Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China.
Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China.
Fungal Genet Biol. 2014 Apr;65:14-24. doi: 10.1016/j.fgb.2014.01.003. Epub 2014 Jan 27.
Mitogen-activated protein kinases (MAPKs) play important roles in the regulation of vegetative and pathogenic growth in plant pathogens. Here, we identified an SLT2-type MAP kinase in Phytophthora sojae, PsMPK1, which was transcriptionally induced in sporulating hyphae and the early stages of infection. Silencing of PsMPK1 caused defects in growth and zoosporogenesis, and increased hyphal swellings after the induction of sporangia formation, along with increasing hypersensitivity to cell wall-degrading enzymes. Transmission electron microscopy showed that the cell wall of PsMPK1-silenced mutants was also deleteriously affected. A dark outermost layer in the cell walls disappeared in the mutants, and an additional layer of the mutant cell wall that was deposited abnormally inside an inner bright layer appeared nonhomogeneous and rough compared to the wild type. Pathogenicity assays showed that PsMPK1-silenced transformants lost their pathogenicity on susceptible soybean host plants and triggered stronger cell death. Overall, PsMPK1 is involved in growth, differentiation, cell wall integrity, and pathogenicity in P. sojae.
丝裂原活化蛋白激酶（MAPKs）在植物病原体的营养和致病性生长的调节中起着重要作用。在这里，我们在大豆疫霉菌中鉴定了一种 SLT2 型 MAP 激酶 PsMPK1，它在孢子形成菌丝和感染的早期阶段转录诱导。PsMPK1 的沉默导致生长和游动孢子发生缺陷，并在诱导形成游动孢子后增加菌丝肿胀，同时对细胞壁降解酶的敏感性增加。透射电子显微镜显示 PsMPK1 沉默突变体的细胞壁也受到了损害。突变体中细胞壁的暗黑最外层消失，而异常沉积在内层明亮层内的突变体细胞壁的额外层看起来不均匀且粗糙，与野生型相比。致病性测定表明，PsMPK1 沉默转化子在易感大豆宿主植物上丧失了致病性，并引发更强的细胞死亡。总体而言，PsMPK1 参与了大豆疫霉菌的生长、分化、细胞壁完整性和致病性。
