| Genetic engineering technique has become an important method in crop germplasminnovation and breeding. The genomic modified crops agaist herbicide and insect have beenproducted commercially and increased year by year, including soybeans, corn, cotton, canola andother crops. The research of high-yield transgenic crop started late, but the rapid development isavailable in this area at home and abroad. Monsanto is targeting at developing high-yieldgenetically modified corn. The high-yield transgenic rice grows quickly in domestic. A lot ofhigh-yield related genes were cloned and transformed into rice, such as arginase gene. Arginine isan important content of storing nitrogen nutrition substance in plants, and a precursor of someimportant messenger molecule, such as the polyamine and nitric oxide, and so on.Overexpressionof the arginase gene can enhance nitrogen utilization efficiency and nutrition substanceaccumulation in plant, thereby increase the yield. In this study, arginase gene ZmArg was clonedfrom corn into an over-expression monocotyledons vector and transformed into the maize inbredlines by agrobacterium-mediated and pollen tube pathway. The new high-yield transgenic plantswere selected by molecular methods, arginase activity detection and yield identification as maizebreeding resource.The results were helpful in speeding up high-yield transgenic maize research andindustrialization process of our country and narrowing the gap with the advanced countries.Themain research results were as follows:1. The arginase gene ZmArg was cloned from corm by homologous sequcing method based onthe arginase gene sequences in Genbank, and inserted into an over-expression vectorsuccessfullynamed pCAMBIA5300-Ubi-ZmArg.2. The gene was transformed into11elite maize inbred lines by agrobacterium-mediated and pollentube pathway. There were67T2generation positive maize lines in PCR test. Southern hybridizationpresented two hybridization signals, indicating it was possible to double-copy.3. T2generation of transgenic lines whose acceptors were K10, KF298and KF513were used todetect the arginase activity during the whole growth period.The arginase activity showed a normalprobability curve, increasing from seed stage firstly, reaching the highest level at jointing stage, andthen reducing. The transgenic line E65-9whose acceptor was KF513showed the highest value atup to0.0876. Excepted in the flowering period, the arginase activity of lines E1-1(K10) was lowerthan non-transformed control,In any other periods and other materials, the arginase activity oftransformed lines were higher than the non-transgenic control. The large increase was foundbetween the transgenic line E61-3(KF298).4. The same transgenic lines used to detect arginase activity aslo were evaluated yield related traits.Compared with acceptors, there was a significant increase in the transgenic plants among thesetraits, including grain length, grain width, the geometric kernel weight. E1-1(K10), E61-5(KF298) and E65-9(KF513) gained9.26%,12.94%and14.16%in kernel weight separately. The plant heightof lines E61-3(KF298) and E65-9(KF513) increased14.80%and7.43%compared with the control,and ear height of them also increased. But there was no significant change in line E1-1(K10).5.T2generation of transgenic lines E61-3whose acceptors were KF298, its arginase activity werehigher than the non-transgenic control in the whole growth period, and in the flowering period,arginase activity was27.71%higher than the non-transgenic control. Their stay green, plant heightand ear height have significantly enhaced than non-transgenic control, and their rows grains, earlength, grain width and the geometric kernel weight were extremely higher than non-transgeniccontrol. |
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