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.