Insights into the trihelix transcription factor responses to salt and other stresses in Osmanthus fragrans

Abstract

Background Osmanthus fragrans is an evergreen plant with high ornamental and economic values. However, they are easily injured by salt stress, which severely limits their use in high salinity areas. The trihelix transcription factor (TF) family, as one of the earliest discovered TF families in plants, plays an essential part in responses to different abiotic stresses, and it has potential functions in improving the salt-tolerance capability of O. fragrans. Results In this study, 56 trihelix genes (OfGTs) were first identified in O. fragrans and then divided into five subfamilies in accordance with a phylogenetic tree analysis. The OfGTs were found to be located randomly on the 20 O. fragrans chromosomes, and an analysis of gene replication events indicated that the OfGT gene family underwent strong purification selection during the evolutionary process. The analysis of conserved motifs and gene structures implied that the OfGT members in the same subfamily have similar conserved motifs and gene structures. A promoter cis-elements analysis showed that all the OfGT genes contained multiple abiotic and hormonal stress-related cis-elements. The RNA-seq data suggested that the OfGTs have specific expression patterns in different tissues, and some were induced by salt stress. The qRT-PCR analysis of 12 selected OfGTs confirmed that OfGT1/3/21/33/42/45/46/52 were induced, with OfGT3/42/46 being the most highly expressed. In addition, OfGT42/OfGT46 had a co-expression pattern under salt-stress conditions. OfGT3/42/46 were mainly localized in the nuclei and exhibited no transcriptional activities based on the analysis of the subcellular localization and transcriptional activity assay. Furthermore, the expression levels of most of the selected OfGTs were induced by multiple abiotic and hormonal stresses, and the expression patterns of some OfGTs were also highly correlated with gibberellic acid and methyl jasmonate levels. Remarkably, the transient transformation results showed lower MDA content and increased expression of ROS-related genes NbAPX in transgenic plants, which implying OfGT3/42/46 may improve the salt tolerance of tobacco. Conclusions The results implied that the OfGT genes were related to abiotic and hormonal stress responses in O. fragrans, and that the OfGT3/42/46 genes in particular might play crucial roles in responses to salt stress. This study made a comprehensive summary of the OfGT gene family, including functions and co-expression patterns in response to salt and other stresses, as well as an evolutionary perspective. Consequently, it lays a foundation for further functional characterizations of these genes.

Transcriptome-Based Identification of the SaR2R3-MYB Gene Family in Sophora alopecuroides and Function Analysis of SaR2R3-MYB15 in Salt Stress Tolerance

“…Moreover, the expression levels of salt-related genes were dramatically increased by temporarily overexpressing SaR2R3-MYB15 in tobacco. Similarly, overexpressing three Osmanthus fragrans TFs in tobacco resulted in a dramatic increase in the expression of stress-related genes, indicating their significant roles in salt stress [ 48 ].…”

“…The expression patterns of salt stress-related genes ( NtSOD , NtCAT , and NtAPX ) were investigated in the transgenic tobaccos and the control groups were investigated. The NbL25 was used as an internal reference in the qRT–PCR analysis [ 48 ]. Additionally, we examined the expression patterns of eight salt stress-related genes ( AtSOS1 , AtSOS2 , AtSOS3 , AtSOD , AtPOD , AtCAT1 , AtNHX1 , and AtLEA3 ) in both the transgenic Arabidopsis and control groups.…”

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

“…Transcription factors form a complex network that regulates gene expression during plant evolution, and they are also key regulators of multiple signaling pathways [ 5 ]. Different transcription factors such as MYB [ 6 ], bHLH [ 7 ], AP2/ERF [ 8 ], GRAS [ 9 ], NAC [ 10 ], Trihelix [ 11 ] and WRKY [ 12 ] play important regulatory roles in different plants.…”

Comprehensive Genomic Analysis of Trihelix Family in Tea Plant (Camellia sinensis) and Their Putative Roles in Osmotic Stress

“…The trihelix family is a small gene family with a relatively modest number of members, ranging from 30 to 60 members in most plant species as compared to other gene families. For instance, Arabidopsis possesses 29 members, rice harbors 41 members, poplar possesses 56 members, sorghum contains 40 members, maize has 44 members, chrysanthemum has 20 members, Oenothera fragrans has 56 members, and quinoa has 47 members [ 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 ]. Previous research has demonstrated the crucial role of trihelix transcription factors in plant development.…”