ABA signalling is fine-tuned by antagonistic HAB1 variants.

Zhijuan Wang,Shuangfeng Wang,Hongtao Zhao,Bin Yao,Bingjian Yuan,Hongtao Ji,Chao Su,Xia Li

doi:10.1038/ncomms9138

Abstract

Group A protein type 2C phosphatases (PP2Cs) are negative regulators of abscisic acid (ABA) signalling and plant adaptation to stress. However, our knowledge of the regulation of PP2C activity is limited. Here we report that the PP2C HAB1 undergoes alternative splicing to produce two splice variants, which encode HAB1.1 and HAB1.2, that play opposing roles in ABA-mediated seed germination and ABA-mediated post-germination developmental arrest. HAB1.2 is predominately formed in the presence of ABA and prevents seed germination and post-germinative growth. HAB1.2 interacts with OST1, but cannot inhibit OST1 kinase activity; thus, it functions as a positive regulator of ABA signalling. We also identified an RNA-recognition motif-containing protein, RBM25, as a potential regulator of HAB1 alternative splicing and molecular diversity. Our results reveal a mechanism for turning ABA signalling on and off and for plant adaptation to abiotic stress.

Highlights

Group A protein type 2C phosphatases (PP2Cs) are negative regulators of abscisic acid (ABA) signalling and plant adaptation to stress
Our results indicate that HAB1 has two transcripts regardless of ABA treatment in the young seedlings (Supplementary Fig. 1)
Our results indicate the production of two splice variants of HAB1 during seed germination and postgermination development under normal conditions (Fig. 1a)

Summary

Introduction

Group A protein type 2C phosphatases (PP2Cs) are negative regulators of abscisic acid (ABA) signalling and plant adaptation to stress. Our work identified an RNA-recognition motif-containing protein, RBM25, as a potential regulator of HAB1 AS and ABA-mediated postgermination growth arrest in Arabidopsis.

Results

Conclusion