Unraveling NPR -like Family Genes in Fragaria spp. Facilitated to Identify Putative NPR1 and NPR3/4 Orthologues Participating in Strawberry- Colletotrichum fructicola Interaction.

The salicylic acid receptor NPR1 (nonexpressor of pathogenesis-related genes) and its paralogues NPR3 and NPR4 are master regulators of plant immunity. Commercial strawberry ( Fragaria × ananassa ) is a highly valued crop vulnerable to various pathogens. Historic confusions regarding the identity of NPR -like genes have hindered research in strawberry resistance. In this study, the comprehensive identification and phylogenic analysis unraveled this family, harboring 6, 6, 5, and 23 members in F. vesca , F. viridis , F. iinumae , and F. × ananassa , respectively. These genes were clustered into three clades, with each diploid member matching three to five homoalleles in F. × ananassa . Despite the high conservation in terms of gene structure, protein module, and functional residues/motifs/domains, substantial divergence was observed, hinting strawberry NPR proteins probably function in ways somewhat different from Arabidopsis . RT-PCR and RNAseq analysis evidenced the transcriptional responses of FveNPR1 and FxaNPR1a to Colletotrichum fructicola . Extended expression analysis for strawberry NPR -likes helped to us understand how strawberry orchestrate the NPRs-centered defense system against C. fructicola . The cThe current work supports that FveNPR1 and FxaNPR1a, as well as FveNPR31 and FxaNPR31a-c, were putative functional orthologues of AtNPR1 and AtNPR3/4, respectively. These findings set a solid basis for the molecular dissection of biological functions of strawberry NPR -like genes for improving disease resistance.