Lysine deacetylase TaSRT1 mediates wheat drought tolerance by deacetylating TaDT-A to reduce its protein stability and transcriptional activity

Abstract

Drought is one of the major environmental stresses limiting crop growth and yield. Epigenetic regulations play crucial roles in plant adaptation to environmental changes, whereas the epigenetic mechanism of drought resistance in crops remains largely elusive. Here, we report that the nicotinamide adenine dinucleotide (NAD⁺)-dependent deacetylase TaSRT1 negatively regulates drought tolerance in wheat. Compared with the wild type, the tasrt1 mutant had higher relative water contents, along with a smaller stomatal aperture and improved water use efficiency under drought conditions, whereas TaSRT1 overexpression plants exhibited opposite phenotypes. TaSRT1 directly interacted with the drought-resistant pivotal factor TaDT-A to regulate its protein stability and transcriptional activity through lysine deacetylation. Furthermore, the key lysine residue of TaDT-A was identified as a deacetylation/acetylation site that plays an important role in regulating its stability. In addition, genetic analysis indicated TaDT-A functions downstream of TaSRT1 to modulate drought resistance. These findings uncover how the functional interplay between epigenetic regulator and transcription factors regulates drought resistance in plants, and illustrate a mechanism by which lysine deacetylase affects gene transcription via influencing non-histone protein acetylation and regulating their function.