Innovative Institute for Plant Health, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China.
Laboratory of Physiological Plant Pathology, South China Agricultural University, Guangzhou 510642, China.
Int J Mol Sci. 2020 Aug 16;21(16):5886. doi: 10.3390/ijms21165886.
f. sp. race 4 (Foc4) causes Fusarium wilt that affects banana plants, and hence, the molecular mechanisms of its virulence need to be investigated. We purified an exo-polygalacturonase (exo-PG), Pgc4, from Foc4. Pgc4 has an apparent molecular weight of 50.87 kDa based on sodium dodecyl sulphate-polyacrylamide gel electrophoresis. We further performed its sequence analysis and biochemical characterization. The two genes encoding Pgc4 from Foc4 and Foc1 were 1434 bp in length and encoded 477 amino acids with differences, due to some nucleotide differences between the two. The m and max values of Pgc4 purified from Foc4 were determined to be 0.45 mg/mL and 105.26 Units·mg·protein ·min, respectively. The recombinant proteins, r-Foc1-Pgc4 and r-Foc4-Pgc4, were expressed and purified from and showed optimal Pgc4 activity at 55 °C and pH 4.0; both could induce tissue maceration and necrosis in the "Guangfen-1" and "Baxi" varieties of banana but to a different extent. Phenotypic assays and complementation analyses revealed that, compared to the wild-type, the generated Foc4Δ mutant strain showed a lower aerial hyphal growth, grew slower, and had a reduced virulence. Therefore, our results demonstrate the function of Pgc4 as a pathogenicity factor of Foc4.
f. sp. race 4 (Foc4) 引起香蕉枯萎病，因此需要研究其毒力的分子机制。我们从 Foc4 中纯化了一种外聚半乳糖醛酸酶（exo-PG），命名为 Pgc4。Pgc4 在十二烷基硫酸钠-聚丙烯酰胺凝胶电泳中的表观分子量为 50.87 kDa。我们进一步对其进行了序列分析和生化特性分析。Foc4 和 Foc1 编码 Pgc4 的两个基因长度均为 1434 bp，编码 477 个氨基酸，由于两个基因之间存在一些核苷酸差异，因此存在差异。从 Foc4 中纯化的 Pgc4 的 m 和 max 值分别为 0.45 mg/mL 和 105.26 Units·mg·protein ·min。从 和 表达和纯化了重组蛋白 r-Foc1-Pgc4 和 r-Foc4-Pgc4，它们在 55°C 和 pH 4.0 下表现出最佳的 Pgc4 活性；两者均可诱导香蕉“广粉 1 号”和“巴西”品种的组织溃烂和坏死，但程度不同。表型分析和互补分析表明，与野生型相比，产生的 Foc4Δ 突变株表现出较低的气生菌丝生长、生长较慢且毒力降低。因此，我们的结果表明 Pgc4 是 Foc4 致病性的一个因素。
