背景回顾：The timing of reproduction is an adaptive trait in many organisms. In plants, the timing, duration, and intensity of flowering differ between annual and perennial species. 

主要研究：To identify interspecies variation in these traits, we studied introgression lines derived from hybridization of annual and perennial species, Arabis montbretiana and Arabis alpina, respectively. 

结果1-关键基因鉴定：Recombination mapping identified two tandem A. montbretiana genes encodingMADS-domain transcription factors that confer extreme late flowering on A. alpina. These genes are related to the MADS AFFECTING FLOWERING(MAF) cluster of floral repressors of other Brassicaceae species and were named A. montbretiana (Am) MAF-RELATED (MAR) genes. 

结果2-基因功能鉴定：AmMAR1 but not AmMAR2 prevented floral induction at the shoot apex of A. alpina, strongly enhancing the effect of the MAF cluster, and MAR1 is absent from the genomes of all A. alpina accessions analyzed. Exposure of plants to cold (vernalization) represses AmMAR1 transcription and overcomes its inhibition of flowering. 

结果3-基因起源与演化：Assembly of the tandem arrays of MAR and MAF genes of six A. alpina accessions and three related species using PacBio long-sequence reads demonstrated that the MARs arose within the Arabis genus by interchromosomal transposition of a MAF1-like gene followed by tandem duplication. 

结果4-转录组测序：Time-resolved comparative RNA-sequencing (RNA-seq) suggested that AmMAR1may be retained in A. montbretiana to enhance the effect of the AmMAF cluster and extend the duration of vernalization required for flowering. 

结论：Our results demonstrate that MAF genes transposed independently in different Brassicaceae lineages and suggest that they were retained to modulate adaptive flowering responses that differ even among closely related species.

 摘 要 

生殖的时间是许多生物的适应性性状。在植物中，开花的时间、持续时间和强度在一年生和多年生植物之间存在差异。为了鉴定这些性状的种间变异，作者研究了一年生植物Arabis montbretiana和多年生植物Arabis alpina杂交形成了基因间滲系。作者通过重组作图鉴定到了两个A. Montbretiana中串联的MADS-box基因，赋予了A. alpina极端晚花表型。这些基因与其他十字花科植物中的开花抑制子MAF相关，作者将其命名为MAF-RELATED（AmMAR）基因。AmMAR1，而非AmMAR2，在A.alpina的茎尖作用于开花诱导的抑制，极大地增强了MAF基因的作用，并且本文所用的所有A.alpina材料均丢失了MAR1基因。低温处理植株（即春化作用）能够抑制AmMAR1的转录，从而克服其对开花的抑制作用。作者进一步通过PacBio长读长测序的方法，对6份A. Alpina材料和3个相关物种的MAR串联群和MAF基因进行了组装，发现MARs基因最早在Arabis属出现，是通过MAF1类基因的染色体间转座及随后的串联产生的。作者还通过时序比较转录组分析，发现AmMAR1可能在A. Montbretiana被保留下来，以增强AmMAF基因簇的作用，延长了其开花所需的春化时间。本文的研究结果揭示了十字花科不同谱系中MAF基因发生了独立的转座，并且这些转座后的基因被保留下来以调节适应性的开花响应，而这些响应甚至是在两个近缘的物种之间都存在差异。