Phenotypic and molecular diagnosis of Fusarium oxysporum and Macrophomina phaseolina isolated from cucumis melon roots

This study aimed to isolate and diagnose some fungi escorted with the Cucumis melon roots plants both morphologically and molecularly. The results of isolation and diagnosis revealed 57 isolates from the sampling areas, which included Anbar, Abu Ghraib and Al-Yusufiya, which were represented by Macrophomina phaseolina, Fusarium spp., and Rhizoctoinia solani. The fungus Macrophomina phaseolina recorded the most significant values by giving the highest frequent reached 27.08%, followed by Fusarium spp. (20.83%), and Rhizoctoinia solani (11.45%). The pathogenicity results of the purified isolates of Fusarium spp., and Macrophomina phaseolina revealed that all isolates were significantly reduced the germination rate. However, the isolate F18 was the most intense isolate in reducing the germination rate (%), which were recorded zero germination rate on Cucumis melon and radish seeds. The isolate F12 revealed a reduction in the germination rate of Cucumis melon and radish seeds (0.67%), followed by the isolate of F. solani (F16; 10%) on Cucumis melon seeds. The isolates of M. phaseolina revealed a decrement in the germination rate, so that the isolate M1 recorded a zero-germination rate on Cucumis melon and radish seeds, followed by M15 with a germination rate of 3.33% on Cucumis melon seeds, while M7 exhibited a germination rate of 3.33% on radish seeds. The DNA electrophoresis results of the pathogenicity tested isolates of radish seeds and Cucumis melon seeds were the most pathogenic using the specialized initiator ITS4 ̸ ITS1, as it recorded the bundles of molecular weight reached 519 for Fusarium oxyspoum and 560 for Macrophomina phaseolina. These were compared with the gene bank for the presence of a high corresponding for the pathogenic fungi, which were deposited in the gene bank by accession numbers of OK560451, OK560452 and also OK560453 and OK560454, indicating by the codes of MP-Iraq1, MP-Iraq2 and also FS- Iraq1 and FS-Iraq2.