ABSTRACT: Influence of grapevine rootstock and scion genotypes on the structure and composition of arbuscular mycorrhizal fungi associated with the root system.
Project description:Arbuscular mycorrhizal symbiosis improves water and nutrient uptake by plants and provides them other ecosystem services. Grapevine is one of the major crops in the world. V. vinifera scions are generally grafted onto a variety of rootstocks that confer different levels of resistance against different pests, tolerance to environmental stress, and influence the physiology of the scions. Arbuscular mycorrhizal fungi are involved in the root architecture and in the immune response to soil-borne pathogens. However, the fine-tuned regulation and the transcriptomic plasticity of rootstocks in response to mycorrhization are still unknown. We compared the responses of 10 different grapevine rootstocks to arbuscular mycorrhizal symbiosis (AMS) formed with Rhizophagus irregularis DAOM197198 using RNA sequencing-based transcriptome profiling. We have highlighted a few shared regulation mechanisms, but also specific rootstock responses to R. irregularis colonization. A set of 353 genes was regulated by AMS in all ten rootstocks. We also compared the expression level of this set of genes to more than 2,000 transcriptome profiles from various grapevine varieties and tissues to identify a class of transcripts related to mycorrhizal associations in these 10 rootstocks. Then, we compared the response of the 351 genes upregulated by mycorrhiza in grapevine to their Medicago truncatula homologs in response to mycorrhizal colonization based on available transcriptomic studies. More than 97% of these homologs were expressed in at least one transcriptome profile, and 64% in all profiles. At the intra-specific level, we described for the first time shared and specific grapevine rootstock genes in response to R. irregularis symbiosis. At the inter-specific level, we defined a shared subset of mycorrhiza-responsive genes
Project description:Grafting is a well-established practice for grapevine to facilitate propagation of productive and tolerant cultivars against several stress factors. It is also considered to be a suitable method for studying molecular aspects of root-to-shoot and/or shoot-to-root signaling events. So far, controlling only effect of rootstock over scion was investigated and root-to-shoot transcriptomic alterations were fallowed on the scions or graft interfaces. The objective of this study was to investigate transcriptomic and physiological influence of scion on the rootstock under drought stress. Therefore, drought tolerant 110R rootstock were firstly grafted with sultana seedless and tested under drought stress with its non-grafted counterpart. The results of treatment indicated that grafted 110R performed the highest root elongation under drought. We carried out a microarray based transcriptome analysis on the roots of grafted and non-grafted 110R to explain this drought derived interaction through scion-to-rootstock. The highest expression increase under drought was recorded for sugar (SWEET) and nitrate or di/tri-peptide (NRT1/ PTR FAMILY) transporter proteins. Expression level of these genes was more highly increased in grafted 110R than its non-grafted counterpart. This situation indicated their potential role in drought tolerance and scion/rootstock harmony. Overexpression of these transporters attributed to increased amount of released nutrient and nitrogen source from abscised leaves of sultana seedless under drought. Remobilization of these rich sources was suggested to chance transcriptomic response of rootstocks and enabled much better growth in grafted 110R. Other transcripts annotated to cell wall modification enzymes (chitinases), osmoregulator proteins (dehydrins, proline-glycine rich proteins) and secondary metabolites (stilbene synthase) were also more highly induced in grafted 110R. This is the first report indicating transcriptomic influence of scion on the grapevine rootstocks and representing the genes responsible in scion/rootstock harmony and drought tolerance.
Project description:Arbuscular mycorrhiza (AM) interactions between plants and Glomeromycota fungi primarily support phosphate aquisition of most terrestrial plant species. To unravel gene expression in Medicago truncatula root colonization by AM fungi, we used genome-wide transcriptome profiling based on whole mycorrhizal roots. We used GeneChips to detail the global programme of gene expression in response to colonization by arbuscular mycorrhizal fungi and in response to a treatment with phosphate and identified genes differentially expressed during this process. Medicago truncatula roots were harvested at 28 days post inoculation with the two different arbuscular mycorrhizal fungi Glomus intraradices (Gi-Myc) and Glomus mosseae (Gm-Myc) under low phosphate conditions (20 µM phosphate) or after a 28 days treatment with 2 mM phosphate in the absence of arbuscular mycorrhizal fungi (2mM-P). As a control, uninfected roots grown under low phosphate conditions (20 µM phosphate) were used (20miM-P). Three biological replicates consisting of pools of five roots were used for RNA extraction and hybridization on Affymetrix GeneChips.
Project description:To determine the roles of the scion and the rootstock in regulating grapevine responses to low Pi supply, the short-term (27 h) root transcriptomic responses were quantified using RNA-Seq.
Project description:Grapevine is a perennial crop often cultivated by grafting a scion cultivar on a suitable rootstock. Rootstocks influence scions, particularly with regard to water uptake and vigor. Therefore, one of the possibilities to adapt viticulture to the extended drought stress periods is to select rootstocks conferring increased tolerance to drought. However, the molecular mechanisms associated with the ability of rootstock/scion combination to influence grape berry metabolism under drought stress are still poorly understood. The transcriptomic changes induced by drought stress in grape berries (cv. Pinot noir) from vines grafted on either 110R (drought tolerant) or 125AA (drought sensitive) rootstock were compared. The experiments were conducted in the vineyard for two years and two grape berry developmental stages (50% and 100 % veraison. The genome-wide microarray approach showed that water stress strongly impacts gene expression in the berries, through ontology categories that cover cell wall metabolism, primary and secondary metabolism, signalling, stress, and hormones, and that some of these effects strongly depend on the rootstock genotype. Indeed, under drought stress, berries from vines grafted on 110R displayed a different transcriptional response compared to 125AA concerning genes related to jasmonate, phenylpropanoid metabolism and PR-proteins. The data also suggests a link between jasmonate and secondary metabolism in water-stressed berries. Overall, genes related to secondary metabolism and jasmonate are more induced and/or less repressed by drought stress in the berries grafted on the drought-sensitive rootstock 125AA. These rootstock-dependent gene expression changes are relevant for berry composition and sensory properties.
Project description:Arbuscular mycorrhiza (AM) interactions between plants and Glomeromycota fungi primarily support phosphate aquisition of most terrestrial plant species. To unravel gene expression in Medicago truncatula root colonization by AM fungi, we used genome-wide transcriptome profiling based on whole mycorrhizal roots. We used GeneChips to detail the global programme of gene expression in response to colonization by arbuscular mycorrhizal fungi and in response to a treatment with phosphate and identified genes differentially expressed during this process.
Project description:Arbuscular mycorrhizal symbiosis is a predominant relationship between plant and arbuscular mycorrhizal fungi. To idendify arbuscular mycorrhiza responsive miRNAs, small RNA libraries were constructed in tomato roots colonized with Rhizophagus irregularis and without Rhizophagus irregularis. We identify miRNAs in tomato roots and provide a new profile of tomato miRNAs. And we found that some miRNAs were responsive to arbuscular mycorrhiza by comparing miRNAs in treatment with that in control.
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. Medicago truncatula GFP-HDEL hairy roots (genotypes A17 and DMI3) were grown in vertically-oriented petri dishes, incubated at 26M-BM-0C and inoculated with 8 Gigaspora margarita spores, which were positioned between the lateral roots. G.margarita spores germinated in 2 to 4 days. Hyphopodia were observed after 5-6 days. Root fragments which reacted to the fungal contact were collected and frozen. Non-inoculated control root fragments were harvested at a comparable age.
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.