Role of biochemical changes of highly resistant and susceptible bean cultivars in the physiology of seedling damping-off and/or root rot disease resistance

Document Type : Research and Review Papers

Authors

1 Plant Pathology Department Faculty of Agriculture Sohag University Sohag 82524 Egypt

2 Plant pathology department, Faculty of agriculture, Sohag university

Abstract

Seventeen fungal isolates obtained from diseased bean plants 
showing seedling damping-off (D-O) and root rotsymptoms 
collected from different locations in Sohag Governorate were 
identified as Fusarium oxysporum Schlecht. (5 isolates), 
Fusarium solani (Mart.) Sacc.(5 isolates), Macrophomina 
phaseolina (Tassi) Goid.(4 isolates), Rhizoctonia solani Kühn (2 
isolates), and Sclerotium rolfsii Sacc. (Only isolate). Moreover, 
F.oxysporum and F.solani were the most frequently isolated fungi 
(29.41%, each), followed by M. phaseolina (23.52%). In contrast,
S.rolfsii and R.solani were the lowest. Pathogenicity tests showed 
that all fungal isolates tested were pathogenic to the bean and 
significantly caused pre- and post-emergence seedling D-O and 
RR disease, except the isolates of F. solani did not cause seedling 
D-O but infecting old seedlings and induced only RR symptoms. 
The response of 5 common bean cultivars to infection by F. solani 
and M. phaseolina, causing D-O and/or RR disease, was studied 
under greenhouse and field conditions during the growing seasons 
of 2021 and 2022. Biochemical changes in the common bean 
plant root showed that highly resistant cultivar Kobo roots 
contained higher total protein contents than highly susceptible 
cultivar Nebraska after 21,28, 35, and 42 days of planting. The 
activity of peroxidase and polyphenol oxidase enzymes increased 
in the plant roots of common bean HR Kobo and HS Nebraska 
cultivars infected by M. phaseolina and F. solani after different 
planting intervals compared with the control plants. Also, the total 
phenolic contents gradually increased in the plant roots of 
common bean Kobo (HR) and Nebraska (HS) cultivars infected 
by M. phaseolina and F. solani after planting intervals.

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