Unravelling the Interplay of Nitrogen Nutrition and the Botrytis cinerea pectin lyase BcPNL1 in Modulating Arabidopsis thaliana Susceptibility

In this study, we investigated the intricate interplay between nitrogen nutrition, and the dynamics of pectin degradation during plant-pathogen interactions, using Arabidopsis thaliana and Botrytis cinerea as a model pathosystem. Our findings revealed a noteworthy impact of nitrogen availability on the pectin degrading activity of the B. cinerea pectin lyase 1 (PNL) for which the mutant strains presented a reduced pathogenicity restored by complementation. More precisely, infected nitrogen-sufficient (high N) plants exhibited an increased release of PNL-derived oligogalacturonides compared to infected nitrogen-deficient (low N) plants. This correlated with an elevated expression of jasmonic acid repressor genes in high N plants, rendering them more susceptible to B. cinerea . Using ΔBcpnl1 deletion mutants, we demonstrated that the increased production of BcPNL1 -derived oligogalacturonides under high N conditions was responsible for the increased expression of jasmonic acid repressor genes, significantly contributing to the higher susceptibility of high N plantsto B. cinerea. In conclusion, we demonstrated that BcPNL1 is a major pathogenicity factor during B. cinerea interaction that is affected by the plant’s N nutrition conditions.