The Studies On Differential Expression Of MRNA In Wheat Germplasm Resistance To Sitobion Avenae (F.)

Sitobion avenae (Fabricius) (Hemiptera: Aphididae), is one of devastating pests of wheat throughout the world. It is a typical of r-insect. So the chemicals insecticide still have been used to control it in the world, but chemicals insecticide causes the serious‘3R’(Resistance, Resurgence, Residue) problem. Plant resistant to pest is a most effective and economical pest management strategy. In China, it has made a great achievements on screening the resistance cultivars and MAS (Marker—Assisted Selection) to the aphids. However, there are rare researches on cloning the resistant gene to the S. avenae until now. According to screening phenotype, we examined the wheat germplasms resistance to S. avenae. Then using the resistance and the susceptible wheat materials created a sufficient backcross population to analysis the resistance genes by DDRT– PCR technique. The main conclusions are as follows:The resistance levels were identified based on the decreased rate of 1 000-kenial weight infected by aphid. Among 21 wheat germplasm accessions,the decreased rete range were from 4.84% to 64.32%. Amigo (U.S.) and 98-10-35 were high resistance wheat germplasm. 1376 is high susceptible wheat germplasm.The resistance character of 44 backcorss population to S. avenae (F.) were observed in seedling phase. The results show that there were 4 germplasm of resistant, and 3 is susceptible to aphid in BC1 population of 98-10-35/1376 and in BC2 is 6 and 1 respectively. In another group there were 7 germplasm of resistant, and 8 is susceptible to aphid in BC1 population and in BC2 is 12 and 3 respectively.The 24 primer pairs, three anchor primers and eight random primers random combinations, were screening to 1376, Amigo and 98-10-35 in order to screen differential primer pairs by DDRT-PCR. The results show that 21 primer pairs could work, and the optimal primer pairs were anchor primer H-T11A and random primer H-AP-2, H-AP-7.Using stabilized differences of primer pairs screen the resistance gene to aphid in backcross population by DDRT– PCR in BC population. It is concluded that the expression of the resistant related genes have three ways, one is the peculiar expression, including two ways: the gene only expressed in resistant plant (A type in 231) or susceptible plant (B in 154); The second way is to enhance expression in resistant plant (C in 302); Another way is abate expression in resistant plant (D in 271) . The 6 differential bands were choose to sequenced. Using the tools of the sequence homologous analysis (BLAST), the results show that these sequences are associated with the gene expression of wheat under the stress. So, they are the expected resistance genes. The more true functions of these genes need to the further studies.