The ARABIDOPSIS accession Pna-10 is a naturally occurring sng1 deletion mutant.
Sinapoylmalate is the major sinapate ester found in leaves of Arabidopsis thaliana, where it plays an important role in UV-B protection. Metabolic profiling of rosette leaves from 96 Arabidopsis accessions revealed that the Pna-10 accession accumulates sinapoylglucose instead of sinapoylmalate. This unique leaf sinapate ester profile is similar to that of the previously characterized sinapoylglucose accumulator1 (sng1) mutants. SNG1 encodes sinapoylglucose:malate sinapoyltransferase (SMT), a serine carboxypeptidase-like (SCPL) enzyme that catalyzes the conversion of sinapoylglucose to sinapoylmalate. In the reference Columbia genome, the SNG1 gene is located in a cluster of five SCPL genes on Chromosome II. PCR and sequencing analysis of the same genomic region in the Pna-10 accession revealed a 13-kb deletion that eliminates the SNG1 gene (At2g22990) and the gene encoding sinapoylglucose:anthocyanin sinapoyltransferase (SAT) (At2g23000). In addition to its sinapoylmalate-deficient phenotype, and consistent with the loss of SAT, Pna-10 is unable to accumulate sinapoylated anthocyanins. Interestingly, the Pna-17 accession, collected from the same location as Pna-10, has no such deletion. Further analysis of 135 lines collected from the same location as Pna-10 and Pna-17 revealed that four more lines contain the deletion found in Pna-10 accession, suggesting that either the deletion found in Pna-10 is a recent event that has not yet been eliminated through selection or that sinapoylmalate is dispensable for the growth of Arabidopsis under field conditions.
Li
Xu
X
Department of Biochemistry, Purdue University, West Lafayette, IN 47907, USA.
Bergelson
Joy
J
Chapple
Clint
C
D000217:Acyltransferases / Q000235:genetics / Q000378:metabolism*; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D002934:Cinnamates / Q000378:metabolism; D005960:Glucosides / Q000378:metabolism; D013058:Mass Spectrometry; D018613:Microscopy, Confocal; D010666:Phenylpropionates / Q000378:metabolism*; D018515:Plant Leaves / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction
D029681:Arabidopsis Proteins; D002934:Cinnamates; D005960:Glucosides; D010666:Phenylpropionates; C103373:sinapoylglucose; D000217:Acyltransferases; C416511:sinapoylglucose malate sinapoyltransferase