Analysis of the thaumatin-like genes of Rosa chinensis and functional analysis of the role of RcTLP6 in salt stress tolerance.

A total of 27 rose thaumatin-like protein (TLP) genes were identified from the rose genome through bioinformatics analyses. RcTLP6 was found to confer salinity stress tolerance in rose. Thaumatin-like proteins (TLPs) play critical roles in regulating many biological processes, including abiotic and biotic stress responses in plants. Here, we conducted a genome-wide screen of TLPs in rose (Rosa chinensis) and identified 27 RcTLPs. The identified RcTLPs, as well as other TLPs from six different plant species, were placed into nine groups based on a phylogenetic analysis. An analysis of the intron-exon structures of the TLPs revealed a high degree of similarity. RcTLP genes were found on all chromosomes except for chromosome four. Cis-regulatory elements (CEs) were identified in the promoters of all RcTLPs, including CEs associated with growth, development and hormone-responsiveness, as well as abiotic and biotic responses, indicating they play diverse roles in rose. Transcriptomics analysis revealed that RcTLPs had tissue-specific expression patterns, and several root-preferential RcTLPs were responsive to drought and salinity stress. Quantitative PCR analysis of six RcTLPs under ABA, PEG and NaCl treatment confirmed the differentially expressed genes identified in the transcriptomics experiment. In addition, silencing RcTLP6 in rose leaves led to decreased tolerance to salinity stress. We also screened proteins which may interact with RcTLP6 to understand its biological roles. This study represents the first report of the TLP gene family in rose and expands the current understanding of the role that RcTLP6 plays in salt tolerance. These findings lay a foundation for future utilization of RcTLPs to improve rose abiotic stress tolerance.