Salicylic acid (SA) is a plant hormone involved in a series of growth, development, and stress responses in plants. Nonexpressor of pathogenesis-related genes 1 (NPR1) is the core regulatory gene in the process of SA-mediated systemic acquired resistance (SAR). Whether NPR1 is involved in pollen tube growth mediated by SA and its derivative MeSA (methyl salicylate) remains to be explored. Here, we found that the contents of endogenous SA and MeSA in self- or cross-pollinated pistils changed significantly, and exogenous SA and MeSA significantly promoted pollen germination and pollen tube elong...
