EFFECT OF DSRNA ASSOCIATED WITH ISOLATES OF CRYPHONECTRIA-PARASITICA FROM THE CENTRAL APPALACHIANS AND THEIR RELATEDNESS TO OTHER DSRNAS FROM NORTH-AMERICA AND EUROPE
EFFECT OF DSRNA ASSOCIATED WITH ISOLATES OF CRYPHONECTRIA-PARASITICA FROM THE CENTRAL APPALACHIANS AND THEIR RELATEDNESS TO OTHER DSRNAS FROM NORTH-AMERICA AND EUROPE
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DOI：
10.1094/phyto-84-528
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发表时间：
1994-05-01
期刊：
影响因子：
3.2
通讯作者：
HILLMAN, BI
中科院分区：
文献类型：
--
作者：
ENEBAK, SA;MACDONALD, WL;HILLMAN, BI
一个12 kb的双链（ds）RNA片段与25%的分离株的Cryphonectria寄生在阿巴拉契亚山脉中部的积极增长的溃疡恢复。这些含dsRNA的分离株的相对毒力范围从与含dsRNA的低毒力对照分离株GH-2相当的水平到显著高于不含dsRNA的毒力对照分离株Ep-155的水平。当含有dsRNA的分离物和它们的不含dsRNA的后代接种到金冠苹果、切除的休眠板栗茎或美国板栗芽中时，不含dsRNA的后代产生的病变都没有显著大于含有dsRNA的分离物产生的病变。当比较不含dsRNA和含dsRNA的同基因分离株时，没有发现培养形态的差异。这些研究表明，单一的12 kb的dsRNA片段既不改变形态，也不赋予病原体的弱毒力，因此，它几乎没有生物防治板栗疫病的潜力。通过使用来自三种不同dsRNA的重组cDNA文库来检查在这些分离物中发现的dsRNA与来自欧洲和北美的低毒力分离物相关的dsRNA的关系。第一种类型，命名为SR-2，含有一个dsRNA片段（12 kb）;第二种类型，命名为D2，含有两个dsRNA片段（5和12 kb）;第三种类型，命名为C-18，含有11个dsRNA片段（1-5 kb）。来自分离物SR-2（马里兰州）、D2（宾夕法尼亚州）和C-18（西弗吉尼亚州）的克隆没有交叉杂交，表明这些dsRNA彼此之间没有密切的亲和力，也与来自新泽西（NB 58）和欧洲（Ep-713和Ep-747）的其他dsRNA没有密切的亲和力。然而，从分离SR-2的克隆交叉杂交与来自26个其他分离物的dsRNA的单个12-kb片段，表明SR-2型的dsRNA是密切相关的。
A 12-kb segment of double-stranded (ds) RNA was associated with 25% of the isolates of Cryphonectria parasitica recovered from actively growing cankers in the central Appalachians. The relative virulence of these dsRNA-containing isolates ranged from a level comparable to that of the dsRNA-containing hypovirulent control isolate GH-2 to a level significantly greater than that of the dsRNA-free Virulent control isolate Ep-155. When dsRNA-containing isolates and their dsRNA-free progeny were inoculated into Golden Delicious apples, excised dormant chestnut stems, or American chestnut sprouts, none of the lesions produced by the dsRNA-free progeny was significantly larger than those produced by the dsRNA-containing isolate from which they were derived. No differences in cultural morphology were noted when dsRNA-free and dsRNA-containing isogenic isolates were compared. These studies indicate that the single 12-kb segment of dsRNA neither alters morphology nor confers hypovirulence to the pathogen, and therefore it has little potential for biological control of chestnut blight. The relationships of the dsRNAs found in these isolates to dsRNAs associated with hypovirulent isolates from Europe and North America were examined by using recombinant cDNA libraries from three different dsRNAs. The first type, designated SR-2, contains one segment of dsRNA (12 kb); the second type, designated D2, contains two segments of dsRNA (5 and 12 kb); and the third type, designated C-18, contains 11 segments of dsRNA (1-5 kb). Clones from isolates SR-2 (Maryland), D2 (Pennsylvania), and C-18 (West Virginia) did not cross-hybridize, indicating that these dsRNAs have neither close affinities to one another nor to the other dsRNAs tested from New Jersey (NB58) and Europe (Ep-713 and Ep-747). However, clones from isolate SR-2 cross-hybridized with the single 12-kb segment of dsRNA from 26 other isolates, indicating that dsRNAs of the SR-2 type are closely related.