Type A2 BTB Members Decrease the ABA Response during Seed Germination by Affecting the Stability of SnRK2.3 in Arabidopsis

International Journal of Molecular Sciences

Sheng Luan¹  Yuan Wang²  Guohua Cai³  Pengwang Chen³  Wenzhi Lan³  Guoqing Tu³ 

[1] Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720, USA;Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai 201602, China;State Key Laboratory for Pharmaceutical Biotechnology, College of Life Sciences, Nanjing University, Nanjing 210093, China;

关键词: BTB-A2 protein;    seed germination;    ABA;    SnRK2.3;    Arabidopsis;   

DOI  :  10.3390/ijms21093153

来源: DOAJ

【 摘 要 】

The Arabidopsis genome comprises eighty genes encoding BTB (broad-complex, tramtrack, and bric-a-brac) family proteins that are characterized with the BTB domain and that potentially serve as substrate adaptors for cullin-based E3-ligases. In addition to the BTB domain, most BTB proteins also contain various other interaction motifs that probably act as target recognition elements. Here, we report three members of the BTB-A2 subfamily that distinctly only contain the BTB domain, BTB-A2.1, BTB-A2.2, and BTB-A2.3, that negatively regulates abscisic acid (ABA) signaling in Arabidopsis. BTB-A2.1, BTB-A2.2, and BTB-A2.3 encoded cytoplasm- and nucleus-localized proteins and displayed highly overlapping expression patterns in Arabidopsis tissues. Disruption of these three genes, but not single or double mutants, resulted in a decrease in ABA-induced inhibition of seed germination. Further analyses demonstrated the expression levels of these three genes were up-regulated by ABA, and their mutation increased ABA signalling. Importantly, protein-protein interaction assays showed that these three BTB-A2 proteins physically interacted with SnRK2.3. Moreover, biochemical and genetic assays indicated that BTB-A2.1, BTB-A2.2, and BTB-A2.3 decreased the stability of SnRK2.3 and attenuated the SnRK2.3 responsible for the ABA hypersensitive phenotype of seed germination. This report thus reveals that BTB-A2s serve as negative regulators for balancing the intensity of ABA signaling during seed germination.

【 授权许可】

Unknown