Are protein disulfide isomerases effectively involved in the rose senescence phenomenon?

Flowers are key organs in many ornamental plants, and various phases of flower development impact their economic value. Previously, a senescence associated expressed sequence tag (EST) was isolated and identified by cDNA-AFLP, RhAC, by comparing two long-and short-vase life rose cultivars treated by ethylene. Protein sequence alignment of At3g54960 revealed that there are two probable proteins PDIA6 and PDI with the utmost similarity (67%) in Rosa chinensis genome. In the present study, the first comprehensive genome-wide explo-ration of the PDI gene family in Rosa chinensis was conducted. Full-length cDNAs of RhPDIA6 and RhPDI, 1994 and 1397 bp, respectively, were obtained by the homology method and confirmed by sequence analysis and structural features. Forty one RcPDIs were unevenly distributed on seven chromosomes of R. chinensis. Phylo-genetic and sequence alignment analyses divided the RcPDIs into two clads and seven subfamilies. Chromosomal distribution, gene structure and motif composition were subsequently investigated and indicated that the motif VEFYAPWCGHCKKLAPEYEK was conserved and C-G-H-C array was observed in all of the RhPDI sequences and most them were localized on Chr3. Promoter sequences analysis showed a total of thirty nine different motifs in the promoter region of PDI genes in rose, of which light-responsive elements and hormonal-responsive elements were the most present with sixteen and fifteen motifs, respectively. Protein interaction revealed that RhPDI and RhPDIA6 were related to other protein disulfide isomerases and oxidases. RhPDI and RhPDIA6 expression pat-terns were analyzed in two varieties of Rosa hybrida (Marroussia and Cool water) under ethylene treatment at two developmental stages of flowers (bud and open) in petals, sepal, and stamen after 24 and 48 h In addition to inducing the expression of both genes by ethylene in all studied tissues, it was found that in Cool water (with short-vase life) the expression of both genes was higher. This study is the first to establish the role of two PDI genes in the aging of cut rose flower parts.

Automated summary

This study conducted the first comprehensive genome-wide exploration of the PDI gene family in Rosa chinensis and revealed their role in flower aging. The researchers identified 41 RcPDIs in the genome of R. chinensis and investigated their chromosomal distribution, gene structure, and conserved protein sequences. Protein interaction analysis also showed that RhPDI and RhPDIA6 were related to other protein disulfide isomerases and oxidases. Additionally, the study found that the expression of both genes in cut roses can be induced by ethylene treatment.