PJB-2024-198
Reactive Oxygen Species and Salicylic Acid Mediate the Responses of Pear to Venturia Nashicola Infection
Yi Liu
Abstract
Reactive oxygen species (ROS) and salicylic acid (SA) are essential signaling molecules in plant cells that participate in responses to biotic and abiotic stresses. Changes in ROS and SA signals during interactions between pear and the pear scab pathogen Venturia nashicola remain unclear. Herein, we analyzed the roles of ROS in the signal transduction pathway of pear scab resistance using the highly resistant ‘Huangguan’ and susceptible ‘Xuehua’ cultivars of pear (Pyrus bretschneideri Rehd). Protoplasts, calluses, and leaves were obtained from 14-year-old pear trees and treated with V. nashicola for different periods. The results showed that ROS rapidly accumulated in protoplasts of both cultivars within a 120-min treatment period, but the fluorescence intensity of ROS differed between cultivars. The H2O2 content in fruit-derived calluses of ‘Huangguan’ peaked at 48h post-infection at levels 1.85-fold higher than in ‘Xuehua’. Induction of H2O2 by V. nashicola in ‘Huangguan’ was more intense than in ‘Xuehua’ throughout a 96-h treatment period. At 96h post-infection, the malondialdehyde content in leaves of ‘Huangguan’ was significantly lower than in ‘Xuehua’, while the activities of superoxide dismutase, peroxidase, and catalase, and the relative expression levels of PbMnSOD, PbPOD, and PbCAT genes were higher in ‘Huangguan’ than ‘Xuehua’. V. nashicola infection also caused a continuous increase in the leaf SA content of ‘Huangguan’, which was 6.76-fold higher than in ‘Xuehua’ at 96h post-infection, and V. nashicola exposure upregulated the expression of PbPAL, PbICS, PbPR1, and PbPR5. In summary, both ROS and SA participated in the responses of pear trees to V. nashicola infection, and played vital roles in the signal transduction pathway of pear scab resistance.
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