Project description:Bacteriophages are increasingly recognised as key players in modulating plant-microbe interactions, including their potential in the biocontrol of plant pathogenic bacteria. In this study, we investigated the tripartite interaction between, Arabidopsis thaliana, the bacterial plant pathogen Xanthomonas campestris pv. campestris (Xcc), and the lytic phage Seregon. Using meta-transcriptomic profiling, we characterized host and pathogen responses during infection and phage treatment. While a single phage treatment did not lead to the eradication of Xcc, treatment with phage Seregon significantly mitigated Xcc-induced disease symptoms, restoring leaf growth to levels comparable to the uninfected control within 14 days post-inoculation. Our data revealed that phage-mediated protection is associated with early bacterial recognition and suppression of jasmonate (JA)-related responses in the host. Analysis of nuclear localized reporter plant cell lines further confirmed a significant reduction in ROS levels in phage-treated plants. Concurrently, Xcc exhibited significant transcriptional downregulation of key virulence factors in the presence of the phage, including the genes encoding the type III secretion system, its associated effectors, and components involved in flagella biosynthesis. Remarkably, phage treatment did not lead to a significant increase in bacterial resistance to phage infection, which is in stark contrast to in vitro conditions. Taken together, this study provides first mechanistic insight into how phages can be harnessed to shape plant-pathogen interactions and highlights their potential role in enhancing plant resilience through targeted modulation of both host immunity and pathogen behaviour.
Project description:Inter-plant communication is key for the successful thriving of plant communities in nature with yet untapped potential for agroecosystem engineering towards more resilient crops and plant defences against pathogens. Arbuscular mycorrhizal fungi (AMF) are ubiquitous root symbionts, well-known to constitute underground common mycelial networks (CMNs) linking multiple plant hosts underground. The wired connection among plants via CMNs are hypothesized to play a key role for information exchange between plants for the neighbour-primed inter-plant defences. However, the key transcriptomic and metabolome responses in receiver plant associated with inter-plant CMN connections remain yet to be elucidated. Moreover, no studies to date have clearly resolved the confounding effects of hyphal damage from the inter-plant network disconnection. To uncover the contribution of CMN integrity to neighbour-primed plant defences, we used model AMF Rhizophagus irregularis to inter-connect two Medicago truncatula plants and explored the effect of sender wounding and flg22 elicitation on receiver plants’ leaf responses and pathogen tolerance. For the first time, we demonstrate that changes in receiver plants’ biotic stress and defence signalling pathways rely on inter-plant signals via the CMN, not on mycelial network damage itself. This response was associated with distinct leaf isoprenoid production, including volatile monoterpenes and triterpene saponins. Furthermore, CMN-mediated signals from stressed senders enhanced receiver resistance to Fusarium sporotrichoides whilst simultaneously increasing susceptibility to Botrytis cinerea. Our findings highlight the critical role of CMNs in inter-plant signalling for pathogen-specific susceptibility and resistance which can be a key for understanding plant community-level defence in nature and agroecosystems.
Project description:Southern corn leaf blight (SCLB), caused by Bipolaris maydis, poses a serious threat to maize production worldwide. In our previous study, Bacillus velezensis BV3 was isolated and demonstrated strong antagonistic activity against maize leaf spot pathogens and effective disease control in greenhouse experiments.
Project description:This study evaluated the biocontrol efficacy, growth-promoting potential, and molecular mechanisms of the actinomycete strain FJSM-07, identified via 16S rDNA sequencing as Streptomyces murinus.
Project description:A first line of defense against pathogen infections is the recognition of pathogen-associated molecular patterns (PAMPs), leading to PAMP-triggered immunity (PTI). MicroRNAs (miRNAs) are primarily known as central regulators of plant development, but a few have also been connected to immunity. We have found that several fungal pathogens lead to a reduction in miR396 levels, suggesting that miR396 are negative regulators of downstream defense responses. In agreement with such as scenario, constitutive attenuation of miR396 activity enhances resistance to infection by fungal pathogens, while increased miR396 activity reduces pathogen resistance. We conclude that constitutive reduction of miR396 levels confer a primed state for enhanced defense reactions
Project description:The free-living soil fungus Trichoderma hamatum GD12 is notable amongst other Trichoderma strains in exhibiting both biocontrol and plant growth promotion (PGP) activities, which are coincident with a markedly expanded genome when compared to other characterised biocontrol and PGP isolates. Here, we make direct comparisons of T. hamatum GD12 transcription during PGP, and during antagonism of the root-infecting pathogen Sclerotinia sclerotiorum, in peat-based microcosms. An extensive mRNA-seq analysis sampling six time-points, 1, 2, 4, 7, 10 and 15 days after microcosm establishment revealed dynamic and biphasic signatures in the transcriptional responses of T. hamatum GD12 during Sclerotinia biocontrol and lettuce growth promotion. Functional analysis of differentially expressed genes demonstrated up-regulation of transportation and oxidation-reduction genes during both processes. Sclerotinia biocontrol is most likely mediated by the synthesis and secretion of antifungal compounds. Notably, the biphasic response during biocontrol was further characterised by the expression of a number of uncharacterised GD12 genes, small-secreted cysteine rich proteins and secondary metabolite producing gene clusters. This work demonstrates that T. hamatum GD12 harnesses a reservoir of uncharacterised genes that are actively engaged during effective biological control of a plurivorous plant pathogen.
