Division of Nematology, Indian Agricultural Research Institute, New Delhi-110 012.
*Present Address: Associate Professor of Entomology, Department of Entomology, Mahatma Phule Agricultural University, Rahuri-413 722 Dist. Ahmednagar, Maharashtra, India.
Investigations on sequential development of chlorogenic acid (CGA), phenylalanine ammonia-lyase (PAL) and tyrosine ammonia-lyase (TAL) were undertaken in two tomato varieties, viz., ‘Pusa Ruby’ and ‘SL-120’ inoculated with the root-knot nematode, Meloidogyne incognita Varieties Pusa Ruby and SL-120 were observed to be susceptible and resistant respectively to M. incognita. The resistance response of SL-120 to M. incognita was characterized by delayed and reduced larval penetration and retarded life cycle of the nematode which corresponded with cell necrosis and hypersensitive reaction.
The content of chlorogenic acid and activities of PAL and TAL were higher in inoculated than uninoculated root and shoot samples and the values for resistant variety were considerably higher than for the corresponding samples from the susceptible variety.
Chlorogenic acid, PAL and TAL increased progressively and consistently at a faster rate with time in inoculated resistant variety over their respective controls. In inoculated susceptible variety similar trend was observed for certain period, and thereafter, percent increase was reduced to a greater extent. In general, chlorogenic acid contents as in shoots were higher than that for root.
The analytical and semi preparative polyacylamide gel electrophoretic analysis of PAL showed two anionic bands for any given interval in uninoculated Pusa Ruby and SL-120 and inoculated Pusa Ruby plants, while two new PAL isozymes having different electrophoreticmobility were resolved in the root extracts from nematode inoculated resistant variety. The first newly synthesized isozyme appeared between 24–72 hrs after inoculation as a response to nematode infestation and the second new PAL component appeared between 8–14 days during post infection period. Activity of TAL appeared to be lower than that of PAL, and only one TAL component was resovled fromall the four samples.
Phenyl alanine ammonia-lyase, tyrosine ammonia-lyase, chlorogenic acid, Meloidogyne incognita, tomato varieties
