College of Plant Protection, Nanjing Agricultural University, Nanjing, China.
Mol Plant Pathol. 2021 Jul;22(7):769-785. doi: 10.1111/mpp.13060. Epub 2021 May 2.
Deoxynivalenol (DON) is a vital virulence factor of Fusarium graminearum, which causes Fusarium head blight (FHB). We recently found that validamycin A (VMA), an aminoglycoside antibiotic, can be used to control FHB and inhibit DON contamination, but its molecular mechanism is still unclear. In this study, we found that both neutral and acid trehalase (FgNTH and FgATH) are the targets of VMA in F. graminearum, and the deficiency of FgNTH and FgATH reduces the sensitivity to VMA by 2.12- and 1.79-fold, respectively, indicating that FgNTH is the main target of VMA. We found FgNTH is responsible for vegetative growth, FgATH is critical to sexual reproduction, and both of them play an important role in conidiation and virulence in F. graminearum. We found that FgNTH resided in the cytoplasm, affected the localization of FgATH, and positively regulated DON biosynthesis; however, FgATH resided in vacuole and negatively regulated DON biosynthesis. FgNTH interacted with FgPK (pyruvate kinase), a key enzyme in glycolysis, and the interaction was reduced by VMA; the deficiency of FgNTH affected the localization of FgPK under DON induction condition. Strains with a deficiency of FgNTH were more sensitive to demethylation inhibitor (DMI) fungicides. FgNTH regulated the expression level of FgCYP51A and FgCYP51B by interacting with FgCYP51B. Taken together, VMA inhibits DON biosynthesis by targeting FgNTH and reducing the interaction between FgNTH and FgPK, and synergizes with DMI fungicides against F. graminearum by decreasing FgCYP51A and FgCYP51B expression.
脱氧雪腐镰刀菌烯醇（DON）是禾谷镰刀菌的重要毒力因子，可引起赤霉病。我们最近发现，氨基糖苷类抗生素.validamycin A（VMA）可用于防治赤霉病并抑制 DON 污染，但它的分子机制尚不清楚。在本研究中，我们发现中性和酸性海藻糖酶（FgNTH 和 FgATH）均为 VMA 在禾谷镰刀菌中的靶标，FgNTH 和 FgATH 的缺失分别使 VMA 的敏感性降低 2.12 倍和 1.79 倍，表明 FgNTH 是 VMA 的主要靶标。我们发现 FgNTH 负责营养生长，FgATH 对有性生殖至关重要，两者在禾谷镰刀菌的产孢和致病中均发挥重要作用。我们发现 FgNTH 位于细胞质中，影响 FgATH 的定位，并正向调控 DON 生物合成；然而，FgATH 位于液泡中，并负向调控 DON 生物合成。FgNTH 与 FgPK（丙酮酸激酶）相互作用，后者是糖酵解中的关键酶，VMA 降低了两者的相互作用；FgNTH 的缺失影响了 DON 诱导条件下 FgPK 的定位。FgNTH 缺失的菌株对脱甲基抑制剂（DMI）类杀菌剂更为敏感。FgNTH 通过与 FgCYP51B 相互作用来调控 FgCYP51A 和 FgCYP51B 的表达水平。综上所述，VMA 通过靶向 FgNTH 并减少 FgNTH 与 FgPK 的相互作用来抑制 DON 生物合成，并通过降低 FgCYP51A 和 FgCYP51B 的表达与 DMI 类杀菌剂协同作用防治禾谷镰刀菌。
