RESUMEN
The artemisinic aldehyde double bond reductase (DBR2) plays an important role in the biosynthesis of the antimalarial artemisinin in Artemisia annua. Artemisinic aldehyde is reduced into dihydroartemisinic aldehyde by DBR2. Artemisinic aldehyde can also be oxidized by amorpha-4,11-diene 12-hydroxylase and/or aldehyde dehydrogenase 1 to artemisinic acid, a precursor of arteannuin B. In order to better understand the effects of DBR2 expression on the flow of artemisinic aldehyde into either artemisinin or arteannuin B, we determined the content of dihydroartemisinic aldehyde, artemisinin, artemisinic acid and arteannuin B content of A. annua varieties sorted into two chemotypes. The high artemisinin producers (HAPs), which includes the '2/39', 'Chongqing' and 'Anamed' varieties, produce more artemisinin than arteannuin B; the low artemisinin producers (LAPs), which include the 'Meise', 'Iran#8', 'Iran#14', 'Iran#24' and 'Iran#47' varieties, produce more arteannuin B than artemisinin. Quantitative PCR showed that the relative expression of DBR2 was significantly higher in the HAP varieties. We cloned and sequenced the promoter of the DBR2 gene from varieties of both the LAP and the HAP groups. There were deletions/insertions in the region just upstream of the ATG start codon in the LAP varities, which might be the reason for the different promoter activities of the HAP and LAP varieties. The relevance of promoter variation, DBR2 expression levels and artemisinin biosynthesis capabilities are discussed and a selection method for HAP varieties with a DNA marker is suggested. Furthermore, putative cis-acting regulatory elements differ between the HAP and LAP varieties.
Asunto(s)
Artemisia annua/genética , Artemisia annua/metabolismo , Artemisininas/metabolismo , Oxidorreductasas/genética , Oxidorreductasas/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Antimaláricos/metabolismo , Artemisia annua/clasificación , Secuencia de Bases , ADN de Plantas/genética , Genes de Plantas , Plantas Medicinales/clasificación , Plantas Medicinales/genética , Plantas Medicinales/metabolismo , Reacción en Cadena de la Polimerasa , Regiones Promotoras Genéticas , Especificidad de la EspecieRESUMEN
Noscapine is an antitumor alkaloid produced in opium poppy (Papaver somniferum) and some members of the Papaveraceae family. It has been primarily used for its antitussive effects; more recently, its anticancer properties were shown. Herein, we detected an SSR embedded in the promoter region of the CYP82Y1 gene, which was found to be the first committed-step enzyme in the noscapine biosynthesis pathway, using the MISA program. Some collected ecotypes of P. somniferum were investigated for understanding of SSRs role in the regulation of gene expression and metabolite content. Quantitative PCR showed that a variation in the motif repeat number (either a decrease or increase) down-regulated the expression of the CYP82Y1 gene. Furthermore, the analysis of noscapine content suggested that a variation in the promoter region influence noscapine amount. Moreover, P. bracteatum was analyzed in both transcript and metabolite levels, and illustrated much less expression and metabolite level in comparison to P. somniferum. By exploiting the transcriptome data from the eight genera of the Papaveraceae family, we found that noscapine biosynthesis genes are present in P. bracteatum and are not shared in other genera of the Papaveraceae family. This results may explain production of a confined metabolite within a genus.
Asunto(s)
Vías Biosintéticas/genética , Sistema Enzimático del Citocromo P-450/genética , Noscapina/metabolismo , Papaver/metabolismo , Proteínas de Plantas/genética , Oxidorreductasas de Alcohol/genética , Oxidorreductasas de Alcohol/metabolismo , Simulación por Computador , Sistema Enzimático del Citocromo P-450/metabolismo , Regulación hacia Abajo , Perfilación de la Expresión Génica , Regulación de la Expresión Génica de las Plantas , Metiltransferasas/genética , Metiltransferasas/metabolismo , Repeticiones de Microsatélite/genética , Papaver/genética , Proteínas de Plantas/metabolismo , Regiones Promotoras Genéticas/genéticaRESUMEN
Salinity is among the most important abiotic stresses affecting crop production throughout the earth. Halophyte plants can sustain high salinity levels, therefore elucidating molecular mechanisms underlying their salinity resistance is beneficial for crop improvement. Aeluropus littoralis, a halophyte weed, is a great genetic resource for this purpose. Isolated expressed sequence taq (EST) sequences from A. littoralis under salinity stress, have given us the chance to find and analyze transcripts of genes involved in response to salinity. Transcriptome analyses indicated the expression levels of mRNAs corresponding to 10 of sequences were increased under treatments. All mRNAs were significantly induced under salt treatment with the highest peaks observed at different hours of treatments. Moreover, the full-length cDNA of vacuolar H+-pyrophosphatase (VP) was isolated utilizing 3' and 5' rapid amplification of cDNA ends polymerase chain reaction (RACE-PCR) and characterized (GenBank accession number of KT253223.1). The extracted full-length of VP was 2732 bp, which contained ORF of 2292 bp encoding 763 amino acids.