the glutamine synthetase gene family in populus杨树的谷氨酰胺合成酶基因家族.pdf

Castro-Rodríguez et al. BMC Plant Biology 2011, 11:119 /1471-2229/11/119 RESEARCH ARTICLE Open Access The glutamine synthetase gene family in Populus 1 1 1 1 2 Vanessa Castro-Rodríguez , Angel García-Gutiérrez , Javier Canales , Concepción Avila , Edward G Kirby and Francisco M Cánovas1* Abstract Background: Glutamine synthetase (GS; EC: , 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. Results: The 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. Conclusions: Our 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 functio