The genome wide analysis of GT transcription factors that respond to drought and waterlogging stresses in maize

Abstract

Trihelix transcription factors (also known as GT transcription factors) are unique to plants and play important roles in abiotic stress. Here, we report the identification of 59 GT factors in maize by the in silico approach. The 59 maize GT factors are classified into five clades: GT-1 (13), GT-2 (7), GTγ (11), SH4 (7), and SIP1 (21). Their amino acid sequence compositions, physical and chemical characteristics, phylogenetic trees, and chromosomal locations are predicted and analyzed. These 59 maize GT factors are distributed on maize chromosomes 1–10 (11, 8, 5, 9, 9, 2, 1, 4, 3 and 7 genes, respectively). The mRNA expression levels of these GT factors in roots are determined using RNA-seq for the waterlogging-tolerant Hz32 maize line. The results showed that the expression levels of 17 of 59 GT factors increase under drought stress, while those of 3 of them decrease. Under waterlogging stress, the mRNA expression levels of 14 of them increase; 8 of these 14 GT factors overlap with the 17 GT factors whose levels increase under drought stress. The spatio-temporal expression patterns of these eight GT factors show that seven of them (SIP1S, GT-2G, GT-2D, GTγG, SIP1F, SIP1D, and SIP1L) are preferentially expressed in leaves, roots, and internodes, indicating that they are the best candidates among the 59 GTs for further study on waterlogging and drought tolerance in maize.