‘鸭梨’芽变‘闫庄梨’自交亲和性分子机制初步研究

 通过‘鸭梨’（S₂₁S₃₄）及其芽变‘闫庄梨’自花授粉和相互授粉结实率和种子数调查发现，‘鸭梨’自花授粉结实率为9.1%，果实平均种子数为0，表现自交不亲和性；‘闫庄梨’自花授粉结实率为56.9%，果实平均种子数为8.64，表现自交亲和性；以‘闫庄梨’为母本，‘鸭梨’为父本，授粉结实率为39.3%，果实平均种子数为3.36，也表现亲和性，而以‘鸭梨’为母本，‘闫庄梨’为父本，授粉结实率仅为2.0%，果实平均种子数为0粒，表现不亲和性。因此，初步推断‘闫庄梨’自交亲和性可能是由于花柱突变所致。利用S₂₁和S₃₄等位基因特异性引物对‘闫庄梨’自交后代S-RNase基因型进行鉴定，结果发现S₂₁在所有后代中均有扩增条带，进一步证明‘闫庄梨’花柱S₂₁等位基因及其编码产物可能发生了突变。蛋白质印迹杂交分析结果表明，‘闫庄梨’花柱S-RNase缺失了一条带，而没有缺失的条带蛋白含量也比‘鸭梨’低。由此初步证明‘闫庄梨’的自交亲和性可能是由于花柱S-RNase的突变和表达量低所致。

Self-compatible Pear Cultivar 'Yanzhuang' Resulting from S-RNase Mutation of 'Ya Li' (Pyrus bretschneideri Rehd.)

Self-compatible pear cultivar 'Yan Zhuang' (Pyrus bretschneideri Rehd.) is recorded as bud mutant of self-imcompatible 'Ya Li'. The possible mutation was explored. Self-pollination experiments proves that 'Ya Li' is self-imcompatible (fruit set ratio of flowers 9.1%, no fertile seed) and 'Yan Zhuang' is self-compatible (fruit set ratio of flowers 56.9%, No. of seeds per fruit 8.64). Cross-pollination results suggested that the mutated gene is expressed in stylar of 'Yan Zhuang'. S-RNase gene has been reported as the key gene in style controlling self-incompatible mechanism. PCR with S-RNase gene sequence specific primers showed that the genotype of 'Ya Li' is S₂₁S₃₄, S₂₁ exits in all the 'Yan Zhuang' progenies by self-crossing. It seems that mutation of S₂₁-RNase gene results in the self-compatible phenotype of 'Yan Zhuang'. Western blot result showed that one of the two S-RNase brands in 'Yan Zhuang' disappeared in 'Ya Li'. So 'Yan Zhuang' pear probably results from S-RNase mutation of 'Ya Li'