Yeh, P.-M. | Search bioRxiv

bioRxiv2024

Modular mechanisms of immune priming and growth inhibition mediated by plant effector-triggered immunity

Excessive activation of effector-triggered immunity (ETI) in plants inhibits plant growth and activates cell death. ETI mediated by intracellular Toll/Interleukin-1 receptor/Resistance protein (TIR) nucleotide-binding leucine-rich-repeat receptors (NLRs) involves two partially redundant signalling nodes in Arabidopsis, EDS1-PAD4-ADR1 and EDS1-SAG101-NRG1. Genetic and transcriptomic analyses show that EDS1-PAD4-ADR1 primarily enhances the immune component abundance and is critical for limiting pathogen growth, whereas EDS1-SAG101-NRG1 mainly activates the hypersensitive cell death response (HR) but is dispensable for immune priming. This study enhances our understanding of the distinct contributions of these two signalling modules to ETI and suggests potential strategies for improving disease resistance in crops without compromising yield.

plant biology↗

bioRxiv2022

Distinct selection signatures during domestication and improvement in crops: a tale of two genes in mungbean

Domestication and improvement are two crucial processes underlying the evolution of crops. Domestication transformed wild plants into a utilizable form for humans; improvement refined cultivars adapting to distinct environments and local preferences. Using whole-genome re-sequencing of Vigna radiata, we investigated the demographic history and compared the genetic footprints of domestication and improvement. The Asian wild population migrated to Australia at about 50 kya, and domestication happened in Asia about 9 kya selecting for non-shattering pods. The key candidate gene for this trait, VrMYB26a, has lower expression in cultivars, consistent with the reduced polymorphism in the promoter region reflecting hard selective sweep. The determinate stems were later selected as an improvement phenotype and associated with the gene VrDet1. Two ancient haplotypes reducing gene expression exhibit intermediate frequencies in cultivars, consistent with selection favoring independent haplotypes in soft selective sweep. Our results suggest domestication and improvement may leave different genomic signatures of selection, reflecting the fundamental differences in the two processes and highlighting the limitations of genome-scan methods relying on hard selective sweep.

plant biology↗