Construction And Phenotypic Analysis Of Mutator-mediated Mutant Library In Maize

Mutator(Mu) elements in maize are the transposons with the highest transposition activity and mutation capability. Although the mechanism of mutator transposon is not clearly known, it is useful in constructing large mutant population of maize and cloning of important gene by transposon tagging strategy. The mutator insertional mutant pool would provide a valuable mutant for gene discovery and functional genomics study in maize. In this research, mutation population was established by crossing between the active mutator transposon donor parents W22 and the recipient parents Mo17. The result showed as following:1.The phenotypes of 42343 M1 plants were identified in the field. A total of 174 plants were observed to be mutated in 19 biological and agronomic characteristics, such as yollow leaf, lobed leaf blade, helical growth leaf, male sterile pollen and etc. Mutation frequence was 0.49%. The mutant was self-pollinated to obtain stable mutant lines, and the hundreds of phenotypcally normal M1 plants were randomly selected to be self-pollinated. Shriveled seeds (mutation frequence was 0.4%) were found and 8.4% reached mottled seeds.2. The seeds from 146 mutants were plants in 2007. The results showed that 129 stable mutation families were obsevered in 7 traits that were red stripe, white stripe and yellow stripe on the leaves, lobed leaf blade, rolled leave,red vains and shriveled leaves. Back mutation frequence was 27.02%。A total of 3540 M3 plants were obtained from self-pollinating M2. Results suggested that mutation frequence in ear kernel was 0.339%; proportion of dotted seeds was 4.7%.3. The color dotted seeds of M1 ear were selected to form another M2 population, a few new mutation phenotypes were discovered, for example, tiller, drawffing plant. Its mutation frequence was 2.06%. Mutation frequence of kernel from self-pollinating ear was 0.52% and dotted seeds accounted for 5.1% of all seeds.4. The seeds from 44 self-pollinating ear of M2 mutants were planted in 2008, the results showed that red stripe leaf, white stripe and yellow stripe leaf, lobed leaf blade and drawffing plant were hereditable.5. A total of 273 mutation plants involving 23 mutation types and 31 mutation ears involving 7 mutation types were found. There were 8 hereditable mutants involving red stripe leaf, white stripe and yellow stripe leaf, lobed leaf blade, drawffing plant and shrivelling seeds.