Metabolomic profiling data.

Anaplerosis refers to enzymatic reactions or pathways replenishing metabolic intermediates in the tricarboxylic acid (TCA) cycle. Pyruvate carboxylase (PYC) plays an important anaplerotic role by catalyzing pyruvate carboxylation, forming oxaloacetate. Although PYC orthologs are well conserved in prokaryotes and eukaryotes, their pathobiological functions in filamentous pathogenic fungi have yet to be fully understood. Here, we delve into the molecular functions of the ortholog gene PYC1 in Fusarium graminearum and F. oxysporum, prominent fungal plant pathogens with distinct pathosystems, demonstrating variations in carbon metabolism for pathogenesis. Surprisingly, the PYC1 deletion mutant of F. oxysporum exhibited pleiotropic defects in hyphal growth, conidiation, and virulence, unlike F. graminearum, where PYC1 deletion did not significantly impact virulence. To further explore the species-specific effects of PYC1 deletion on pathogenicity, we conducted comprehensive metabolic profiling. Despite shared metabolic changes, distinct reprogramming in central carbon and nitrogen metabolism was identified. Specifically, alpha-ketoglutarate, a key link between the TCA cycle and amino acid metabolism, showed significant down-regulation exclusively in the PYC1 deletion mutant of F. oxysporum. The metabolic response associated with pathogenicity was notably characterized by S-methyl-5-thioadenosine and S-adenosyl-L-methionine. This research sheds light on how PYC1-mediated anaplerosis affects fungal metabolism and reveals species-specific variations, exemplified in F. graminearum and F. oxysporum.

回补反应（anaplerosis）指通过酶促反应或代谢通路补充三羧酸循环（tricarboxylic acid cycle, TCA循环）代谢中间产物的过程。丙酮酸羧化酶（pyruvate carboxylase, PYC）可催化丙酮酸羧化生成草酰乙酸，发挥关键的回补作用。尽管PYC同源物在原核生物与真核生物中高度保守，但其在丝状致病真菌中的致病生物学功能仍未得到完全阐明。本研究以两种具有独特致病系统的重要植物病原真菌——禾谷镰孢菌（Fusarium graminearum）与尖孢镰孢菌（Fusarium oxysporum）为研究对象，深入探究了其同源基因PYC1的分子功能，揭示了碳代谢变异与致病过程的关联。令人意外的是，尖孢镰孢菌的PYC1缺失突变体在菌丝生长、产孢及致病力方面均表现出多效性缺陷；而禾谷镰孢菌的PYC1缺失并不会对其致病力产生显著影响。为进一步探究PYC1缺失对致病性的物种特异性影响，我们开展了全面的代谢组分析。尽管二者存在共有代谢变化，但研究团队在中心碳氮代谢中发现了显著的重编程差异。具体而言，α-酮戊二酸（alpha-ketoglutarate）——三羧酸循环与氨基酸代谢之间的关键连接分子——仅在尖孢镰孢菌的PYC1缺失突变体中出现显著下调。与致病性相关的代谢响应则以S-甲基-5-硫代腺苷（S-methyl-5-thioadenosine）和S-腺苷-L-甲硫氨酸（S-adenosyl-L-methionine）为显著特征。本研究阐明了PYC1介导的回补反应如何影响真菌代谢，并以禾谷镰孢菌与尖孢镰孢菌为例，揭示了二者在致病过程中的物种特异性差异。