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Molecular mechanism of symbiotic specific gene expression

共生特异性基因表达的分子机制

基本信息

批准号：
10660062
负责人：
TAJIMA Shigeyuki
金额：
$ 2.11万
依托单位：
Kagawa University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 1999
项目状态：
已结题

项目摘要

The profiles of ureide (allantoin and allantoic acid) accumulation under different nitrogen nutrient conditions were surveyed in various tissues of alfalfa, Medicago sativa. The ratios of ureide to asparagine in xylem saps of two amide type legumes, Medicago sativa and Lotus corniculatus were 14 times less than that of a typical ureide type legume, Glycine max. when they are growing with nitrogen-free nutrient solution.Two cDNA clones, MsU2 and MsU9 encoding uricase (EC 1.7.3.3., Nodulin-35) were isolated from a cDNA library prepared from nodule tissues of alfalfa, Medicago sativa, plants. Both MsU2 and MsU9 encoded 3 08 amino acid polypeptides with a difference of 5 amino acids, and the deduced amino acid sequences shared 980/0 homology. Between these two cDNA clones and uricase genes of soybean which were designated as Nod-35s, more than 800/0 identity was observed in nucleotides and deduced amino acid sequences, suggesting that these MsU2 and MsU9 are homologs of Nod-35.Using the reverse transcription-PCR technique, we detected the transcripts of these two genes in almost all tissues of alfalfa. The operation of uricase genes was confirmed by the presence of ureide in the xylem sap and uricase activity in the nodules. In situ hybridization analysis revealed that MsU2 and MsU9 were expressed only in uninfected cells of the infected zone of the nodule tissue. The cell specific-expression of the two uricase genes was observed in an identical manner to that of Nod-35 in soybean nodules.

研究了不同氮营养条件下紫花苜蓿（Medicago sativa）各组织中尿囊素（尿囊素和尿囊酸）的积累情况。两种酰胺型豆科植物紫花苜蓿（Medicago sativa）和白莲（Lotus corniculatus）木质部汁液中尿素与天冬酰胺的比例比典型的酰胺型豆科植物Glycine max低14倍。当它们在无氮营养液中生长时。两个cDNA克隆，MsU2和MsU9编码尿酸酶（EC 1.7.3.3）。从苜蓿、紫花苜蓿（Medicago sativa）的根瘤组织cDNA文库中分离得到2个基因。MsU2和MsU9编码3 08个氨基酸多肽，差异5个氨基酸，推导出的氨基酸序列同源性为980/0。这两个cDNA克隆与大豆尿酸酶基因Nod-35s之间的核苷酸和推导出的氨基酸序列同源性大于800/0，表明MsU2和MsU9与Nod-35同源。利用反转录pcr技术，我们在紫花苜蓿的几乎所有组织中检测到这两个基因的转录本。木质部汁液中尿素的存在和根瘤中尿酸酶的活性证实了尿酸酶基因的作用。原位杂交分析显示，MsU2和MsU9仅在结节组织感染区的未感染细胞中表达。两种尿酸酶基因在大豆根瘤中的细胞特异性表达与Nod-35相同。