Plant Molecular Biology Reporter | 2021
Gene Expression Characteristics in Response to Abscisic Acid Under Shade
Abstract
Plant stress hormone ABA (abscisic acid) is induced by unfavorable environmental conditions such as drought, salt, oxidative, and cold stresses and leads to a series of reactions that enable plants to adapt to the changing environment. To investigate the effect of ambient light quality upon the ABA response, we interrogated the gene expression change in response to ABA treatment in the background of either high or low R:FR light (red to far-red light ratio) conditions, simulating regular light or proximity shade conditions, respectively. Wild-type Arabidopsis plants were treated with or without ABA and/or supplemental far-red light, creating four different conditions. Five different microarray analyses were conducted by different combinations of gene chip data from those four conditions. Our analyses revealed high levels of overall similarity in the expression patterns between the two ABA responses, with or without the supplemental far-red light. In contrast, we also found ABA-responsive genes that are specific to high or low R:FR backgrounds. We isolated various groups of background-specific genes using clustering analysis and computing the differences in expression changes among the five experiments. These genes are concentrated among the biological processes such as pathogen defense and jasmonic acid, anthocyanin, auxin, and ribosome biogenesis. Our data suggest that plants modify specific subsets of their responses to ABA to optimize their response in different light quality backgrounds. On the other hand, our data also indicate that ABA treatment suppresses the shade avoidance responses, prioritizing the stress coping mechanism over the competition for light.