Genome-wide identification, evolution, and expression level analysis of the TALE gene family in Sorghum bicolor

Abstract

Background: The three-amino-acid-loop-extension (TALE) is a ubiquitous homeodomain transcription factor among plant species involved in regulating plant growth, development, and environmental responses. However, this has not been systematically analyzed or reported in sorghum.

Results: In this study, 23 SbTALE genes were identified using bioinformatics and other methods at the genome level of sorghum, classified into two families, KNOX and BEL1-like family, and localized on ten chromosomes. One pair of tandem duplicated and seven pairs of segmentally duplicated genes were found, and the conserved motifs of SbTALEs among the same subfamilies were highly conserved, with highly conserved gene structures. SbTALEs genes have the most collinear genes with monocotyledonous Zea mays and are more closely related; SbTALEs have undergone purification and diversification selection in the evolutionary process. Overall, except for SbTALE21 and SbTALE23, the expression of the other six SbTALEs was higher in the stems, whereas the expression of SbTALE21 and SbTALE23 was higher in the leaves. In sorghum grain development, the lowest relative expression of SbTALEs was observed in grains in the late stage, and the expression of SbTALE21 was higher in grains in the early stage and husks in the late stage. In addition, SbTALE14 and SbTALE21 showed higher expression in the roots and stems under the cold treatment, and SbTALE02 and SbTALE12 showed higher expression in the roots and stems under the PEG treatment. Under the four hormone treatments, the expression of eight SbTALEs was relatively low in stems, the expression of SbTALE13 was higher in leaves than in roots and stems, and the expression of SbTALE23 was higher under the MeJA and SA treatments.

Conclusion: This study lays a theoretical foundation for the study of the biological function and mechanism of SbTALE genes and is of great significance for the mining of resistance genes and trait improvement.

Keywords: Sorghum bicolor; TALE gene family; Evolution; Gene expression; Genome-wide.