Rafi Shahid, Shoaib Amna, Awan Zoia Arshad, Rizvi Nayab Batool, Shafiq Muhammad
Institute of Agricultural Sciences, University of the Punjab, Lahore, Pakistan.
Institute of Chemistry, University of the Punjab, Lahore, Pakistan.
Folia Microbiol (Praha). 2017 May;62(3):207-219. doi: 10.1007/s12223-016-0489-0. Epub 2016 Dec 26.
Sclerotium rolfsii is one of the most destructive fungal plant pathogens that can infect over 500 plants and can adapt to diverse environmental conditions. The present research work was carried out to evaluate the impact of both hexa- and trivalent chromium (Cr) on growth, morphology, enzymatic characteristics, and metal accumulation in S. rolfsii under laboratory conditions. Experiments were performed in both malt extract broth and agar growth medium amended with six different concentrations (10, 20, 40, 60, 80, and 100 ppm) of each Cr(III) and Cr(VI) ions inoculated with fungus and incubated for 6-7 days at 25 ± 3 °C. In broth medium, the total protein content was declined and activities of antioxidant enzymes were increased with an increase in metal concentrations. Lower concentrations (10 ppm) of the metal ions stimulated the growth of fungus and higher concentrations (60-100) inhibited it. The Fourier transform infrared spectroscopy (FTIR) assessment showed hydroxyl, carboxyl, and amine groups as major metal binding sites. In agar medium, tolerance index was decreased up to 0.56 at 10-80 ppm of Cr(III) and up to 0.62 at 10-60 ppm of Cr(VI). Considerable modifications were observed in hyphal and sclerotial morphology with an increase in concentration of metal ions. The current study concluded that interference of Cr with growth and physiological process of S. rolfsii could affect its infection level on its host plant. This study provides important information regarding cultivation of susceptible plant varieties in Cr-polluted soil as evidenced by pathogen growth up to 50 ppm of Cr(III) and Cr(VI) ions.
齐整小核菌是最具破坏性的真菌植物病原体之一，可感染500多种植物，并能适应多种环境条件。本研究旨在评估六价铬和三价铬对实验室条件下齐整小核菌的生长、形态、酶特性和金属积累的影响。实验在麦芽提取物肉汤和琼脂生长培养基中进行，分别添加六种不同浓度（10、20、40、60、80和100 ppm）的三价铬和六价铬离子，接种真菌后在25±3℃下培养6-7天。在肉汤培养基中，随着金属浓度的增加，总蛋白含量下降，抗氧化酶活性增加。较低浓度（10 ppm）的金属离子刺激真菌生长，而较高浓度（60-100 ppm）则抑制其生长。傅里叶变换红外光谱（FTIR）评估显示，羟基、羧基和胺基是主要的金属结合位点。在琼脂培养基中，三价铬浓度为10-80 ppm时耐受指数降至0.56，六价铬浓度为10-60 ppm时耐受指数降至0.62。随着金属离子浓度的增加，菌丝和菌核形态出现了显著变化。当前研究得出结论，铬对齐整小核菌生长和生理过程的干扰可能会影响其对寄主植物的感染水平。本研究提供了关于在铬污染土壤中种植易感植物品种的重要信息，病原体在高达50 ppm的三价铬和六价铬离子环境中仍能生长即证明了这一点。
