A promising strain of endophytic Streptomyces sp for biological control of cucumber anthracnose
A promising strain of endophytic Streptomyces sp for biological control of cucumber anthracnose
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DOI：
10.1007/s10327-008-0138-9
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发表时间：
2009-02-01
影响因子：
1.2
通讯作者：
Ushijima, Yusuke
中科院分区：
文献类型：
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作者：
Shimizu, Masafumi;Yazawa, Sachiko;Ushijima, Yusuke
在对黄瓜炭疽病病原菌轮纹炭疽菌有效生防剂的调查中，从黄瓜和南瓜植株的表面灭菌器官中分别分离到43株(MBCu系列)和135株(MBPu系列)内生放线菌。在IMA-2琼脂上用轮枝线虫培养，测定它们的体外拮抗能力。筛选出11株对病原菌菌丝生长有强烈抑制作用的菌株作为拮抗菌。黄瓜离体子叶在攻毒接种前1d浸泡在拮抗菌株的孢子悬浮液中，其中6种拮抗剂(MBCu32、36、42、45、56和MBPu-75)与未处理的对照相比，显著减少了子叶上的病斑数量和大小。同样，这6个菌株对3周龄黄瓜幼苗附着叶的病斑发育也有抑制作用。在这些菌株中，最具抑制力的菌株MBCu56被选作进一步测试。当浓度为10(7)、10(8)和10(9)cfu/ml时，对病害的抑制率分别为72%、79%和93%。这些结果有力地表明MBCu-56对黄瓜炭疽病具有很强的防治潜力。经分类鉴定和16S rDNA序列分析，该菌株为链霉菌属(Streptomyces sp.)经扫描电子显微镜观察，该菌株的底物菌丝定植于叶表面角质层以上。一些菌丝也穿透并生长在角质层下。
In a survey for effective biocontrol agents of Colletotrichum orbiculare, causal agent of cucumber anthracnose, 43 (MBCu series) and 135 (MBPu series) endophytic actinomycete strains were recovered from surface-sterilized organs of cucumber (Cucumis sativus) and pumpkin (Cucurbita moschata) plants, respectively. The strains were cultured with C. orbiculare on IMA-2 agar medium to determine their in vitro antagonistic ability. Eleven strains that strongly inhibited hyphal growth of the pathogen were selected as potent antagonists. Detached cotyledons of cucumber were soaked in a spore suspension of an antagonistic strain 1 day before challenge-inoculation with the pathogen, and six of these antagonists (MBCu-32, 36, 42, 45, and 56, and MBPu-75) significantly reduced the number and size of the lesions on the cotyledons compared to the untreated control. In the same way, these six strains inhibited lesion development on attached leaves of 3-week-old cucumber seedlings. Strain MBCu-56, the most suppressive of the strains, was selected for further tests. Its suppressiveness increased as concentrations increased; pretreatment of leaves with the strain at 10(7), 10(8) and 10(9) cfu/ml suppressed disease by 72, 79 and 93%, respectively. These results strongly indicated that MBCu-56 has strong potential for controlling cucumber anthracnose. Based on the taxonomic characteristics and 16S rDNA sequence, MBCu-56 was identified as Streptomyces sp. With scanning electron microscopy, the substrate mycelia of the strain were seen to colonize the surface of leaves above the cuticle. Some hyphae also penetrated and grew underneath the cuticle.