Genome-wide identification and characterization of the PbrMDH family in Pyrus bretschneideri and functional analysis of PbrMDHs in response to Botryosphaeria dothidea.

Abstract

Malate dehydrogenase (MDH) catalyzes the interconversion of malate and oxaloacetate, but its role in pear disease resistance remains unclear. In this study, 17 PbrMDH genes were identified in the pear genome and classified into seven subfamilies, with members unevenly distributed across 10 chromosomes. Promoter analysis revealed the presence of multiple hormone-, light-, and stress-responsive cis-acting elements. Expression analysis showed that more than half of these genes were up-regulated after inoculation with Botryosphaeria dothidea (B. dothidea), suggesting their involvement in pathogen response. Among them, PbrMDH1, PbrMDH5, PbrMDH6, and PbrMDH13 were selected for functional analysis. Virus-induced gene silencing showed that silencing each of these genes significantly increased lesion size after B. dothidea infection, indicating reduced resistance in pear leaves. Subcellular localization showed that PbrMDH5 is localized to the plasma membrane. In addition, stable overexpression of PbrMDH5 in pear calli significantly enhanced resistance to B. dothidea. These results demonstrate that multiple PbrMDH genes participate in pear defense, and that PbrMDH5 acts as a positive regulator of resistance to B. dothidea. This study provides a foundation for further elucidating the functions of MDH genes in pear disease resistance.

Supplementary information: The online version contains supplementary material available at 10.1007/s12298-026-01771-x.