新疆雪莲毛状根的诱导及其植株再生体系的建立

利用发根农杆菌R1601、R1000、LBA9402感染新疆雪莲的叶片、叶柄和根段外植体，诱导产生毛状根。毛状根接种量为2.8 g/L(FW)时,20d生长量可达66.7 g/L，黄酮含量达到干重的10.23%。冠瘿碱的检测和rolB基因的PCR分析表明，Ri质粒中的T_DNA片段已经整合到毛状根细胞的基因组中。预培养时间、外植体类型以及发根农杆菌的菌株属性对毛状根诱导有着重要的影响。其中预培养2 d的新疆雪莲根段外植体，经过R1601感染后，毛状根的诱导率可达100%。诱导产生的毛状根在附加生长素的液体培养基中，有少量愈伤组织产生。由毛状根再生的植株与雪莲外植体再生的植株在形态上无明显区别，但前者的黄酮含量仅为后者的53%。

Establishment of Saussurea involucrata Hairy Roots Culture and Plantlet Regeneration

Hairy root clones of Saussurea involucrata transformed with Agrobacterium rhizogenes strains R1601, R1000, and LBA9402 were established to investigate the flavonoid production. Opine synthesis and PCR analysis confirmed the integration of the T-DNA fragment of Ri plasmid from A. rhizogenes strain R1601 into the transformed root genome. The frequency of hairy root formation from root segments, which were pre-cultured 2 days in N6 solid medium without plant growth regulators, amounted to 100% following infection with R1601 strain of A. rhizogenes. The transformed roots were kept in hormone-free N6 liquid medium in the dark at 25 degrees C, 110r/min and routinely subcultured every 20 - 24 days. One hairy root clone, which grew vigorously with lateral branches, was periodically examined for the ability to produce flavonoid. The maximum of biomass and flavonoid yield achieved 66.7 g/L (fresh weight) and 102.3mg/g dry weight after incubation 20 days. The calli were induced from the hairy root culture in the presence of 0.5mg/L IBA and intact plantlets were regenerated from these calli. The regeneration plantlets from hairy roots, in which the flavonoid content were 53% in that of untransformed plants, weren't different in growth and morphology of the untransformed plantlets. Therefore plant regeneration from hairy roots may be also a means for producing transformed S. involucrata plants. Hairy root cultures of S. involucrata clearly showed higher flavonoid contents compared to the wild plant or the regeneration seedlings. As the wild S. involucrata grows only in special regions with peculiar climate, and cultivation of this species in a normal climate has been unsuccessful so far. The success in obtaining a method for high production of flavonoid might very well be one of the solutions for this problem in the future.