RESUMEN
Bacteria inject effector proteins into host cells to manipulate cellular processes that promote disease. Since bacteria deliver minuscule amounts of effectors only into targeted host cells, it is technically challenging to capture effector-dependent cellular changes from bulk-infected host tissues. Here, we report a new technique called effector-inducible isolation of nuclei tagged in specific cell types (eINTACT), which facilitates affinity-based purification of nuclei from Arabidopsis plant cells that have received Xanthomonas bacterial effectors. Analysis of purified nuclei reveals that the Xanthomonas effector XopD manipulates the expression of Arabidopsis abscisic acid signalling-related genes and activates OSCA1.1, a gene encoding a calcium-permeable channel required for stomatal closure in response to osmotic stress. The loss of OSCA1.1 causes leaf wilting and reduced bacterial growth in infected leaves, suggesting that OSCA1.1 promotes host susceptibility. eINTACT allows us to uncover that XopD exploits host OSCA1.1/abscisic acid osmosignalling-mediated stomatal closure to create a humid habitat that favours bacterial growth and opens up a new avenue for accurately elucidating functions of effectors from numerous gram-negative plant bacteria in native infection contexts.
Asunto(s)
Proteínas de Arabidopsis , Arabidopsis , Xanthomonas , Arabidopsis/metabolismo , Virulencia , Ácido Abscísico/metabolismo , Xanthomonas/fisiología , Proteínas de Arabidopsis/metabolismo , Canales de Calcio/metabolismo , Enfermedades de las Plantas/microbiología , Proteínas Bacterianas/genéticaRESUMEN
The phytohormones salicylic acid (SA) and jasmonic acid (JA) are major players in plant immunity. Numerous studies have provided evidence that SA- and JA-mediated signaling interact with each other (SA-JA crosstalk) to orchestrate plant immune responses against pathogens. At the same time, SA-JA crosstalk is often exploited by pathogens to promote their virulence. In this review, we summarize our current knowledge of molecular mechanisms for and modulations of SA-JA crosstalk during pathogen infection.
Asunto(s)
Reguladores del Crecimiento de las Plantas , Ácido Salicílico , Ciclopentanos , Regulación de la Expresión Génica de las Plantas , Oxilipinas , Reguladores del Crecimiento de las Plantas/fisiología , Inmunidad de la PlantaRESUMEN
Bidirectional root-shoot signalling is probably key in orchestrating stress responses and ensuring plant survival. Here, we show that Arabidopsis thaliana responses to microbial root commensals and light are interconnected along a microbiota-root-shoot axis. Microbiota and light manipulation experiments in a gnotobiotic plant system reveal that low photosynthetically active radiation perceived by leaves induces long-distance modulation of root bacterial communities but not fungal or oomycete communities. Reciprocally, microbial commensals alleviate plant growth deficiency under low photosynthetically active radiation. This growth rescue was associated with reduced microbiota-induced aboveground defence responses and altered resistance to foliar pathogens compared with the control light condition. Inspection of a set of A. thaliana mutants reveals that this microbiota- and light-dependent growth-defence trade-off is directly explained by belowground bacterial community composition and requires the host transcriptional regulator MYC2. Our work indicates that aboveground stress responses in plants can be modulated by signals from microbial root commensals.
Asunto(s)
Arabidopsis/crecimiento & desarrollo , Arabidopsis/genética , Arabidopsis/metabolismo , Raíces de Plantas/crecimiento & desarrollo , Raíces de Plantas/microbiología , Brotes de la Planta/crecimiento & desarrollo , Brotes de la Planta/microbiología , Adaptación Ocular/fisiología , Adaptación Fisiológica , Bacterias , Hongos , Regulación de la Expresión Génica de las Plantas , Variación Genética , Genotipo , Microbiota/fisiología , Mutación , Desarrollo de la Planta/genética , Desarrollo de la Planta/fisiología , Estrés Fisiológico/fisiología , Simbiosis/genética , Simbiosis/fisiologíaRESUMEN
Reminiscent to the microbiota-gut-brain axis described in animals, recent advances indicate that plants can take advantage of belowground microbial commensals to orchestrate aboveground stress responses. Integration of plant responses to microbial cues belowground and environmental cues aboveground emerges as a mechanism that promotes stress tolerance in plants. Using recent examples obtained from reductionist and community-level approaches, we discuss the extent to which perception of aboveground biotic and abiotic stresses can cascade along the shoot-root axis to sculpt root microbiota assembly and modulate the growth of root commensals that bolster aboveground stress tolerance. We propose that host modulation of microbiota-root-shoot circuits contributes to phenotypic plasticity and decision-making in plants, thereby promoting adaptation to rapidly changing environmental conditions.