Cloning and Bioinformatics Analysis of <i>Rosa rugosa β</i>-1,3-Glucanase Gene (<i>RrGlu</i>)

Abstract

In order to reveal which role the callose played in R. rugosa pollination incompatibility, the full-length cDNA sequence of β -1,3-glucanase gene was cloned for the first time from the stylus of Rosa rugosa “Tanghong” with RT-PCR and RACE methods and named as RrGlu . The full-length cDNA is 1380 bp with an open reading frame of 1041 bp, encoding 346 amino acids. The derived protein has a molecular weight of 37.85 kD, a calculated pI of 9.12, a pfam00332 conserved domain at position 36 - 345, and belongs to glycosyl hydrolase family 17. The derived protein is a hydrophilic protein secreted into the vacuole. There is a signal peptide cleavage site at position 34 - 35, a transmembrane domain at position 13 - 32, six Ser phosphorylation sites, three Thr phosphorylation sites, three Tyr phosphorylation sites, one N-glycosylation site, and five O-glycosylation sites. There are 31.50% α -helixes, 30.92% random coil, 25.14% extended peptide chain, and 12.43% β -corner structure. This protein and the Glu protein from eight other species, including Prunus persica , share a sequence homology of greater than 72%; all of the proteins contain a pfam00332 conserved domain and a β -1,3-glucanase active center sequence (LIVM)-X-(LIVMFYW)3-(STAG)-E-(ST)-G-W-P-(ST)-X-G. Furthermore, their phylogenetic relationships are consistent with their traditional classifications. These results were meaningful to reveal the molecular mechanism of R. rugosa pollination incompatibility and improve the theory and techniques of breeding ornamental R. rugosa .