Chalcone isomerase (CHI) is the second rate-limiting enzyme involved in the biosynthetic pathway of flavonoids in Glycyrrhiza uralensis. Based on our previous studies, we selected the specific CHI haplotype (GenBank Accession No. KY115232) to maximize flavonoid accumulation. We constructed a plant binary expression vector for overexpression of this CHI gene by the gene fusion method and transfected the plasmid into Agrobacterium tumefaciens ACCC10060 by electroporation. The recombinant A. tumefaciens ACCC10060 subsequently was used to infect cotyledons and hypocotyls of G. uralensis to obtain transgenic hairy roots. A qRT-PCR method was used to determine the copy number of CHI and a UPLC method was used to assay the content of four flavonoids in different hairy root lines. The qRT-PCR results showed that the copy number of CHI in hairy roots was 1 or 5. UPLC results showed that the content of total flavonoids, liquiritin, liquiritigenin, and isoliquiritigenin in transgenic hairy root samples was significantly higher than that in wild-type samples. This study demonstrates that overexpression of CHI significantly increases the content of flavonoids in hairy roots of G. uralensis. This work provides a theoretical basis for clarifying the function of CHI. Three transgenic hairy root lines of G. uralensis were isolated which can be used to increase the accumulation of licorice flavonoids in vitro.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |