Genetic analyses of interactions between ABA and GA in the control of leaf development in Arabidopsis thaliana

Although abscisic acid (ABA) and gibberellins (GAs) play pivotal roles in many physiological processes in plants, their interaction in the control of leaf growth remains elusive. In this study, genetic analyses of ABA and GA interplay in leaf growth were performed in Arabidopsis thaliana. The results indicate that for ABA and GA interaction, leaf growth of both the aba2/ga20ox1 and aba2/GA20OX1-OE plants exhibits partially additive effects but is similar to the aba2 mutant. Consistent with this result, transcriptome analysis suggests that a substantial proportion (45-65%) of the gene expression profile of aba2/ga20ox1 and aba2/GA20OX1-OE plants overlaps and shares a similar pattern to the aba2 mutant. Thus, these data support that ABA deficiency dominates leaf growth regardless of GA levels. Moreover, gene ontology (GO) analysis indicates gene enrichment in the categories of hormone response, developmental and metabolic processes, and cell wall organization in these three genotypes. Leaf developmental genes are also involved in ABA-GA interaction. Collectively, these data support that the genetic relationship of ABA and GA interaction involves multiple coordinated pathways rather than a simple linear pathway in the regulation of leaf growth.

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Chiang MH, Shen HL, Cheng WH