Histone Deacetylase Gene SlHDA3 Involves in ABA, Drought and Salt Response in Tomato 

Abstract Histone deacetylation, one of vital modifying factors of post-translation modifications, which is catalyzed by histone deacetylase. The genes of histone deacetylase(HDACs) play critical roles in various stress responses. However, detailed functions for most SlHDAC members in tomato still unknown. In this work, we found that a histone deacetylase, SlHDA3, involved in response to NaCl and drought abiotic stresses. The expression of SlHDA3 was also induced significantly by NaCl, drought stress and endogenous hormone treatments. Silencing of SlHDA3 in tomato, the RNAi transgenic plants presented depressed tolerance to drought and salt stresses compared with WT tomato. The results of sensitivity analysis indicated that the length of hypocotyl and roots in RNAi plants were more inhibited by ABA and salt stress than that of WT at post-germination stage. Worse growth status were exhibited in SlHDA3 transgenic plants under salt and drought stress as are evaluated by a series of physiological parameters related to stress responses, such as decreased RWC, survival rate, ABA content, chlorophyll content and CAT activity, and increased MDA content and proline content. Besides, the expressions analysis of transgenic plants showed that the transcripts of genes which associated with responses to abiotic stress were down-regulated under salt-stressed conditions. To sum up, SlHDA3 acts as a stress-responsive gene, plays a role in the positive regulation of abiotic stress tolerance, and may be one of the new members in the engineering breeding of salt- and drought-tolerant tomato.