Study On Pathogenicity Of Several Pine Parasitic Nematodes And Their ITS Sequence Analysis

Aiming at the problem of a large number of dead pine trees of unknown causes in production,this paper carried out some research work in following two aspects: (1)the pathogenicity of pine parasitic nematodes on Pinus taiwanensis, Pinus nigra, Pinus massoniana; (2) ITS sequence analysis of some pine parasitic nematodes,and so on.The results achieved are as follows:(1) Different Bursaphelenchus xylophilus inoculum amount were set, through analysis and comparison, for 2-year-old Pinus taiwanensis, 4-year-old Pinus nigra, 4-year-old Pinus massoniana, the optimal inoculum of nematode were 2000 nematodes /plant, 8000 nematodes /plant, 8000 nematodes /plant respectively.(2)Compared with 25℃, the development process of Pinus taiwanensis under the condition of 30℃significantly speed up, the extent of incidence significantly increase.(3) Different strains of B. mucronatus inoculated into 2-year-old Pinus taiwanensis have different pathogenicity. Among 22 strains of B. mucronatus tested, 10 strains are pathogenic, 12 strains could not cause Pinus taiwanensis to show pathogenic Symptoms.(4) Seinura wuae is pathogenic for 2-year-old Pinus taiwanensis.(5)Inoculated with A. macronucleatus,B. hofmanni SF2,Ektaphelenchidae sp. chuishang8, unidentified nematode 2, the 2-year-old Pinus taiwanensis has not shown pathogenic symptoms .(6) In outdoor conditions, the above-mentioned 22 strains of B. mucronatus, nine strains of other nematode can not make 4-year-old Pinus nigra, Pinus massoniana show pathogenic symptoms.(7)The rDNA ITS regions of Ektaphelenchidae sp., B. hofmanni , A. macronucleatus , Seinura lii ,Seinura wuae 5 population were amplified using universal primers of nematode ITS region and sequenced, the length of ITS regions are 840bp, 986bp, 771bp, 888bp and 978bp respectively.The sequence alignment and cluster analysis showed that difference in ITS area among the five kinds of nematodes is relatively large.