Partial sequences of nitrogen metabolism genes in hexaploid wheat

Abstract

Our objective was to partially sequence genes controlling nitrogen metabolism in wheat species in order to find sequence polymorphism that would enable their mapping. Primers were designed for nitrate reductase, nitrite reductase, glutamate dehydrogenase and glutamate synthase (GOGAT), and gene fragments were amplified on Triticum aestivum, T. durum, T. monococcum, T. speltoides and T. tauschii. We obtained more than 8 kb of gene sequences, mainly as coding regions (60%). Polymorphism was quantified by comparing two-by-two the three genomes of the hexaploid cultivar Arche and genomes of diploid wheat species. On average, the polymorphism rate was higher for non-coding regions, where it ranged from 1/60 to 1/23, than for coding regions (range: 1/110-1/40) except when the hexaploid D genome was compared to that of T. tauschii (1/800 and 1/816, respectively). Genome-specific primers were devised for the ferredoxin-dependent (Fd)-GOGAT gene, and they enabled the mapping of this gene on homoeologous chromosomes of group 2 using Chinese Spring deletion lines. A single nucleotide polymorphism (SNP) detected between the two hexaploid wheat cultivars Arche and Recital was used to genetically map Fd-GOGAT on chromosome 2D using a population of dihaploid lines. Fd-GOGAT-specific primers were used to estimate the SNP rate on a set of 11 hexaploid and nine Durum wheat genotypes leading to the estimate of 1 SNP/515 bp. We demonstrate that polymorphism detection enables heterologous, homeologous and even paralogous copies to be assigned, even if the elaboration of specific primer pairs is time-consuming and expensive because of the sequencing.

Combined agronomic and physiological aspects of nitrogen management in wheat highlight a central role for glutamine synthetase

“…The two cultivars also differ in N-uptake efficiency at harvest (Le Gouis et al ., 2000). Arche and Récital have been crossed to produce a population of double haploid lines for quantitative genetic studies of the basis of N-use efficiency (Boisson et al ., 2005 12 May 2003). Low N-level plots (N -) received 80 kg ha − 1 N at tillering.…”

Characterization of Ferredoxin-Dependent Glutamine-Oxoglutarate Amidotransferase (Fd-GOGAT) Genes and Their Relationship with Grain Protein Content QTL in Wheat

“…The first plant complete genomic sequences identified were two genes from Arabidopsis [13]. For the Triticeae crops (wheat, barley, rye), no complete sequence has been known although partial sequences were reported for barley [14] and fragments for wheat [15].…”

Allelic Variants of Glutamine Synthetase and Glutamate Synthase Genes in a Collection of Durum Wheat and Association with Grain Protein Content

“…GOGAT genes genomic sequences have been reported for maize [21], tobacco [22], Arabidopsis [23] and barley [24] and partial sequences were also reported in bread wheat [25]. Recently, NADH and Fd-GOGAT gene structures, genomic sequences, gene localization, and involvement in GPC control have been reported in durum wheat [26,27].…”