A SEARCH FOR THE KEY MATERIAL INVOLVED IN SOYBEAN SUPERNODULATION.

2000 Fiscal Year Final Research Report Summary

• Project/Area Number: 11660059
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Plant nutrition/Soil science
• Research Institution: TOKYO UNIVERSITY OF AGRICULTURE AND TECHNOLOGY
• Principal Investigator: ARIMA Yasuhiro TOKYO UNIV.OF AGRIC.AND TECH., FAC.OF AGRIC., PROFESSOR, 農学部, 教授 (90011973)
• Co-Investigator(Kenkyū-buntansha): YOKOYAMA Tadashi TOKYO UNIV.OF AGRIC.AND TECH., FAC.OF AGRIC., ASSOCIATE PROFESSOR, 農学部, 助教授 (70313286)
• Project Period (FY): 1999 – 2000
• Keywords: Soybean / Supernodulation / Phloem sap solutes / Amino acids / saccharides / Regulation of root nodule formation

Research Abstract

1) Establishment of an efficient method for the collecting phloem sap solutes from soybean NOD 1-3(a supernodulating mutant of Williams) and Williams82.
By pre- or simultaneous treatment of excised soybean shoots with EDTA, phloem sap solutes were collected, and the conditions for the efficient collection were clarified. A method for removing EDTA from the collected liquid of phloem sap solutes was examined, and most of EDTA was removed as precipitate by standing the liquid under ice-cooled and acidic condition.
2) The establishment of a bioassay system for evaluating the phloem sap solutes in the activity of regulating root nodule formation.
Plantlets was produced by cuttage of NOD1-3 and William82 triplet leaves. The plantlets respectively showed supernodulating or normal nodulating trait corresponding to catage source. By the individual introduction of sucrose or urea into the plantlet leaf through vacuum infiltration, the number of root nodule and root nodule anlage was clearly change d. In case of the urea introduction, it was also confirmed by heavy nitrogen tracer technique that the nitrogen derived from urea was abundantly transported to the roots. Hence, it was suggested that the plantlet-vacuum infiltration system was applicable for evaluating the phloem sap solutes in the activity of regulating root nodule formation.
3) Composition of phloem sap solutes collected from NOD1-3 and William82, and isolation of key material which controls root nodule formation.
On the free amino acid composition, some remarkable differences were detected between NOD1-3 and Williams82 regardless of root nodulation or non-nodulation. On the saccharide composition, there was no remarkable difference between them. An CDS column HPLC revealed that there were some unidentified materials which were much different in content between NOD1-3 and Williams82. However, key material, which controls the root nodule formation, could not be detected in the examination of phloem sap solute introduction into bioassay plantlets.