ABI5 modulates seed germination via feedback regulation of the expression of the PYR/PYL/RCAR ABA receptor genes. Issue 2 (4th July 2020)

• Record Type: Journal Article
• Authors: Zhao, Hongyun; Nie, Kaili; Zhou, Huapeng; Yan, Xiaojing; Zhan, Qidi; Zheng, Yuan; Song, Chun‐Peng
• Is Part Of: New phytologist. Volume 228:Issue 2(2020)
• Page Start: 596
• Page End: 608
• Publication Date: 2020-07-04
• Subjects: ABI5 -- abscisic acid (ABA) -- feedback regulation -- PYR1/PYL/RCARs -- seed germination -- transcriptional regulation; Botany -- Periodicals; 580
• DOI: 10.1111/nph.16713
• Languages: English
• ISSNs: 0028-646X

Abstract

Summary: As abscisic acid (ABA) receptors, PYR1/PYL/RCAR (PYLs) play important roles in ABA‐mediated seed germination, but the regulation of PYLs in this process, especially at the transcriptional level, remains unclear. In this study, we found that expression of 11 of 14 PYL s changes significantly during seed germination and is affected by exogenous ABA. Two PYLs, PYL11 and PYL12, both of which are expressed specifically in mature seeds, positively modulate ABA‐mediated seed germination. However, ABI5 was found to modulate the PYL11‐ and PYL12‐mediated ABA response. In the abi5‐7 mutant, ABA hypersensitivity caused by PYL11 and PYL12 overexpression was totally or partially blocked. By contrast, ABI5 regulates the expression of PYL11 and PYL12 by directly binding to their promoters. Moreover, the expression of eight other PYL s is also affected during the germination of abi5 mutants. Promoter analysis revealed that an ABI5‐binding region is present next to the TATA box or initiator box. Together, our data demonstrate the role of PYL11 and PYL12 in seed germination. In addition, the identification of PYL s as targets of ABI5 reveals a role of ABI5 in the feedback regulation of ABA‐mediated seed germination.