| A monosomic alien addition lines of Beta corolliflora in sugar beet, designated asM14, constituting of the normal 18 B. vulgaris chromosomes plus B. corolliflorachromosome 9, was found to have a high chromosome transmission frequency amonggenerations. Line M14 was evaluated to be a facultative apomixis material withmorphology, genetics, cytology, embroyolgy and molecular biology. It was presumedthat the apomixis of M14 was related with FIS gene and SERK gene, because the downregulated expression or terminated expression of FIS was correlated with the apomixisof Hieracium. and the expression of SERK gene with plant parthenogenesis. The FIS3fragment and SERK fragment were cloned in Beta vulgaris M14 with RT-PCR andPCR based on the facultative primers or primers designed according to the conservativeregions of FIS3 and SERK sequences in Genbank. The results of Southern dot blotting,M14 and B. vulgaris as template DNA, cloned FIS3 fragment or SERK fragment asprobe, indicated that M14 and B. vulgaris both had FIS3 and SERK genes and the copyin M14 was higher than in Beta vulgaris, showing that there were FIS3 and SERKgene or homological sequence of FIS3 and SERK in the ninth chromosome of Betacorolliflora. Northern blotting was conducted in order to detect the different expressionof FIS3 and SERK genes between line M14 and Beta vulgaris flower buds during thekey stages, i.e., maiosis of macrospore mother cell, synergid degeneration andnonfertilized egg division, of M14 apomixis embryo development. Northern blottingresults showed that the expression of FIS3 gene stabilized in Beta vulgaris, reducedobviously at the synergid degeneration phase in M14 line and continued to reduce at thenonfertilized egg division phase. The expression of SERK gene was higher in M14 line than in Beta vulgaris both at the syrergid degeneration and the nonfertilized eggdivision phase. All of these results indicated that FIS3 and SERK were possiblycorrelated with the apomixis of M14 line. |
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