جداسازی و شناسایی جدایه های قارچی ارتقا دهنده رشد گیاهی (PGPF) از فضای ریزوسفری و ارزیابی تاثیر آنها بر فعال شدن آنزیم‌های دفاعی گیاه گوجه فرنگی

One of the important ways to reduce the application of fertilizers is to pay attention to the coexistence of plants with beneficial microorganisms and the use of biological fertilizers. These biological fertilizers actually contain microorganisms such as PGPF fungi and rhizospheric bacteria that through special processes can increase the solubility of phosphorus compounds in the soil and increase part of the phosphorus needed by the plant. This research was conducted in terms of quality and quantity in order to identify and separate fungi isolates which can absorb phosphorus and are also able to produce IAA hormones.The studied fungi were extracted from samples of rhizosphere collected from hosts Mirabilis jalapa,Solanum. sp, Phaseolus vulgaris and Pelargonium.sp of from Tonekabon region of Mazandaran province. For this purpose, the number of active colonies per gram of CFU soil from the above hosts was investigated. The highest CFU of 3×105 as from the soil collected from the host of Phaseolus vulgaris.Of the collected soils,31 fungal isolate were isolated. Evaluation of the ability of p hosphorus dissolution in BM(Basal medieum) containing 4 grams of Tricalcium phosphate (ca3(po4)2 as source of insoluble phosphorus by vanadium anhydride at intervals of 5,10,15,20 days and the ability to produce indole- acetic(IAA) hormones in a potato culture medium Dextrose broth(PDB)containing broth one gram of tryptophan was done by Weber and Gordon (1951) methods. Of the 31 isolates studied ,six isolates had a significant difference in phosphate solubility and production of indole acetic acid(IAA)at a probability level of (P≤%1)with other isolates.tow isolates with the highest solubilizing potential of phosphate and indole acetic acid hormone production were identified by ITS-PCR method as Aspergillus parasiticus and Cladosporium s phaero spermum. Investigation on the effect of each fungal isolates on the increasing in the activity of the defense enzymes were done by treatment tomato plant roots in the 4 to 5 leaf stage and in a completely randomized design with 3 replications for each fungal treatment. Both fungal isolates had a significant effect (P≤%1)on increasing the activity of defense enzymes PAL,POX,PPO compared to the control. the results of the study indicated that the tomato seedlings roots prematurely affect the activation of defense enzymes and probably increasing the resistance of the plant against pathogens.