State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Ministerial and Provincial Joint Innovation Centre for Safety Production of Cross-Strait Crops, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.
Marine and Agricultural Biotechnology Laboratory, Institute of Oceanography, Minjiang University, Fuzhou, 350108, China.
Appl Microbiol Biotechnol. 2022 Sep;106(17):5587-5602. doi: 10.1007/s00253-022-12100-z. Epub 2022 Aug 3.
Amidophosphoribosyltransferase catalyzes the conversion of 5-phosphoribosyl-1-pyrophosphate into 5-phosphoribosyl-1-amine in the de novo purine biosynthetic pathway. Herein, we identified and characterized the functions of MoAde4, an orthologue of yeast Ade4 in Magnaporthe oryzae. MoAde4 is a 537-amino acid protein containing GATase_6 and pribosyltran domains. MoADE4 transcripts were highly expressed during the conidiation, early-infection, and late-infection stages of the fungus. Disruption of the MoADE4 gene resulted in ΔMoade4 exhibiting adenine, adenosine, and hypoxanthine auxotrophy on minimal medium. Conidia quantification assays showed that sporulation was significantly reduced in the ΔMoade4 mutant. The conidia of ΔMoade4 could still form appressoria but mostly failed to penetrate the rice cuticle. Pathogenicity tests showed that ΔMoade4 was completely nonpathogenic on rice and barley leaves, which was attributed to restricted infectious hyphal growth within the primary cells. The ΔMoade4 mutant was defective in the induction of strong host immunity. Exogenous adenine partially rescued conidiation, infectious hyphal growth, and the pathogenicity defects of the ΔMoade4 mutant on barley and rice leaves. Taken together, our results demonstrated that purine nucleotide biosynthesis orchestrated by MoAde4 is required for fungal development and pathogenicity in M. oryzae. These findings therefore act as a suitable target for antifungal development against recalcitrant plant fungal pathogens. KEY POINTS: • MoAde4 is crucial for de novo purine nucleotide biosynthesis. • MoAde4 is pivotal for conidiogenesis and appressorium development of M. oryzae. • MoAde4 is involoved in the pathogenicity of M. oryzae.
amidophosphoribosyltransferase 催化 5-磷酸核糖-1-焦磷酸转化为从头嘌呤生物合成途径中的 5-磷酸核糖-1-胺。在此，我们鉴定并表征了酵母 Ade4 在稻瘟病菌中的同源物 MoAde4 的功能。MoAde4 是一种含有 GATase_6 和 pribosyltran 结构域的 537 个氨基酸的蛋白质。MoADE4 转录本在真菌的分生孢子形成、早期感染和晚期感染阶段高度表达。MoADE4 基因的敲除导致 ΔMoade4 在最小培养基上表现出腺嘌呤、腺苷和次黄嘌呤营养缺陷。分生孢子定量测定表明，ΔMoade4 突变体的孢子形成明显减少。ΔMoade4 的分生孢子仍能形成附着胞，但大多未能穿透水稻角质层。致病性试验表明，ΔMoade4 在水稻和大麦叶片上完全没有致病性，这归因于在初级细胞内限制了感染性菌丝的生长。ΔMoade4 突变体在诱导强烈的宿主免疫方面存在缺陷。外源性腺嘌呤部分挽救了 ΔMoade4 突变体在大麦和水稻叶片上的分生孢子形成、感染性菌丝生长和致病性缺陷。总之，我们的结果表明，由 MoAde4 协调的嘌呤核苷酸生物合成是稻瘟病菌发育和致病性所必需的。因此，这些发现为针对顽固植物真菌病原体的抗真菌药物开发提供了一个合适的目标。 关键点： • MoAde4 对从头嘌呤核苷酸生物合成至关重要。 • MoAde4 对稻瘟病菌的分生孢子发生和附着胞发育至关重要。 • MoAde4 参与稻瘟病菌的致病性。
