Showing 3 results for Meloidogyne Javanica
N. Sahebani , J. Zad , A. Sharifi-Tehrani , A. Kheiri ,
Volume 12, Issue 43 (4-2008)
Abstract
Polyphenol oxidase (PPO) activities were measured spectrophotometrically in tomato(Roma VF: resistant to Fusarium oxysporum f.sp. lycopersici and susceptible to Meloidogyne javanica) roots inoculated with nematode and fungi in four biological life stages of nematode. PPO specific activity showed a significant decrease in treatments (nematode + fungi) as compared with control plants. Results showed that nematode is able to change or suppress induction of this enzyme in spite of fungal induction. Nematode in all biological stages suppressed the induction of PPO activity in tomato roots but in young adult formation stage the suppression was higher than other life stages including giant cell formation, egg-laying and penetration. Native polyacrylamide gel revealed the presence of five isozymes of PPO with Rm values of 0.26, 0.31, 0.44, 0.50 and 0.63. Isoforms with Rm values of 0.26, 0.44, 0.50 and 0.53 showed significant changes in nematode + fungus inoculated tomato plants compared to plants inoculated with fungus alone. Based on the results obtained in this study, nematode infection resulted in suppression of tomato defenses against the fungi (as secondary pathogen) and intensified the fungal disease. Five PPO isoforms with Rm values of 0.26, 0.31, 0.44, 0.50 and 0.63 were shown in native polyacrylamide gel among which the isoform with Rm value of 0.31 had a thicker band in tomato plants inoculated with nematode or fungus alone. Two isoforms with Rm values of 0.44 and 0.53 in nematode-inoculated plants were similar to the corresponding bands in the healthy control. Isoforms with Rm values of 0.26, 0.44, 0.50 and 0.53 in nematode-fungus-inoculated tomato plants showed significant changes compared to plants inoculated with the fungus alone. Nematode infection of root tissue caused suppression of PPO specific activity and induced changes in PPO isoforms with Rm values of 0.26, 0.44, 0.50 and 0.63 more significantly than isoform 0.31.
N. Sahebani, N. Hadavi,
Volume 12, Issue 43 (4-2008)
Abstract
This research was conducted to study the effect of nematode (Meloidogyne javanica) on severity of tomato Fusarium wilt (Fusarium oxysporum f.sp. lycopersici race 1) and changes in Phenylalanine ammonia lyase (PAL) activity in split-root assays to show the possibility of systemic induced susceptibility caused by nematode to the fungus by local nematode infection. The results showed that the activity of nematode in one part of root confered susceptibility to Fusarium wilt in other part of the plant root and subsequently disease symptoms increased significantly in comparison to the control (without nematode inoculation). PAL specific activity showed a significant decrease in one half of split-root inoculated with fungus when the other half was inoculated with nematode as compared with the control (without nematode inoculation). Based on the results obtained in this study, nematode infection in one part of tomato plant root resulted in suppression of tomato defenses in all parts of the root, reduced tolerance or resistance to the fungus (as secondary pathogen) and intensified the fungal disease.
H Askarian, B Sharifnabi, M Olia, E Mahdikhani, A Akhavan,
Volume 13, Issue 47 (4-2009)
Abstract
Root knot nematodes (Meloidogyne spp.) cause yield loss in all countries, of which, M. javanica, is the most widespread species in Iran. In order to identify M. javanica, 100 infected root and soil samples of root knot nematode were collected from different regions of Kerman province. After purification of populations and identification of M. javanica based on morphological and morphometerical characters of females and second stage juveniles (J2), total DNA was extracted from eggs, J2 and female adults. Specific 670 and 1600 bp bands were amplified in all M. javanica populations using species-specific primer pairs including OPARjav / OPAFjav and Mjavf / Mjavr These specific bands could not be amplified in other species such as M. incognita and M. arenaria. It seems that, application of these species specific primers in comparison with morphological characters would be more applicable, leading to easier identification of M. javanica.
