, in the interaction zone, can be attenuated by BOT produced by B. cinerea B05.10. The present work provides evidence for a metabolic dialogue between T. arundinaceum and B. cinerea that is mediated by sesquiterpenes and polyketides, and that affects the outcome of the interaction of these fungi with each other and their environment.

Living organisms establish complex networks of mutualistic and antagonistic interactions in nature, which impact strongly on their own survival and on the stability of the whole population. Fungi, in particular, can shape natural as well as man-managed ecosystems due to their ubiquitous occurrence and the range of interactions they establish with plants, animals and other microbes. This review describes some examples of mutualistic and antagonistic fungal interactions that are of particular interest for their ecological role, or because they can be exploited by man to improve plant health and/or productivity in sustainable agriculture and forestry.

Trichoderma arundinaceum IBT 40837 (Ta37) and Botrytis cinerea produce the sesquiterpenes harzianum A (HA) and botrydial (BOT), respectively, and also the polyketides aspinolides and botcinins (Botcs), respectively. We analysed the role of BOT and Botcs in the Ta37-B. cinerea interaction, including the transcriptomic changes in the genes involved in HA (tri) and ergosterol biosynthesis, as well as changes in the level of HA and squaleneergosterol. We found that, when confronted with B. cinerea, the tri biosynthetic genes were up-regulated in all dual cultures analysed, but at higher levels when Ta37 was confronted with the BOT non-producer mutant bcbot2D. The production of HA was also higher in the interaction area with this mutant. In Ta37-bcbot2D confrontation experiments, the expression of the hmgR gene, encoding the 3-hydroxy-3-methylglutaryl coenzyme A reductase, which is the first enzyme of the terpene biosynthetic pathway, was also up-regulated, resulting in an increase in squalene production compared with the confrontation with B. cinerea B05.10. Botcs had an up-regulatory effect on the tri biosynthetic genes, with BotcA having a stronger effect than BotcB. The results indicate that the interaction between Ta37 and B. cinerea exerts a stimulatory effect on the expression of the tri biosynthetic genes, which, in the interaction zone, can be attenuated by BOT produced by B. cinerea B05.10. The present work provides evidence for a metabolic dialogue between T. arundinaceum and B. cinerea that is mediated by sesquiterpenes and polyketides, and that affects the outcome of the interaction of these fungi with each other and their environment.

A survey of two aromatic grasses Cymbopogon jwarancusa and Veteviria zizanioides was conducted to determine the morphological diversity of mycorrhiza collected from various habitats of southern Punjab and northern areas of Pakistan. The mycorrhizal colonization has been categorized as extraradical and internal colonization along with Arum-type and Paris-type mycorrhiza. The extraradical phase consists of various types of hyphae while internal phase is comprised hyphae and a variety of endogenous structures (i.e. vesicles, arbuscules, hyphal coils and cuttings of hyphae in the cortical regions of the fine roots). Hyphal coiling was frequently observed in C. jwarancusa, coiled hypha were mostly aseptate, and coenocytic, while hyphal coiling was uncommon in V. zizanioides. No arbuscule had been observed in C. jwarancusa but feeder roots in V. zizanioides had extensive arbuscular colonization. Higher morphological diversity was observed in the roots of C. jwarancusa as compared to V. zizanioides. Both Paris and Arum type of Mycorrhiza were observed in the studied grasses. Many extraradical and intraradical non-mycorrhizal dark septate endophytic fungi along with unique type of hyphae with hyaline wall were also observed. The dark septate endophytic fungi had melanized hyphae and microsclerotia. The dimeter of microsclerotia ranged from 1.9 to 3.8µm.

Living organisms establish complex networks of mutualistic and antagonistic interactions in nature, which impact strongly on their own survival and on the stability of the whole population. Fungi, in particular, can shape natural as well as man-managed ecosystems due to their ubiquitous occurrence and the range of interactions they establish with plants, animals and other microbes. This review describes some examples of mutualistic and antagonistic fungal interactions that are of particular interest for their ecological role, or because they can be exploited by man to improve plant health and/or productivity in sustainable agriculture and forestry.

Living organisms establish complex networks of mutualistic and antagonistic interactions in nature, which impact strongly on their own survival and on the stability of the whole population. Fungi, in particular, can shape natural as well as man-managed ecosystems due to their ubiquitous occurrence and the range of interactions they establish with plants, animals and other microbes. This review describes some examples of mutualistic and antagonistic fungal interactions that are of particular interest for their ecological role, or because they can be exploited by man to improve plant health and/or productivity in sustainable agriculture and forestry.

Living organisms establish complex networks of mutualistic and antagonistic interactions in nature, which impact strongly on their own survival and on the stability of the whole population. Fungi, in particular, can shape natural as well as man-managed ecosystems due to their ubiquitous occurrence and the range of interactions they establish with plants, animals and other microbes. This review describes some examples of mutualistic and antagonistic fungal interactions that are of particular interest for their ecological role, or because they can be exploited by man to improve plant health and/or productivity in sustainable agriculture and forestry.

Living organisms establish complex networks of mutualistic and antagonistic interactions in nature, which impact strongly on their own survival and on the stability of the whole population. Fungi, in particular, can shape natural as well as man-managed ecosystems due to their ubiquitous occurrence and the range of interactions they establish with plants, animals and other microbes. This review describes some examples of mutualistic and antagonistic fungal interactions that are of particular interest for their ecological role, or because they can be exploited by man to improve plant health and/or productivity in sustainable agriculture and forestry.

Living organisms establish complex networks of mutualistic and antagonistic interactions in nature, which impact strongly on their own survival and on the stability of the whole population. Fungi, in particular, can shape natural as well as man-managed ecosystems due to their ubiquitous occurrence and the range of interactions they establish with plants, animals and other microbes. This review describes some examples of mutualistic and antagonistic fungal interactions that are of particular interest for their ecological role, or because they can be exploited by man to improve plant health and/or productivity in sustainable agriculture and forestry.

Fungal pathogens are a significant threat to crops worldwide. The soil fungus, Magnaporthiopsis maydis, severely affects sensitive maize hybrids by causing the rapid wilting of plants at the maturity stage. Similarly, the soil fungus, Macrophomina phaseolina, develops in a variety of host plants, which leads to rot and plant mortality. The presence of both pathogens together in diseased cotton plants in Israel suggests possible interactions between them. Here, these relationships were tested in a series of experiments accompanied by real-time PCR tracking in maize and cotton. Despite the fact that neither of the pathogens was superior in a growth plate confrontation assay, their co-inoculum had a significant influence under field conditions. In maize sprouts and fully matured plants, infection by both pathogens (compared to inoculation with each of them alone) led to lesser amounts of M. maydis DNA but to increased amounts of M. phaseolina DNA levels. These results were obtained under a restricted water regime, while optimal water irrigation led to less pronounced differences. In water-stressed cotton sprouts, infection with both pathogens led to an increase in DNA amounts of each of the pathogens. Whereas the M. maydis DNA levels in the double infection remain high at the end of the season, a reduction in the amount of M. phaseolina DNA was observed. The double infection caused an increase in growth parameters in maize and cotton and decreased levels of dehydration in maize plants accompanied by an increase in yield production. Dehydration symptoms were minor in cotton under an optimal water supply. However, under a restricted water regime, the double infection abolished the harmful effect of M. phaseolina on the plants' development and yield. These findings are the first report of interactions between these two pathogens in maize and cotton, and they encourage expanding the study to additional plant hosts and examining the potential involvement of other pathogens.