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Previous studies have revealed the functions of rice and maize

Expression patterns of BdGT genes in various B. distachyon (a) organs (Leaf, inflorescence, anther, pistil, plant embryo, and endosperm) and abiotic stresses (CK, ABA, SA, JA, PHX, and Ethylene). (PDF 364 kb)

Chromosome location of B. distachyon Trihelix genes. (PDF 100 kb)

Functional categorization of Trihelix genes in wheat and B. distachyon. TaGT and BdGT genes were categorized according to Gene Ontology annotation. The number and proportion of each category were displayed based on three functional classification categories (biological process, molecular function and cellular component). (PDF 284 kb)

Expression patterns of TaGT genes in various wheat tissues (a) and stresses (b).The expression data was collected through pubic RNA-seq data. The tissues expression of TaGT genes at different growth stages, such as roots (cotyledon emergence stage), stems (FL.02 1/2 of flowers open stage) leaves tissues (cotyledon emergence stage) and flowers (FL.02 1/2 of flowers open stage). Heatmap of expression profiles for TaGT genes across different stresses under 1 and 6â hâ s treatments, including heat stress, drought stress and drought&heat combined stress. (PDF 461 kb)

Multiple sequence alignment of GT domains of wheat and B. distachyon Trihelix TFs. Helix 1, 2 and 3 rectangular bars represent trihelix structure identified in the GT domain. Yellow shade indicates conserved amino acids. (PDF 6136 kb)

Previous studies have revealed the functions of rice and maize AGAMOUS LIKE 6 (AGL6) genes OsMADS6 and ZAG3, respectively, in floral development; however, the functions of three wheat (Triticum aestivum) AGL6 genes are still unclear. Here, we report the main functions of wheat AGL6 homoeologous genes in stamen development. In RNAi plants, stamens showed abnormality in number and morphology, and a tendency to transform into carpels. Consistently, the expression of the B-class gene TaAPETALA3 (AP3) and the auxin-responsive gene TaMGH3 was downregulated, whereas the wheat ortholog of the rice carpel identity gene DROOPING LEAF was ectopically expressed in RNAi stamens. TaAGL6 proteins bind to the promoter of TaAP3 directly. Yeast one-hybrid and transient expression assays further showed that TaAGL6 positively regulates the expression of TaAP3 in vivo. Wheat AGL6 transcription factors interact with TaAP3, TaAGAMOUS and TaMADS13. Our findings indicate that TaAGL6 transcription factors play an essential role in stamen development through transcriptional regulation of TaAP3 and other related genes. We propose a model to illustrate the function and probable mechanism of this regulation. This study extends our understanding of AGL6 genes.

Phylogenetic tree of Trihelix proteins by NJ. The five different subfamilies were indicated by different colors. Trihelix proteins of TaGT and BdGT TFs were indicated by red and blue circles respectively. (PDF 595 kb)

Expansins are plant cell wall-loosening proteins that involve in response to environmental stimuli and various development processes. In this study, 1858 expansin members were identified in 40 plant species by using Hidden Markov Model profiles and searching against to rice and Arabidopsis expansins. They were classified into four groups: EXPA, EXPB, EXLA, and EXLB. The distribution of expansin genes in different plant species indicated that EXPA genes emerged first, and genes in EXPB, EXLA, and EXLB subgroups might be resulted from gene duplication. In wheat, there are 104 expansins, including 88 TaEXPAs, 8 TaEXPBs, and 8 TaEXLAs. Phylogenetic analysis showed that wheat, rice, and Arabidopsis expansins shared high bootstrap values, and the phylogenetic relationship of wheat expansins were supported by conserved motifs and gene structures. Evolutionary analysis of Triticum urartu, Triticum turgidum, and wheat expansin genes revealed that gene duplication, gene loss, and chromosomal rearrangement events occurred during the evolution process of wheat expansins. Three kinds of cis-elements, including development-related, hormones-related, and abiotic stress-related were identified in the promoters of wheat expansin genes. Meanwhile, the expression of wheat expansin genes is extensive and affected by abiotic stresses. Additionally, by overexpressing in Arabidopsis, the functions of TaEXPB1A in root and seed development were characterized. In combination with previous reports, these results indicated the extensive functions of wheat expansins. Shortly, this study identified wheat expansins more accurately, and extended the knowledge of expansin genes.

Plant expansin belongs to a group of cell wall proteins and functions in plant growth and development. However, limited data are available on the contributions of expansins in Brachypodium distachyon. In the present study, a total of 38 expansins were identified in B. distachyon genome. Phylogenetic analysis divided the expansins into four groups, namely EXPA, EXPB, EXLA, and EXLB. Chromosomal distribution showed that they were unevenly distributed on 4 chromosomes. A total of six tandem duplication pairs and four segmental duplication pairs were detected, which contributed to the expansion of the B. distachyon expansin gene family. Expansins in the same group shared similar gene structure and motif composition. Three types of cis-elements, development-related, hormone-related, and abiotic stresses-related elements were found in the B. distachyon expansin gene promoters. Expression profiles indicated that most of B. distachyon expansin genes participate in plant development and abiotic stress responses. Overexpression of BdEXPA27 increased seed width and length, root length, root hair number and length in Arabidopsis and showed higher germination rate in transgenic lines. This study establishes a foundation for further investigation of B. distachyon expansin genes and provides novel insights into their biological functions.

The BRS1 (BRI1 Suppressor 1) gene encodes a serine carboxypeptidase that plays a critical role in the brassinosteroid signaling pathway. However, its specific biological function remains unclear. In this study, the developmental role of BRS1 was investigated in Arabidopsis thaliana. We found that overexpressing BRS1 resulted in significantly more lateral roots in different Arabidopsis ecotypes (WS2 and Col-0) and in brassinosteroid mutants (bri1-5 and det2-28). Further research showed that BRS1 facilitates the process whereby lateral root primordia break through the endodermis, cortex, and epidermis. Consistent with this, BRS1 was found to be highly expressed in the root endodermis and accumulated in the extracellular space around the dome of the lateral root primordia. Taken together, these results highlight the role of BRS1 in the process of lateral root emergence and provide new insight into the role of serine carboxypeptidases in plant root development.