Identification And Molecular Mechanism Of Wheat Cultivars Resistance To Heterodera Avenae

Using the CCN population of Zhengzhou region,32 wheat cultivars planted in Henan province were identified for resistance to CCN(Heterodera avenae) by infested soil and 2nd-stage juveniles inoculation.The results show that there were no immune cultivars to CCN in all tested cultivars.The identification result of infested soil shows that Taikong6 is a high resistant cultivar,Zhongyu6 and Xinmai11 are resistant cultivars,10 cultivars including Zhoumai18 are moderate-resistance cultivars,12 cultivars including Xinmai9-998 are susceptible cultivars,6 cultivars including Weimail 9 are high susceptible cultivars.The result of wheat cultivars which inoculated 300 2nd-stage juveniles shows that Xinmai9-998,Taikong6 and Pumai9 are resistant cultivars,11 cultivars including Zhengmai98 are moderate-susceptible cultivars,13 cultivars including Zhoumai18 are susceptible cultivars,6 cultivars including Gaoyou505 are high susceptible cultivars.The results of two identification methods were not entirely consistent.The disease on wheat cultivars which inoculated cyst(16 cysts per 100g) was a little severe.The highest amount of white female on single plant was 65.2.The disease on cultivars 300 2nd-stage juveniles was commonly light.The highest amount of white female on single plant was just 16.6.Expression analysis about wheat chitinase gene,in the different growing periods and different positions of different resistance wheat cultivars after cereal cyst nematode inoculation,was carried by semi-quantitative RT-PCR,using wheat Actin as a control. The result shows that the quantity of chitinase gene expression had no obvious increase after 12h inoculation,and there were no obvious difference between resistant and susceptible cultivars.After 36h inoculation,the expression quantity in both cultivars increased obviously,and the quantity in resistant cultivars was more than susceptible cultivars,and in leaves was more than in roots.After 60h inoculation,the gene expression quantity in resistant and susceptible cultivars was keeping a high level,and the former was more than the latter.The expression in susceptible cultivars after 84h inoculation had no obvious difference with the ones without inoculation,but the expression quantity in resistance cultivars was still higher than those without inoculation.After 120h and 240h inoculation,the expression quantity between resistant or susceptible cultivars and water(CK) was no significantly different,and in roots,the genes in inoculated cutivars or CK didn't express.Actin gene in wheat for internal reference,the expression of conserved sequence in Cre3 gene resistant to CCN on different resistant cultivars root inoculated during different periods was carried by the technology of semi-quantitative RT-PCR.The results show that there was no obvious difference between resistant and susceptible cultivars,the same results between inoculated cultivars and CK.The amplified target fragments were sequenced.The results show that the homology of the nucleotide and amino acid reached to more than 98%among three sequences.The homology of the nucleotide and amino acid reached to more than 95%between three sequences and Cre3 gene.Phylogenetic trees were established using the there genes from sequencing and other plant resistance genes landed in GenBank.They are Flax L6 gene,Tobacco N gene,Cre3 gene,RCCN gene and the Arabidopsis RPM1 gene.Three genes from sequencing were most homophylic with Cre3.They may be the same kind gene as Cre3.