بررسی مهار زیستی قارچ های عامل فساد انباری مرکبات با استفاده از گونه های مختلف Trichoderma spp

Citrus fruits are important garden products that have a good storage capacity, but despite this, some of them are lost in cold storage for various reasons, including fungal diseases. The use of fungicides and chemical poisons is the most common method to control pathogenic agents, but the noteworthy point in this field is the numerous environmental damages of these compounds, which makes their indiscriminate use suspicious. Therefore, the control strategy should be directed towards alternative cases. Among the alternatives, we can refer to biological control. Therefore, the purpose of this research is to control post-harvest diseases by using different species of antagonistic fungi Trichoderma spp. In this research, in order to prepare pathogenic fungi, samples were taken from infected orange fruits in the warehouses and fruit and vegetable stores of Gorgan and after being transferred to the mycology laboratory of Gorgan University of Agricultural Sciences and Natural Resources for isolation necessary measures were taken for these pathogens. Infected samples were placed on water agar culture medium (WA) after surface disinfection with Clorox 10%. After the growth of the mentioned fungi, their morphological characteristics were examined by the identification keys of the monograph Raper and Thomas, 1949. In this research, the DNA of pathogens was extracted by CTAB method and ITS4 and ITS5 primers were used for PCR amplification. The genome sequence obtained by BLAST software was analyzed in NCBI. In addition, in this experiment, from the three species of Trichoderma atroviridae (MG807425.1), T. harzianum (KC576649.1) and T. virens (KP671477.1) available in the collection of the department of plant protection of Gorgan University of Agricultural Sciences and Natural Resources, used. The amount of antagonistic activity of T. atroviride, T. harzianum and T. virens fungi against the pathogens was measured by mutual cultivation and simultaneously and asynchronously (antagonist cultivation 72 hours after the pathogen). In this research, Penicillium digitatum, P. expansum and Aspergillus niger species were isolated and identified. Also, the results showed that in co-cultivation, T. atroviridae with 76.15% inhibited the growth of P. digitum and T. virens with 50.45 of P. italicum. In the cross-culture of both mentioned species, the lowest inhibition percentage was related to T. harzianum with 40.57%. In A. niger species, the highest inhibition percentage was related to T. virens species and the lowest inhibition percentage was related to T. atroviridae species. In non-simultaneous culture, the highest percentage of inhibition in dual-culture with P. italicum and P. digitatum was related to T. atroviridae, which was 66.41 and 87.35% respectively. In the results of the dual-culture test, it was observed that Trichoderma species were able to be effective against the examined pathogens.