Genome-wide identification of trihelix transcription factors in the apple genome in silico

Trihelix transcription factors are involved in the growth and development of plants, as well as various stress responses. In the study presented, we identified 37 trihelix family genes in the apple genome (MdTH). The trihelix genes were located on 13 chromosomes. Phylogenetic analysis of these MdTH and the trihelix genes of other species divided them into six subfamilies: GT-1, GT-2, SH4, SIP1, GTγ, and GTδ. The genes of different groups significantly diverged in their gene structure and conserved functional domains. Cis-element analysis showed that promoter sequences of MdTH genes contained light response elements, phytohormone response elements, and stress-related cis-elements. The expression pattern analysis results demonstrated that MdTH were regulated by drought, salinity, as well as high and low temperatures. MdTH4 and MdTH24 were highly regulated by soil salinity, MdTH4-by drought. MdTH30 showed high expression under low temperature; MdTH8, MdTH20, and MdTH36-under high temperature.

Transcriptome-Wide Integrated Analysis of the PgGT25-04 Gene in Controlling Ginsenoside Biosynthesis in Panax ginseng

Panax ginseng is a valuable medicinal herb of the Araliaceae family with various pharmacological activities. The Trihelix transcription factors family is involved in growth and secondary metabolic processes in plants, but no studies have been reported on the involvement of Trihelix genes in secondary metabolic processes in ginseng. In this study, weighted co-expression network analysis, correlation analysis between PgGTs and ginsenosides and key enzyme genes, and interaction network analysis between PgGTs and key enzyme genes were used to screen out the PgGT25-04 gene, which was negatively correlated with ginsenoside synthesis. Using ABA treatment of ginseng hair roots, PgGT genes were found to respond to ABA signals. Analysis of the sequence characteristics and expression pattern of the PgGT25-04 gene in ginseng revealed that its expression is spatiotemporally specific. The interfering vector pBI121-PgGT25-04 containing the PgGT25-04 gene was constructed, and the ginseng adventitious roots were transformed using the Agrobacterium-mediated method to obtain the pBI121-PgGT25-04 positive hairy root monocot line. The saponin contents of positive ginseng hair roots were measured by HPLC, and the changes in PgGT25-04 and key enzyme genes in positive ginseng hair roots were detected via fluorescence quantitative RT-PCR. These results preliminarily identified the role of the PgGT25-04 gene in the secondary metabolism of ginseng in Jilin to provide a theoretical basis for the study of Trihelix transcription factors in Panax ginseng.

Overexpression of cotton Trihelix transcription factor GhGT-3b_A04 enhances resistance to Verticillium dahliae and affects plant growth in Arabidopsis thaliana

Verticillium wilt is a soil-borne fungal disease that severely affects cotton fiber yield and quality. Herein, a cotton Trihelix family gene, GhGT-3b_A04, was strongly induced by the fungal pathogen Verticillium dahliae. Overexpression of the gene in Arabidopsis thaliana enhanced the plant's resistance to Verticillium wilt but inhibited the growth of rosette leaves. In addition, the primary root length, root hair number, and root hair length increased in GhGT-3b_A04-overexpressing plants. The density and length of trichomes on the rosette leaves also increased. GhGT-3b_A04 localized to the nucleus, and transcriptome analysis revealed that it induced gene expression for salicylic acid synthesis and signal transduction and activated gene expression for disease resistance. The gene expression for auxin signal transduction and trichome development was reduced in GhGT-3b_A04-overexpressing plants. Our results highlight important regulatory genes for Verticillium wilt resistance and cotton fiber quality improvement. The identification of GhGT-3b_A04 and other important regulatory genes can provide crucial reference information for future research on transgenic cotton breeding.

The trihelix family of transcription factors: functional and evolutionary analysis in Moso bamboo (Phyllostachys edulis)

BACKGROUND

Trihelix transcription factors (TTFs) are photoresponsive proteins that have a representative three-helix structure (helix-loop-helix-loop-helix). Members of this gene family have been reported to play roles in many plant processes.

RESULTS

In this study, we performed a functional and evolutionary analysis of the TTFs in Moso bamboo (Phyllostachys edulis). A total of 35 genes were identified and grouped into five subfamilies (GT-1, GT-γ, GT-2, SIP1 and SH4) according to their structural properties. Gene structure analysis showed that most genes in the PeTTF family had fewer introns. A unique motif (Motif 16) to the GT-γ subfamily was identified by conserved motif analysis. Promoter analysis revealed various cis-acting elements related to plant growth and development, abiotic and biotic stresses, and phytohormone responses. Data for the 35 Moso bamboo TTF genes were used to generate heat maps, which indicated that these genes were expressed in different tissues or developmental stages. Most of the TTF genes identified here had high expression in leaves and panicles according to the expression profile analysis. The expression levels of the TTF members in young leaves were studied using quantitative real-time PCR to determine their tissue specificity and stress-related expression patterns to help functionally characterize individual members.

CONCLUSIONS

The results indicated that members of the TTF gene family may be involved in plant responses to stress conditions. Additionally, PeTTF29 was shown to be located in the nucleus by subcellular localization analysis and to have transcriptional activity in a transcriptional activity assay. Our research provides a comprehensive summary of the PeTTF gene family, including functional and evolutionary perspectives, and provides a basis for functionally characterizing these genes.