Three Conifer Species To Establish Genetic Transformation Of Receptor Systems And Agrobacterium-mediated Genetic Transformation Research

Masson pine (Pinus massoniana L.) and Chinese fir (Cunninghamia lanceolata H.)are very important evergreen conifer trees for afforestation in South-east China andhave great economic values. Hybrid pine (Pinus elliottii var. elliottii × Pinus caribaeavar. hondurensis) is an eminent variety crossbreeded by means of gene recombinationand have excellent heterosis. In this study, different explants of masson pine, Chinesefir and hybrid pine were cultured to investigate the process of in vitro propagation.The influences of basal media, plant growth regulators and methods for budsinduction, shoots elongation and rooting were studied. The culture conditions of eachplant regeneration system were optimized. We also investigated the genetictransformation of masson pine primary stem apex and Chinese fir stem section usingthe gene transfer system mediated by Agrobacterium tumefaciens. Factors includingantibiotics, preculture, infection and co-culture time, concentration of bacteria andacetosyringone, and selection procedures that influence transgene expression areevaluated. The main results and innovations got as follows: ① The efficient system ofplant regeneration from mature zygotic embryo and primary stem apex of massonpine was established;② Genetic transformation of masson pine was studied for thefirst time and a novel transgene system using primary stem apex was established;③ Astable and efficient shoot regeneration system of hybrid pine from mature zygticembryos, cotyledons and stem segments was first reported;④ Using mature zygoticembryos and stem sections, efficient organogenesis process in Chinese fir wasobtained and direct somatic embryogenesis was successfully developed from stemsections for the first time;⑤ Using stem section system, genetic transformation ofChinese fir was studied and the preliminary results were obtained.