Biology subjects

Kremer, J. M.

Publications and source records attributed to Kremer, J. M..

3 recordsLinked to original sources

bioRxiv2023

A critical role of a eubiotic microbiota in gating proper immunocompetence in Arabidopsis

Although many studies have shown that microbes can ectopically stimulate or suppress plant immune responses, the fundamental question of whether the entire preexisting microbiota is indeed required for proper development of plant immune response remains unanswered. Using a recently developed peat-based gnotobiotic plant growth system we found that Arabidopsis grown in the absence of a natural microbiota lacked age-dependent maturation of plant immune response and were defective in several aspects of pattern-triggered immunity. Axenic plants exhibited hypersusceptibility to infection by the bacterial pathogen Pseudomonas syringae pv. tomato DC3000 and the fungal pathogen Botrytis cinerea. Microbiota-mediated immunocompetence was suppressed by rich nutrient conditions, indicating a tripartite interaction between the host, microbiota, and abiotic environment. A synthetic microbiota composed of 48 culturable bacterial strains from the leaf endosphere of healthy Arabidopsis plants was able to substantially restore immunocompetence similar to plants inoculated with a soil-derived community. In contrast, a 52-member dysbiotic synthetic leaf microbiota overstimulated the immune transcriptome. Together, these results provide evidence for a causal role of a eubiotic microbiota in gating proper immunocompetence and age-dependent immunity in plants.

plant biology↗

bioRxiv2021

The genetic interaction of REVOLUTA and WRKY53 links plant development, senescence, and immune responses

In annual plants, tight coordination of successive developmental events is of primary importance to optimize performance under fluctuating environmental conditions. The recent finding of the genetic interaction of WRKY53, a key senescence-related gene with REVOLUTA, a master regulator of early leaf patterning, raises the question of how early and late developmental events are connected. Here, we investigated the developmental and metabolic consequences of an alteration of the REVOLUTA and WRKY53 gene expression, from seedling to fruiting. Our results show that REVOLUTA critically controls late developmental phases and reproduction while inversely WRKY53 determines vegetative growth at early developmental stages. We further show that these regulators of distinct developmental phases frequently, but not continuously, interact throughout ontogeny and demonstrated that their genetic interaction is mediated by the salicylic acid (SA). Moreover, we showed that REVOLUTA and WRKY53 are keys regulatory nodes of development and plant immunity thought their role in SA metabolic pathways, which also highlights the role of REV in pathogen defence. Together, our findings demonstrate how late and early developmental events are tightly intertwined by molecular hubs. These hubs interact with each other throughout ontogeny, and participate to the interplay between plant development and immunity.

plant biology↗

bioRxiv2018

FlowPot axenic plant growth system for microbiota research

The presence of resident microbiota on and inside plants is hypothesized to influence many phenotypic attributes of the host. Likewise, host factors and microbe-microbe interactions are believed to influence microbial community assembly. Rigorous testing of these hypotheses necessitates the ability to grow plants in the absence or presence of resident or defined microbiota. To enable such experiments, we developed the scalable and inexpensive FlowPot growth platform. FlowPots have a sterile peat substrate amenable to colonization by microbiota, and the platform supports growth of the model plant Arabidopsis thaliana in the absence or presence of soil-derived microbial communities. Mechanically, the FlowPot system is unique in that it allows for total-saturation of the sterile substrate by \"flushing\" with water and/or nutrient solution via an irrigation port. The irrigation port also facilitates passive drainage of the substrate, preventing root anoxia. Materials to construct an individual FlowPot total [~]$2. A simple experiment with 12 FlowPots requires [~]4.5 h of labor following peat and seed sterilization. Plants are grown on FlowPots within a standard tissue culture microbox after inoculation, thus the Flowpot system is modular and does not require a sterile growth chamber. Here, we provide a detailed assembly and microbiota inoculation protocol for the FlowPot system. Collectively, this standardized suite of tools and colonization protocols empowers the plant microbiome research community to conduct harmonized experiments to elucidate the rules microbial community assembly, the impact of microbiota on host phenotypes, and mechanisms by which host factors influence the structure and function of plant microbiota.

plant biology↗