Transgenic Study Of Genes Related To High Utilization Efficiency Of Potassium In Maize

As one of our major food crops in China, the improvement of unit yield andincrease of total cropping area of maize have overpassed that in other developingcountries. Research on genes related to nutrient utilization efficiency, especially thetransgenic study of genes related to efficient utilization of Potassium would bring thesignificance to the theory and practice in maize breeding.Maize node transgenic system is a simple and efficient system, which was notrestricted by season and genotype. Targeting on problems of dysfunction roots and theeasy broken nature of the regeneration seedlings’ root during the process of the maizenode regeneration, current study optimized the kind of and the concentration ofdisinfectants, as well as the concentration of the ager, the roots’ character wereimproved and a maize node transgenic system was established to produce the putativeT1generation seeds, which have the target gene of AlHAK1and AtCBL9.The two keypoints of maize node transgenic system were to use2%NaClO as disinfectant and toadd ager with concentration of5g/L to the culture medium.Pollen tube mediated method was a kind of simple transgenic method of themaize. Basta and PCR amplification were used to screen the putative T5generationtransgenic seedlings, which obtained by using normal vectors. Totally28putativetransgenic seedlings were obtained, and the positive rates of proposed transferAlHAK1and AtCBL9gene strain were15.1%and3.45%, respectively. Thereafter,T6generation seeds were obtained. To improve the method, a linear vector was builtand transformed into the genome of inhered line of Four-144, and the T1generationseeds was obtained within the limit of the study period.To further study the reason for changes of roots phenotype of regenerated plantsMSAP analysis was made in the roots. The results showed that, no matter the seedstreated by Mercuric chloride or sodium hypochlorite, methylation level will change, both in internodes of seedlings and roots of regenerated plants, and the effects ofsodium hypochlorite is relatively small. Based on results of the sequencing analysis,5gene fragments were chosen from204sequencing fragments, because they are relatedto the morphogenesis and the growth of the regeneration seedlings’ root. The plantexpression vectors were built to verify the genes function under study. Then three ofthem were constructed vectors and made preliminary functional verification.The Pollen tube mediated method and the Maize node transgenic system wereoptimized in this study, the putative transgenic seeds was obtained successfully.Further research showed that different disinfectants would change the methylationpattern of regeneration seedling. Preliminarily functional verification of genesscreened related to the root phenotypes of the regeneration seedling were carriedout.This study would bring the significance to the theory and practice in maizetransgenic breeding.