The Sclerotinia sclerotiorum Slt2 mitogen-activated protein kinase ortholog, SMK3, is required for infection initiation but not lesion expansion
The Sclerotinia sclerotiorum Slt2 mitogen-activated protein kinase ortholog, SMK3, is required for infection initiation but not lesion expansion
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DOI：
10.1139/cjm-2016-0091
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发表时间：
2016-10-01
影响因子：
2.8
通讯作者：
Hegedus, Dwayne D.
中科院分区：
文献类型：
--
作者：
Bashi, Zafer Dallal;Gyawali, Sanjaya;Hegedus, Dwayne D.
丝裂原活化蛋白激酶（MAPK）在细胞外刺激信号传递和基因表达调控中发挥重要作用。在植物病原真菌核盘菌中鉴定了酿酒酵母细胞壁完整性MAPK的直系同源物。S. Sclerotiorum Smk3基因在完整的寄主叶片上严重降低了毒力，但在剥除角质层蜡的叶片上不降低毒力。这是由于菌丝顶端优势的改变导致无法聚集和形成感染垫。该突变还导致产生菌核的能力丧失，气生菌丝形成增加，菌丝疏水性和细胞壁完整性改变。突变体在固体培养基上的径向膨胀速率较慢，但对高温的耐受性更强。SMK3细胞壁完整性MAPK的缺失似乎削弱了S.核盘菌感知其周围环境，导致各种功能的失调。许多表型与S.核盘菌腺苷酸环化酶和SMK1 MAPK突变体，这表明这些信号通路共同调节真菌生长，生理学和致病性方面。
Mitogen-activated protein kinases (MAPKs) play a central role in transferring signals and regulating gene expression in response to extracellular stimuli. An ortholog of the Saccharomyces cerevisiae cell wall integrity MAPK was identified in the phytopathogenic fungus Sclerotinia sclerotiorum. Disruption of the S. sclerotiorum Smk3 gene severely reduced virulence on intact host plant leaves but not on leaves stripped of cuticle wax. This was attributed to alterations in hyphal apical dominance leading to the inability to aggregate and form infection cushions. The mutation also caused loss of the ability to produce sclerotia, increased aerial hyphae formation, and altered hyphal hydrophobicity and cell wall integrity. Mutants had slower radial expansion rates on solid media but more tolerance to elevated temperatures. Loss of the SMK3 cell wall integrity MAPK appears to have impaired the ability of S. sclerotiorum to sense its surrounding environment, leading to misregulation of a variety of functions. Many of the phenotypes were similar to those observed in S. sclerotiorum adenylate cyclase and SMK1 MAPK mutants, suggesting that these signaling pathways co-regulate aspects of fungal growth, physiology, and pathogenicity.