Przysiecka Łucja, Książkiewicz Michał, Wolko Bogdan, Naganowska Barbara
Department of Genomics, Institute of Plant Genetics of the Polish Academy of Sciences Poznań, Poland ; NanoBioMedical Centre, Adam Mickiewicz University Poznań, Poland.
Department of Genomics, Institute of Plant Genetics of the Polish Academy of Sciences Poznań, Poland.
Front Plant Sci. 2015 Apr 21;6:268. doi: 10.3389/fpls.2015.00268. eCollection 2015.
Lupins, like other legumes, have a unique biosynthesis scheme of 5-deoxy-type flavonoids and isoflavonoids. A key enzyme in this pathway is chalcone isomerase (CHI), a member of CHI-fold protein family, encompassing subfamilies of CHI1, CHI2, CHI-like (CHIL), and fatty acid-binding (FAP) proteins. Here, two Lupinus angustifolius (narrow-leafed lupin) CHILs, LangCHIL1 and LangCHIL2, were identified and characterized using DNA fingerprinting, cytogenetic and linkage mapping, sequencing and expression profiling. Clones carrying CHIL sequences were assembled into two contigs. Full gene sequences were obtained from these contigs, and mapped in two L. angustifolius linkage groups by gene-specific markers. Bacterial artificial chromosome fluorescence in situ hybridization approach confirmed the localization of two LangCHIL genes in distinct chromosomes. The expression profiles of both LangCHIL isoforms were very similar. The highest level of transcription was in the roots of the third week of plant growth; thereafter, expression declined. The expression of both LangCHIL genes in leaves and stems was similar and low. Comparative mapping to reference legume genome sequences revealed strong syntenic links; however, LangCHIL2 contig had a much more conserved structure than LangCHIL1. LangCHIL2 is assumed to be an ancestor gene, whereas LangCHIL1 probably appeared as a result of duplication. As both copies are transcriptionally active, questions arise concerning their hypothetical functional divergence. Screening of the narrow-leafed lupin genome and transcriptome with CHI-fold protein sequences, followed by Bayesian inference of phylogeny and cross-genera synteny survey, identified representatives of all but one (CHI1) main subfamilies. They are as follows: two copies of CHI2, FAPa2 and CHIL, and single copies of FAPb and FAPa1. Duplicated genes are remnants of whole genome duplication which is assumed to have occurred after the divergence of Lupinus, Arachis, and Glycine.
羽扇豆与其他豆科植物一样，具有独特的5-脱氧型黄酮类化合物和异黄酮类化合物生物合成方案。该途径中的关键酶是查尔酮异构酶（CHI），它是CHI折叠蛋白家族的成员，包括CHI1、CHI2、类CHI（CHIL）和脂肪酸结合（FAP）蛋白亚家族。在此，利用DNA指纹图谱、细胞遗传学和连锁图谱分析、测序及表达谱分析，鉴定并表征了两个窄叶羽扇豆（Lupinus angustifolius）的CHIL基因，即LangCHIL1和LangCHIL2。携带CHIL序列的克隆被组装成两个重叠群。从这些重叠群中获得了完整的基因序列，并通过基因特异性标记定位到两个窄叶羽扇豆连锁群中。细菌人工染色体荧光原位杂交方法证实了两个LangCHIL基因在不同染色体上的定位。两种LangCHIL同工型的表达谱非常相似。转录水平最高的是在植物生长第三周的根部；此后，表达下降。两种LangCHIL基因在叶和茎中的表达相似且较低。与参考豆科植物基因组序列的比较图谱显示出很强的共线性联系；然而，LangCHIL2重叠群的结构比LangCHIL1保守得多。LangCHIL2被认为是祖先基因，而LangCHIL1可能是复制的结果。由于两个拷贝都具有转录活性，因此出现了关于它们假设的功能分化的问题。用CHI折叠蛋白序列筛选窄叶羽扇豆基因组和转录组，随后进行系统发育的贝叶斯推断和跨属共线性调查，鉴定出了除一个主要亚家族（CHI1）外的所有亚家族的代表。它们如下：两个CHI2拷贝、FAPa2和CHIL，以及FAPb和FAPa1的单拷贝。重复基因是全基因组复制的残余物，全基因组复制被认为发生在羽扇豆、花生和大豆分化之后。
