Isolation and identification of pathogenic fungi and oomycetes associated with beans and cowpea root diseases in Oman

PeerJ

article

Asma Al-Jaradi¹  Issa Al-Mahmooli²  Rhonda Janke²  Sajeewa Maharachchikumbura²  Nadiya Al-Saady³  Abdullah M. Al-Sadi² 

[1] Oman Botanic Garden, Diwan of Royal Court;Department of Crop Sciences, College of Agricultural and Marine Sciences, Sultan Qaboos University;Oman Animal and Plant Genetic Resources Center

关键词: Phaseolus;    Pothogenicity;    Disease diagnosis;    Aggressiveness;    Pathogens;   

DOI  :  10.7717/peerj.6064

学科分类：社会科学、人文和艺术（综合）

来源: Inra

【 摘 要 】

The purpose of this study was to characterize fungal and oomycete species associated with root diseases of Phaseolus vulgaris, Vigna unguiculata, V. radiata and Vicia faba in Oman. Root samples were collected from plants suffering from weakened growth and yellowing symptoms. Fungal species were isolated on 2.5% potato dextrose agar amended with 10 mg l−1 rifampicin and 200 mg l−1 of ampicillin and identification was based on sequences of the internal transcribed spacer region of the ribosomal RNA gene (ITS rRNA), glycerol-3-phosphate dehydrogenase (GPDH), translation elongation factor-1 alpha (TEF), beta-tubulin (TUB), calmodulin (CMD), actin (ACT). Isolations yielded 204 fungal isolates belonging to nine different genera, with most isolates belonging to Alternaria and Fusarium. Molecular identification revealed that the isolates belong to 20 fungal species, the most dominant of which was Alternaria alternata. Pathogenicity tests were conducted on each plant species. The inoculations on P. vulgaris revealed that Pythium aphanidermatum induced rotting, damping-off and wilt symptoms while Fusarium equiseti induced yellowing symptoms on the leaves. Rhizoctonia solani produced lesions and root rot on Vigna unguiculata while Curvularia muehlenbeckiae and Curvularia caricae-papayae produced root lesions on the roots of V. unguiculata and V. radiata, respectively. Alternaria alternata produced brown symptoms on the tap root of Vicia faba. P. aphanidermatum resulted in a significant reduction in the fresh weight, dry weight and shoot length of Phaseolus vulgaris. The study shows that several fungal species can be found associated with the roots of beans and Vigna unguiculata in Oman and can result in varying disease symptoms. This is the first report of root lesions produced by Curvularia muehlenbeckiae on the roots of V. unguiculata and by C. caricae-papayae on V. radiata worldwide.

【 授权许可】

CC BY