粉红螺旋聚孢霉67‐1厚垣孢子生物学特性的研究

Biological characteristics of chlamydospores of Clonostachys rosea 67-1

粉红螺旋聚孢霉(粉红粘帚霉)是多种植物病原真菌的重寄生菌,具有巨大的生防潜力。以实验室前期分离筛选的高效粉红螺旋聚孢霉67‐1菌株为材料,研究其厚垣孢子和分生孢子的生物学特性。结果表明,以厚垣孢子为接种体,其生长速度和菌丝鲜重与以分生孢子为接种体形成的菌落没有明显差异,但产孢水平提高6倍以上。粉红螺旋聚孢霉对高温和干燥的耐受程度较差,尤其分生孢子更为敏感。当加工温度范围在40–50℃时,厚垣孢子和分生孢子的活性存在显著差异(P<0.05)。菌株67‐1的厚垣孢子耐紫外线能力明显优于分生孢子。在无保护剂条件下,紫外灯照射60s,厚垣孢子活性保持在62.6%,是分生孢子活性1倍以上。土壤抑菌作用对真菌厚垣孢子的影响相对较小,24h孢子萌发率为47.2%,而分生孢子仅为4.6%。除了百菌清,菌株67‐1厚垣孢子对多种化学农药有较强的耐受力,在药剂田间使用浓度下,厚垣孢子萌发率均大于70%,其中对15%恶霉灵、1.8%阿维菌素和3%克百威的耐受力显著高于分生孢子(P<0.05),而对井冈霉素和两种杀虫剂没有显著提高。对菌株67‐1的寄生性测定结果表明,2种孢子对核盘菌菌核的寄生能力没有差异,菌核感染达到4级的占58.9%–60.0%。106/m L浓度厚垣孢子与分生孢子对黄瓜枯萎病的防效均达到65%以上,二者没有显著差异。

Clonostachys rosea （=Gliocladium roseum） is a mycoparasite of many plant fungal pathogens and potentia biocontrol agent. An effective strain 67-1 of the fungus screened in lab was chosen to study the biological characteristics of its chlamydospores and conidia harvested in different media in submerged culture. The results showed that no differ- ence existed in growth rate and fresh hyphal weight between the colonies respectively generated from its chlamydos- pores and conidia. However, the amount of spores produced on colonies generated from chlamydospores was 6 times higher than that from conidia. C, rosea was sensitive to higher temperature and dryness, especially the conidia. During processing course at 40-50~C, the two types of spores were significantly different in activities （P〈0.05）. The chlamydos- pores of strain 67-1 showed much higher ability to bear UV-irradiation as compared with the conidia. Illuminating UV ght without adding protective agent for 60s, the activity of the chlamydospores maintained 62.6%, one time higher than that of the conidia under the same treatment. The chlamydospores of strain 67-1 were relatively insensitive to soil fun- gistasis. The chlamydospore germination rate reached 47.2% in 24h, but the conidial germination rate only 4.6%. Except chlorothalonil, the chlamydospores of strain 67-1 had a good resistibility to most tested chemical pesticides. Under nor- mal concentration of pesticides in field, the chlamydospore maintained germination rate of more than 70%, much higher than conidial germination rate （P〈0.05）. The investigation of parasitism to 5clerotinia sclerotiorurn indicated that parasit- ic ability of chlamydospores and conidia was no dissimilarity, and 4th grade infection of sclerotia accounted for 58.9%-60.0%. When chlamydospores and conidia of strain 67-1 were respectively mixed with cucumber seeds at con- centration of 10^6spores/mL, their control efficiency to cucumber Fusarium wilt both reached over 65%.