Genome-wide identification and expression analysis of the NAC transcription factor family in tomato (Solanum lycopersicum) during aluminum stress

The family of NAC proteins (NAM, ATAF1/2, and CUC2) represent a class of large plant-specific transcription factors. However, identification and functional surveys of NAC genes of tomato (Solanum lycopersicum) remain unstudied, despite the tomato genome being decoded for several years. This study aims to identify the NAC gene family and investigate their potential roles in responding to Al stress. Ninety-three NAC genes were identified and named in accordance with their chromosome location. Phylogenetic analysis found SlNACs are broadly distributed in 5 groups. Gene expression analysis showed that SlNACs had different expression levels in various tissues and at different fruit development stages. Cycloheximide treatment and qRT-PCR analysis indicated that SlNACs may aid regulation of tomato in response to Al stress, 19 of which were significantly up- or down-regulated in roots of tomato following Al stress. This work establishes a knowledge base for further studies on biological functions of SlNACs in tomato and will aid in improving agricultural traits of tomato in the future.