In silico analyses of TALE transcription factors revealed its potential role for organ development and abiotic stress tolerance in Cotton

Three Amino-acid Loop Extension (TALE) family homeoproteins are involved in plant growth and development can have potential to promote resistance in response to various abiotic or biotic stresses. This class of proteins has been widely studied in many plant species. In current study, in silico analyses were performed to reveal the putative role of TALE transcription factors in stress tolerance and organ development. A total of 89 proteins were identified in G. hirsutum, which were further categorized into 17 subfamilies such as BLH1, BLH2, BLH6, BLH7, BLH8, BLH9, BLH11, BEL1, KNAT2, KNAT3, KNAT4, KNAT6, KNAT7, KN1, OSH6, H1 and ATH1. Biological information analysis showed that amino acid length is 250-850 aa among TALE proteins and molecular weight ranges between 30-90 kDa, persistent with characterization of TALE protein itself. Chromosomal mapping showed similar pattern of distribution of genes on A and D sub-genome of tetraploid cotton. Gene structure and motif distribution analysis revealed that each cluster of TALE proteins have identical intron-exon number and motif pattern. Among 89 TALE proteins, 34 gene pairs in G. hirsutum showed the segmental duplication with Ka/Ks value less than 1. Expression analysis confirmed up-regulated expression of TALE members belonging to subfamilies KNAT3, KNAT4, BEL1 and BLH1 under various abiotic stresses, suggested their putative role in response to stresses. Furthermore, significant expression level of these genes in various plant tissues also predicted their role in plant development. Promoter analysis illuminated the presence of several tissue specific or developmental plant hormone and stress responsive cis-elements in the promoter region of TALE members in G. hirsutum. In conclusion, comprehensive analysis of TALE transcription factor family revealed its potential candidature for breeding stress tolerant genotypes and exploring its role in organ development of cotton.