Overexpression of artemisinic aldehyde Δ11 (13) reductase gene–enhanced artemisinin and its relative metabolite biosynthesis in transgenic Artemisia annua L.

Abstract

Artemisinic aldehyde Δ11 (13) reductase (DBR2) is the checkpoint enzyme catalyzing artemisinic aldehyde to form dihydroartemisinic aldehyde directly involved in artemisinin biosynthetic pathway. In the present study, DBR2 was employed to engineer the biosynthetic pathway of artemisinin in transgenic plants of Artemisia annua L. Seven independent transgenic plants of A. annua with DBR2 overexpression driven by the cauliflower mosaic virus 35S promoter were obtained by Agrobacterium-mediated genetic transformation and confirmed by genomic PCR. The results of real-time qPCR analysis showed that the expression levels of DBR2 gene in all the seven transgenic lines were significantly higher than in nontransgenic control. The high-performance liquid chromatography analysis of artemisinin and its relative metabolites demonstrated that the contents of artemisinin and its direct precursor dihydroartemisinic acid were remarkably increased in the transgenic plants of A. annua with DBR2 overexpression. Interestingly, it was also found that the contents of arteannuin B and its direct precursor artemisinic acid in the branch pathway competing against artemisinin biosynthesis were also improved in DBR2-overexpressed A. annua plants. The transgenic results in the present study indicated that DBR2 is a useful structural gene in engineering the artemisinin biosynthetic pathway to develop genetically modified A. annua with the higher yield of artemisinin.

The Genome of Artemisia annua Provides Insight into the Evolution of Asteraceae Family and Artemisinin Biosynthesis

“…The A. annua genomic and associated transcriptomic datasets provide not only new insights into the artemisinin biosynthetic pathway and its regulation but also valuable tools for artemisinin metabolic engineering. Previous studies manipulating artemisinin biosynthesis in A. annua mainly focused on either upstream (Nafis et al, 2011) or downstream (Yuan et al, 2015) of the artemisinin biosynthetic pathway, resulting in increased but still limited artemisinin accumulation in transgenic A. annua lines. Multiple enzymatic steps are involved in artemisinin biosynthesis, implying that there may be more than one enzymatic step limiting the metabolic flux into artemisinin biosynthesis.…”

Evaluación del efecto de las artemisininas provenientes del extracto etanólico de Artemisia cina sobre L3 de Haemonchus contortus en una técnica de explantes abomasales

“…La lactona sesquiterpénica endoperoxida se encuentra en muy baja concentración en plantas que crecen bajo condiciones de trópico y subtrópico. A la fecha, no se puede determinar la forma en que se encuentra en el ambiente (28). Esos autores han sugerido que la artemisinina puede tener una presentación similar a un alcohol artemisínico, aldehído artemísico, aldehído dihidroartemisínico, ácido dihidroartemisínico o ácido artemisínico, y dependiendo de su presentación es el tipo de actividad que presenta en contra de patógenos.…”

Expression of artemisinin biosynthesis genes in eight Artemisia species at three developmental stages

“…Lei et al (2011) reported that ADS and DBR2 expression was rapidly increased by chitosan treatment and that this over-expression could explain the increase in the artemisinin content. While, Yuan et al (2014) reported that overexpression of DBR2 gene increased artemisinin and its related metabolites in transgenic A. annua. Several studies also reported a relationship between increased ADS expression and the amount of artemisinin.…”