Project description:Two potato cultivars, Russet Burbank and Bionta, were inoculated with three different endophytes containing different AHL types. The impact of the endophytes to the different cultivars was measured by gene expression analysis with a customized microarray
Project description:Root-microbe interaction and its specialized root nodule structures and functions are well studied. In contrast, leaf nodules harboring microbial endophytes in special glandular leaf structures have only recently gained increased interest as plant-microbe phyllosphere interactions. Here, we applied a comprehensive metabolomics platform in combination with natural product isolation and characterization to dissect leaf and leaf nodule metabolism and functions in <i>Ardisia crenata</i> (Primulaceae) and <i>Psychotria punctata</i> (Rubiaceae). The results indicate that abiotic stress resilience plays an important part within the leaf nodule symbiosis of both species. Both species showed metabolic signatures of enhanced nitrogen assimilation/dissimilation pattern and increased polyamine levels in nodules compared to leaf lamina tissue potentially involved in senescence processes and photosynthesis. Multiple links to cytokinin and REDOX-active pathways were found. Our results further demonstrate that secondary metabolite production by endophytes is a key feature of this symbiotic system. Multiple anhydromuropeptides (AhMP) and their derivatives were identified as highly characteristic biomarkers for nodulation within both species. A novel epicatechin derivative was structurally elucidated with NMR and shown to be enriched within the leaf nodules of <i>A. crenata</i>. This enrichment within nodulated tissues was also observed for catechin and other flavonoids indicating that flavonoid metabolism may play an important role for leaf nodule symbiosis of <i>A. crenata.</i> In contrast, pavettamine was only detected in <i>P. punctata</i> and showed no nodule specific enrichment but a developmental effect. Further natural products were detected, including three putative unknown depsipeptide structures in <i>A. crenata</i> leaf nodules. The analysis presents a first metabolomics reference data set for the intimate interaction of microbes and plants in leaf nodules, reveals novel metabolic processes of plant-microbe interaction as well as the potential of natural product discovery in these systems.
Project description:Broad-host root endophytes establish long-term interactions with a large variety of plants, thereby playing a significant role in natural and managed ecosystems and in evolution of land plants. To exploit plants as living substrates and to establish a compatible interaction with morphologically and biochemically extremely different hosts, endophytes must respond and adapt to different plant signals and host metabolic states. Here we identified host-adapted colonization strategies and host-specific effector candidates of the mutualistic root endophyte Piriformospora indica by a global investigation of fungal transcriptional responses to barley and Arabidopsis at different symbiotic stages. Additionally we examined the role played by nitrogen in these two diverse associations. Cytological studies and colonization analyses of a barley mutant and fungal RNAi strains show that distinct physiological and metabolic signals regulate host-specific lifestyle in P. indica. This is the foundation for exploring how distinct fungal and host symbiosis determinants modulate biotrophy in one host and saprotrophy in another host and, ultimately, gives hints into the mechanisms underlying host adaptation in root symbioses.
Project description:Broad-host root endophytes establish long-term interactions with a large variety of plants, thereby playing a significant role in natural and managed ecosystems and in evolution of land plants. To exploit plants as living substrates and to establish a compatible interaction with morphologically and biochemically extremely different hosts, endophytes must respond and adapt to different plant signals and host metabolic states. Here we identified host-adapted colonization strategies and host-specific effector candidates of the mutualistic root endophyte Piriformospora indica by a global investigation of fungal transcriptional responses to barley and Arabidopsis at different symbiotic stages. Additionally we examined the role played by nitrogen in these two diverse associations. Cytological studies and colonization analyses of a barley mutant and fungal RNAi strains show that distinct physiological and metabolic signals regulate host-specific lifestyle in P. indica. This is the foundation for exploring how distinct fungal and host symbiosis determinants modulate biotrophy in one host and saprotrophy in another host and, ultimately, gives hints into the mechanisms underlying host adaptation in root symbioses. Arabidopsis and barley roots were inoculated with Piriformospora indica and grown for 14 days. Additionally P. indica was grown on 1/10 PNM medium alone. Samples were taken 3 and 14 dpi (Arabidopsis), 14 dpi (barley) and 3dpi (1/10 PNM). Each experiment was performed in three independent biological repetitions. Piriformospora indica gene expression examined only.
Project description:A comparative study to determine the pepper leaf curl virus resistance machanism between resistant and susceptible genotypes at three leaf stage. To study the molecular mechanism of pepper leaf curl virus (PepLCV) resistance, pepper plants were exposed to PepLCV through artificial inoculation and hybridization on Agilent tomato microarrays. The expression analysis of PepLCV resistant and susceptible genotypes after artificial inoculation at three leaf stage showed that the resistance against PepLCV is due to sum of expression of hundreds of genes at a particular stage.
Project description:We used microarrays to discern patterns of gene expression in response to global climate change factors on leaf tissue of an annual dicot, Geranium dissectum, growing in a natural grassland. Keywords: multifactorial global change treatments
Project description:Background: Maize plants developed typical gray leaf spot disease (GLS) symptoms initiating at the lower leaves and progressing to upper leaves through the season. Leaf material was collected at 77 days after planting, at which stage there were a large number of GLS disease necrotic lesions on lower leaves (8% surface area on average determined by digital image analysis), but very few lesions and only at chlorotic stage on leaves above the ear (average of 0.2% lesion surface area). Method:To collect material that reflected a difference between C.zeina infected B73 leaves and control B73 leaf material, samples were collected from two lower GLS infected leaves (second and third leaf internode below ear) , and two upper leaves with minimal GLS symptoms (second and third internode above ear), respectively. The two lower leaves from each plant were pooled prior to RNA extraction, and the two upper leaves from each plant were pooled prior to RNA extraction. Upper and lower leaf samples from three maize B73 plants were subjected to RNA sequencing individually. The three maize plants were selected randomly as one plant per row from three rows of ten B73 plants each. Result: A systems genetics strategy revealed regions on the maize genome underlying co-expression of genes in susceptible and resistance responses, including a set of 100 genes common to the susceptible response of sub-tropical and temperate maize.
Project description:In Arabidopsis thaliana it is known that plants that harboured eggs of the White cabbage butterfly (Pieris brassicae) before larval feeding can defend better against the herbivore stress. As Arabidopsis thaliana is an annual plant we were interested in the plant defense and possible priming reaction of the closest biannual/perennial relative Arabidopsis lyrata. The main aim of the experiment was to compare the effect induced by insect egg deposition of Pieris brassicae between A. thaliana and A. lyrata plants grown in parallel on the transcriptional level. We used a full factorial setup consisting of a) untreated control plants , b) plants which experienced eggs for 6 days without larval feeding after that period, c) plants which experienced no eggs before larval feeding for 24 hours d) plants which experienced eggs for 6 days and larval herbivory for 24 hours. This setup was conducted with 7 week old vegetative plants For all treatments leaf tissue from the leaves that experienced egg oviposition and/or larval feeding were collected.
Project description:Two potato cultivars, Russet Burbank and Bionta, were inoculated with three different endophytes containing different AHL types. The impact of the endophytes to the different cultivars was measured by gene expression analysis with a customized microarray B. phytofirmans type strain PsJN was originally isolated as a contaminant from surface-sterilized, Glomus vesculiferum-infected onion roots (Nowak et al., 1998), whereas strain P6 RG6-12 was isolated from the rhizosphere of a grassland in the Netherlands (Salles et al., 2006). This strain was selected based on its similarity to strain PsJN based on 16S rRNA gene homology, and similar phenotypic features. Both strains were generally cultivated on King's medium (King et al., 1954). For the mutant AHL to the strain B. phytofirmans PsJN a quorum quenching approach as described by Wopperer et al., 2006 was employed. Plasmid pMLBAD-aiiA, which contains aiiA, the Bacillus sp. 240B1 lactonase gene, was transferred to B. phytofirmans PsJN by triparental mating as described by de Lorenzo and Timmis (1994). 2 cultivars, 3 endophytes