PATHOGENESIS-RELATED PROTEINS: identification, evolution and functional analysis in pear (Pyrus bretschneideri)

Abstract

Pathogenesis-related proteins (PRs) are essential for plant defense against both biotic and abiotic stresses. However, knowledge regarding PRs in pears remains limited. In this study, 637 PRs, classified into 16 families, were identified in Pyrus bretschneideri. Phylogenetic, sequence similarity, and secondary structure analyses enabled the classification of several PRs with conserved sequences, including PR-11, PR-8, PR-15, and PR-16. Genomic analysis revealed that the expansion of most PR families resulted from recent whole-genome duplication (WGD) events, occurring approximately 30–45 million years ago (Mya). Various gene duplication mechanisms have collectively contributed to the proliferation of PR families, with purifying selection indicated by the low Ka/Ks ratios. Examination of apoplastic fluid composition showed that only a subset of PRs was present in the apoplast. Transcriptomic data from Pyrus infected with Erwinia amylovora and Colletotrichum fructicola revealed the expression profiles of PR genes post-infection, underscoring the complexity of PR regulation. This study elucidates the evolutionary expansion, regulation, and functional roles of PRs in disease resistance, highlighting certain PRs as reliable markers of pear disease resistance. These findings offer valuable insights for future functional analyses and breeding strategies to enhance pear resistance to pathogens.

Keywords

Pathogenesis-related proteins / Pear / Classification / Evolution / Transcriptome sequencing / Biotic stress / Biological Sciences / Genetics

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Funding

National Key Research and Development Program of China(2022YFF1003100-02)

National Natural Science Foundation of China(32172511)

Jiangsu Agriculture Science and Technology Innovation Fund(CX(22)2025)

Seed Industry Promotion Project of Jiangsu(JBGS(2021)022)

Guidance Foundation of the Hainan Institute of Nanjing Agricultural University(NAUSY-MS08)

Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions, and the Earmarked Fund for China Agriculture Research System(CARS-28)

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