Effects of Pseudomonas putida and Glomusintraradices Inoculations on Morphological and Biochemical Traitsin Trigonellafoenum-graecum L

Fenugreek (Trigonellafoenum-graecum L.) is a traditional medicinal plant belonging to the legume family Fabaceae. Diverse groups of microorganisms are symbiotic with Fenugreek roots system. This integration leads to significant increases in the development and production by increasing nitrogen fixation, phytohormones production, siderophores and phosphate solubilization. Plant growth-promoting bacteria increase plant growth byimproving nutrientuptake and phytohormones production. In addition, the beneficial effect of these bacteria could be due totheirinteractionwithArbuscularMycorrhizal fungi(VAM). Drought is one of the major limiting factors for crop production in many parts of the world including Iran. Symbiotic microorganisms can enhance plant tolerance to drought. This experiment was carried out to investigate the effect of Vesicular ArbuscularMycorrhiza (VAM) and Plant Growth Promoting Rhizobacteria (PGPR) on morphological and biochemical characteristics of Fenugreek in drought stress conditions.
The experiment was carried out in completely random design with 3 replications.There were four treatments including inoculation with Pseudomonas putida, inoculation with Glomusintraradices, combined association of Pseudomonas putida and Glomusintraradices and untreated as a check under drought stress (40% of field capacity) and non-stress conditions (80% of field capacity). In this experiment fiveseeds were sowninplastic pots. Before sowing, seeds were inoculated with microorganisms. In order to inoculation ofseed with Mycorrhizal fungi, for each kilogram of soil, 100 grams of powder containing 10 to 15 thousand spores of fungal soil (produced by the biotech company Toos) was added to three centimeters of soil in the pot. For seed inoculation with Plant Growth Promoting Rhizobacteria, the growth curve of the bacteria was drawn at first and then the best time for the growth of bacteria was determined. The bacteria at the best time and at a dilution of 0.5 McFarland was added to the seed.Pots were placed in a growth chamber (with a temperature of 25 ° C and 16 hours of light and 8 hours of darkness photoperiod).After ten days of planting, the water treatment was applied and continued until the end of the experiment.
The results showed that the use of co -inoculation treatment ofP.putidaandG.intraradicesand application of G.intraradices aloneat non-stress conditions did not make a significant difference on the amount of plant biomass. In drought conditions, application of G.intraradice alone had significant difference (P≤0.05) compare with control (no inoculation microorganisms) for biomass.In stress conditions, P.putida inoculation and also in combination with G.intraradicesincreased biomass in compare with control (no inoculation of micro-organisms), but this increasing was not statistically significant.VAMare important ecological symbiotic with roots are important component of the ecosystem and affect the absorption of minerals through the roots. The results of the present study showed that the amount of phosphorus in all of treatments was increased and the greatest increase was related to G.intraradicetreatment.The results also showed that drought stress increased the leaf soluble proteins in compared with non-stress condition. Increasing the concentration of soluble proteins under drought stress can be related to increased protein synthesis that maybe related to adaptation and reprogramming under new situation and itprotect the cells against stress. The results showed that the use of co -inoculation treatment ofP.putidaand G.intraradices, as well as each individual treatment, increased the amount of soluble proteins in leaves.In the case of the Diosgenin percentage, drought stress reduced the amount of Diosgenin percentage. Underdrought stress conditions, use of co -inoculation treatment ofP.putidaand G.intraradicesand application of G.intraradicewithout presence of bacteria made a significant increase in plant Diosgenin concentration.
Theresults revealed that seed treatment with Pseudomonas putida and Glomusintraradices increased the biomass, protein content, phosphorus uptake and diosgenin percent in Fenugreek under drought stress condition. Since Diosgenin is very important medicinal compound, inoculation of fenugreek with these microorganisms can be a way to increase the Diosgenin production.