Genome-wide analysis of pathogenesis-related protein-1 (PR-1) genes from Qingke ( L. var. ) reveals their roles in stress responses.

Proteins that are pathogenesis-related 1 (PR-1) can accumulate to high levels when plants employ defenses, being major participants in processes critical for stress responses as well as development of many species. Yet we still lack information concerning family members in Qingke plants ( L. var. ). In this work, we distinguished 20  from the Qingke genome whose encoded proteins often featured at the N-terminus a signal peptide; all 20 PR-1s were predicted to localize either periplasmically or extracellularly. The CAP domain was confirmed as being highly conserved in all these PR-1s. Phylogeny-based inference revealed that PR-1 proteins clustered into four major clades, with the majority of Qingke PR-1s distributed in clade I (17 out 20), and the other 3 distributed in clade II. Gene structure analysis showed that 16  did not contain any introns, whereas the other four had 1-4 introns. We identified a variety of motifs that are -acting in the promoter regions of ; these included those potentially involved in Qingke's light response, hormonal and stress responses, circadian control and regulation of development and growth, in addition to sites where transcription factors bind to. Expression analysis uncovered several members of genes that were strongly and rapidly induced by powdery mildew infection, phytohormones, and cold stimulus. Altogether, our study's findings enhance what is known about genetic features of PR-1 family members in plants, especially Qingke, and could thereby facilitate further exploration aiming to elucidate the functioning of these proteins.