Molecular Characterization and Expression Analysis of NAC Family Transcription Factors in Tomato

Abstract

The NAC family is considered one of the largest plant-specific transcription factors families, and functions in diverse and vital physiological processes during development. In the present study, we performed a complete bioinformatics analysis of the NAC family transcription factors in tomato, and annotated the non-redundant SlNAC1-74 proteins into 12 subgroups. Six NAC genes from tomato, which were designated SNAC4–SNAC9, were studied instensively. The expression analysis indicated that each SNAC gene exhibited a specific expression pattern in the tissues examined. SNAC4 and SNAC6 were most highly expressed in the stems and leaves, whereas the expression levels of SNAC5, SNAC8 and SNAC9 were higher in young leaves and old leaves, respectively. In addition, the expression patterns of SNAC genes were characterized during the development of tomato fruits. All of the genes were further investigated to determine their responsiveness to hormones, and a coordinated expression was observed. The expression of the SNAC gene transcripts was induced by ABA, SA and short-time ethylene treatment, whereas their transcription was inhibited by GA, 6-BA and IAA. Our present study provides a useful reference for future investigations of NAC genes in tomato and other fleshy fruits.