Functional characterization of Fusarium verticillioides CPP1, a gene encoding a putative protein phosphatase 2A catalytic subunit
Functional characterization of Fusarium verticillioides CPP1, a gene encoding a putative protein phosphatase 2A catalytic subunit
复制标题
DOI：
10.1099/mic.0.2007/011411-0
复制
发表时间：
2008-01-01
期刊：
影响因子：
2.8
通讯作者：
Shim, Won-Bo
中科院分区：
文献类型：
--
作者：
Choi, Yoon-E;Shim, Won-Bo
轮枝镰刀菌在玉米粒上产生真菌毒素伏马菌素B-1（FB 1）。在这项研究中，我们确定了一个假定的蛋白磷酸酶基因CPP 1轮枝藻，并研究其在FB 1的调控作用。先前的工作表明，CPP 1表达在FB 1抑制遗传背景中升高。因此，我们假设CPP 1与FB 1的产生呈负相关。为了验证这一假设，我们产生了CPP 1敲除突变体，PP 179，并研究了基因缺失对FB 1生物合成和真菌发育的影响。PP 179显示FUM基因的表达升高，从而产生比野生型祖细胞更高水平的FB 1。其他显着的突变体表型包括减少琼脂平板上的径向生长，降低分生孢子萌发率，显着增加大分生孢子形成，和菌丝肿胀。为了验证这些表型是直接由于CPP 1缺失，我们用野生型CPP 1基因补充PP 179。互补菌株PPC 4显示出与野生型相似的FUM 1表达和FBI产生，提供了CPP 1与FB 1生物合成负相关的证据。其他PP 179表型，如大孢子和菌丝肿胀，也恢复到野生型祖。此外，我们补充了F。轮枝孢菌PP 179菌株与粗糙脉孢菌野生型ppe-1基因的同源性分析表明，Cpp 1和PPE-1蛋白在功能上是保守的。CPP 1缺失的多效性效应使我们假设CPP 1与轮枝镰刀菌中的多个下游信号通路相关。下游Cpp 1相互作用蛋白的鉴定和功能表征对于更好地理解与Cpp 1相关的复杂调控机制是必要的。
Fusarium verticillioides produces the mycotoxin fumonisin B-1 (FB1) on maize kernels. In this study, we identified a putative protein phosphatase gene CPP1 in F verticillioides, and investigated its role in FB1 regulation. Previous work has shown that CPP1 expression is elevated in an FB1-suppressing genetic background. Thus, we hypothesized that CPP1 is negatively associated with FB1 production. To test this hypothesis, we generated a CPP1 knockout mutant, PP179, and studied the effects of gene deletion on FB1 biosynthesis and fungal development. PP179 showed elevated expression of FUM genes, and in turn produced higher levels of FB1 than the wild-type progenitor. Other significant mutant phenotypes included reduced radial growth on agar plates, reduced conidia germination rates, significantly increased macroconidia formation, and hyphal swelling. To verify that these phenotypes were directly due to CPP1 deletion, we complemented PP179 with the wild-type CPP1 gene. The complemented strain PPC4 showed FUM1 expression and FBI production similar to that of the wild-type, providing evidence that CPP1 is negatively associated with FB1 biosynthesis. Other PP179 phenotypes, such as macroconidiation and hyphal swelling, were also restored to that of wild-type progenitor. Furthermore, we complemented F. verticillioides PP179 strain with Neurospora crassa wild-type ppe-1 gene, demonstrating that Cpp1 and PPE-1 proteins are functionally conserved. Pleiotropic effects of CPP1 deletion led us to hypothesize that CPP1 is associated with multiple downstream signalling pathways in F verticillioides. Identification and functional characterization of downstream Cpp1-interacting proteins are necessary to better understand the complex regulatory mechanisms associated with Cpp1.