Impact of Gamma Irradiation on Tomato, and Pepper Growth Parameters, Phytochemical, Nematode Infectivity and detection of DNA Damage by Comet Assay

Abstract

Root -knot nematode is a challenge of most vegetable production and there is a critical need to an alternative, effective, safe technique for control. The main objective of this study was to detect the effect of five doses of gamma irradiation on Meloidogyne incognita (Mi) infectivity, host growth, and DNA damage. Three-week-old- seedlings of: tomato, (Solanum lycopersicum), and pepper (Capsicum annum), were irradiated with five doses i.e. 100, 250,500,750, and 1000 Gy and transplanted in 20cm diameter pots in the screen-house. Halves of the replicates/ dose were inoculated with 1000 2IJs, while others were kept as controls. DNA damage was measured by comet assay which performed on the host leaves. Data demonstrated that, all nematode parameters were decreased beginning from the lowest does (100Gy), while, the plant growth parameters were enhanced significantly at 100 and 250Gy even when infected with nematodes and so did the chlorophyll a,b, carotenoids, and total phenols, antioxidative enzymes; Polyphenol oxidase (PPO), peroxidase (POX), Catalase (CAT) and Superoxide dismutase (SOD). Likewise, quantity of DNA damage was represented as mean of % DNA in tail, tail moment, tail length, and olive tail moment which were more pronounced than the control. As a conclusion, gamma irradiation at 100 and 250 Gy could protect host plants of nematode infection and increase the plant growth. Therefore, this approach introduces a promising technique in the integrated pest programs without any suppressive effects on the growth of plant hosts.