Nitric oxide (NO) has been shown to be an essential regulatory molecule in plant response to pathogen infection in synergy with reactive oxygen species (ROS). At the present, nothing is known about the role of NO in disease resistance to nematode infection. To investigate the key components involved in oxidative and nitrosative metabolism, experiments were carried out at different infection times by using a resistant tomato cultivar with different sensitivity to avirulent and virulent populations of the root-knot nematode Meloidogyne incognita. We analyzed the superoxide radical (O2.-) production, hydrogen peroxide (H2O2) content, and nitric oxide synthase (NOS)-like, and nitrate reductase (NR) activities, as potential sources of NO. A rapid NO accumulation and ROS production were differently linked to incompatible and compatible tomato-nematode interactions. NOS-like arginine-dependent rather than NR was the main source of NO production, and NOS-like activity increased substantially in the incompatible interaction. We can envisage a functional overlap of both NO and ROS in tomato defence response to nematode invasion, NO and H2O2 cooperating in triggering hypersensitive cell death. The results obtained from this studies reveal a defence mechanism that has not been previously described in tomato-nematode interaction and provide new insight into the complex regulation of ROS and NO metabolism by avr- and vir- RKN pathotypes in their hosts roots.
ROS and NO: their role in tomato roots challenged by Meloidogyne incognita.
Melillo MT;Leonetti P;Veronico P;
2011
Abstract
Nitric oxide (NO) has been shown to be an essential regulatory molecule in plant response to pathogen infection in synergy with reactive oxygen species (ROS). At the present, nothing is known about the role of NO in disease resistance to nematode infection. To investigate the key components involved in oxidative and nitrosative metabolism, experiments were carried out at different infection times by using a resistant tomato cultivar with different sensitivity to avirulent and virulent populations of the root-knot nematode Meloidogyne incognita. We analyzed the superoxide radical (O2.-) production, hydrogen peroxide (H2O2) content, and nitric oxide synthase (NOS)-like, and nitrate reductase (NR) activities, as potential sources of NO. A rapid NO accumulation and ROS production were differently linked to incompatible and compatible tomato-nematode interactions. NOS-like arginine-dependent rather than NR was the main source of NO production, and NOS-like activity increased substantially in the incompatible interaction. We can envisage a functional overlap of both NO and ROS in tomato defence response to nematode invasion, NO and H2O2 cooperating in triggering hypersensitive cell death. The results obtained from this studies reveal a defence mechanism that has not been previously described in tomato-nematode interaction and provide new insight into the complex regulation of ROS and NO metabolism by avr- and vir- RKN pathotypes in their hosts roots.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
