Study On Transformation Of Starch Synthesis-related Genes In Maize

Maize, originated in the Americas, is one of the world’s most important foodcrops. The usage of maize is very extensive, with the development of modern society,the importance of the industry use of maize has become increasingly prominent, anddemand for high amylose corn will be increasing. However, starch content inordinary corn is about70%, and amylose content in normal corn is only about25%.Itwill be low efficiency and high cost to extracted amylose from normal corn, andusing traditional breeding methods to cultivate high amylose corn will leads to totalstarch content decreased and grain moisture increased. Therefore, usingbiotechnological tools combing traditional breeding with molecular-assistedbreeding for corn starch (especially high amylose) genetic improvement isparticularly important.To solve this problem, this test was start from a key enzyme in the pathway ofstarch biosynthesis in maize. Granule-bound starch synthase I gene and Barleyendosperm-specific promoter HorD were cloned, plant expression vectorpHorD-GBSS I was obtained based on pCAMBIA3301vector.Through Agrobacterium-mediated method, we transferred pHorD-GBSSI carrierinto somatic embryo of maize inbred line Y423successfully, differentiation andobtained35positive plants of T0generation with Bar gene, Statistics for the positiverate of15%, we also did PCR-Southern blot. Finally, we obtained6positive plants ofT1generation with target gene.Through Agrobacterium-mediated method, we transferred pHord-GBSSI carrierinto immature embryo of maize inbred line Y412, Y423and Chang7-2successfully,then differentiation and obtained13positive plants of T0generation with Bar gene,8positive plants of T1generation with target gene. Statistics for the positive rate of12%.Plant expression vector pHorD-GBSSI, pRP5-ZmAGPL, pRP5-ZmAGPS, pRP5-AtAGPL, pHorp-Isa-H1were transformed into maize inbred lines:Chang7-2,Zheng58and W9812through pollen tube pathway.By resistance screening132T0transgenic plants were obtained,gene-positive rate of Bar is2%.92T1transgenicplants was obtained,gene-positive rate of Bar is2.6%. The amylase content of T1seeds being detected, the amylase content of transgenic seeds have some changesafter analysis the consequence of detection. Compared with control, the amylasecontent of transgenic seeds have improved0.34％-3.38％, and different inbred lineshave the different improvement.This research has great scientific value and commercial value. It laid atheoretical foundation and experimental basis for cultivation of high starch and highamylase Gene-Modified Maize in the future.