Variation in the DNA Content of Glycine Species

Nuclei were isolated from cotyledons of a range of accessionsfrom 14 species of Glycine. These were stained with ethidiumbromide and the relative fluorescence for each genotype wasmeasured by flow cytometry. The DNA content was estimated bycomparison of relative fluorescence with that from nuclei fromseedling leaves of Allium cepa, whose DNA content has been calculatedpreviously by chemical assay. The 4C amounts for diploid Glycineranged from 3.80 to 6.59 pg. Two groups of diploid species appearedfrom the analysis. The first consisted of species with amountsranging from 3.80 to 5.16 pg and included G. canescens (AA),G. argyrea (A₁ A₁), G. clandestina (A²A²), G. microphylla(BB),G. latifolia (B₁B₁), G. tabacina 2n=40 (B²B²), G. tomentella2n=38 (EE) and 2n=40 (DD), G. max and G. soja (GG), G. arenariaand G. latrobeana. A second group had higher DNA contents rangingfrom 5.27 to 6.59 pg, and consisted of G. curvata, G. cyrtoloba(CC), and G. falcata (FF). The polyploid species, G. tabacina2n=80 (AABB, BBB¹B¹), G. tomentella 2n=78 and 2n=80 (AAEE andDDEE, respectively) contained amounts approximating to the sumsof the respective parental diploid species thought to have givenrise to these allotetraploids. Intraspecific variation was detectedin the DNA content of G. canescens. Within the overall distributionof DNA amounts found in A genome species, each genome containeda range of DNA contents specific to that species. This phenomenonwas also detected amongst B genome species.     

Agrobacterium rhizogenes Mediated Transformation of the Wild Soybeans Glycine canescens and G. clandestine: Production of Transgenic Plants of G. canescens

Six accessions of Glycine canescens and four of G. clandestinawere evaluated for their response to inoculation with Agrobacteriumrhizogenes strain LBA 9402. The response was accession-dependent,with 9% to 70% of the seedlings producing roots following infectionof the hypocotyl. Excised cotyledons were less responsive thanhypocotyls. Roots exhibited plagiotropic and negatively geotropicgrowth in culture on hormone-free agar medium; those of G. canescensproduced shoots on B5 based medium containing 10 mg dm^–3BAP and 0.05 mg dm^–3 IBA. Cultured roots and regeneratedshoots synthesized opines. DNA sequences homologous to thoseof pRi TL and TR-DNA were present in a clonally propagated regeneratedplant of G. canescens. Key words: Agrobacterium rhizogenes, Glycine canescens, G. clandestina, transformed roots, transgenic plants