Project
Exploring plant genes that participate in the response to the phytotoxic metabolite botrydial produced by Botrytis cinerea
The plant pathogenic fungus Botrytis cinerea attacks a broad range of host species. Due to the genetic plasticity of B. cinerea and its various modes of attack, B. cinerea is difficult to control by fungicides. It is important to utilize natural host resistance resources for sustainable control. In this project, we aim to explore plant genes that participate in the response to a toxin produced by B. cinerea, and identify plant resistance or susceptibility genes against the disease.
Background
Botrytis cinerea has been ranked as the second most important plant pathogenic fungus from the economic and scientific perspective. Major genes conferring complete resistance to the necrotroph B. cinerea have not been found, while deletion of particular susceptibility (S) genes seems to provide an alternative for resistance to B. cinerea.
One promising strategy to discover S genes is to identify plant components that are hijacked by a cell-death-inducing molecule of B. cinerea. Since host cell death can facilitate the invasion of B. cinerea, the plant genes that are involved
in the response to the molecule would be considered as S genes.
The toxin botrydial produced by B. cinerea can cause host cell death and is important for the fungal virulence. Therefore, botrydial can be used as a tool to discover S genes.
Project description
Botrydial (BOT) is one of the major phytotoxic metabolites produced by Botrytis cinerea, which can induce programmed cell death (PCD) in the host by interacting with plant components, and thereby facilitate fungal infection. Thus, the genes encoding plant components involved in the PCD pathways may serve as susceptibility (S) genes.
We observed that a mutant which does not synthesize BOT, was avirulent on the model plant Arabidopsis. This observation encouraged us to explore the underlying mechanisms of the plant-phytotoxin interaction and identify potential S genes to B. cinerea.
We apply genomic and genetic strategies to study the interactions between Arabidopsis genes/proteins and BOT at molecular level.
- We assessed the sensitivity to pure BOT of 359 Arabidopsis ecotypes belonging to a haplotype mapping population. Subsequently, we employed genome-wide association studies (GWAS) to pinpoint allelic variations correlated with plant sensitivity to BOT. The GWAS identified several loci in the Arabidopsis genome that are associated with the phenotype. 36 candidate genes (including receptor-like protein/kinase genes) in these loci were functionally validated using Arabidopsis mutant lines in a BOT sensitivity assay.
- We crossed a BOT-sensitive Arabidopsis ecotype with a relatively insensitive ecotype and subsequently assessed the BOT-sensitivity among the F1 and F2 populations. A bulk-segregant analysis was performed by sequencing two DNA samples extracted from the most insensitive and sensitive F2 plants, in order to identify genetic loci that may contribute to PCD triggered by BOT.