The sugar sensor, trehalose-6-phosphate synthase (Tps1), regulates primary and secondary metabolism during infection by the rice blast fungus: will Magnaporthe oryzae's "sweet tooth" become its "Achilles' heel"?
The sugar sensor, trehalose-6-phosphate synthase (Tps1), regulates primary and secondary metabolism during infection by the rice blast fungus: will Magnaporthe oryzae's "sweet tooth" become its "Achilles' heel"?
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DOI：
10.1080/21501203.2011.563431
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发表时间：
2011-01-01
期刊：
影响因子：
--
通讯作者：
Wilson, R. A.
中科院分区：
文献类型：
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作者：
Fernandez, J.;Wilson, R. A.
稻瘟病被认为是栽培稻上最严重的病害之一，并且是由病原体Magnaporthe potassium介导的。在感染过程中，圆顶状的真菌细胞，称为附着胞，形成在叶片表面，并通过甘油的积累产生膨压。这种巨大的压力直接作用在从细胞基部出现的薄的渗透菌丝上，迫使它穿过水稻叶片的表面，并允许真菌在植物内部定植。非还原性二糖海藻糖存在于M.在附着胞形成过程中，被激活。海藻糖生物合成的第一步涉及海藻糖-6-磷酸合酶（Tps 1），以及M.它消除了它引起疾病的能力。这种致病性的丧失被认为是由于海藻糖可能在附着胞的膨压产生中发挥的作用，或者是由于海藻糖中间体海藻糖-6-磷酸（其他生物体中的已知信号分子）的丧失。然而，随后的分析确定，在M.然而，Tps 1蛋白本身是植物感染的中心调节因子。在这里，我们讨论了海藻糖代谢的作用，在M。植物的发育与其他真核生物不同，并显示了Tps 1如何独立于其生物合成作用，作为糖传感器整合碳和氮代谢，并调节初级和次级代谢途径的子集，如氧化戊糖磷酸途径和色素形成，分别在植物定殖过程中。这是一个关键的作用，使真菌适应植物细胞中遇到的营养和氧化还原条件，并建立疾病。
Rice blast disease is considered one of the most serious diseases of cultivated rice and is mediated by the causal agent, Magnaporthe oryzae. During infection, dome-shaped fungal cells, called appressoria, form on the surface of the leaf and generate turgor through the accumulation of glycerol. This enormous pressure is directed down onto a thin penetration hypha emerging from the base of the cell, forcing it through the surface of the rice leaf and allowing fungal colonization of the plant interior. The non-reducing disaccharide, trehalose, is present in conidia of M. oryzae and is mobilised during appressorium formation. The first step in trehalose biosynthesis involves trehalose-6-phosphate synthase (Tps1), and deletion of the TPS1 gene in M. oryzae abolishes its ability to cause disease. This loss of pathogenicity was thought to be due to the role trehalose might play in turgor generation in the appressorium, or from the loss of the trehalose intermediate, trehalose-6-phosphate, a known signalling molecule in other organisms. However, subsequent analysis determined that, in M. oryzae, it is the Tps1 protein itself that is a central regulator of plant infection. Here, we discuss how the role of trehalose metabolism in M. oryzae development was determined to differ from other eukaryotes and show how, independent of its biosynthetic role, Tps1 functions as a sugar sensor to integrate carbon and nitrogen metabolism and regulate a subset of primary and secondary metabolic pathways, such as the oxidative pentose phosphate pathway and pigment formation, respectively, during plant colonisation. This is a critical role that allows the fungus to adapt to the nutritional and redox conditions encountered in the plant cell and establish disease.