School of Fundamental Sciences, Massey University, Palmerston North, New Zealand.
Bio-Protection Research Centre, Lincoln, New Zealand.
Mol Microbiol. 2020 Jun;113(6):1101-1121. doi: 10.1111/mmi.14480. Epub 2020 Feb 12.
Although lipid signaling has been shown to serve crucial roles in mammals and plants, little is known about this process in filamentous fungi. Here we analyze the contribution of phospholipase D (PLD) and its product phosphatidic acid (PA) in hyphal morphogenesis and growth of Epichloë festucae and Neurospora crassa, and in the establishment of a symbiotic interaction between E. festucae and Lolium perenne. Growth of E. festucae and N. crassa PLD deletion strains in axenic culture, and for E. festucae in association with L. perenne, were analyzed by light-, confocal- and electron microscopy. Changes in PA distribution were analyzed in E. festucae using a PA biosensor and the impact of these changes on the endocytic recycling and superoxide production investigated. We found that E. festucae PldB, and the N. crassa ortholog, PLA-7, are required for polarized growth and cell fusion and contribute to ascospore development, whereas PldA/PLA-8 are dispensable for these functions. Exogenous addition of PA rescues the cell-fusion phenotype in E. festucae. PldB is also crucial for E. festucae to establish a symbiotic association with L. perenne. This study identifies a new component of the cell-cell communication and cell fusion signaling network for hyphal morphogenesis and growth of filamentous fungi.
尽管脂质信号在哺乳动物和植物中发挥着至关重要的作用，但在丝状真菌中，人们对此过程知之甚少。在这里，我们分析了磷脂酶 D (PLD) 及其产物磷脂酸 (PA) 在禾柄锈菌和粗糙脉孢菌菌丝形态发生和生长中的作用，以及禾柄锈菌与黑麦草之间共生关系的建立。通过光镜、共聚焦和电子显微镜分析了禾柄锈菌和粗糙脉孢菌 PLD 缺失菌株在无菌培养中的生长情况，以及禾柄锈菌与黑麦草共生时的生长情况。使用 PA 生物传感器分析了禾柄锈菌中 PA 的分布变化，并研究了这些变化对细胞内吞循环和超氧化物产生的影响。我们发现，禾柄锈菌的 PldB 和粗糙脉孢菌的同源物 PLA-7 对于极性生长和细胞融合以及分生孢子发育是必需的，而 PldA/PLA-8 则对这些功能是可有可无的。外源性添加 PA 可挽救禾柄锈菌的细胞融合表型。PldB 对于禾柄锈菌与黑麦草建立共生关系也是至关重要的。本研究鉴定了一个新的丝状真菌菌丝形态发生和生长的细胞间通讯和细胞融合信号网络的组成部分。
