Stress associated protein 1 regulates the development of glandular trichomes in Artemisia annua

Artemisinin, a sesquiterpene lactone endoperoxide extracted from the aerial part of Artemisia annua L., is widely known as the useful treatment for malaria. Increasing the density of the glandular trichomes in A. annua is an effective method for increasing the production of artemisinin. Here, we identified a transcription factor, AaSAP1 containing A20/AN1 zinc finger motif, which encodes stress associated protein 1 (SAP1). The expression analysis in various tissues indicated that AaSAP1 predominately expressed in the trichomes. Methyl jasmonate, abscisic acid and gibberellic acid induced the expression of AaSAP1. Notably, up-regulation or down-regulation of the transcriptional level of AaSAP1 led to an increase or decrease in the density of the glandular trichomes of A. annua, respectively. In addition, overexpression of AaSAP1 significantly enhanced the content of artemisinin in A. annua. Our results reveal that AaSAP1 positively regulates the development of the glandular trichomes, and it is a valuable gene in genetic engineering of A. annua for increasing the production of artemisinin. Key message AaSAP1 positively regulates the development of the glandular trichomes and the production of artemisinin in A. annua.