Marker-free Transgenic Wheat With WYMV-Nib8 Gene Obtained By Co-transformation

With the development of plant biotechnology, genetic transformation of crop plants is becoming increasingly routine and shows its potential application value in crop breeding. Transgenic crops have been developed in commercialized scale in some countries,but their biosafety have attracted public concerns in the world at the same time .Therefore,it is becoming more and more important to eliminate the selective genes because of their negative function, such as antibiotics resistance and herbicide resistance .Furthermore , marker-free transgenic plants(MFTPs) have a number of special advantages ,such as decreasing the conerns about safety of selective gene and stack of transgenes progressively into transgenic plants.Major approachs used recently for obtaining MFTPs were reviewed in this paper,which has shown a tendency to deleting any unuseful DNA sequences in the final product.(1) In this study, 268 lines of TS transgenic wheat from T2 generation line N12 of Yangmai 158 containing Wheat Yellow Mosaic Virus Nib8 gene(WYMV-Nib8) and bar selection gene that were obtained by Co-transformation of biolistic particle were analysized by PCR procedure .The results indicated that 28 lines only with the target gene were identified finally.(2) Genetic segregation of interest gene and bar gene in the Ta generation were studied in the paper,and segregation ratio was 1:1 approximately.Our results showed that foreign DNA integrated were inherited in aberrant Mendelian manner.The reasons may be loss, truncation and rearrangement of transgene and so on.With the development of study of offspring of transgenic plants and technique of transformation,genetic regulation of transgene in plants will be identified.(3) The resistance to WYMV of 20 lines whose genotype were Nib+bar- by PCR analysis were tested in Jiangyan , Yizheng citiesJiangSu province,and the resistance to herbicide were tested in CAAS.The results of resistance testing agreed with PCR analysis roughly.lt was proven that 19 out of 20 lines contained WYMV-Nib8 gene without selective marker gene (bar) and the resistance to WYMV could be inherited stablly .The obtainment of 19 transgenic lines made a full preparation for releasing in environment , evaluating biosafety and commercilization of transgenic wheat.It hasn't been reported at present in China that transgenic wheat conferring resistance to WYMV without bar gene were obtained by Co-transformation.