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 th...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 （sngl） 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 Chro- mosome 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.展开更多
文摘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 （sngl） 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 Chro- mosome 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.
