Upregulation of tandem duplicated BoFLC1 genes is associated with the non-flowering trait in Brassica oleracea var. capitata
Upregulation of tandem duplicated BoFLC1 genes is associated with the non-flowering trait in Brassica oleracea var. capitata
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DOI：
10.1007/s00122-023-04311-3
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发表时间：
2023-03
影响因子：
5.4
通讯作者：
Y. Kinoshita;Koichi Motoki;M. Hosokawa
中科院分区：
文献类型：
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作者：
Y. Kinoshita;Koichi Motoki;M. Hosokawa
关键信息串联重复的BoFLC 1基因（BoFLC 1a和BoFLC 1b）被鉴定为甘蓝突变体"nfc“中不开花性状的候选致病基因，它们在”nfc“中的冬季表达上调。在这项研究中，我们调查了“nfc”不开花性状的分子基础。首先，采用嫁接成花诱导法诱导‘nfc’开花，并产生三个F2群体。各F2群体开花表型分布较广，两个群体中都有不开花个体。QTL-seq分析在三个F2群体中的两个群体中检测到与开花日期相关的基因组区域，该区域位于第9染色体上约51 Mb处。随后的验证和精细定位的候选基因组区域使用QTL分析确定的数量性状基因座（QTL）在50，177，696 - 51，474，818 bp的9号染色体上覆盖241个基因。此外，在“nfc”和“T15”植物的叶和茎尖中的RNA-seq分析分别鉴定了19个和15个与开花时间相关的差异表达基因。基于这些结果，我们确定串联重复BoFLC 1基因，这是同源的花抑制基因FLOWERINGLOFLC，作为候选基因负责的非开花性状的'nfc'。我们将串联重复的BoFLC 1基因命名为BoFLC 1a和BoFLC 1b。表达分析表明，BoFLC 1a和BoFLC 1b在“T15”中的表达量在冬季下调，而在“nfc”中的表达量在冬季上调并保持不变。此外，花整合子BoFT的表达水平在‘T15’中在春季上调，而在‘nfc’中几乎没有上调。这些结果表明，BoFLC 1a和BoFLC 1b的表达水平上调与“nfc”的不开花性状有关。
Key messageTandem duplicatedBoFLC1genes (BoFLC1aandBoFLC1b), which were identified as the candidate causal genes for the non-flowering trait in the cabbage mutant ‘nfc’, were upregulated during winter in ‘nfc’.AbstractThe non-flowering natural cabbage mutant ‘nfc’ was discovered from the breeding line ‘T15’ with normal flowering characteristics. In this study, we investigated the molecular basis underlying the non-flowering trait of ‘nfc’. First, ‘nfc’ was induced to flower using the grafting floral induction method, and three F2populations were generated. The flowering phenotype of each F2population was widely distributed with non-flowering individuals appearing in two populations. QTL-seq analysis detected a genomic region associated with flowering date at approximately 51 Mb on chromosome 9 in two of the three F2populations. Subsequent validation and fine mapping of the candidate genomic region using QTL analysis identified the quantitative trait loci (QTL) at 50,177,696–51,474,818 bp on chromosome 9 covering 241 genes. Additionally, RNA-seq analysis in leaves and shoot apices of ‘nfc’ and ‘T15’ plants identified 19 and 15 differentially expressed genes related to flowering time, respectively. Based on these results, we identified tandem duplicatedBoFLC1genes, which are homologs of the floral repressorFLOWERINGLOCUSC, as the candidate genes responsible for the non-flowering trait of ‘nfc’. We designated the tandem duplicatedBoFLC1genes asBoFLC1aandBoFLC1b. Expression analysis revealed that the expression levels ofBoFLC1aandBoFLC1bwere downregulated during winter in ‘T15’ but were upregulated and maintained during winter in ‘nfc’. Additionally, the expression level of the floral integratorBoFTwas upregulated in the spring in ‘T15’ but hardly upregulated in ‘nfc’. These results suggest that the upregulated levels ofBoFLC1aandBoFLC1bcontributed to the non-flowering trait of ‘nfc’.