Effect of biocontrol agent Bacillus subtilis and mycorrhizal fungus Glomus mosseae on growth, mineral nutrition, physiological changes and Essential Oil quality and quantity of Thymus daenensis Celak

Abstract

In order to study the effects of biocontrol agent (Bacillus subtilis) and Arbuscular mycorrhizal (Glomus mosseae) on the plant growth, peroxidase (POX) and phenylalanine ammonia-lyase (PAL) activity, nutrient content, essential oil yield and root colonization of Thymus daenensis transplants, a randomized complete block design with three replications and four treatments was carried out at the Glasshouse, in 2011-2012. Treatments were included: 1- Glomus mosseae 2- Bacillus subtilis 3- co-inoculation of G. mosseae and B. subtilis and 4- no inoculated. Results showed that the Co-inoculation with G. mosseae and B. subtilis resulted 74% increase in shoot /root dry weight, increased dry herb yield by about 30% and stimulated essential oil yield by 14 % compared to uninoculated controls. The percent of root colonization in the plants inoculated with G. mosseae was more than 7 times higher compared to non-inoculated plants, but dual inoculation resulted in a 68 % reduction in root colonization compared to single inoculation with G. mosseae. The Zn content significantly increased about three times higher than the control plants after dual inoculation. All microbial inoculation treatments significantly increased the concentration of Thymol and carvacerol in T. daenensis plants with respect to the control plants. This study further revealed that the single inoculation with B. subtilis significantly enhanced PAL and pox activity compared to the other treatments. Our findings confirm that plants Co-inoculated with G. mosseae and B. subtilis during the nursery stage, can create a more synergistic effect that supports thyme (T. deneansis) quality and quantity yields in a sustainable cultivation