Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China.
Wageningen Plant Research, Wageningen University and Research, 6700 AA, Wageningen, Netherlands.
BMC Genomics. 2019 Jul 10;20(1):570. doi: 10.1186/s12864-019-5949-x.
Cucumber Fusarium wilt, caused by Fusarium oxysporum f. sp. cucumerinum (Foc), is one of the most notorious diseases in cucumber production. Our previous research showed the virulence of Foc significantly increases over consecutive rounds of infection in a resistant cultivar. To understand the virulence variation of Foc under host pressure, the mildly virulent strain foc-3b (WT) and its virulence-enhanced variant Ra-4 (InVir) were selected and their transcriptome profiles in infected cucumber roots were analyzed at 24 h after inoculation (hai) and 120 hai.
A series of differentially expressed genes (DEGs) potentially involved in fungal pathogenicity and pathogenicity variation were identified and prove mainly involved in metabolic, transport, oxidation-reduction, cell wall degradation, macromolecules modification, and stress and defense. Among these DEGs, 190 up- and 360 down-regulated genes were expressed in both strains, indicating their importance in Foc infection. Besides, 286 and 366 DEGs showed up-regulated expression, while 492 and 214 showed down-regulated expression in InVir at 24 and 120 hai, respectively. These DEGs may be involved in increased virulence. Notably, transposases were more active in InVir than WT, indicating transposons may contribute to adaptive evolution.
By a comparative transcriptome analysis of the mildly and highly virulent strains of Foc during infection of cucumber, a series of DEGs were identified that may be associated with virulence. Hence, this study provides new insight into the transcriptomic profile underlying pathogenicity and virulence differentiation of Foc.
由尖孢镰刀菌黄瓜专化型（Fusarium oxysporum f. sp. cucumerinum，Foc）引起的黄瓜枯萎病是黄瓜生产中最严重的病害之一。我们之前的研究表明，在一个抗性品种中，Foc 连续几轮感染后其毒力显著增加。为了了解 Foc 在宿主压力下的毒力变化，选择了毒力较弱的菌株 foc-3b（WT）及其毒力增强的变体 Ra-4（InVir），并在接种后 24 小时（hai）和 120 hai 分析了它们在感染的黄瓜根中的转录组图谱。
鉴定出一系列可能参与真菌致病性和致病性变异的差异表达基因（DEGs），并证明它们主要参与代谢、运输、氧化还原、细胞壁降解、大分子修饰以及应激和防御。在这些 DEGs 中，WT 和 InVir 中均有 190 个上调和 360 个下调基因表达，表明它们在 Foc 感染中很重要。此外，在 24 和 120 hai 时，InVir 中分别有 286 和 366 个 DEGs 上调表达，而 492 和 214 个 DEGs 下调表达。这些 DEGs 可能参与了毒力的增强。值得注意的是，转座酶在 InVir 中的活性高于 WT，表明转座子可能有助于适应性进化。
通过比较感染黄瓜的 Foc 弱毒和强毒株的转录组分析，鉴定出一系列可能与毒力相关的 DEGs。因此，本研究为深入了解 Foc 致病性和毒力分化的转录组特征提供了新的视角。
