Gene Silencing Promotes a Defense Response in Rice and Enhances Resistance to .

Rice blast disease is a serious disease in rice caused by (). Ascorbic acid (AsA), or vitamin C, is a strong antioxidant that prevents oxidative damage to cellular components and plays an essential role in plant defense response. GDP-D-mannose pyrophosphorylase (GMP or VTC1) is an enzyme that generates GDP-D-mannose for AsA, cell wall, and glycoprotein synthesis. The gene has three homologs in the rice genome: , , and . Using RNAi lines, this study investigated the role of the gene during rice blast fungus inoculation. The RNAi inoculated with rice blast fungus induced changes to cell wall monosaccharides, photosynthetic efficiency, reactive oxygen species (ROS) accumulation, and malondialdehyde (MDA) content. Additionally, the RNAi lines were shown to be more resistant to rice blast fungus than the wild type. Genes and proteins related to defense response, plant hormone synthesis, and signaling pathways, especially salicylic acid and jasmonic acid, were up-regulated in the RNAi lines after rice blast inoculation. These results suggest that the gene regulates rice blast resistance through several defense mechanisms, including hormone synthesis and signaling pathways.