Structural and transcriptional analysis of plant genes encoding the bifunctional lysine ketoglutarate reductase saccharopine dehydrogenase enzyme

BMC Plant Biology

Research Article

Yong Q Gu¹  Olin D Anderson¹  Sekou Heath²  Devin Coleman-Derr³ 

[1] Genomics and Gene Discovery Research Unit, Western Regional Research Center, USDA-ARS, 800 Buchanan Street, 94710, Albany, CA, USA;Genomics and Gene Discovery Research Unit, Western Regional Research Center, USDA-ARS, 800 Buchanan Street, 94710, Albany, CA, USA;783 Euclid Avenue, 94708, Berkeley, CA, USA;Genomics and Gene Discovery Research Unit, Western Regional Research Center, USDA-ARS, 800 Buchanan Street, 94710, Albany, CA, USA;Department of Plant Sciences, University of California, 94720, Berkeley, CA, USA;

关键词: Hexaploid Wheat;    Wheat Genome;    Wheat ESTs;    Derive Amino Acid Sequence;    Saccharopine;   

DOI  :  10.1186/1471-2229-10-113

 received in 2009-11-13, accepted in 2010-06-16,  发布年份 2010

来源: Springer

【 摘 要 】

BackgroundAmong the dietary essential amino acids, the most severely limiting in the cereals is lysine. Since cereals make up half of the human diet, lysine limitation has quality/nutritional consequences. The breakdown of lysine is controlled mainly by the catabolic bifunctional enzyme lysine ketoglutarate reductase - saccharopine dehydrogenase (LKR/SDH). The LKR/SDH gene has been reported to produce transcripts for the bifunctional enzyme and separate monofunctional transcripts. In addition to lysine metabolism, this gene has been implicated in a number of metabolic and developmental pathways, which along with its production of multiple transcript types and complex exon/intron structure suggest an important node in plant metabolism. Understanding more about the LKR/SDH gene is thus interesting both from applied standpoint and for basic plant metabolism.ResultsThe current report describes a wheat genomic fragment containing an LKR/SDH gene and adjacent genes. The wheat LKR/SDH genomic segment was found to originate from the A-genome of wheat, and EST analysis indicates all three LKR/SDH genes in hexaploid wheat are transcriptionally active. A comparison of a set of plant LKR/SDH genes suggests regions of greater sequence conservation likely related to critical enzymatic functions and metabolic controls. Although most plants contain only a single LKR/SDH gene per genome, poplar contains at least two functional bifunctional genes in addition to a monofunctional LKR gene. Analysis of ESTs finds evidence for monofunctional LKR transcripts in switchgrass, and monofunctional SDH transcripts in wheat, Brachypodium, and poplar.ConclusionsThe analysis of a wheat LKR/SDH gene and comparative structural and functional analyses among available plant genes provides new information on this important gene. Both the structure of the LKR/SDH gene and the immediately adjacent genes show lineage-specific differences between monocots and dicots, and findings suggest variation in activity of LKR/SDH genes among plants. Although most plant genomes seem to contain a single conserved LKR/SDH gene per genome, poplar possesses multiple contiguous genes. A preponderance of SDH transcripts suggests the LKR region may be more rate-limiting. Only switchgrass has EST evidence for LKR monofunctional transcripts. Evidence for monofunctional SDH transcripts shows a novel intron in wheat, Brachypodium, and poplar.

【 授权许可】

CC BY   
© Anderson et al; licensee BioMed Central Ltd. 2010