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Arabidopsis VQ 18 and VQ 26 proteins interact with ABI 5 transcription factor to negatively modulate ABA response during seed germination
Author(s) -
Pan Jinjing,
Wang Houping,
Hu Yanru,
Yu Diqiu
Publication year - 2018
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/tpj.13969
Subject(s) - biology , abscisic acid , germination , transcription factor , arabidopsis , seedling , microbiology and biotechnology , botany , gene , genetics , mutant
Summary Seed germination and early seedling establishment, critical developmental stages in the life cycle of seed plants, are modulated by diverse endogenous hormones and the surrounding environment. Arabidopsis ABSCISIC ACID ‐ INSENSITIVE 5 ( ABI 5) is a central transcription factor of abscisic acid ( ABA ) signaling that represses those processes. ABI 5 is precisely modulated at post‐translational level; however, whether it interacts with other crucial transcriptional regulators remains to be investigated. In this study, VQ 18 and VQ 26, two members of the recently‐identified VQ family, were found to interact with ABI 5 in vitro and in vivo . Phenotypic analysis showed that VQ 18 and VQ 26 are responsive to ABA and negatively mediate ABA signaling redundantly during seed germination. Simultaneously decreasing VQ 18 and VQ 26 expression levels enhanced ABA signaling to suppress seed germination, whereas overexpressing these two VQ genes resulted in the germinated seeds being less ABA ‐sensitive. Consistently, the expression levels of several ABI 5 targets were modulated by VQ 18 and VQ 26. The increased ABA signaling of plants in which VQ 18 and VQ 26 were simultaneously suppressed required ABI 5. Additionally, VQ 18 and VQ 26 acted as negative interactors of the ABI 5 transcription factor. Our study reveals a previously unidentified regulatory role of VQ proteins, which act antagonistically with ABI 5 to maintain the appropriate ABA signaling level to fine‐tune seed germination and early seedling establishment.