GABA negatively regulates adventitious root development in poplar. (19th November 2019)

• Record Type: Journal Article
• Authors: Xie, Tiantian; Ji, Jing; Chen, Wei; Yue, Jianyun; Du, Changjian; Sun, Jiacheng; Chen, Lanzhen; Jiang, Zeping; Shi, Shengqing
• Editors: Foyer, Christine
• Is Part Of: Journal of experimental botany. Volume 71:Number 4(2020)
• Page Start: 1459
• Page End: 1474
• Publication Date: 2019-11-19
• Subjects: Adventitious root -- adventitious root primordia -- γ-aminobutyric acid -- carbon and nitrogen metabolism -- hormone -- poplar; Botany -- Periodicals; Botany, Experimental -- Periodicals; Plant physiology -- Periodicals; 580
• DOI: 10.1093/jxb/erz520
• Languages: English
• ISSNs: 0022-0957

Abstract

Abstract: γ-Aminobutyric acid (GABA) influences plant growth, but little is known about how this metabolite regulates adventitious root (AR) development. Here, we investigate the effects of GABA on ARs using poplar lines overexpressing glutamate decarboxilase 2 ( GAD2 ) and by treating poplar stem cuttings with exogenous GABA or vigabatrin (VGB; a specific GABA transaminase inhibitor). Endogenous GABA accumulation not only inhibited AR growth, but it also suppressed or delayed AR formation. Anatomical observations revealed that the GABA and VGB treatments resulted in a 1 d delay in the formation of AR primordia and the appearance of ARs. This delay coincided with changes in primary metabolism, including transient increases in hexose and amino acid levels. GABA-dependent changes in the expression of genes related to hormone synthesis and signalling, as well as analysis of hormone levels revealed that ethylene-dependent pathways were decreased at the earliest stage of AR formation. In contrast, auxin and abscisic acid were increased at 1–5 d as well as GA4 over a 5 d period of AR formation. These results demonstrate that GABA plays a crucial role in AR development. Evidence is presented demonstrating that GABA can interact with hormone-related pathways as well as carbon/nitrogen metabolism. These findings also elucidate the functions of GABA in plant development. Abstract : Accumulation of endogenous GABA negatively regulates adventitious root formation and growth in poplar, together with changes in carbon/nitrogen metabolism and hormone signalling, suggesting a crucial role for GABA in adventitious root development.