Isolation of Pythium acanthicum, P-oligandrum, and P-periplocum from soil and evaluation of their mycoparasitic activity and biocontrol efficacy against selected phytopathogenic Pythium species
Isolation of Pythium acanthicum, P-oligandrum, and P-periplocum from soil and evaluation of their mycoparasitic activity and biocontrol efficacy against selected phytopathogenic Pythium species
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DOI：
10.1023/a:1007065010931
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发表时间：
1999-01-01
期刊：
影响因子：
5.5
通讯作者：
Saleh, ASF
中科院分区：
文献类型：
--
作者：
Ali-Shtayeh, MS;Saleh, ASF
采用菌核诱饵技术（SBT）和表土稀释板法（SSDP），在选择性VP3培养基上，对巴勒斯坦50块不同耕作方式的带刺卵原体的霉寄生菌进行了调查。SSDP法和SBT法分别从21种（42%）土壤和37种（74%）土壤中获得了霉菌种类。两种方法均可分离棘皮霉和寡孢霉，而粗皮霉仅用SBT法分离。采用新改良的双平板培养方法（MDPCM），在不同的体外条件下，3种分枝寄生虫对几种寄主Pythium表现出不同的拮抗作用。结果表明，长叶假单胞菌（P. periplocum）和寡叶假单胞菌（P. oligandrum）对黄瓜的枯败菌（P. ultimum）有较好的防效。该病原菌在水琼脂薄膜上被3种支寄生虫拮抗，对长枝假单胞菌（P. periplocum）中度敏感，对棘芽假单胞菌（P. acanthicum）和寡枝假单胞菌（P. oligandrum）轻微敏感。在室内条件下，将拮抗支原体掺入人工侵染青霉的泥炭/沙混合液中，500 CFUg（-1）浓度下的oligandrum和periplocum显著提高了幼苗出苗率，保护了幼苗免于受潮。在包衣法中，两种类型的种子处理（匀浆或卵孢子包衣种子）的生物防治效果与直接施用的效果相当。
Mycoparasitic Pythium species with spiny oogonia were surveyed in 50 Palestinian agricultural fields subject to different cropping practices using the Sclerotia Bait Technique (SBT) and the Surface-Soil-Dilution-Plate method (SSDP) with the selective VP3 medium. The mycoparasitic Pythium species were obtained from 21 (42%) soils using the SSDP method and from 37 (74%) soils using SBT. Pythium acanthicum and P. oligandrum were isolated by both methods, whereas P. periplocum was isolated only by the SBT. Using a newly modified dual plate culture method (MDPCM), the three mycoparasites showed varying antagonistic performance against several Pythium host species under a range of in vitro conditions. However, P. periplocum and P. oligandrum were found to be active biocontrol agents against P. ultimum, the damping-off organism of cucumber. This pathogen was antagonized, on thin films of water agar, by the three mycoparasites, and was moderately susceptible to P. periplocum while slightly susceptible to P. acanthicum and P. oligandrum. In direct application method in which antagonistic mycoparasites were incorporated into peat/sand mixture artificially infested with P. ultimum under growthroom conditions, Pythium oligandrum and P. periplocum (at 500 CFUg(-1)) significantly improved seedling emergence and protected seedlings from damping-off. In the seed coating method, biocontrol by two types of seed dressing (homogenate- or oospore coated seeds), was comparable to that achieved by direct application.