Research shows that the TALE transcription factors in Sorghum bicolor regulate growth, development, and stress responses, showing evolutionary conservation, tissue-specific expression, and hormone-induced activity.

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

The three-amino-acid-loop-extension (TALE) transcription factor family plays a critical role in regulating plant growth, development, and environmental responses. Researchers from Guizhou University, Chinese Academy of Agricultural Sciences, and Chengdu University conducted a systematic analysis in Sorghum bicolor and have identified 23 SbTALE genes categorized into two major families: KNOX and BEL1-like. These families were further divided into functional subgroups based on conserved structures and evolutionary relationships.   Gene structural analysis revealed that intron-exon arrangements varied significantly, with the KNOX family displaying more introns, which may indicate complex evolutionary processes. Chromosomal mapping showed uneven distribution, with the highest density on chromosome 1, and identified one tandem and seven segmental duplication events, highlighting a gene expansion mechanism . Evolutionary analyses suggested that SbTALE genes have undergone purifying and diversifying selection, with monocotyledons like Zea mays showing the highest synteny, indicating close evolutionary relationships.

Expression studies revealed that SbTALE genes exhibit a variety of expression patterns across tissue types and stress conditions. Promoter analysis identified cis-regulatory elements responsive to light, hormones, and drought, underscoring the SbTALE genes’ roles in stress adaptation and growth regulation. For example, SbTALE02 and SbTALE12 were associated with drought response via ABA and MeJA pathways, while SbTALE14 and SbTALE21 showed cold tolerance. Hormone treatments including ABA, GA, and MeJA further modulated gene expression, suggesting their involvement in complex regulatory networks. These findings provide foundational insights into the functional roles of SbTALEs, with potential applications in improving sorghum traits and stress resistance.

SorghumBase examples: 

Figure 1: The authors did a systematic analysis on three-amino-acid-loop-extension (TALE) transcription factor families and identified 23 in Sorghum bicolor. Among them, SbTALE01 (SORBI_3001G075101) is classified as a KNOX-like gene. This phylogenetic tree illustrates the evolutionary relationships between SbTALE01 and its homologs across diverse plant species, as determined by Ensembl Compara. The alignment overview shows conserved protein domains, color-coded by InterPro annotations.
Figure 2: This figure shows the expression profile SbTALE01 of under the Expression Tab (all paralogs) in SorghumBase. It displays the baseline expression done in one study in different tissue types. The overall expression for all genes represented indicates that during early and emerging inflorescence all genes are expressed. The datasets are curated and processed by EMBL-EBI Expression Atlas in collaboration with the SorghumBase team.

Reference:

Yao X, Yang S, Lai D, Weng W, Fan Y, Wu W, Ma C, Cheng J, Zhou M, Ruan J. Genome-wide identification, evolution, and expression level analysis of the TALE gene family in Sorghum bicolor. BMC Plant Biol. 2024 Nov 30;24(1):1152. PMID: 39614134. doi: 10.1186/s12870-024-05735-9. Read more

Comprehensive Analysis of TALE Transcription Factors in Sorghum bicolor: Evolution, Expression, and Functional Roles

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