The Characterization of the Gene Family Associated with Resistance to in .

In plants, phloem is not only a vital structure that is used for nutrient transportation, but it is also the location of a response that defends against various stresses, named phloem-based defense (PBD). Phloem proteins (PP2s) are among the predominant proteins in phloem, indicating their potential functional role in PBD. Sclerotinia disease (SD), which is caused by the necrotrophic fungal pathogen , is a devastating disease that affects oil crops, especially mainly by blocking nutrition and water transportation through xylem and phloem. Presently, the role of in SD resistance is still largely estimated. Therefore, in this study, we identified 62 members of the gene family in the genome with an uneven distribution across the 19 chromosomes. A phylogenetic analysis classified the into four clusters (I-IV), with cluster I containing the most members (28 genes) as a consequence of its frequent genome segmental duplication. A comparison of the gene structures and conserved motifs suggested that genes were well conserved in clusters II to IV, but were variable in cluster I. Interestingly, the motifs in different clusters displayed unique features, such as motif 6 specifically existing in cluster III and motif 1 being excluded from cluster IV. These results indicated the possible functional specification of A transcriptome data analysis showed that the genes in clusters II to IV exhibited dynamic expression alternation in tissues and the stimulation of , suggesting that they could participate in SD resistance. A GWAS analysis of a rapeseed population comprising 324 accessions identified four genes that were potentially responsible for SD resistance and a transgenic study that was conducted by transiently expressing in tobacco () leaves validated their positive role in regulating SD resistance in terms of reduced lesion size after inoculation with hyphal plugs. This study provides useful information on gene functions in and could aid elaborated functional studies on the gene family.