Project description:Endophytic fungi are root-inhabiting fungi that can promote plant growth in a variety of ways. They can directly stimulate plant growth by producing phytohormones, such as auxin and gibberellins. They can also indirectly promote plant growth by helping plants to acquire nutrients, such as nitrogen and phosphorus, and by protecting plants from pests and pathogens.In this study, we used a proteomic approach to identify the proteins that are expressed in rice plants after they are treated with endophytic fungi. We found that the treatment with endophytic fungi resulted in the expression of a number of proteins involved in plant growth, nutrient acquisition, and defense. These results suggest that endophytic fungi can promote plant growth and improve plant resilience to stress.
Project description:Coevolutionary change requires reciprocal selection between interacting species, i.e., that the partner genotypes that are favored in one species depend on the genetic composition of the interacting species. Coevolutionary genetic variation is manifested as genotype ´ genotype (G ´ G) interactions for fitness from interspecific interactions. Although quantitative genetic approaches have revealed abundant evidence for G ´ G interactions in symbioses, the molecular basis of this variation remains unclear. Here we study the molecular basis of G ´ G interactions in a model legume-rhizobium mutualism using gene expression microarrays. We find that, like quantitative traits such as fitness, variation in the symbiotic transcriptome may be partitioned into additive and interactive genetic components. Our results suggest that plant genetic variation is the largest influence on nodule gene expression, and that plant genotype and the plant genotype ´ rhizobium genotype interaction determine global shifts in rhizobium gene expression that in turn feedback to influence plant fitness benefits. Moreover, the transcriptomic variation we uncover implicates regulatory changes in both species as drivers of symbiotic gene expression variation. Our study is the first to partition genetic variation in a symbiotic transcriptome, and illuminates potential molecular routes of coevolutionary change. We assayed gene expression using three biological replicates for each plant genotype × rhizobium genotype combination (4 combinations) for a total of 12 chips. We compared gene expression in each of four combinations of Medicago truncatula families and Sinorhizobium meliloti strains using Affymetrix Medicago GeneChips to study how the entire transcriptome and individual genes responded to differences between plant families, between rhizobium strains, and due to the plant family × rhizobium strain (G × G) interaction.
Project description:Coevolutionary change requires reciprocal selection between interacting species, i.e., that the partner genotypes that are favored in one species depend on the genetic composition of the interacting species. Coevolutionary genetic variation is manifested as genotype ´ genotype (G ´ G) interactions for fitness from interspecific interactions. Although quantitative genetic approaches have revealed abundant evidence for G ´ G interactions in symbioses, the molecular basis of this variation remains unclear. Here we study the molecular basis of G ´ G interactions in a model legume-rhizobium mutualism using gene expression microarrays. We find that, like quantitative traits such as fitness, variation in the symbiotic transcriptome may be partitioned into additive and interactive genetic components. Our results suggest that plant genetic variation is the largest influence on nodule gene expression, and that plant genotype and the plant genotype ´ rhizobium genotype interaction determine global shifts in rhizobium gene expression that in turn feedback to influence plant fitness benefits. Moreover, the transcriptomic variation we uncover implicates regulatory changes in both species as drivers of symbiotic gene expression variation. Our study is the first to partition genetic variation in a symbiotic transcriptome, and illuminates potential molecular routes of coevolutionary change. We assayed gene expression using three biological replicates for each plant genotype × rhizobium genotype combination (4 combinations) for a total of 12 chips.
Project description:Arbuscular mycorrhiza (AM) interactions between plants and Glomeromycota fungi primarily support phosphate aquisition of most terrestrial plant species. To unravel gene expression during early stages of Medicago truncatula root colonization by AM fungi, we used genome-wide transcriptome profiling based on mycorrhizal root fragments enriched for early fungal infection stages. We used Medicago GeneChips to detail the global programme of gene expression in response to early stages of colonization by arbuscular mycorrhizal fungi and identified genes differentially expressed during these early stages.
Project description:Cooperation involving Plant Growth-Promoting Rhizobacteria results in improvements of plant growth and health. While pathogenic and symbiotic interactions are known to induce transcriptional changes for genes related to plant defense and development, little is known about the impact of phytostimulating rhizobacteria on plant gene expression. In this context, this study aimed at identifying genes significantly regulated in rice roots upon Azospirillum inoculation, considering possible favored interaction between a strain and its original host cultivar. Genome-wide analyses of root gene expression of Oryza sativa japonica cultivars Cigalon and Nipponbare were performed, by using microarrays, seven days post inoculation with A. lipoferum 4B (isolated from Cigalon roots) or Azospirillum sp. B510 (isolated from Nipponbare) and compared to the respective non-inoculated condition.
Project description:The rapid global plant diversity and productivity loss has resulted in ecosystem functional degeneration in recent decades, and the relationship between plant diversity and productivity is a pressing issue around the world. Here, we sampled six plant communities that have not been grazed for 20 years, i.e., Agropyron mongolicum, Stipa bungeana, Cynanchum komarovii, Glycyrrhiza uralensis, Sophora alopecuroides, Artemisia ordosica, located in a desertified steppe, northwestern China, and tested the relationship between plant diversity and productivity in this region. We found a positive linear relationship between AGB (above-ground biomass) and BGB (below-ground biomass), and the curves between plant diversity and AGB were unimodal (R 2 = 0.4572, p < 0.05), indicating that plant productivity increased at a low level of diversity but decreased at a high level of diversity. However, there was no significant relationship between BGB and plant diversity (p > 0.05). Further, RDA (redundancy analysis) indicated that soil factors had a strong effect on plant diversity and productivity. Totally, GAMs (generalized additive models) showed that soil factors (especially total nitrogen TN, total carbon TC, soil microbial biomass nitrogen SMB-N, soil microbial biomass carbon SMB-C) explained more variation in plant diversity and productivity (78.24%), which can be regarded as the key factors driving plant diversity and productivity. Therefore, strategies aiming to increase plant productivity and protect plant diversity may concentrate on promoting soil factors (e.g., increasing TC, TN, SMB-N and SMB-C) and plant species, which can be regarded as an effective and simple strategy to stabilize ecosystems to mitigate aridity in desertified steppes in northwestern China.
Project description:Velvet domain proteins coordinate developmental processes and secondary metabolism in fungi. In this study, we characterized the role of all four velvet proteins in the life cycle of the plant pathogenic fungus Verticillium dahliae. From other fungi, the formation of different homo-and heterodimers as well as complexes with non-velvet proteins is known. We could show that V. dahliae Vel1 is important for initial plant root colonization. In planta, Vel1 together with Vel3 is involved in fungal distribution by conidia. Disease symptom induction in tomato plants also depends on Vel1. In the senescent plant formation of microsclerotia as resting structure ex planta is controlled by Vel1, Vel2 and Vel3. In vitro protein pull-downs were conducted to identify interaction partners of velvet proteins in V. dahliae. In this study, we were able to identify interactions between Vel1 and Vel2, Vel2 and Vos1, and Vel3 and Vos1 during vegetative hyphae growth, respectively. Similar interactions are known for A. nidulans. Further interacting candidates were identified for the velvet proteins except for Vel3, for which only interaction with Vos1 was found during the tested conditions. Velvet-interacting candidate proteins included redox-regulating proteins and metabolic enzymes, but also proteins involved in energy metabolism and transport.
Project description:Tetranychus urticae is an important pest that causes severe damage on a wide variety of plants and crops, leading to a substantial loss of productivity. Previous research has focused on the study of Arabidopsis short-term response to T. urticae, but a comprehensive evaluation of the interaction through whole plant life cycle has not been previously studied. Here, through a physiological trait, transcriptomic and hormonomic evaluation we uncovered the molecular pathways directing the interaction of T. urticae during the complete plant life cycle. Upon mite infestation, plant suffers a process of adaptation to cope the stress and survive, led by the establishment of defence-growth trade-offs in the plant. Transcriptional and hormonal evaluation reveal how plant defence response upon mite perception determines the later growth responses and plant survival. In addition, a delay in plant development with a negative effect on plant fitness was observed, being fitness negatively affected with seed ageing. Taken together, our findings uncover the dynamics regulating plant-mite interactions and determining plant survival and reproductive success, providing new potential targets for improving plant response. Additionally, trade-offs suppose a cost on final plant fitness, demonstrating the underlying impact of the mite on the establishment of the offspring.
Project description:Endophytic fungi are fungi that live inside the roots of plants. They can promote plant growth through a variety of direct and indirect mechanisms. Direct mechanisms include the production of phytohormones, such as auxin and gibberellins, which can stimulate plant growth. Endophytic fungi can also fix nitrogen, solubilize phosphate, and produce siderophores, which are compounds that chelate iron and make it available to plants. In addition, some endophytic fungi produce antimicrobial metabolites that can protect plants from pests and pathogens. Indirect mechanisms include the induction of systemic resistance, which is a plant's ability to defend itself against pests and pathogens. Endophytic fungi can also help plants to tolerate abiotic stresses, such as drought, salinity, and heavy metals. In this study, we used a proteomic approach to identify the proteins that are expressed in rice plants after they are treated with endophytic fungi. We found that the treatment with endophytic fungi resulted in the expression of a number of proteins involved in plant growth, stress response, and defense. These results suggest that endophytic fungi can promote plant growth and improve plant resilience to stress.