Arabidopsis ubiquitin ligase PUB41 is a positive regulator of the ABA response

Abstract

Seed germination is a highly controlled developmental process. Prevention of early germination is essential to avoid germination at a time that is not likely to allow the completion of the plant life cycle before entering unfavorable seasons. The plant hormone ABA is the key regulator of seed dormancy and inhibition of germination. ABA is also involved in the plant response to drought. Here we report on the involvement of AtPUB41, a U-BOX E3 ubiquitin ligase from Arabidopsis thaliana, in regulating ABA signaling, seed dormancy, germination, and drought resilience. AtPUB41 is expressed in most plant vegetative and reproductive tissues. AtPUB41 protein is localized in the cytosol and nucleus. pub41 T-DNA insertion mutants display reduced seed dormancy, and their germination is less inhibited by exogenous ABA than seeds of wild-type plants. pub41 mutant plants are also hypersensitive to drought. ABA induces AtPUB41 promoter activity and steady-state mRNA levels in the roots. Our data suggest that AtPUB41 is a positive regulator of ABA signaling. Main ConclusionArabidopsis ubiquitin ligase PUB41 is induced by ABA and acts as a positive regulator of ABA signaling by modulating seed dormancy, germination, and drought resilience.