玉米矮化病株及其根际土壤内线虫的分离与分子鉴定

Isolation and molecular identification of nematodes of main nematodes in rhizosphere soils and seedlings associated with corn dwarf

为探究玉米矮化病的病原,采用Ludox TM悬浮法对从吉林和辽宁采集的玉米矮化病株及其根际土壤和健康株根际土壤分离的线虫进行了鉴定和种群比较,并对矮化病株茎基组织PCR产物进行测序分析。结果表明:玉米健康株根际土壤分离出29属线虫,特有线虫是角咽线虫属Actinolaimus和木盾移线虫属Peltamigratus,矮化玉米病株根际土壤分离出28属线虫,特有线虫为锥线虫属Dolichorus,二者相同的线虫属有27个。矮化玉米病株根际土壤中植物线虫种类和数量明显比健康株根际土壤中高,线虫种群数量差异明显的主要是矮化线虫属Tylenchorhynchus、短体线虫属Pratylenchus和刺线虫属Belonolaimus,病株根际土壤中这3个属线虫总数约占病株土壤分离线虫总数的20.23%、11.27%和10.40%。玉米矮化病株茎基组织中短体线虫属和矮化线虫属数量占优势,2个属的线虫数量分别占测序总数的22%、14%(吉林长岭)和16%、20%(辽宁黑山)。表明玉米矮化病的发生与植物线虫相关,很可能是多种线虫共同引起的病害。

In order to explore the pathogens of the corn dwarf,Ludox TM suspension method was used to separate the nematode and then its population in the rhizosphere soil of diseased and healthy corn seedlings collected from Jilin and Liaoning provinces was identified; meanwhile,PCR products amplified from basal stem tissue of the corn dwarf were sequenced and analyzed. The results demonstrated that 29 genera of nematodes were isolated from rhizosphere soil of healthy corn seedlings, where special nematodes were the genera Actinolaimus and Peltamigratus. There were 28 genera of nematodes isolated from diseased rhizosphere soil,where special nematode was the genera Dolichorus. Between the healthy and diseased corn rhizosphere soil,27 genera of nematodes were the same. The number and species of nematodes in the rhizosphere soil of corn dwarf were significantly higher than in healthy plant rhizosphere soil and the main different nematode populations between the above two soil samples was the genera Tylenchorhynchus,Pratylenchus and Belonolaimus. The three genera of nematodes was more in corn dwarf rhizosphere soil and the total number of nematodes from rhizosphere soil of corn dwarf accounted for20. 23%, 11. 27% and 10. 40%, respectively. The numbers of the genera Pratylenchus and Trylenchorhynchus sequenced from corn dwarf basal stem tissue were dominant,accounted for 22%,14%（ Changling County,Jilin Province） and 16%,20%（ Heishan County,Liaoning Province） of the total sequences,respectively. It indicated that corn dwarf was associated with plant parasitic nematodes and probably many genera of nematodes synergistically caused the maize dwarf syndrome.