In bacteria, FtsZ proteins form a Z ring that is the initial step preceding septal fission. FtsZ proteins enable the division of mitochondria in early eukaryotes and are present in some kingdoms but have been lost in animals, fungi, and plants. Here, we have identified two Phytophthora capsici ortholog genes of Escherichia coli FtsZs, designated PcFtsZ1 and PcFtsZ2. Overexpression of PcFtsZ2 in E. coli fully complemented the overexpression phenotype of EcFtsZ. In contrast, overexpression of PcFtsZ1 in E. coli had minimal impact on cell division and separation. Thus, we focused on evaluating the impact of altered expression of PcFtsZ2 in P. capsici, as it exhibited the strongest phenotype. PcFtsZ2 was expressed at the highest levels in mycelia, sporangia, and germinating cysts, as well as in late infection. PcFtsZ2 mis-expression lines showed aberrant asexual growth and development of P. capsici. Alterations in the expression of PcFtsZ2 changed the distribution of mitochondria in hyphae and sporangia and, also, affected the number, size, and shape of actin plaques. Silencing of PcFtsZ2 restrained growth and development of invasive structures, especially cysts and sporangia, substantially inhibiting the ability of transformants to cause blight lesions. In overexpressed transformant lines, cyst and sporangial germination rates were only half that of controls, but hyphal growth from direct germination of sporangia was more rapid than controls. These transformant lines were only slightly impaired in virulence relative to controls. This study emphasizes the essential role of the evolutionarily conserved FtsZ2 proteins in affecting cytoskeleton dynamics.

中文翻译：

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辣椒疫霉菌PcFtsZ2是无性发育和植物感染所必需的。

在细菌中，FtsZ蛋白形成Z环，这是隔裂之前的第一步。FtsZ蛋白能使线粒体在真核生物中分裂，并存在于某些王国中，但已在动物，真菌和植物中丢失。在这里，我们确定了大肠杆菌FtsZs的两个辣椒疫霉直系同源基因，分别命名为PcFtsZ1和PcFtsZ2。PcFtsZ2在大肠杆菌中的过表达完全补充了EcFtsZ的过表达表型。相反，在大肠杆菌中过表达PcFtsZ1对细胞分裂和分离的影响很小。因此，我们集中于评估辣椒辣椒中PcFtsZ2表达改变的影响，因为它表现出最强的表型。PcFtsZ2在菌丝体，孢子囊和发芽性囊肿以及晚期感染中均以最高水平表达。PcFtsZ2错误表达谱系显示辣椒的无性繁殖异常。PcFtsZ2表达的改变改变了线粒体在菌丝和孢子囊中的分布，并且还影响了肌动蛋白噬菌斑的数量，大小和形状。PcFtsZ2的沉默抑制了侵入性结构（尤其是囊肿和孢子囊）的生长和发育，从而大大抑制了转化子引起枯萎病的能力。在过表达的转化株中，囊肿和孢子囊的发芽率仅是对照的一半，但是来自孢子囊直接发芽的菌丝生长比对照组快。相对于对照，这些转化株的毒力仅略微受损。这项研究强调了进化上保守的FtsZ2蛋白在影响细胞骨架动力学中的重要作用。