Variability in conidial thermotolerance of Metarhizium anisopliae, isolates from different geographic origins
Variability in conidial thermotolerance of Metarhizium anisopliae, isolates from different geographic origins
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DOI：
10.1016/j.jip.2004.11.007
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发表时间：
2005-02-01
影响因子：
3.4
通讯作者：
Roberts, DW
中科院分区：
文献类型：
--
作者：
Rangel, DEN;Braga, GUL;Roberts, DW
对金龟子绿僵菌（Metarhizium anisopliae var.）的16个分生孢子进行了耐热性研究。anisopliae和M.小孢acridum孤立于北纬61度至南纬54度之间。将分生孢子悬浮液暴露于40或45 ℃下2、4、8和12 h。大多数分离株耐受40摄氏度非常好，与相对发芽（发芽相对于未加热的控制）超过90%后，12小时的曝光。其中3个菌株来自高纬度地区，ARSEF 2038（北纬38度，韩国）、4295（南纬54.4度，澳大利亚）和5626（北纬61.2度，芬兰）具有大约80%的发芽率。然而，在45摄氏度的分离物中观察到高变异性;即，暴露2 h后，6个菌株的相对发芽率在80%以上，3个菌株在50 ~ 70%之间，8个菌株在0 ~ 30%之间。在45 ℃下培养8和12 h后，只有两株M.对蚱蜢致病的绿僵菌分离物，即，ARSEF 324（纬度号，澳大利亚）和3609（15度N，泰国），有较高的相对发芽率（91.6和79.4%，分别为8小时曝光;和90和47.1%，分别为12小时）。这些分离物也是对UV-B辐射最耐受的[J. Invertebr. Pathol. 78（2001）98-108]。分离株ARSEF 324暴露2小时和4小时的半数致死剂量（LD 50）分别为49.4和47.9 ℃。分生孢子暴露于湿热条件下，可大大延迟某些菌株的萌发。在一般情况下，从高纬度的菌株表现出更大的热敏感性比从赤道附近的菌株。干分生孢子在水悬浮液中耐受50 ℃优于45 ℃。(c)2004年爱思唯尔公司All rights reserved.
Notable variability in thermotolerance was found among conidia of 16 isolates of the insect-pathogenic fungi Metarhizium anisopliae var. anisopliae and one M. anisopliae var. acridum isolated from latitudes 61 degrees N to 54 degrees S. Conidial suspensions were exposed to 40 or 45 degrees C for 2, 4, 8, and 12 h. Most of the isolates tolerated 40 degrees C very well, with relative germination (germination relative to unheated controls) above 90% after 12 h of exposure. Exceptions were three isolates originating from high latitude, viz., ARSEF 2038 (38 degrees N, South Korea), 4295 (54.4 degrees S, Australia), and 5626 (61.2 degrees N, Finland) that had approximately 80% germination. High variability, however, was observed among isolates at 45 degrees C; viz., after 2 h exposure, relative germination was above 80% for six isolates, between 50 and 70% for three isolates, and between 0 and 30% for eight isolates. After 8 and 12 h at 45 degrees C, only two M. anisopliae isolates pathogenic to grasshoppers, viz., ARSEF 324 (latitude Nos, Australia) and 3609 (15 degrees N, Thailand), had high relative germination (91.6 and 79.4%, respectively, for 8 h exposures; and 90 and 47.1%, respectively, for 12 h). These isolates also were the most tolerant to UV-B radiation [J. Invertebr. Pathol. 78 (2001) 98-108]. The median lethal dose (LD50) for isolate ARSEF 324 was 49.4 and 47.9 degrees C, for 2 and 4 h of exposures, respectively. Exposure of conidia to wet-heat greatly delayed germination of some isolates. In general, isolates from higher latitudes demonstrated greater heat susceptibility than isolates from nearer the equator. Dry conidia tolerated 50 degrees C better than 45 degrees C in aqueous suspension. (c) 2004 Elsevier Inc. All rights reserved.