Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China.
Lett Appl Microbiol. 2014 Apr;58(4):318-24. doi: 10.1111/lam.12193. Epub 2013 Nov 29.
The promising biocontrol isolate Clonostachys rosea 67-1 was investigated to clarify the effects of culture conditions on chlamydospore production in submerged fermentation. Culture conditions significantly affected both performance and types of C. rosea sporulation. C. rosea 67-1 was hard to generate chlamydospores under conventional conditions. However, the proportion of resistant spores increased to 17·4 and 15·5% in PD and rice meal media, respectively, in 8 days. Chlamydospore productivity was boosted (>threefold) with the addition of 50-200 mg l(-1) CuSO4 . The pH of the medium played a vital role in 67-1 sporulation. The percentage of chlamydospores decreased rapidly with increased pH (88·1% at pH 3·0 to 1·0% at pH 6·5). The optimal pH for conidia production was 6·0-6·5, at which chlamydospore forming was strongly inhibited. Regulating pH during fermentation contributed to improving output and proportion of resistant spores. When 67-1 was inoculated into broth with an initial pH of 6·5, followed by adjustment to pH 3·5 after 48 h, the number of chlamydospores reached 1·1 × 10(8) ml(-1). The impact of temperature and rotational speed was also analysed; an ultimate capacity of chlamydospores was achieved at 30°C and the speed above 120 rev min(-1) (P < 0·05).
Clonostachys rosea is one of the most promising biocontrol agents in countering many plant fungal diseases. However, large-scale production and commercialization are hampered by the lack of understanding of the impacts of culture conditions on performance and types of C. rosea sporulation and subsequently inadequate research on the techniques for chlamydospore production. In addressing these concerns, this study provides a unique insight into the manipulation of C. rosea sporulation and chlamydospore fermentation of the biocontrol fungus.
本研究旨在探讨生防菌玫瑰座腔菌 67-1 的培养条件对其液体深层发酵中产厚垣孢子的影响。培养条件对玫瑰座腔菌的生长和产孢类型有显著影响。常规条件下，玫瑰座腔菌 67-1 难以产生厚垣孢子。然而，在 PD 和米糠培养基中分别培养 8 天，抗性孢子的比例分别增加到 17.4%和 15.5%。添加 50-200 mg l(-1)CuSO4 可使厚垣孢子的产量提高（3 倍以上）。培养基的 pH 值对 67-1 的产孢有重要作用。随着 pH 值的升高（pH 3.0 时为 88.1%，pH 6.5 时为 1.0%），厚垣孢子的比例迅速下降。产分生孢子的最适 pH 值为 6.0-6.5，此时厚垣孢子的形成受到强烈抑制。发酵过程中调节 pH 值有助于提高产量和抗性孢子的比例。当 67-1 接种到初始 pH 值为 6.5 的培养液中，48 h 后调整至 pH 3.5 时，厚垣孢子数达到 1.1 × 10(8) ml(-1)。还分析了温度和转速的影响；在 30°C 和转速高于 120 rev min(-1)（P < 0.05）时达到最大厚垣孢子产量。
玫瑰座腔菌是防治多种植物真菌病害最有前途的生防菌之一。然而，由于缺乏对培养条件对生防菌性能和产孢类型的影响的了解，以及对厚垣孢子生产技术的研究不足，限制了其大规模生产和商业化。本研究针对这些问题，深入探讨了生防菌玫瑰座腔菌的产孢调控机制和厚垣孢子发酵技术。
