In this study, 28 HDAC genes from soybean genome were identified, which were asymmetrically distributed on 12 chromosomes. Phylogenetic analysis demonstrated that GmHDACs fall into three major groups previously named RPD3/HDA1, SIR2, and HD2. Subcellular localization analysis revealed that YFP-tagged GmSRT4, GmHDT2 and GmHDT4 were predominantly localized in the nucleus, whereas GmHDA6, GmHDA13, GmHDA14 and GmHDA16 were found in both the cytoplasm and nucleus. Real-time quantitative PCR showed that GmHDA6, GmHDA13, GmHDA14, GmHDA16 and GmHDT4 were broadly expressed across plant tissues, while GmHDA8, GmSRT2, GmSRT4 and GmHDT2 showed differential expression across various tissues. Interestingly, we measured differential changes in GmHDACs transcripts accumulation in response to several abiotic cues, indicating that these epigenetic modifiers could potentially be part of a dynamic transcriptional response to stress in soybean. Finally, we show that the levels of histone marks previously reported to be associated with plant HDACs are modulated by cold and heat in this legume.
We have identified and classified 28 HDAC genes in soybean. Our data provides insights into the evolution of the HDAC gene family and further support the hypothesis that these genes are important for the plant responses to environmental stress.
Figure 1: Phylogenetic tree and domain architecture of HDACs in soybean. a Phylogenetic tree of HDAC proteins in soybean and Arabidopsis. The phylogenetic tree was generated using the MEGA 5.0 software and the Maximum Parsimony method with the following parameters: bootstrap analysis of 1000 replicates and partial deletion. The numbers at the nodes indicate the bootstrap values. b The schematic diagrams show the domain organization of these proteins according to analysis by NCBI Batch-CD, SMART and PFAM searches. Different domains are indicated by the use of different colors. The proteins belonging to each family are grouped together