| Purple sweet potato also known as purple potato,originally produced in southern Kyushu,Japan.In the 1990 s,Chinese agricultural science and technology personnel brought back to China and successfully planted.Purple sweet potato is an annual or perennial herb.Purple sweet potato is a kind of high nutrition sweet potato variety with edible,medicinal and health care functions.It has high economic value.The research on purple sweet potato in Japan and South Korea is developing rapidly.The development and utilization of purple sweet potato in China has been dependent on some imported varieties,because its low yield greatly restricts the development of purple sweet potato processing industry in China.At present,the improvement of new purple potato varieties mainly depends on systematic breeding and hybrid breeding.Purple potato tissue culture is an important way to obtain asexual mutants by cell engineering technology.At present,only some varieties have been reported,and the transgenic system of purple potato has not been reported.This thesis focuses on two pathways,namely,purple sweet potato healing tissue adventitious shoot and somatic embryo,and establishes an in-province system for purple sweet potato tissue culture according to the actual situation.The positive transgenic healing tissues and transgenic plants were found.The main contents of this paper are as follows.1.Establishment of regeneration system for adventitious bud pathway in callus(1)The optimum medium and hormone combination suitable for callus induction and differentiation of purple potato leaves and stem explants were selected by comparing the effects of different hormone types and concentrations on proliferation rate and differentiation rate.The results showed that the medium suitable for leaf proliferation was MS basic medium additional NAA 0.3mg/L and 6-BA 0.5mg/L,differentiation medium were also additional NAA 0.3mg/L and 6-BA0.5mg/L.The proliferation medium suitable for stem segment is MS basic medium additional NAA 0.3mg/L and 6-BA 0.6mg/L,differentiation medium are also additional NAA 0.3mg/L and 6-BA 0.6mg/L.2.Establishment of purple sweet potato-induced regeneration system by somatic cell embryonic pathwayThe histological structure of purple sweet potato was investigated,and its leaves as well as stem segment parts belonged to the explants.Experiments were conducted by comparing the possible effects of different hormone types and concentrations on the induction and differentiation rates of healing tissues of leaf and stem segment explants,finding a more suitable medium,and selecting a more suitable hormone combination.After investigation,it was found that the study of explants from leaves and their stem segment parts of purple potato showed that their non-embryonic guarantor tissues differed in their ability to induce dedifferentiation and redifferentiation of embryonic guarantor tissues on different media.The best medium suitable for the re-differentiation of purple potato healing tissues was MS basic medium supplemented with2,4-D 2.5 mg/L and 6-BA 2.5 mg/L.3.Preliminary study on genetic transformation of purple potato(1)The thaumatin concentration suitable for purple potato stem segments as transformants was screened.The results showed that the best experimental results were obtained when a concentration of 30mg/L was selected for purple potato stem segments.Experiments were conducted for different concentrations as well as the time of immersion to observe how the differences in these factors might affect the transformation rate of purple potato.It was found that the experiment was conducted using LB liquid medium,plus the overnight culture of the bacterium,which was diluted by adding O.D.0.5.After the dilution was completed,it was then submerged for 60 min,and the results showed that the conversion rate was generally higher on the third day.(2)The method of Agrobacterium-mediated method was used to introduce the thaumatin resistance gene into purple potato for the first time for the experiment,and from the test results,the final results showed that purple potato transgenic healing tissues were grown and transgenic plants were cultivated. |
