Molecular Basis Of Difference Between Self-compatibility And Self-incompatibility In Katy, Xinshiji And Their F₁ Hybrid Apricots (Prunus Armeniaca)

Self-compatible (SC) Katy, self-incompatible (SI) Xinshiji and their F1 hybrids were used for probing into molecular and physiological mechanism of difference between self-compatible (SC) and self-incompatible (SI) apricot (Prunus armeniaca). Physiological characterization associated with self-incompatibility was compared between self-compatible (SC) and self-incompatible (SI) apricot. Stylar S-RNases gene in Katy, Xinshiji and their F1 hybrids were isolated, cloned and compared, and expression characteristic of stylar S-RNase in transcript and translation level were identified. The stylar proteins in the SI and SC hybrids were used to compare proteome expression profile. The main results were as followings:(1) After self-pollinated, pollen tubes traveling along the style in Katy could grow into ovary, and most of them in Xinshiji could stop growing with tip expanded into ball. Traveling periods of pollen tube from the stigma to ovary were between 24 h and 72 h and the inhibited degree of self-pollen tube growth in Xinshiji were weakened when traveling speed was quick.(2) Three novelty S-RNase genes (P.a S8 from Katy and P.a S9, P.a S10 from Xinshiji) were found and they have been deposited in GenBank (The accession numbers are AY884212, AY864826, AY864825, AY853594 and AY846872). The introns of P.a S8, P.a S9, and P.a S10 were 406 bp, 471 bp, 104 bp and lied in the hypervariable region (RHV) between C2 and C3. Three genes were compared and displayed similarity at the deduced amino acid level. Most of amino acid sequences of S-RNase gene in Rosaceae Prunus genus were used to form their phyligenetic tree. The evolutionary relationships showed S-RNase genes did not form a distinct cluster within species. Intra-species similarity was not higher than inter-species one.(3) Expression of the S-RNase genes in Katy and Xinshiji were different; Transcript abundance was distinctly diverse at the key stage (i.e., at 24h after self-pollination) in both genotypes, and was greater in Xinshiji than in Katy; In addition, the abundance of the S-RNase transcript was higher in upper-half part of style than in the lower-half part of style or in the ovary; In the SI cultivar Xinshiji, the expression of S-RNase reminded a relatively high level after cross-pollination, but it dropped continuously after self-pollination and non-pollination.(4) Recombination and S-gene mutation had not been found in S-RNase of Katy×...