Two genes encoding distinct cytosolic glutamine synthetases are closely linked in the pine genome

Sáez, Concepción Ávila; Muñoz‐Chápuli, Ramón; Plomion, Christophe; Frigério, Jean‐Marc; Cánovas, Francisco M.

doi:10.1016/s0014-5793(00)01796-8

Cited by 33 publications

(24 citation statements)

References 36 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It has been proposed that the gain of a N-terminal transit peptide in GS2 would provide adaptive advantages to plants through enhanced photorespiratory ammonium assimilation in the plastids [12]. Members of the GS1 clade in angiosperms are grouped in subfamilies as previously reported by others [6,10,21]. PtGS1.2 and PtGS1.3 duplicates were found associated to these subfamilies suggesting they could play similar functions to those described for these isoforms.…”

Section: Discussionmentioning

confidence: 66%

“…Recently it has been reported that plant GS holoenzyme has a decameric structure composed of two face-to face pentameric rings of subunits, with active sites formed between every two neighboring subunits within each ring [4,5]. Phylogenetic studies of nucleotide and amino acid sequences have shown that genes for chloroplastic and cytosolic GS in plants form two sister groups with a common ancestor which diverged by duplication before the split between angiosperms and gymnosperms [6]. …”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

The glutamine synthetase gene family in Populus

et al. 2011

View full text Add to dashboard Cite

BackgroundGlutamine synthetase (GS; EC: 6.3.1.2, L-glutamate: ammonia ligase ADP-forming) is a key enzyme in ammonium assimilation and metabolism of higher plants. The current work was undertaken to develop a more comprehensive understanding of molecular and biochemical features of GS gene family in poplar, and to characterize the developmental regulation of GS expression in various tissues and at various times during the poplar perennial growth.ResultsThe GS gene family consists of 8 different genes exhibiting all structural and regulatory elements consistent with their roles as functional genes. Our results indicate that the family members are organized in 4 groups of duplicated genes, 3 of which code for cytosolic GS isoforms (GS1) and 1 which codes for the choroplastic GS isoform (GS2). Our analysis shows that Populus trichocarpa is the first plant species in which it was observed the complete GS family duplicated. Detailed expression analyses have revealed specific spatial and seasonal patterns of GS expression in poplar. These data provide insights into the metabolic function of GS isoforms in poplar and pave the way for future functional studies.ConclusionsOur data suggest that GS duplicates could have been retained in order to increase the amount of enzyme in a particular cell type. This possibility could contribute to the homeostasis of nitrogen metabolism in functions associated to changes in glutamine-derived metabolic products. The presence of duplicated GS genes in poplar could also contribute to diversification of the enzymatic properties for a particular GS isoform through the assembly of GS polypeptides into homo oligomeric and/or hetero oligomeric holoenzymes in specific cell types.

show abstract

Section: Discussionmentioning

confidence: 66%

Section: Introductionmentioning

confidence: 99%

The glutamine synthetase gene family in Populus

et al. 2011

View full text Add to dashboard Cite

show abstract

“…To our knowledge, this is the first report of a duplication of a plastid located gene, and interestingly, the duplication seems to be quite recent in view of the estimation of the age of divergence of the cytosolic GS genes. Studies in Pinus sylvestris , estimate that the duplication of an ancestral cytosolic GS occurred long before the divergence of gymnosperms/angiosperms [40]. …”

Section: Discussionmentioning

confidence: 99%

Medicago truncatula contains a second gene encoding a plastid located glutamine synthetase exclusively expressed in developing seeds

et al. 2010

View full text Add to dashboard Cite

Background Nitrogen is a crucial nutrient that is both essential and rate limiting for plant growth and seed production. Glutamine synthetase (GS), occupies a central position in nitrogen assimilation and recycling, justifying the extensive number of studies that have been dedicated to this enzyme from several plant sources. All plants species studied to date have been reported as containing a single, nuclear gene encoding a plastid located GS isoenzyme per haploid genome. This study reports the existence of a second nuclear gene encoding a plastid located GS in Medicago truncatula . Results This study characterizes a new, second gene encoding a plastid located glutamine synthetase (GS2) in M. truncatula . The gene encodes a functional GS isoenzyme with unique kinetic properties, which is exclusively expressed in developing seeds. Based on molecular data and the assumption of a molecular clock, it is estimated that the gene arose from a duplication event that occurred about 10 My ago, after legume speciation and that duplicated sequences are also present in closely related species of the Vicioide subclade. Expression analysis by RT-PCR and western blot indicate that the gene is exclusively expressed in developing seeds and its expression is related to seed filling, suggesting a specific function of the enzyme associated to legume seed metabolism. Interestingly, the gene was found to be subjected to alternative splicing over the first intron, leading to the formation of two transcripts with similar open reading frames but varying 5' UTR lengths, due to retention of the first intron. To our knowledge, this is the first report of alternative splicing on a plant GS gene. Conclusions This study shows that Medicago truncatula contains an additional GS gene encoding a plastid located isoenzyme, which is functional and exclusively expressed during seed development. Legumes produce protein-rich seeds requiring high amounts of nitrogen, we postulate that this gene duplication represents a functional innovation of plastid located GS related to storage protein accumulation exclusive to legume seed metabolism.

show abstract

“…Two different genes, GS1a and GS1b , encode GS1 isoforms in pine, and the isoforms exhibit distinct molecular and kinetic properties (Avila et al. , 1998; Avila‐Sáez et al. , 2000; de la Torre et al.…”

Section: Introductionmentioning

confidence: 99%

Differential regulation of two glutamine synthetase genes by a single Dof transcription factor

et al. 2008

Self Cite

View full text Add to dashboard Cite

SummaryThe PpDof5 transcription factor from maritime pine (Pinus pinaster) is a regulator of the expression of glutamine synthetase (GS) genes in photosynthetic and non-photosynthetic tissues. PpDof5 mRNA is detected almost ubiquitously during pine development with low levels of gene expression in green tissues and much higher levels in roots and lignified shoots. The PpDof5 protein expressed in bacteria binds to oligonucleotide probes containing the AAAG core sequence derived from the promoters of GS1a and GS1b genes. Transient expression experiments in agroinfiltrated tobacco leaves and in pine protoplasts demonstrated that PpDof5 is able to trans-regulate differentially the transcription of both GS1a and GS1b. PpDof5 activated transcription of the GS1b promoter and, in contrast, behaved as a transcriptional repressor of the GS1a promoter. These results support a regulatory mechanism for the transcriptional control of the spatial distribution of cytosolic GS isoforms in pine. Considering the precise expression patterns of GS1 genes required to fulfil the ammonium assimilation requirements during tree development, we hypothesize that PpDof5 could have a key role in the control of ammonium assimilation for glutamine biosynthesis in conifers. A regulatory model of GS1 gene expression in pine is proposed.

show abstract

Two genes encoding distinct cytosolic glutamine synthetases are closely linked in the pine genome

Cited by 33 publications

References 36 publications

The glutamine synthetase gene family in Populus

The glutamine synthetase gene family in Populus

Medicago truncatula contains a second gene encoding a plastid located glutamine synthetase exclusively expressed in developing seeds

Differential regulation of two glutamine synthetase genes by a single Dof transcription factor

Contact Info

Product

Resources

About