Abstract:

【Objective】 The objective of this study was to elucidate whether the α- and β- null character was result from the absence or variance of α- and β-subunit genes. 【Method】 SDS-PAGE technique, PCR amplification, cloning and sequencing methods were used. 【Result】 With specific primers for α- subunit, the PCR band pattern between (α+β)-null type and normal type was identical, but the PCR band pattern of β-subunit gene was unique. For PCR amplified DNA fragment of the α-subunit gene, a high degree of nucleotide homology (90.9%) exists between the (α+β)-null type and normal type. Sequenced difference mainly exists in 5′-flanking. While, for β-subunit gene, a low degree of nucleotide homology (53.1%) was exists. Furthermore, a short inverted sequence was detected in PCR amplified DNA fragment of the β-subunit gene.【Conclusion】The deficiency character of α- and β-subunit of (α+β)-null type is not related to the deletion of a chromosome segment with the genes encoding α- and β-subunit of soybean 7S globulin. Differences exist in both α- and β-subunit gene sequence between (α+β)-null type and normal type soybean. Further studies to confirm whether the differences in gene sequence are main reason that result in the absence of α- and β-subunit are necessary.

Key words: soybean, 7S globulin, α- and β- subunit, novel subunit combination, DNA sequencing