Identification Of Root-knot Nematode From Tetrastigma Hemsleyanum And Resistance Mechanism Of Gynura Bicolor To Meloidoyvne Incognita

Root knot nematodes are mainly distributed in tropical or subtropical areas and facilities cultivation. They are enphytotic to plants by ways of normal repeatedly infection and jointly with the other composite infection pathogens, puncturing plant cells by stylet to infect esophageal gland secretion as pathogenic factor and draw nutrition. Because of the abuse of chemical nematicides, heavy pest resistance and pollution were caused.Nematode identification and screening the resistant plant materials are very important for root-knot nematode disease managements. Based on the research background in the Lab, the paper made the morphological and molecular identificaton of root-knot nematode from Tetrastigma hemsleyanum, infection characteristics and resistant mechanism of Gynura bicolor to Meloidogyne incognita. The main research results are as follows:1. The pathogenic nematode from Tetrastigma hemsleyanum was identified with morphological and molecular method. The morphology and morphometrics of J2 and mature female perineal pattern similar with Meloidogyne incognita, PCR amplication and sequence of rDNA ITS region,28 s D2A/D3B regionn with high simlarity to M. incognita,99% and99%, respectively. And SCAR primers MiF/R for M. incognita PCR reaction got positive result. To our knowledge this is the first report of Tetrastigma hemsleyanum infect Meloidogyne inconita. i.e. Tetrastigma hemsleyanum is a new host of M. inconita..2. Optimized the cutting propagation methods of Gynura bicolor and used one month-old seedlings as experimental material. Based on the Magentadye and Mossphenol blue staining method, the infection and development Meloidogyne inconita in Gynura bicolor were observed. There was a relatively massive invasion at 12 dpi with a intrusionrate of 0%-0.1% with a relatively large number of J2 in root at 18 dpi and 27 dpi, while about 60% J2 were dead at 35dpi, few J3 was observed and no J4 or adult nematodes was detected along with tiller, deposition,thickening in the vascular tissue of seedling.3. A series of primers to obtain NBS-LRR disease resistance homologous sequences of Gynura bicolor were designed.9 out 79 sequences were choose for analyzed their expression over the following 45 days after inoculated with J2, about 24h earlier than the histopatho-logical observation.All the resistance homologous sequences belong to TIR family.3 out 9 selected sequences had a certain high level of expression (GbD-gn16, GbD-gn16, GbD-gn137), other 5 sequences had more obvious expression levels (GbD-cn110, GbD-cn129, GbD-cn117-1,GbD-cn117-5, GbD-cn117-10) than that at normal conditions.