| Seven apricot cultivars, named Badanshuixing, Hongyuxing, Katy, Hongfeng, Xinshiji and Honghebao, were used in this study, provided by Fruit farm of HengLing in Taian. Their compatibility was identified through crossing and detached styles culturing. Six S-genes related to self-incompatibility were cloned and sequenced. And their corresponding amino acid sequences were concluded from their cDNA sequences according to other S-RNases of Rosaceaus in Badanshuixing, Hongyu and Katy. Then characteristics of S-RNases in Rosaceous were analyzed. Furthermore, expressions of S-genes in apricot were studied and the reason of self-incompatibility in Katy was put forward. In the last a method to identify self- incompatibility genotypes was developed in apricot. All results were summarized to the following:1. Pollen tubes growths using detached styles culture technique were studied among 50 cross-combinations. The growths of pollen tubes were not inhibited at excised style shortened to 1/3 of original length and the protruding tube numbers showed no difference between compatibility and incompatibility combinations. Inhibitions were observed at excised style shortened to 1/2, and protruding tube numbers were differences, but no distinction between two types. While the average numbers of protruding pollen tubes from the basal portion (i.e. full style but ovary) were quite difference between two types. So the average number of protruding pollen tubes from the basal portion could be used as an identification index to distinguish compatibility and incompatibility combinations.2. In self-compatibility cultivars S-protein had no inhibition to itself-pollen germination and growth at lower concentration, while S-protein concentration higher than 2.0 u g/ p L showed little inhibiting. But in self-incompatibility cultivars, self-style protein had significant inhibition to self-pollen germination and growth. And inhibition increased following the enhancing of protein concentration. When concentration was lower than 1.0 u g/ u L, the inhibition disappeared in both types. The results showed high concentration protein was easy to induce incompatible than lower one.3. Three gene were obtained by RT-PCR and RACE from mRNA of Badanshuixing, Hongyuxing, Katy, named PA1, PA2 and PA3, respectively. PA1 and PA2 include 3' region of cDNA. PA3 was complete sequence of Katy cDNA, with 891bp long, and encoded 230 amino acid. Accession numbers in Genbank were: AF468673, AF468675, AF468676.4. Four conservation region (Cl, C2, C3, C5)and nypervariable region(RHV) were found by comparing amino acid sequences of PA 1 ,PA2,PA3 with other species of Rosaceous. Induced amino acid sequence of PA1, PA2, PA3 were not quite similarly in RC4 region, so RC4 is not rosaceae-specific conserved region. Amino acid sequences of PA 1 andPA3 were high homologous to those Sb of almond and P.M.MSRN-2 of Japanese apricot when comparing among the S-RNases of Rosaceous. In the phylogenetic tree, the rosaceous S-RNases formed subfamily- specific subgroups, but did not formed specied-specific groups.5. PCR was performed using C2-C5 fragments of Badanshuixing and Katy genomic DNA. Two DNA fragments were obtained, which were 417bp and 736bp, respectively, in Badanshuixing. One DNA fragment, 359bp long, was obtained in Katy apricot. Blasting in Genebank confirmed they were S-RNase, named S8, S9, S10. Accession numbers in Genebank is AF468678, AF468679, AF468677. Comparison between S8 and PA 1, S10 and PA2, S10 and PA3, showed S8 had two intron in C2-C5 region, with 21bp and 9bp long, respectively. And S10 had no intron in this region.6. S-alleles-specific PCR of seven apricot cultivars was carried out using PruC2 and PruC4 primers. Genotypes of Badanshuixing, Hongyuxing, Katy, Hongfeng, Xinshiji, Honghebao, Erhuacao were named as S8S9, S10S11, S12S13, S13S14, S13S14, S15S16, S13S17.This method can quickly identify genotypes at seedling stage, which would be useful to select pollen donors and parents in production and breeding programs.7...
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