Table_2_Analysis of Self-Incompatibility and Genetic Diversity in Diploid and Hexaploid Plum Genotypes.docx

During the last decade, S-genotyping has been extensively investigated in fruit tree crops such as those belonging to the Prunus genus, including plums. In plums, S-allele typing has been largely studied in diploid species but works are scarcer in polyploid species due to the complexity of the polyploid genome. This study was conducted in order to analyze the S-genotypes of 30 diploid P. salicina, 17 of them reported here for the first time, and 29 hexaploid plums (24 of P. domestica and 5 of P. insititia). PCR analysis allowed identifying nine S-alleles in the P. salicina samples allocating the 30 accessions in 16 incompatibility groups, two of them identified here for the first time. In addition, pollen tube growth was studied in self-pollinated flowers of 17 Tunisian P. salicina under the microscope. In 16 samples, including one carrying the Se allele, which has been correlated with self-compatibility, the pollen tubes were arrested in the style. Only in one cultivar (“Bedri”), the pollen tubes reached the base of the style. Twelve S-alleles were identified in the 24 P. domestica and 5 P. insititia accessions, assigning accessions in 16 S-genotypes. S-genotyping results were combined with nine SSR loci to analyze genetic diversity. Results showed a close genetic relationship between P. domestica and P. salicina and between P. domestica and P. insititia corroborating that S-locus genotyping is suitable for molecular fingerprinting in diploid and polyploid Prunus species.

近十年来，科研人员对李属（Prunus）果树作物的S基因分型（S-genotyping）开展了大量研究，其中包括李属的李类作物。在李类作物中，二倍体物种的S等位基因分型已得到广泛研究，但由于多倍体基因组结构复杂，相关研究在多倍体物种中较为匮乏。本研究旨在分析30份二倍体中国李（P. salicina，其中17份为首次报道）以及29份六倍体李的S基因型：其中24份为欧洲李（P. domestica），5份为李（P. insititia）。通过聚合酶链式反应（PCR）分析，研究人员在中国李样本中鉴定出9种S等位基因，将30份种质划分为16个不亲和组，其中2个不亲和组为本次研究首次发现。此外，本研究通过显微镜观察了17份突尼斯中国李自花授粉后的花粉管生长情况：在16份样本（包括1份携带与自交亲和性相关的Se等位基因的样本）中，花粉管均在花柱内被阻滞；仅在栽培品种"Bedri"中，花粉管能够抵达花柱基部。研究人员在24份欧洲李与5份李的种质中鉴定出12种S等位基因，将这些种质划分为16种S基因型。本研究将S基因分型结果与9个SSR位点（Simple Sequence Repeat）相结合，用于分析遗传多样性。结果显示，欧洲李与中国李、欧洲李与李之间存在紧密的遗传亲缘关系，这证实了S位点基因分型可适用于二倍体与多倍体李属物种的分子指纹图谱分析。