Genome-wide analysis of BURP genes and identification of a BURP-V gene RcBURP4 in Rosa chinensis.

KEY MESSAGE: Nine RcBURPs have been identified in Rosa chinensis, and overexpression of RcBURP4 increased ABA, NaCl sensitivity, and drought tolerance in transgenic Arabidopsis. BURP proteins are unique to plants and may contribute greatly to growth, development, and stress responses of plants. Despite the vital role of BURP proteins, little is known about these proteins in rose (Rosa spp.). In the present study, nine genes belonging to the BURP family in R. chinensis were identified using multiple bioinformatic approaches against the rose genome database. The nine RcBURPs, with diverse structures, were located on all chromosomes of the rose genome, except for Chr2 and Chr3. Phylogenic analysis revealed that these RcBURPs can be classified into eight subfamilies, including BNM2-like, PG1ß-like, USP-like, RD22-like, BURP-V, BURP-VI, BURP-VII, and BURP-VIII. Conserved motif and exon-intron analyses indicated a conserved pattern within the same subfamily. The presumed cis-regulatory elements (CREs) within the promoter region of each RcBURP were analyzed and the results showed that all RcBURPs contained different types of CREs, including abiotic stress-, light response-, phytohormones response-, and plant growth and development-related CREs. Transcriptomic analysis revealed that a BURP-V member, RcBURP4, was induced in rose leaves and roots under mild and severe drought treatments. We then overexpressed RcBURP4 in Arabidopsis and examined its role under abscisic acid (ABA), NaCl, polyethylene glycol (PEG), and drought treatments. Nine stress-responsive genes expression were changed in RcBURP4-overexpressing leaves and roots. Furthermore, RcBURP4-silenced rose plants exhibited decreased tolerance to dehydration. The results obtained from this study provide the first comprehensive overview of RcBURPs and highlight the importance of RcBURP4 in rose plant.