Pyrimidine metabolism during somatic embryo development in white spruce (Picea glauca)

被引:22
作者
Ashihara, H
Loukanina, N
Stasolla, C
Thorpe, TA
机构
[1] Univ Calgary, Dept Biol Sci, Plant Physiol Res Grp, Calgary, AB T2N 1N4, Canada
[2] Ochanomizu Univ, Fac Sci, Dept Biol, Bunkyo Ku, Tokyo 1128610, Japan
基金
加拿大自然科学与工程研究理事会;
关键词
Picea glauca; embryo development; orotate phosphoribosyltransferase; pyrimidine biosynthesis; somatic embryogenesis; uracil degradation; uracil phosphoribosyltransferase; uridine kinase;
D O I
10.1078/0176-1617-00318
中图分类号
Q94 [植物学];
学科分类号
071001 ;
摘要
Pyrimidine metabolism was investigated at various stages of somatic embryo development of white spruce (Picea glauca). The contribution of the de novo and the salvage pathways of pyrimidine biosynthesis to nucleotide and nucleic acid formation and the catabolism of pyrimidine was estimated by the exogenously supplied [6-C-14]erotic acid, an intermediate of the de novo pathway, and with [2-C-14]uridine and [2-C-14]uracil, substrates of the salvage. pathways. The de novo pathway was very active throughout embryo development. More than 80% of [6-C-14]orotic acid taken up by the tissue was utilized for nucleotide and nucleic acid synthesis in all stages of this process. The salvage pathways of uridine and uracil were also operative. Relatively high nucleic acid biosynthesis from uridine was observed, whereas the contribution of uracil salvage to the pyrimidine nucleotide and nucleic acid synthesis was extremely limited. A large proportion of uracil was degraded as (CO2)-C-14, probably via beta -ureidopropionate. Among the enzymes of pyrimidine metabolism, orotate phosphoribosyltransferase was high during the initial phases of embryo development. after which it gradually declined. Uridine kinase,responsible for the salvage of uridine, showed an opposite pattern, since its activity increased as embryos developed. Low activities of uracil phosphoribosyltransferase and non-specific nucleoside phosphotransferase were also detected throughout the developmental period. These results suggest that the flux of the de novo and salvage pathways of pyrimidine nucleotide biosynthesis in vivo is roughly controlled by the amount of these enzymes. However, changing patterns of enzyme activity during embryo development that were measured in vitro did not exactly correlate with the flux estimated by the radioactive precursors. Therefore, other fine control mechanisms, such as the fluctuation of levels of substrates and/or effecters may also participate to the real control of pyrimidine metabolism during white spruce somatic embryo development.
引用
收藏
页码:613 / 621
页数:9
相关论文
共 28 条
[1]   CHANGES IN ACTIVITIES OF DENOVO AND SALVAGE PATHWAYS OF PYRIMIDINE NUCLEOTIDE BIOSYNTHESIS DURING GERMINATION OF BLACK GRAM (PHASEOLUS-MUNGO) SEEDS [J].
ASHIHARA, H .
ZEITSCHRIFT FUR PFLANZENPHYSIOLOGIE, 1977, 81 (03) :199-211
[2]   Purine and pyrimidine metabolism in cultured white spruce (Picea glauca) cells:: Metabolic fate of 14C-labeled precursors and activity of key enzymes [J].
Ashihara, H ;
Stasolla, C ;
Loukanina, N ;
Thorpe, TA .
PHYSIOLOGIA PLANTARUM, 2000, 108 (01) :25-33
[3]   OROTATE PHOSPHORIBOSYLTRANSFERASE AND OROTIDINE-5'-MONOPHOSPHATE DECARBOXYLASE OF BLACK GRAM (PHASEOLUS-MUNGO) SEEDLINGS [J].
ASHIHARA, H .
ZEITSCHRIFT FUR PFLANZENPHYSIOLOGIE, 1978, 87 (03) :225-241
[4]   PYRIMIDINE NUCLEOTIDE BIOSYNTHESIS DURING SOMATIC EMBRYOGENESIS IN A CARROT CELL-SUSPENSION CULTURE [J].
ASHIHARA, H ;
FUJIMURA, T ;
KOMAMINE, A .
ZEITSCHRIFT FUR PFLANZENPHYSIOLOGIE, 1981, 104 (02) :129-137
[5]  
ASHIHARA H, 1981, Acta Physiologiae Plantarum, V3, P77
[6]   Gene expression patterns, and uptake and fate of fed ABA in white spruce somatic embryo tissues during maturation [J].
Dong, JZ ;
Perras, MR ;
Abrams, SR ;
Dunstan, DI .
JOURNAL OF EXPERIMENTAL BOTANY, 1997, 48 (307) :277-287
[7]  
Dong JZ, 1996, PLANTA, V199, P459
[8]   METABOLISM OF (+)-ABSCISIC AND (-)-ABSCISIC ACID BY SOMATIC EMBRYO SUSPENSION-CULTURES OF WHITE SPRUCE [J].
DUNSTAN, DI ;
BOCK, CA ;
ABRAMS, GD ;
ABRAMS, SR .
PHYTOCHEMISTRY, 1992, 31 (05) :1451-1454
[9]  
FLINN BS, 1993, PHYSIOL PLANTARUM, V89, P719, DOI 10.1111/j.1399-3054.1993.tb05278.x
[10]   PLANTLET REGENERATION THROUGH SOMATIC EMBRYOGENESIS IN PICEA-ABIES (NORWAY SPRUCE) [J].
HAKMAN, I ;
VONARNOLD, S .
JOURNAL OF PLANT PHYSIOLOGY, 1985, 121 (02) :149-158