【摘要】 为了研究查尔酮异构酶（CHI）对橡胶树叶片发育过程中黄酮类化合物合成的影响，本研究利用CHI的功能域Chalcone(PF02431)鉴定橡胶树查尔酮异构酶Hb CHI基因家族成员，分析其蛋白序列理化性质、保守结构域、保守基序和系统进化树分析；利用qRT-PCR分析Hb CHI在橡胶树叶片发育过程中的表达模式；利用农杆菌介导的烟草瞬时表达技术分析Hb CHI2影响植物黄酮合成的功能。结果表明：从橡胶树基因组数据库中鉴定获得9个HbCHI基因家族成员（HbCHI1～HbCHI9），其编码的蛋白质包含177～474个氨基酸，等电点为5.1～9.52，主要为亲水蛋白；大部分HbCHI含有1～3个数量不等的基序，只有HbCHI1含有6个保守基序（motif1～motif6）；系统进化分析显示，HbCHI1～HbCHI4是I型CHI,HbCHI6～HbCHI9表现出脂肪酸结合位点，是Ⅲ型CHI,HbCHI5是IV型CHI；橡胶树HbCHI基因家族的相对表达量检测结果均表现出从小古铜期到成熟期先下降后上升的趋势，其中在淡绿期时的相对表达量最低，且总黄酮含量与CHI基因相对表达量变化趋势一致；相关性分析表明HbCHI2表达量与黄酮含量相关性最高，皮尔逊系数为0.97；在烟草中过表达HbCHI2促进了本氏烟草中类黄酮的生物合成，增加了叶片的总黄酮含量，是对照的2.13倍。本研究结果表明HbCHI2基因正调控橡胶树叶片中类黄酮生物合成。更多还原

【Abstract】 In order to study the effect of chalcone isomerase on the synthesis of flavonoids during the development of rubber leaves, this study used the CHI functional domain chalcone(PF02431) to identify the HbCHI gene family members of the Ccalcone isomerase, and to analyze the physicochemical properties, conserved domain, conserved motif and phylogenetic tree of the protein sequences. qRT-PCR was used to analyze the expression pattern of HbCHI during the development of rubber leaves. The effect of HbCHI2 on plant flavonoid synthesis was analyzed using Agrobacterium-mediated transient expression technique in Nicotiana benjamina. Nine HbCHI gene family members(HbCHI1-HbCHI9) were identified from the genomic database of H. brasiliensis. The proteins encoded by HbCHI1-HbCHI9 contained 177-474 amino acids with isoelectric points ranging from 5.1 to 9.52. The proteins were mainly hydrophilic proteins. Only HbCHI1 contained 6 conserved motif1-motif6 motifs, and phylogenetic analysis showed that HBCHI1-HBCHI4 was type I CHI. HbCHI6-HbCHI9 showed fatty acid binding sites, which were type Ⅲ CHI. HbCHI5 was type IV CHI. The relative expression level of HbCHI gene family in rubber trees showed a trend of first decreasing and then increasing from small bronzer to mature stage. The relative expression level was the lowest in light green stage, and the change trend of total flavonoids content was consistent with the relative expression level of CHI gene. Correlation analysis showed that HbCHI2 had the highest significant correlation with flavoniods content. The Pearson coefficient was 0.97. Overexpression of HbCHI2 in N. benjamina promoted the biosynthesis of flavonoids and increased the total flavonoids content in leaves, which was 2.13 times that of control. These results indicate that HbCHI2 gene regulates flavonoid biosynthesis in rubber leaves.更多还原