The Effect of Bacillus Cereus on the Ion Homeostasis, Growth Parameters, and the Expression of Some Genes of Artemisinin Biosynthesis Pathway in Artemisia Absinthium Under Salinity Stress

Soil salinity is a major problem in the world that affects the growth and yield of plants. Application of newand up-to-date techniques can help plants in dealing with salinity stress. One of the approaches for reducing environmental stress is the use of rhizosphere bacteria. The aim of present study was to investigate the effect of the inoculation of Bacillus cereus on physiologicaland biochemical indicators and the expression of some key genes involved in the Artemisinin biosynthesis pathway inArtemisia absinthium under salinity stress. The results showed that with increasing salinity, root and stem length, root and stem weight, root and stemdry weight, and potassium content were decreased, although the content of sodium was increased. Rhizosphere bacteriaincreased the contents of Artemisinin, potassium, calcium, magnesium, and iron and the expression of Amorpha-4,11-diene synthase and Cytochrome P450 monooxygenase1 genes as well as the growth indicators; although decreased the sodium content. The highest ADS expression was related to co-inoculation with B. cereus isolates E and B in 150 mM salinity. The highest CYP71AV1 expression was related to co-inoculation with B. cereus isolates E and B in 150 mM salinity. These findings showed that the increase in growth indices under salinity stress was probably due to theimprovement of nutrient absorption conditions as a result of ion homeostasis, sodium ion reduction and Artemisininproduction conditions by rhizosphere B. cereus isolates E and B.