Inhibitory effect of leaf extracts of Citrus sinensis and C. aurantium on fungi isolated from the adjacent soil

A study was conducted on the fungal content of some soils adjacent to Citrus sinensis ( sweet orange ) trees and C. aurantium (bitter orange) trees as well as uncultivated soil from scattered gardens belonging to the University of Mosul in the city of Mosul, Iraq . T he most common fung i in these soils w ere Aspergillus niger then Aspergillus fumigatus and Aspergillus flavus , and with less frequency Penicillium melanoconidium and Cladosporium cladosporioides . Saccharomy c es cerevisiae and Pichia fermentans were identified by PCR amplification and DNA sequencing of molecular gene markers and Pichia fermentans was recorded for the first time in the gene bank of the National Center for Biotechnology Inform a tion (NCBI): Saccharomyces cerevisiae MAZSS2 with the gene bank sequence LC768856.1and MAZSS1 with the s e quence LC767347. In our research, it was found that the soils most contaminated with fungi were those next to orange trees while fungal contamination wa s light and almost non-existent in uncultivated soils, Testing the impact of sweet orange and bitter orange aqueous leaf extract on the growth of various soil-isolated fungi revealed that Penicillium melanoconidium was more sensitive to the two extracts compared to the fung i Cladosporium cladosporioides and Aspergillus niger . The two extracts had a gradual inhibitory effect that increased with increasing concentration.