Study On Increasing Insect Resistance Of Potato By Transformation Of Cry3A And GNA Genes

The Colorado potato beetle(Leptinotarsa decemlineata Say, CPB) is a fatal pest. The CPB is a quarantine pest in China, but has now invaded the Xinjiang Uygur Autonomous Region and is spreading eastward. Aphid, the largest group of sap-sucking pests, causes significant yield losses in agricultural crops worldwide every year. The massive use of pesticides causing severe damage to the ecological environment, and pesticide residues is a threaten to human health. cry3 A gene is a BT gene and GNA gene is Snowdrop lectin gene。In this study, we developed transgenic potato plants expressing cry3 A gene and GNA gene separately, which were driven by Ca MV 35 S promoter and ST-LS1 promoter respectively. Their resistance to CPB and aphid were evaluated in the test in laboratory to control the damage caused by those two pests and to stop overspreading of CPB in 2014. The main results of this dissertation are listed below.1. Quantitative real-time polymerase chain reaction(qRT-PCR) analysis indicated that the cry3 A and GNA gene expressed in leaves, stems and roots of the transgenic plants under the control of Ca MV 35 S promoter, while expressed only in leaves and stems under the control of potato leaf and stem-specific promoter ST-LS1.2. The mortality of the CPB larvae was higher(28% and 36%) on the transgenic plant line 35S1-Cry in the 3rd and 4th day, and on ST3-Cry(48%) in the 5th day after inoculation with instar larvae. Insect biomass accumulation of CPB larvae on the foliage of the transgenic plant lines 35S1-Cry, 35S2-Cry and ST3-Cry was significantly lower(0.42%, 0.43% and 0.42%). Foliage consumption of CPB larvae was the lowest on the transgenic lines 35S8-Cry and ST2-Cry among all plant foliage(7.47 mg/larvae/day and 12.46 mg/larvae/day). The survivors on the transgenic lines were smaller than their original size. They were extremely weak and moved slowly.3. All the levels of aphid mortality in first 5 days about transgenic lines were different and ranged from 20% to 80%, the ST6-GNA had the highest mortality at 80%. On transgenic lines, the aphid population increased slowly than NT and rose to a maximum from(17.03±1.43)(ST2-GNA) to(38.5±3.5)(ST6-GNA) aphids per plant on day 15, which was from 24.92% to 56.34% for the NT aphid population. The results showed that GNA could express in potato and represent high mortality to aphid.