Abscisic acid signaling and crosstalk with phytohormones in regulation of environmental stress responses

Frequently changing environmental conditions pose unwarranted threat to plants life and impose serious penalties in terms of arrested growth, metabolism and ultimately the yield. Being rooted, plants cannot avoid the stresses but equipped well to survive and produce. Among the stress modulatory responses, an isoprenoid phytohormone abscisic acid (ABA) proved its significance by regulating the growth, development and stress responses as a signaling mediator. Abscisic acid also controls various physiological, biochemical and molecular processes in plants under non-stress conditions. It regulates seed dormancy, stomatal closure, leaf abscission, senescence, fruit ripening, legume-Rhizobium symbiosis and a number of stress related functions. In stressful conditions, ABA perception and signaling controls downstream responses at transcriptional and posttranscriptional level. The present review discusses ABA homeostasis, its perception and signaling along with physiological and molecular responses of ABA under critical conditions including drought, heavy metal, salinity, and temperature stress is specified. The recent molecular diagnostics reported through high throughput technologies reveal the role of ABA in regulation of different physiological mechanisms through integration of environmental cues via its positive and negative crosstalks with other phytohormones (like auxin, gibberellin, cytokinin, ethylene, salicylic acid, brassinosteroids, jasmonic acid, strigolactones, and melatonin) and potent chemical messengers like polyamines, sugars, NO and H2S mediated by several receptors, transporters, bZIP TFs and regulatory proteins has also been focused in detail. The data supporting the findings of this study are available from the corresponding author, (Author name), upon request.