Small molecules targeting bZIP23 TF improve stomatal conductance and photosynthesis under drought stress

Drought induced Abscisic acid (ABA) accumulation plays a key role in plant water relations by regulating stomatal movements. Though ABA helps in the survival of the plants, reduced carbon gain affects plant productivity. To improve crop productivity under mild drought stress conditions, it is necessary to manipulate ABA responses.

In this study, we identified indolyl-ethyl amine (IEA) and serotonin small molecules using a reverse chemical genomics approach, which act as potent inhibitors of ABA biosynthesis through transient regulation of bZIP23 transcription factor activity. We tested the efficacy of these molecules in rice, wheat and soybean, each of the small molecules enhanced the germination of seeds, even in the presence of ABA. These molecules nullified the effect of ABA on intact and detached leaves, resulting in higher photosynthesis. Rice plants treated with the small molecules were found to have improved stomatal conductance, spikelet fertility and yield in comparison with untreated plants under mild drought stress conditions. Our results suggest that IEA and serotonin small molecules could be utilised to improve yield under mild drought conditions.

Vanitha PA, Preethi V, Akshay U, Akashata D, Sujitha, Ashwin, Babitha, Vidya N, Sheshshayee MS, Anuradha CV, Udayakumar M, Vemanna RS. Novel small molecules targeting bZIP23 TF improve stomatal conductance and photosynthesis under mild drought stress by regulating ABA. 2022, https://doi.org/10.1111/febs.16461