• 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 PYLs 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 PYLs 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 PYLs as targets of ABI5 reveals a role of ABI5 in the feedback regulation of ABA‐mediated seed germination.

中文翻译：

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ABI5 通过反馈调节 PYR/PYL/RCAR ABA 受体基因的表达来调节种子萌发。

• 作为脱落酸 (ABA) 受体，PYR1/PYL/RCAR (PYLs) 在 ABA 介导的种子萌发中发挥重要作用，但 PYLs 在此过程中的调控，尤其是在转录水平上的调控仍不清楚。
• 在这项研究中，我们发现 14 个PYL中的 11 个在种子萌发过程中的表达发生了显着变化，并且受到外源 ABA 的影响。两种 PYL，PYL11 和 PYL12，都在成熟种子中特异性表达，正向调节 ABA 介导的种子萌发。
• 然而，发现 ABI5 可以调节 PYL11 和 PYL12 介导的 ABA 反应。在abi5-7突变体中，由PYL11和PYL12过表达引起的 ABA 超敏反应被完全或部分阻断。相比之下， ABI5通过直接结合其启动子来调节PYL11和PYL12的表达。此外，在abi5突变体的萌发过程中，其他 8 个PYL的表达也受到影响。启动子分析显示 ABI5 结合区域存在于 TATA 框或启动器框旁边。
• 总之，我们的数据证明了 PYL11 和 PYL12 在种子萌发中的作用。此外，将PYL鉴定为 ABI5 的靶标揭示了 ABI5 在 ABA 介导的种子萌发的反馈调节中的作用。