Institute of Crop Science and Resource Conservation, Plant Breeding, University of Bonn, Katzenburgweg 5, 53115 Bonn, Germany.
Int J Mol Sci. 2019 Jan 8;20(1):202. doi: 10.3390/ijms20010202.
Trait variation among natural populations and their cultivated relatives occurs due to evolutionary forces, including selection and drift. In the present study, we analyzed these forces at the locus level in a global barley diversity set using population genetics analysis. Genome-wide outlier loci detection found a locus on chromosome 2H at which a common single nucleotide polymorphism (SNP) marker SCRI_RS_170235 accounted for the highest diversity index (Fst) values between cultivars and landraces and between cultivars and wild accessions. For a population wide genetic analysis, we developed a Polymerase Chain Reaction (PCR)-based cleaved amplified polymorphic marker at the identified locus. Marker genotyping of 115 genotypes identified a characteristic distribution of polymorphisms among the cultivated, landraces, and wild barley accessions. Using this marker, we screened a library of wild barley introgression lines (IL) and selected IL S42IL-109 that carried the wild introgression of the outlier locus in cultivar 'Scarlett' background. A plethora of phenotypic evaluation was performed between the S42IL109 and 'Scarlett' to dissect the putative effect of the identified outlier locus. Comparison of S42IL109 and 'Scarlett' revealed significant difference in the development of phyllochron two (Phyl-2), phyllochron three (Phyl-3), and phyllochron four (Phyl-4). Across the three phyllochrons, it was consistently observed that S42IL109 developed successive leaves in a shorter time span, by one to two days, compared to 'Scarlett'. These data suggest that outlier locus may influence phyllochron variation which underwent positive selection in barley.
自然种群及其栽培亲缘体之间的性状变异是由于进化力量引起的，包括选择和漂变。在本研究中，我们使用群体遗传学分析在全球大麦多样性群体中分析了这些力量在基因座水平上的作用。全基因组外显子位点检测发现，2H 染色体上的一个常见单核苷酸多态性（SNP）标记 SCRI_RS_170235 在品种和地方品种以及品种和野生近缘种之间的最高多样性指数（Fst）值。为了进行全群体遗传分析，我们在鉴定的基因座上开发了一种基于聚合酶链反应（PCR）的切割扩增多态性标记。115 个基因型的标记基因分型鉴定了栽培品种、地方品种和野生大麦品种之间的多态性特征分布。利用该标记，我们筛选了野生大麦导入系（IL）文库，并选择了携带品种“Scarlett”背景下外显子标记野生导入的 IL S42IL-109。在 S42IL109 和“Scarlett”之间进行了大量的表型评价，以剖析鉴定的外显子标记的潜在效应。S42IL109 和“Scarlett”之间的比较显示，在 Phyllochron 2（Phyl-2）、Phyllochron 3（Phyl-3）和 Phyllochron 4（Phyl-4）的发育方面存在显著差异。在这三个 Phyllochron 中，一致观察到 S42IL109 比“Scarlett”在更短的时间内发育出连续的叶子，时间提前了一到两天。这些数据表明，外显子标记可能影响叶龄变化，而叶龄变化在大麦中经历了正选择。
