Project description:Although Cochliobolus miyabeanus is an important fungal leaf pathogen on rice plants worldwide, it is largely neglected by molecular plant phytopathologists. To shed new light on the molecular and genetic basis of the rice – C. miyabeanus interaction, we compared the transcriptome of rice leaves 12h post inoculation to uninfected leaves. Even though usable sources of resistance against brown spot disease caused by C. miyabeanus are scarce, silicon application emerges as a sustainable protection strategy. Many articles report the beneficial effect of silicon on brown spot resistance. however the underlying mechanisms remain largely unclear. The influence of silicon application on the transcriptome of healthy and infected rice leaves 12hpi was compared as well in an attempt to disentangle the modulation of silicon-induced brown spot resistance.
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.
2016-10-15 | GSE81344 | GEO
Project description:Microbial community of phyllosphere bacteria from tobacco Corynespora leaf spot
Project description:Although Cochliobolus miyabeanus is an important fungal leaf pathogen on rice plants worldwide, it is largely neglected by molecular plant phytopathologists. To shed new light on the molecular and genetic basis of the rice M-bM-^@M-^S C. miyabeanus interaction, we compared the transcriptome of rice leaves 12h post inoculation to uninfected leaves. Even though usable sources of resistance against brown spot disease caused by C. miyabeanus are scarce, silicon application emerges as a sustainable protection strategy. Many articles report the beneficial effect of silicon on brown spot resistance. however the underlying mechanisms remain largely unclear. The influence of silicon application on the transcriptome of healthy and infected rice leaves 12hpi was compared as well in an attempt to disentangle the modulation of silicon-induced brown spot resistance. Comparison between C. miyabeanus- and mock-infected rice leaves 12h post inoculation. This study consist of a 2 x 2 factorial design (infected and non-infected; untreated and silicon-treated) in three biological replicates.
Project description:<p>Chemistry in eukaryotic intercellular spaces is shaped by both hosts and symbiotic microorganisms such as bacteria. Pathogenic microorganisms like barley associated Xanthomonas translucens (Xt) swiftly overtake the inner leaf tissue becoming the dominant microbial community member during disease development. The dynamic metabolic changes due to Xt pathogenesis in the mesophyll spaces remain unknown. Genomic group I of Xt consists of 2 barley-infecting lineages: pathovar <em>translucens</em> (Xtt) and pathovar <em>undulosa</em> (Xtu). Xtu and Xtt, although genomically distinct, cause similar water-soaked lesions. To define the metabolic signals associated with inner leaf colonization, we used untargeted metabolomics to characterize Xtu and Xtt metabolism signatures associated with mesophyll growth. We found that mesophyll apoplast fluid from infected tissue yielded a distinct metabolic profile and shift from catabolic to anabolic processes over time compared to water-infiltrated control. The pathways with the most differentially expressed metabolites by time were glycolysis, tricarboxylic acid cycle, sucrose metabolism, pentoses interconversion, amino acids, galactose, and purine metabolism. Hierarchical clustering and principal components analysis showed that metabolic changes were more affected by the time point rather than by the individual colonization of the inner leaves by Xtt compared to Xtu. Overall, in this study, we identified metabolic pathways that explain carbon and nitrogen usage during host-bacterial interactions over time for mesophyll tissue colonization. This foundational research provides initial insights into shared metabolic strategies of inner leaf colonization niche occupation by related but phylogenetically distinct phyllosphere bacteria.</p>
Project description:To verify the pathogenicity of Lecanicillium psalliotae invasive pathogens on tsearch leaves, Lecanicillium psalliotae was identified by isolation and purification. sweet orange leaves were infested with it. The results of the experiments showed that 15 days after Lecanicillium psalliotae infested the leaves of sweet orange, yellow spots grew around the pores and irregular yellow spots appeared on both sides of the leaf veins. This was highly similar to the disease in the field, suggesting that Lecanicillium psalliotae is the causal agent of the yellow spots on sweet orange leaves that cause the leaves to wilt and fall off. In previous studies, Verticillium cutaneum was mainly identified as a biological control agent and a suspected pathogen. In this study, the pathogenicity of Verticillium cutaneum was verified for the first time as a causal agent of leaf spot disease of plants.
Project description:Arthrobacter chlorophenolicus A6 is a 4-chlorophenol degrading soil bacterium with high phyllosphere colonization capacity. Till now the genetic basis for the phyllosphere competency of Arthrobacter or other pollutant-degrading bacteria is uncertain. We investigated global gene expression profile of A. chlorophenolicus grown in the phyllosphere of common bean (Phaseolus vulgaris) compared to growth on agar surfaces.
2013-06-21 | GSE48198 | GEO
Project description:Microbial community of phyllosphere fungi from tobacco Corynespora leaf spot
Project description:Plants are colonized by a variety of microorganisms, the plant microbiota. In the phyllosphere, the above-ground parts of plants, bacteria are the most abundant inhabitants. Most of these microorganisms are not pathogenic and the plant responses to commensals or to pathogen infection in the presence of commensals are not well understood. We report the Arabidopsis leaf transcriptome after 3 to 4 weeks of colonization by Methylobacterium extorquens PA1 and Sphingomonas melonis Fr1, representatives of two abundant genera in the phyllosphere, compared to axenic plants. In addition, we also sequenced the transcriptome of Arabidopsis 2 and 7 days after spray-infection with a low dose of P. syringae DC3000 and in combination with the commensals.