A systematic analysis of the subtilase gene family and expression and subcellular localization investigation of anther-specific members in maize.

Subtilases (SBTs), also known as Subtilisin-like serine proteases, are extracellular alkaline protease proteins. SBTs function in all stages of plant growth, development and stress responses. Maize (Zea mays L.) is a crop widely used worldwide as food, feed, and industrial materials. However, information about the members and their functions of the SBT proteins in maize is lacking. In this study, we identified 58 ZmSBT genes from the maize genome and conducted a comprehensive investigation of ZmSBTs by phylogenetic, gene duplication event, gene structure, and protein conserved motif analyses. The ZmSBT proteins were phylogenetically classified into seven groups, and collinearity analysis indicated that many ZmSBTs originate from tandem or segmental duplications. Structural and homolog protein comparison revealed ZmSBTs have conserved protein structures with reported subtilase proteins, suggesting the conserved functions. Further analysis showed that ZmSBTs are expressed in different tissues, and many are responses to specific abiotic stress. Analysis of the anther-specific ZmSBT genes showed their expression peaked at different developmental stages of maize anthers. Subcellular localization analysis of selected maize ZmSBTs showed they are located in different cellular compartments. The information provided in this study is valuable for further functional study of ZmSBTs.