Cloning Of Scab Resistance Like-Gene Hcrp And It's Promoter And Receptor-Like Protein Analysis In Pear(Pyrus Spp.)

Pear(Pyrus spp.) has extensive and long history of cultivation in our country. Pear scab, caused by Venturia nashicola Tanaka et Yamamoto, is an important disease on pear in worldwide. It prevalent in south and north pear cultivation region of our country, especially serious in shanxi, hebei, shanxi provence. The fungus mainly infect leaves, fruits and bring about early leaves fallen and young fruit malformation, and so on. It has been become the main restrictive factor affecting the production and quality of pear fruit in China. In addition, it hampers the healthy development of pear industry. Consequently, resistance breeding become the most effective and essential ways to control the pear scab disease. With the rapidly development of biotechnology, it provide a new approach for resistance breeding, shorten the breeding cycle, quicken the breeding process and widen the breeding range. Most importantly is solve the difficulities of conventional breeding with wide sexual incompatibility and long juvenility in most pear cultivars.The main purpose of the this research is to isolate the scab resistance gene Hcrp and its promoter, we use the bioinformatics to analysis and predict the fuction of Hcrp and its promoter. On this basis, we analysis the sequences variation about eithteen pear cultivars. The main results achieved are as following:1. The Hcrp DNA sequence of coding region was amplified from cuiguan pear with utilization of a pair of primers designed based on Hcrvf2 cDNA sequence.The gene didn't contain intron and have a open reading frame with 2928 bases, which was the same as Hcrvfs gene family in apple(Malus spp.), and codon protein with 975 amino acids whose molecular weight is 109.4kD, pⅠis 5.75. Hcrp is a extracellular protein, which belongs to LRR-TM type of R gene codoning. Bioinformatics analysis implict that it has 28 LRRs composed byαhelix andβsheet, and which it has many modification and activation sites of protein, it acvanced structure is a helix-loop-helix protein.2.907 bases upstream sequence of Hcrp was isolated via homologous clone and a PCR of verify. Bioinformatics analysis of the upstream sequence was performed and the essential cis-acting elements and environmental stress response elements for the promoter were found, stress responsive elements including WRKY, W-BOX, MYB, MYC, BIHD, light responsive elements including GATA, I-BOX,GT1 and S1F, and so on. The potential transcription start site possibly locate on 39 bases of upstream of the putative start codon. 3. Phylogenetic tree divide into four group for 18 pear cultivars. The average ka/ks ratios of group I show a high score with 1.275. The group I have statistical significance compared with other's group. It implicated a positive select. Nucleotide diversity of four group have no difference, but the region of LRR show more high variation than the two ends. Neutrality tests of InDel polymorphism display statistical significance in the all populations, Tajima's D is-2.04978(p<0.05). The genetic differentiation among populations is little. The gene flow among three populations is between 12.07 and 14.03.