DETECTION OF A SINGLE GENE ENCODING GLUTAMINE-SYNTHETASE IN SINAPIS-ALBA (L)

作者：HOPFNER M; OCHS G; WILD A

来源：Journal of Plant Physiology, 1991, 139(1): 76-81.

• SINAPIS-ALBA
• AMMONIA ASSIMILATION
• GLUTAMINE SYNTHETASE GENE
• ISOENZYMES
• NORTHERN BLOT ANALYSIS
• SOUTHERN BLOT ANALYSIS

Ion-exchange chromatography of glutamine synthetase polypeptides (GS; EC 6.3.1.2) from green leaves and the roots of Sinapis alba yielded identical elution patterns. This is likewise true for GS from etiolated cotyledons. As we have previously demonstrated the identity of GS-enzymes from etiolated and green leaf tissues, the obviously very similar charge properties of GS-proteins indicate the eventual existence of only one type of GS in all mustard plant organs. To further prove this possibility, Southern blot analysis of mustard DNA was carried out using hybridization probes specific to different GS-isoforms. Concluding from the relative strength of the hybridization signals, the GS2-specific probes showed a higher sequence homology with mustard DNA fragments compared with the probes, specific for cytosolic GS-forms. Moreover, the latter hybridized to the same DNA-fragments as the GS2-specific probes. Generally, a small number of obviously GS-encoding mustard DNA fragments was found. Digestion of mustard DNA by means of Cla 1 or Hind 3 each yielded one single detectable fragment of about 10 or 4.7 kilobase pairs, respectively. Northern blot analysis revealed a single transcript type about 1.7 kilobases in length. Our results suggest that Sinapis alba holds a single GS-gene and hence only one GS-form, being the plastidic enzyme GS2. Thus, mustard plants probably show an exceptional GS-gene pattern, in contrast to the finding of small GS-encoding multigene families in all other plant species examined so far.

• 出版日期1991-11