Population Structure of the Rice Blast Pathogen in Vietnam
Population Structure of the Rice Blast Pathogen in Vietnam
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越南稻瘟病菌种群结构
DOI：
10.3186/jjphytopath.65.475
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发表时间：
1999
期刊：
影响因子：
--
通讯作者：
S. Mayama
中科院分区：
文献类型：
--
作者：
L. D. Don;Y. Tosa;H. Nakayashiki;S. Mayama
在越南，由稻瘟病菌引起的稻瘟病是红河和湄公河三角洲两大水稻主产区特有的病害。在红河三角洲，1991年颈部爆炸袭击了138,000公顷土地，1992年袭击了217,000公顷土地。1978年，叶枯病摧毁了天江省和湄公河三角洲其他省份300多公顷的苗圃(如19816年的厚江和安江)，尽管这些地区普遍使用杀菌剂和种植抗病品种进行预防性喷洒。然而，水稻品种对稻瘟病的抗性并不持久。它的崩溃可能归因于致病类型(小种)、分离物的不稳定性和种群的多样性。利用DNA指纹和分子标记技术，研究了菲律宾、中国、日本、哥伦比亚、美国和欧洲等水稻种植国家稻瘟病菌种群的遗传多样性。这些研究表明，稻瘟病种群由不同的克隆谱系组成。从谱系水平了解稻瘟病种群结构有助于了解稻瘟病的流行病学特征。本文报道了从越南两个主要稻区采集的稻瘟菌分离物的性亲和性、遗传结构和毒力模式的研究结果。1998年从红河三角洲的两个省(河泰和泰平)和1996年从湄公河三角洲的三个省(龙安、天江和厚江)采集到78株分离物(表1，图1)。在每一块田中随机采集几片感染稻瘟菌的水稻叶片，并在每一省调查5块以上的田。从叶片上的单个病斑上分离出一个分生孢子，保存在PDA培养基上短期使用或在灭菌大麦种子上长期保存。分离株命名为VHT1.1、VHG2.1等。字母表示其所在地(省)(表1)，字母后面的数字表示每个省的字段编号，小数点后的数字(.)在一个字段中显示隔离编号。首先，将78个菌株与从日本谷子中分离到的高育性参考菌株G10-1(MAT1-1；A)和Z2-1(MAT1-2；a)杂交，测定其育性。每-87%
In Vietnam rice blast disease caused by Pyricularia oryzae Cavara (synonym Pyricularia grisea Sacc., teleomorph Magnaporthe grisea (Hebert) Barr)12) is endemic to the two major rice production areas, the Red River and Mekong River Deltas. Neck blast attacked 138,000 ha in 1991 and 217,000 ha in 1992 in the Red River Delta19). Leaf blast destroyed more than 300 ha of seedling nurseries at Tien Giang province in July 1978 and in other provinces in the Mekong River Delta such as Hau Giang and An Giang in 19816), although preventive spraying with fungicides and growing resistance varieties is widely practiced in most of these areas. Resistance to blast disease in rice cultivars, however, has not been durable. Its breakdown may be attributable to pathotype (race) instability in the isolates and diversity in their populations24). By using DNA fingerprinting with molecular markers, the genetic diversity in the blast fungal populations has been studied in rice growing countries such as the Philippines1), China14), Japan2,16), Columbia9), the United States21) and European countries13). These studies showed that rice blast populations are composed of distinct clonal lineages. Information on the population structure at the lineage level is helpful to understand the epidemiological properties of the rice blast disease. In this report we present results of studies on the sexual compatibility, genetic structure and virulence pattern of rice blast isolates collected from the two major rice areas in Vietnam. A total of 78 isolates were collected from two provinces (Ha Tay and Thai Binh) in the Red River Delta in 1998 and three provinces (Long An, Tien Giang, and Hau Giang) in the Mekong River Delta in 1996 (Table 1, Fig. 1). Several rice leaves infected with the blast fungus were randomly collected in each field, and more than five fields were surveyed in each province. A single conidium was isolated from a single lesion on a leaf and maintained on PDA medium for short-term use or on sterilized barley seeds for long-term storage. The isolates were designated as VHT1.1, VHG2.1, and so on. The letters represent their locality (provinces) (Table 1), while the numeral after the letters refers to the field number in each province, and the numeral after the decimal point (.) shows the isolate number in one field. First, the fertility of the 78 isolates was tested by crossing with highly fertile reference isolates, G10-1 (MAT1-1; A) and Z2-1 (MAT1-2; a) which had been isolated from finger millet in Japan5). Eighty-seven per-