Characterization of Metarhizium species and varieties based on molecular analysis, heat tolerance and cold activity
Characterization of Metarhizium species and varieties based on molecular analysis, heat tolerance and cold activity
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DOI：
10.1111/j.1365-2672.2009.04422.x
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发表时间：
2010-01-01
影响因子：
4
通讯作者：
Roberts, D. W.
中科院分区：
文献类型：
--
作者：
Fernandes, E. K. K.;Keyser, C. A.;Roberts, D. W.
方法和结果：采用分子标记技术[AFLP和rDNA（ITS 1、ITS 2和5个中心点8 S）基因测序]对绿僵菌属（Metarhizium spp.）从广泛的来源分离。将分离物的分生孢子悬浮液暴露于湿热（45 +/-0中心点2 ℃）并铺在马铃薯葡萄糖琼脂加酵母提取物（PDAY）培养基上。暴露8 h后，菌株明显分为两组：（i）所有菌株的金龟子绿僵菌变种。金龟子绿僵菌（Metarhizium anisopliae var.）acridum（Ma-ac）分离物表现出高耐热性（c. 70-100% RG）。分生孢子悬浮液也接种在PDAY上，并在5 ℃下培养15 d，在此期间，Ma-an和Ma-ac分离物的RG几乎为零，而两个Mf具有高度的冷活性（100%RG.Conclusions：热和冷暴露可以作为快速工具来初步鉴定一些重要的绿僵菌种和变种。目前主要依赖于DNA为基础的方法，我们建议一个简单的温度为基础的屏幕，以快速获得初步鉴定的分离株的物种或物种复合体。
Aims:The genetic relationships and conidial tolerances to high and low temperatures were determined for isolates of several Metarhizium species and varieties.Methods and Results:Molecular-based techniques [AFLP and rDNA (ITS1, ITS2 and 5 center dot 8S) gene sequencing] were used to characterize morphologically identified Metarhizium spp. isolates from a wide range of sources. Conidial suspensions of isolates were exposed to wet heat (45 +/- 0 center dot 2 degrees C) and plated on potato dextrose agar plus yeast extract (PDAY) medium. After 8-h exposure, the isolates divided clearly into two groups: (i) all isolates of Metarhizium anisopliae var. anisopliae (Ma-an) and Metarhizium from the flavoviride complex (Mf) had virtually zero conidial relative germination (RG), (ii) Metarhizium anisopliae var. acridum (Ma-ac) isolates demonstrated high heat tolerance (c. 70-100% RG). Conidial suspensions also were plated on PDAY and incubated at 5 degrees C for 15 days, during which time RGs for Ma-an and Ma-ac isolates were virtually zero, whereas the two Mf were highly cold active (100% RG).Conclusions:Heat and cold exposures can be used as rapid tools to tentatively identify some important Metarhizium species and varieties.Significance and Impact of the Study:Identification of Metarhizium spp. currently relies primarily on DNA-based methods; we suggest a simple temperature-based screen to quickly obtain tentative identification of isolates as to species or species complexes.