Enhancing artemisinin yields through an ecologically functional community of endophytes in Artemisia annua

Studying the role of endophytic microbial diversity in plant growth is helpful to understand plant-microbe interaction. The present experiment was aimed to investigate the effect of seed endophytes of Artemisia annua on plant biomass and artemisinin content. All the ten bacterial endophytes were found to express a varying degree of plant growth-promoting ability in pots, and of these six better performing were inoculated in A. annua in monocultures and all possible combinations thereof for analyzing the contribution of species identity and species richness on plant growth and artemisinin yield. The significant effect of species identities was found on plant biomass and artemisinin yields by inoculated endophytes. Community identity was found to be a more important factor than species richness in predicting biomass and artemisinin content. Most of the microbial combinations could not enhance plant growth over their monocultures. In this way, it has been demonstrated that there is a significant role of ecological interactions in bacterial mixtures, which are directly linked with the net performance of the community. In the presence of a combination of four endophytes comprising of Bacillus subtilis, Bacillus licheniformis, Burkholderia sp. and Acinetobacter pittii, artemisinin yield was found exceeding all of these microbes as in monocultures. This microbial consortium was able to increase the artemisinin yield of about 658 % over uninoculated control. Application of endophytic microbial consortium, similar to that found in this study, may prove an effective alternative to chemical fertilizers for enhancing artemisinin yield in an economically and eco-friendly manner with the reduced cost of its production.