Investigation And Identification Of Pratylenchus Species In Field Crops In Three Provinces Of Huang-Huai Region

Root lesion nematodes(Pratylenchus Filipjev,1936)are important migratory endoparasite of plants,which severely harms various agronomic and horticultural crops,and is widespread in China.Root lesion nematodes rank the third only to root-knot and cyst nematodes as having the greatest impact on crops worldwide.At present,there is a lack of studies on the occurrence,distribution and damage of the root lesion nematodes in the Huang-Huai region.In order to more systematically and accurately understand the distribution and damage of the root lesion nematodes in the Huang-Huai region,and provide a theoretical basis for the prevention and treatment of these nematodes,this study investigated the population of root lesion nematodes in the Huang-Huai region and identified the species with a combination of morphological and molecular methods.In this study,a total of 209 rhizospheric soil samples of the main field crops were collected from the 27 cities of Henan,Shandong and Anhui provinces.The root lesion nematodes in these samples were identified and classified.At the same time,the reproduction factor of the p.coffeae was measured by the inoculation with carrot disks.The results were as follows:1.In wheat,corn,sesame,soybean,tobacco and other crops,a total of 58 root lesion nematode populations were isolated from the Zhengzhou,Luoyang,Xuchang,Shangqiu,Jiaozuo,Nanyang,and Pingdingshan City of Henan Province,the Linyi,Taian,Xintai,Laiwu City of Shandong Province and the Suzhou City in Anhui Province.The 22 different populations of root lesion nematodes were purified and cultured on carrot disks by means of single female expansion.The 25 different populations of root lesion nematodes were identified using a combination of morphological and molecular methods.They belong to three species of Pratylenchus,which are P.coffeae,P.scribnei,and P.neglectus.2.Eight 18 S sequences,twenty three 28 S sequences,and twenty five ITS sequences were obtained in this study.Among them,There were seven populations ofP.coffeae,obtained two 18 S sequences,six 28 S sequences and seven ITS sequences.The length of these 18 S sequences were 1003 bp;the length of these 28 S sequences were 780-781 bp and the length of these ITS sequences were 1245-1254 bp.There were two 18 S sequences,eight 28 S sequences and ten ITS sequences of these ten populations of P.scribnei.The length of these 18 S sequences were 897 bp and898 bp;the length of these 28 S sequences were 785-786 bp and the length of the sequences were 1099-1106 bp.These eight populations of P.neglectus obtained four18 S sequences,nine 28 S sequences and eight ITS sequences.The length of these 18 S sequences were 888-891 bp;the length of these 28 S sequences were 776-781 bp and the length of these ITS sequences were 897-914 bp.Phylogenetic analysis of Pratylenchus used 18 S,28S D2D3 regions and ITS sequences.The results showed that the 25 population of Pratylenchus sequences identified in this paper all form a monophyletic sequence with the reported Pratylenchus sequences.3.The carrot disks were inoculated with 30,50,and 100 nematodes(p.coffeae)respectively.After 60 days,the amount of nematodes was counted.The results showed that p.coffeae could reproductive on carrot disks and there were significant differences between different treatments(p < 0.05).With the increase of the initial inoculation,the number of nematodes increased gradually.