Type 2A phosphoprotein phosphatase is required for asexual development and pathogenesis of Sclerotinia sclerotiorum
Type 2A phosphoprotein phosphatase is required for asexual development and pathogenesis of Sclerotinia sclerotiorum
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DOI：
10.1094/mpmi-20-8-0944
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发表时间：
2007-08-01
影响因子：
3.5
通讯作者：
Yarden, O.
中科院分区：
文献类型：
--
作者：
Erental, A.;Harel, A.;Yarden, O.
核盘菌是一种广泛分布于世界各地的坏死性杂食性植物病原菌。核盘菌的菌核是一种有色的多菌丝结构，在该病原菌的生活和感染循环中起着核心作用。植物侵染依赖于富含黑色素的侵染垫的形成，以及水解酶和草酸的分泌。2A型丝氨酸/苏氨酸磷酸酶(PP2As)参与多种细胞过程的调节。在PP2A特异性抑制剂斑泻素的存在下，菌丝伸长和菌核数量受到损害，而菌核大小增加。我们通过反义表达编码PP2A催化亚基的基因(Pph1)来部分灭活PP2A。当反义表达被诱导时，观察到真菌生长几乎完全停止，这表明PP2A在真菌生长中起着至关重要的作用。基于RNAi的基因沉默被用来改变55 kDa R-2(B调节亚基)的表达。Rgb1 RNA水平降低的菌株生长缓慢，但仍有活力。在Rgb1突变体中，黑色素的生物合成、侵染缓冲产生和致病作用显著受损，但这些突变体在受伤的叶片上是致病的。在核盘菌中，ERK(细胞外信号调节激酶)类丝裂原活化蛋白激酶(MAPK)功能的降低导致NADPH氧化酶和PP2A活性水平的降低，这表明MAPK、活性氧和PP2A活性之间存在功能联系。
Sclerotinia sclerotiorum is a necrotrophic, omnivorous plant pathogen with worldwide distribution. Sclerotia of S. sclerotiorum are pigmented, multihyphal structures that play a central role in the life and infection cycles of this pathogen. Plant infection depends on the formation of melanin-rich infection cushions, and secretion of hydrolytic enzymes and oxalic acid. Type 2A Ser/Thr phosphatases (PP2As) are involved in the regulation of a variety of cellular process. In the presence of cantharidin, a PP2A-specific inhibitor, hyphal elongation and sclerotia numbers were impaired whereas sclerotial size increased. We partially inactivated PP2A by antisense expression of the gene (pph1) encoding the PP2A catalytic subunit. When antisense expression was induced, almost complete cessation of fungal growth was observed, indicative of a crucial role for PP2A in fungal growth. RNAi-based gene silencing was employed to alter the expression of the 55-kDa R-2 (B regulatory subunit). Isolates in which rgb1 RNA levels were decreased were slow growing, but viable. Melanin biosynthesis, infection-cushion production, and pathogenesis were significantly impaired in the rgb1 mutants, yet theses mutants were pathogenic on wounded leaves. Reduced ERK (extracellular signal-regulated kinases)-like mitogen-activated protein kinase (MAPK) function conferred a reduction in NADPH oxidase and PP2A activity levels, suggesting a functional link between MAPK, reactive oxygen species, and PP2A activity in S. sclerotiorum.