Biochemical and plant nutrient alterations induced by Meloidogyne javanica and Fusarium oxysporum f.Sp.radicis lycopersici co-infection on tomato cultivars with differing level of resistance to M. javanica
2017
Lobna, Hajji | Aymen, ElouaerMohamed | Hajer, Regaieg | Naima, M’Hamdi-Boughalleb | Najet, Horrigue-Raouani
The experiment was conducted to assess plant nutrient levels and biochemical changes in tomato roots Solanum lycopersicum Mill. cultivars in response to Fusarium oxysporum f.sp. radicis lycopersici (FORL) and/or Meloidogyne javanica (RKN) infection. The enzyme activity, total sugar concentration, total phenol and protein content in tomato roots of resistant (Firenze), intermediate resistant (Colibri) and susceptible cultivar (Riogrande) at seven days post infection by FORL and RKN were measured. Tomato plants (45 days post-inoculation) were quantified by atomic spectrometry for Cu, Zn, Fe, Mn, Mg, K and Ca contents in roots. At seven days post infection, defense responses involving enzymes were observed in tomato roots. Peroxidase (POX), catalase (CAT), polyphenoloxidase (PPO) and superoxide dismutase (SOD) enzymes activities were enhanced after pathogen infection and this increase was greater with synergetic infection by RKN and FORL and more in the resistant cultivar when compared to the susceptible one. Total protein content, sugar concentration and total phenol content variations were correlated to pathogen co-infection and not to the resistance level of the tomato. It was concluded that synergetic infection by FORL and RKN induced plant defense response especially in resistant cultivars. Those responses diverged with single or dual infection by pathogens and with resistance level on host plant. The nematode-fungi disease complex had great impact on unbalancing nutrients contents in roots by reducing significantly (P < 0.05) the contents of Cu, Zn, Fe, Mn, Mg and K. However, The Ca content was increased in roots. All tomato cultivars responded similarly on changing nutrient content independently with resistance level.
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