| Mutator(Mu) is the most active and mutagenic plant transposon discovered to date. Its high ability ofmutation and preferentially insertion in the gene-rich region and low copy sequences has make itbecome a powerful tool for constructing of mutant libraries and cloning maize genes. Researching ongenes controlling development of maize kernel not only has theoretical significant but also has goodapplication prospects.On our research, F2population came from self-pollinated F1plants that was generated by outcrossingthe Mu active lines as female to plants of maize hybrid line B73. We totally got about5700F2ears andabout700kernel mutants was isolated from them. We divide the mutant into five groups according tothe phenotype of their kernel. It mainly comprises empty pericarp kernel, rough endospermkernel,shrunk kernel, small kernel, high sugar content kernel.sk1mutant was isolated from serials of small kernel mutants. Its hundred-kernel weight is14.69gram, just60%weight of wild type's. We measured the length,width and thickness of the mutant andwild type kernel, the results as follows: the average length, width and thickness of the mutant kernel are1.07cm0.57cm and0.38cm respectively contrasted with the. normal kernle's1.15cm,0.69cm,and0.47cm. all the above indexes show significant different between the mutant and the wild type tested bya stastistical mothod of two-tailed t-test. Germination of the mutant kernel was also tested, it wassignificantly decreased. In addition, according to the results of genetic research, we found the mutantcontrolled by a recessive single gene. On that bases, we cloned the gene SK1by a method DLA that isdevelopped for isolating flanking sequences of transposon insertions. This gene located on the long armof chromosome5,and its function is unknown in maize. The function of its homologous genes inarabidopsis and rice are also unknown. The transcripts of SK1in mutant and wild type were analyzed,and the results show that transcripts is absent in mutant leaves but normal in wild type. According to thedata on line, SK1and its homologous gene in arabidopsis and rice were found all highly expressed inkernel.Further more, linkage analysis in the progeny of SK1was done to confirm that SK1just the candidategene, in fact we indeed found that the genotype and phenotype absolutely co-associated.Basing on above evidences, This research initially concluds that SK1gene is a critical gene in theprogress of maize kernel development, the kernel size depends on whether the gene expresses or not. |
