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Counteraction of ABA-Mediated Inhibition of Seed Germination and Seedling Establishment by ABA Signaling Terminator in Arabidopsis

Authors :
Xia Li
Zhijuan Wang
Yang Zhao
Shimin Xu
Hongtao Zhao
Chunhong Cheng
Xinying Wu
Jingjing Lu
Tao Wang
Jian-Kang Zhu
Zhiping Deng
Hongtao Ji
Liu Liu
Mengmeng Cao
Liya Zhi
Ziyin Ren
Source :
Molecular Plant. 13:1284-1297
Publication Year :
2020
Publisher :
Elsevier BV, 2020.

Abstract

Seed germination and seedling establishment are important for the reproductive success of plants, but seeds and seedlings typically encounter constantly changing environmental conditions. By inhibiting seed germination and post-germinative growth through the PYR1/PYL/RCAR ABA receptors and PP2C co-receptors, the phytohormone abscisic acid (ABA) prevents premature germination and seedling growth under unfavorable conditions. However, little is known about how the ABA-mediated inhibition of seed germination and seedling establishment is thwarted. Here, we report that ABA Signaling Terminator (ABT), a WD40 protein, efficiently switches off ABA signaling and is critical for seed germination and seedling establishment. ABT is induced by ABA in a PYR1/PYL/RCAR-PP2C-dependent manner. Overexpression of ABT promotes seed germination and seedling greening in the presence of ABA, whereas knockout of ABT has the opposite effect. We found that ABT interacts with the PYR1/PYL/RCAR and PP2C proteins, interferes with the interaction between PYR1/PYL4 and ABI1/ABI2, and hampers the inhibition of ABI1/ABI2 by ABA-bound PYR1/PYL4, thereby terminating ABA signaling. Taken together, our results reveal a core mechanism of ABA signaling termination that is critical for seed germination and seedling establishment in Arabidopsis.

Details

ISSN :
16742052
Volume :
13
Database :
OpenAIRE
Journal :
Molecular Plant
Accession number :
edsair.doi.dedup.....dd7814fb54b29b90f144ad2185a16f68