Abscisic acid (ABA) and gibberellins (GA) are plant hormones which antagonistically mediate numerous physiological processes, and their optimal balance is essential for normal plant development. However, the molecular mechanism underlying ABA and GA antagonism still needs to be determined. Here, we report that ABA- INSENSITIVE 4 (ABI4) is a central factor for GA/ABA homeostasis and antagonism in post-germination stages. ABI4 over-expression in Arabidopsis (OE-ABI4) leads to developmental defects including a decrease in plant height and poor seed production. The transcription of a key ABA biosynthetic gene, NCED6, and of a key GA catabolic gene, GA2ox7, is significantly enhanced by ABI4 over-expression. ABI4 activates NCED6 and GA2ox7 transcription by directly binding to the promoters, and genetic analysis revealed that mutation in these two genes partially rescues the dwarf phenotype of ABI4 overexpressing plants. Consistently, ABI4 overexpressing seedlings have a lower GA/ABA ratio compared to the wild type. We further show that ABA induces GA2ox7 transcription while GA represses NCED6 expression in an ABI4-dependent manner; and that ABA stabilizes the ABI4 protein, whereas GA promotes its degradation. Taken together, these results propose that ABA and GA antagonize each other by oppositely acting on ABI4 transcript and protein levels.

ABI4 Mediates Antagonistic Effects of Abscisic Acid and Gibberellins at Transcript and Protein Levels / Shu, Kai; Chen, Qian; Wu, Yaorong; Liu, Ruijun; Zhang, Huawei; Wang, Pengfei; Li, Yanli; Wang, Shengfu; Tang, Sanyuan; Liu, Chunyan; Yang, Wenyu; Cao, Xiaofeng; Serino, Giovanna; Xie, Qi. - In: PLANT JOURNAL. - ISSN 0960-7412. - STAMPA. - 85:3(2016), pp. 348-361. [10.1111/tpj.13109]

ABI4 Mediates Antagonistic Effects of Abscisic Acid and Gibberellins at Transcript and Protein Levels

SERINO, Giovanna;
2016

Abstract

Abscisic acid (ABA) and gibberellins (GA) are plant hormones which antagonistically mediate numerous physiological processes, and their optimal balance is essential for normal plant development. However, the molecular mechanism underlying ABA and GA antagonism still needs to be determined. Here, we report that ABA- INSENSITIVE 4 (ABI4) is a central factor for GA/ABA homeostasis and antagonism in post-germination stages. ABI4 over-expression in Arabidopsis (OE-ABI4) leads to developmental defects including a decrease in plant height and poor seed production. The transcription of a key ABA biosynthetic gene, NCED6, and of a key GA catabolic gene, GA2ox7, is significantly enhanced by ABI4 over-expression. ABI4 activates NCED6 and GA2ox7 transcription by directly binding to the promoters, and genetic analysis revealed that mutation in these two genes partially rescues the dwarf phenotype of ABI4 overexpressing plants. Consistently, ABI4 overexpressing seedlings have a lower GA/ABA ratio compared to the wild type. We further show that ABA induces GA2ox7 transcription while GA represses NCED6 expression in an ABI4-dependent manner; and that ABA stabilizes the ABI4 protein, whereas GA promotes its degradation. Taken together, these results propose that ABA and GA antagonize each other by oppositely acting on ABI4 transcript and protein levels.
2016
Arabidopsis; abscisic acid; gibberellin; plant; transcription; development
01 Pubblicazione su rivista::01a Articolo in rivista
ABI4 Mediates Antagonistic Effects of Abscisic Acid and Gibberellins at Transcript and Protein Levels / Shu, Kai; Chen, Qian; Wu, Yaorong; Liu, Ruijun; Zhang, Huawei; Wang, Pengfei; Li, Yanli; Wang, Shengfu; Tang, Sanyuan; Liu, Chunyan; Yang, Wenyu; Cao, Xiaofeng; Serino, Giovanna; Xie, Qi. - In: PLANT JOURNAL. - ISSN 0960-7412. - STAMPA. - 85:3(2016), pp. 348-361. [10.1111/tpj.13109]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11573/838190
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