School of Life Sciences, State Key Laboratory of Biocontrol and Guangdong Provincial Key Laboratory of Plant Stress Biology, Sun Yat-sen University, Guangzhou 510275, China.
School of Ecology, Sun Yat-sen University, Guangzhou 510275, China.
Int J Mol Sci. 2024 Sep 24;25(19):10250. doi: 10.3390/ijms251910250.
Understanding the genetic basis of species differences in flowering time and inflorescence architecture can shed light on speciation and molecular breeding. shows rapid speciation, with about 100 species formed in the past few million years, and, meanwhile, possesses high ornamental values. Two largely sympatric and closely related species of this genus, and , differ markedly in flowering time and flower number per inflorescence. Here, we constructed an F2 population between and , and used extreme bulks for flowering time and flower number per inflorescence in this population to identify genomic regions underlying the two traits. We found high differentiation on nearly the whole chromosome 7 plus a few regions on other chromosomes between the two extreme bulks for flowering time. Large chromosomal inversions on chromosome 7 between the two species, which contain flowering-related genes, can explain recombinational suppression on the chromosome. We identified 1872 genes with one or more highly differentiated SNPs between the two bulks for flowering time, including , , , , , , , , , and , known to be related to flowering. We also identified 680 genes with one or more highly differentiated SNPs between the two bulks for flower number per inflorescence, including , and , knows to play important roles in inflorescence development. These large inversions on chromosome 7 prevent us from narrowing down the genomic region(s) associated with flowering time differences between the two species. Flower number per inflorescence in appears to be controlled by multiple genes, without any gene of major effect. Our study indicates that large chromosomal inversions can hamper the identification of the genetic basis of important traits, and the inflorescence architecture of species may have a complex genetic basis.
了解开花时间和花序结构的物种差异的遗传基础可以揭示物种形成和分子育种的原理。报春花属植物表现出快速的物种形成，在过去的几百万年中形成了大约 100 个物种，同时具有很高的观赏价值。该属的两个主要同域和密切相关的物种， 和 ，在开花时间和花序上的花数上有显著差异。在这里，我们构建了 和 之间的 F2 群体，并使用该群体中开花时间和花序上花数的极端群体来鉴定这两个性状的基因组区域。我们发现，在两个极端群体之间，几乎整个染色体 7 加上其他染色体上的几个区域在开花时间上存在高度分化。两个物种之间的染色体 7 上的大染色体倒位包含与开花相关的基因，可以解释染色体上的重组抑制。我们在两个开花时间极端群体之间鉴定了 1872 个具有一个或多个高度分化 SNP 的基因，包括 、 、 、 、 、 、 、 和 ，已知与开花有关。我们还在两个花序每花序花数极端群体之间鉴定了 680 个具有一个或多个高度分化 SNP 的基因，包括 、 和 ，在花序发育中起着重要作用。这些染色体 7 上的大倒位使我们无法缩小与两个物种之间开花时间差异相关的基因组区域。花序中每花序的花数似乎由多个基因控制，没有任何主效基因。我们的研究表明，大染色体倒位会阻碍对重要性状遗传基础的识别，并且 物种的花序结构可能具有复杂的遗传基础。
