Hao J J, Meng Q X, Yin J F, Kirk W W
Department of Plant Pathology, Michigan State University, East Lansing 48824.
Department of Plant Pathology, University of Georgia, Tifton 31793.
Plant Dis. 2009 Dec;93(12):1329-1334. doi: 10.1094/PDIS-93-12-1329.
A novel strain of Streptomyces (named DS3024) was isolated from a potato field in Michigan in 2006. The taxonomy of the organism was determined by morphology, biochemistry, and genetic analysis. Analysis of the 16S ribosomal RNA gene sequence indicated that the organism was most similar to an isolate of Streptomyces sp., ME02-6979.3a, which is not pathogenic to potato tubers but is distinct from other known pathogenic Streptomyces spp. Strain DS3024 has genes that encode thaxtomin synthetase (txtAB), which is required for pathogenicity and virulence, and tomatinase (tomA), which is a common marker for many pathogenic Streptomyces spp. However, the nec1 gene (associated with virulence in most pathogenic Streptomyces spp.) was not detected. The new strain was capable of growth at pH 4.5, caused necrosis on potato tuber slices, and produced thaxtomin A. In greenhouse experiments, DS3024 caused scab symptoms on potato tubers similar to those caused by Streptomyces scabies on tubers of potato cv. Atlantic, which is scab susceptible. We propose that DS3024 is a new strain of Streptomyces capable of causing common scab on potato tubers. The prevalence of this strain of Streptomyces in potato-producing areas in the north-central United States has not been determined.
2006年，从密歇根州的一块马铃薯田中分离出一种新型链霉菌菌株（命名为DS3024）。通过形态学、生物化学和遗传分析确定了该生物体的分类学地位。对16S核糖体RNA基因序列的分析表明，该生物体与链霉菌属的分离株ME02 - 6979.3a最为相似，ME02 - 6979.3a对马铃薯块茎无致病性，但与其他已知的致病性链霉菌属不同。菌株DS3024具有编码致病力和毒力所需的thaxtomin合成酶（txtAB）以及许多致病性链霉菌属常见标志物的番茄酶（tomA）的基因。然而，未检测到nec1基因（与大多数致病性链霉菌属的毒力相关）。新菌株能够在pH 4.5下生长，导致马铃薯块茎切片坏死，并产生thaxtomin A。在温室试验中，DS3024在马铃薯块茎上引起的疮痂症状与疮痂链霉菌在马铃薯品种大西洋（对疮痂敏感）块茎上引起的症状相似。我们认为DS3024是一种能够在马铃薯块茎上引起普通疮痂病的新型链霉菌菌株。尚未确定该链霉菌菌株在美国中北部马铃薯产区的流行情况。
