CRISPR/Cas9-targeted mutagenesis of OsERA1 confers enhanced responses to abscisic acid and drought stress and increased primary root growth under nonstressed conditions in rice.

Takuya Ogata,Takuma Ishizaki,Miki Fujita,Yasunari Fujita,Keqiang Wu

doi:10.1371/journal.pone.0243376

Abstract

Abscisic acid (ABA) signaling components play an important role in the drought stress response in plants. Arabidopsis thaliana ENHANCED RESPONSE TO ABA1 (ERA1) encodes the β-subunit of farnesyltransferase and regulates ABA signaling and the dehydration response. Therefore, ERA1 is an important candidate gene for enhancing drought tolerance in numerous crops. However, a rice (Oryza sativa) ERA1 homolog has not been characterized previously. Here, we show that rice osera1 mutant lines, harboring CRISPR/Cas9-induced frameshift mutations, exhibit similar leaf growth as control plants but increased primary root growth. The osera1 mutant lines also display increased sensitivity to ABA and an enhanced response to drought stress through stomatal regulation. These results illustrate that OsERA1 is a negative regulator of primary root growth under nonstressed conditions and also of responses to ABA and drought stress in rice. These findings improve our understanding of the role of ABA signaling in the drought stress response in rice and suggest a strategy to genetically improve rice.

Highlights

The increased occurrence of extreme weather events due to climate change severely hinders crop production
Three OsERA1 clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 constructs containing each guide RNAs (gRNAs) were used to transform the rice cultivar Nipponbare, which is widely used as a standard cultivar for studies of lowland rice
We demonstrated that the osera1 mutant lines M1G and M2T display an enhanced response to abscisic acid (ABA) and drought stress via stomatal regulation (Figs 3 and 4), consistent with previous reports of ENHANCED RESPONSE TO ABA1 (ERA1) homologs in other plant species [26,27,28,29]

Summary

Introduction

The increased occurrence of extreme weather events due to climate change severely hinders crop production. Drought is a major abiotic stress limiting rice productivity in rainfed lowland rice agro-ecosystems [1, 2]. A number of physiological and molecular studies have revealed that phytohormone signaling pathways, such as those of abscisic acid (ABA), auxin, and brassinosteroids, play key roles in regulating the drought stress response in plants [3]. ABA signaling components function as central regulators in the drought stress response [4, 5]. ABA coordinates the plant’s responses to decreased water availability.

Methods

Results

Conclusion