Document Type : Research Paper
Authors
1 Dryland Agricultural Research Inst. (DARI), Agricultural Research, Education and Extension Organization, Kermanshah. Iran
2 Illam Agricultural and Natural Resources Research and Education Center, Agricultural Research, Education and Extension Organization, Illam, Iran.
3 Agricultural Education and Natural Resources Research Center of Golestan, Agricultural Research, Education and Extension Organization (AREEO), Gonbad, Iran
Abstract
Introduction: The chickpea (Cicer arietinum L.) is grown in more than 50 countries and is the third most important food legume in the world after beans and peas in terms of both cultivated area and total production. Chickpea is affected by a wide range of fungal and viral diseases that can cause economic losses. Among these diseases, fusarium wilts and root rot, caused by Fusarium oxysporum f.sp ciceris and F. solani, respectively Are the most important soil-brone pathogens affecting chickpea. These assays will provide plant pathologists a valuable tool to refine the control and management of diseases caused by Fusarium spesies in chickpea. The present study aimed to identify the Fusarium species associated with root rots and wilting of chickpea, as well as the pathogenic strains affecting the crop.
Methodology: Fusarium species were isolated from roots of chickpea plants showing wilt and yellowing symptoms in different chickpea-growing regions of Kermanshah, Illam and Golstan provinces. Plant samples were cut into small pieces, washed under running water for 20 mins, sterilized with 5% sodium hypochlorite for 3 minutes, rinsed in sterile distilled water, and then placed on filter papers. Afterward, the pieces were transferred to petri dish containing potato dextrose agar media (PDA). All the plates were incubated at 25° C for 5-10 days. To determine pathogenicity, purified isolates of Fusarium species were used. Total DNA was extracted using a modified protocol previously described by Talbot et al. Each fungal species was characterized morphologically and molecularly based on DNA sequence data for ITS-rDNA. The PCR sequencing products of the tested isolates were aligned with Clustal (ver. 2). The MEGA6 program was used for phylogenetic analysis. Aligned sequences were checked for quality and compared with deposited sequences in Gene-Bank, NCBI, using BLAST.
Research findings: Based on morphological characteristics and molecular data obtained from ITS-rDNA amplification, F. solani, F. acuminatum, F. equiseti, F. oxysporum f. sp. ciceris and Fusarium spp. were identified in the samples, among which F. oxysporum was the most dominant and common species and had the highest abundance. F. acuminatum and F. equiseti were mostly isolated from adult plants, while F. oxysporum and F. solani were isolated at all stages of growth, from seedling to podding. The phylogenetic tree, based on the comparison of ITS-rDNA sequences, classified the identified Fusarium species into four phylogenetic groups. The results showed that the use of ITS-rDNA sequencing can be used as a suitable complementary method for the identification of different Fusarium species.
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