Medicago truncatula Vapyrin is a novel protein required for arbuscular mycorrhizal symbiosis
Medicago truncatula Vapyrin is a novel protein required for arbuscular mycorrhizal symbiosis
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DOI：
10.1111/j.1365-313x.2009.04072.x
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发表时间：
2010-02-01
期刊：
影响因子：
7.2
通讯作者：
Harrison, Maria J.
中科院分区：
文献类型：
--
作者：
Pumplin, Nathan;Mondo, Stephen J.;Harrison, Maria J.
丛枝菌根（AM）共生是一种广泛存在于维管束植物和球囊霉门真菌之间的互惠共生关系。在这种内共生中，真菌菌丝进入根部，通过表皮细胞生长到皮层，在皮层细胞中建立称为丛枝的分化菌丝。植物表皮和皮层细胞的重编程使真菌共生体能够在细胞内生长;然而，这一过程背后的植物基因在很大程度上是未知的。在这里，通过使用RNAi，我们证明了一个名为Vapyrin的蒺藜苜蓿基因的表达是必不可少的丛枝形成，也为AM真菌有效的表皮渗透。Vapyrin在菌丝穿透时在表皮中短暂诱导，然后在丛枝形成期间在皮质中诱导。Vapyrin蛋白质是细胞质的，并且在含有AM真菌菌丝的细胞中，蛋白质积累在穿过细胞质的小斑点中。Vapyrin是一种新型的蛋白质，由两个结构域组成，介导蛋白质-蛋白质相互作用：N-末端VAMP相关蛋白（VAP）/主要精子蛋白（MSP）结构域和C-末端锚定重复结构域。推定的Vapyrin直系同源物广泛存在于植物界，但不在拟南芥或非植物物种中。这些数据表明Vapyrin在细胞重塑中的作用，以支持AM共生过程中真菌菌丝的细胞内发育。
Arbuscular mycorrhizal (AM) symbiosis is a widespread mutualism formed between vascular plants and fungi of the Glomeromycota. In this endosymbiosis, fungal hyphae enter the roots, growing through epidermal cells to the cortex where they establish differentiated hyphae called arbuscules in the cortical cells. Reprogramming of the plant epidermal and cortical cells occurs to enable intracellular growth of the fungal symbiont; however, the plant genes underlying this process are largely unknown. Here, through the use of RNAi, we demonstrate that the expression of a Medicago truncatula gene named Vapyrin is essential for arbuscule formation, and also for efficient epidermal penetration by AM fungi. Vapyrin is induced transiently in the epidermis coincident with hyphal penetration, and then in the cortex during arbuscule formation. The Vapyrin protein is cytoplasmic, and in cells containing AM fungal hyphae, the protein accumulates in small puncta that move through the cytoplasm. Vapyrin is a novel protein composed of two domains that mediate protein-protein interactions: an N-terminal VAMP-associated protein (VAP)/major sperm protein (MSP) domain and a C-terminal ankyrin-repeat domain. Putative Vapyrin orthologs exist widely in the plant kingdom, but not in Arabidopsis, or in non-plant species. The data suggest a role for Vapyrin in cellular remodeling to support the intracellular development of fungal hyphae during AM symbiosis.