ISHS Acta Horticulturae 763: XXVII International Horticultural Congress - IHC2006: International Symposium on Structural and Functional Genomics of Horticultural Plants
HOMEOTIC GENE ANALYSIS OF CMS LINES DERIVED FROM INTERSPECIFIC CHIMERA IN BRASSICACEAE |
| Authors: | R. Okunishi, Y. Hirata, G. Hattori |
| Keywords: | Brassica rapa, Brassica oleracea, Raphanus sativus, petaloid, carpeloid, AGAMOUS gene |
| Abstract:
Interspecific chimeras between Brassica rapa cv. 'Komatsuna' and B. oleracea cv. 'Ruby ball' were synthesized by 'in vitro approach grafting'. A cytoplasmic male sterile (CMS) variant was obtained amongst the progenies derived from the chimeras. This CMS line expressed morphological changes in floral organs such as stamen, petals and carpels. These changes were similar to the homeotic mutants of Arabidopsis. According to the ABC model, floral organ specificity is principally determined by three class homeotic gene combinations. The AGAMOUS (AG) gene belongs to class-C, which involves the development of stamen and carpels in Arabidopsis. Therefore, the abnormal stamen and carpels in the obtained CMS lines might relate to AG gene expression. Partial AG genes were isolated from total DNA of the CMS line. These sequences showed high similarity with those of the pollen parental plant. We found that mitochondrial DNA of the CMS line showed similar RFLP patterns to the ogura type of CMS radish. It is suggested that the mitochondrial genome of the CMS line would affect the homeotic gene expression and floral organ specificity. Further investigation on the floral morphological changes in the CMS line would contribute to clarifying the mechanism of nuclear-mitochondrial interactions. | |
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