Trichoderma virens colonizes roots and develops a symbiotic relationship with plants where the fungal partner derives nutrients from plants and offers defence, in return. Tsp1, a small secreted cysteine-rich protein, was earlier found to be upregulated in co-cultivation of T. virens with maize roots. Tsp1 is well conserved in Ascomycota division of fungi, but none of its homologs have been studied yet. We have expressed and purified recombinant Tsp1, and resolved its structure to 1.25 Å resolutions, from two crystal forms, using Se-SAD methods. The Tsp1 adopts a β barrel fold and forms dimer in structure as well as in solution form. DALI based structure analysis revealed the structure similarity with two known fungal effector proteins: Alt a1 and PevD1. Structure and evolutionary analysis suggested that Tsp1 belongs to a novel effector protein family. Tsp1 acted as an inducer of salicylic acid mediated susceptibility in plants, rendering maize plants more susceptible to a necrotrophic pathogen Cochliobolus heterostrophus, as observed using plant defence assay and RT-qPCR analysis.

Trichoderma virens定植根部并与植物建立共生关系，其中真菌伙伴从植物中获取营养并提供防御，作为回报。Tsp1 是一种小而分泌的富含半胱氨酸的蛋白质，较早发现在T. virens 的共培养中上调与玉米根。Tsp1 在真菌的子囊菌门中非常保守，但尚未研究过其同源物。我们已经表达并纯化了重组 Tsp1，并使用 Se-SAD 方法从两种晶型中将其结构解析为 1.25 Å 分辨率。Tsp1 采用 β 桶状折叠并在结构和溶液形式上形成二聚体。基于 DALI 的结构分析揭示了与两种已知真菌效应蛋白的结构相似性：Alt a1 和 PevD1。结构和进化分析表明 Tsp1 属于一个新的效应蛋白家族。正如使用植物防御测定和 RT-qPCR 分析所观察到的那样，Tsp1 作为水杨酸介导的植物易感性的诱导剂，使玉米植物更容易受到坏死性病原体 Cochliobolus heterostrophus 的影响。