Nonthermal microwave radiations affect the hypersensitive response of tobacco to tobacco mosaic virus.
OBJECTIVE
The aim of the present study was to evaluate the effects of nonthermal extremely high-frequency microwave radiations in a plant-based bioassay, represented by tobacco plants reacting to tobacco mosaic virus with a hypersensitive response leading to the appearance of necrotic lesions at the infection sites.


METHODS
This study was performed blind and different experimental protocols on tobacco plants inoculated with tobacco mosaic virus were used. BIO-OBJECTS: Tobacco plants (Nicotiana tabacum L. cultivar Samsun) carrying the resistance gene N against tobacco mosaic virus.


METHODS
Tobacco plants or leaf disks were either directly or indirectly (water-mediated) irradiated using a medical device, designed for microwave resonance therapy. It produces nonthermal weak-intensity extremely high-frequency radiations, either modulated at extremely low frequency or in continuous flux of waves, coupled with a nonthermal red/near-infrared radiation.


METHODS
The working variable was the number of hypersensitive lesions per leaf disk.


RESULTS
Both direct and indirect nonthermal microwave radiations led to significant effects on the hypersensitive response of tobacco plants: modulated radiations generally induced a resistance increase, whereas a continuous flux of waves induced a resistance decrease with direct treatments only.


CONCLUSIONS
Nonthermal microwave radiations are effective on the hypersensitive response of tobacco to tobacco mosaic virus and their low-frequency modulation seems to be more bioactive than the continuous-flux of waves, particularly in the indirect water-mediated treatments.
Betti
Lucietta
L
Department of Agro-Environmental Science and Technology, Faculty of Agriculture, Bologna University, Italy.
Trebbi
Grazia
G
Lazzarato
Lisa
L
Brizzi
Maurizio
M
Calzoni
Gian Lorenzo
GL
Marinelli
Fiorenzo
F
Nani
Daniele
D
Borghini
Francesco
F
D001681:Biological Assay; D008872:Microwaves; D010935:Plant Diseases / Q000821:virology; D018515:Plant Leaves / Q000528:radiation effects* / Q000821:virology; D014026:Nicotiana / Q000528:radiation effects* / Q000821:virology; D014027:Tobacco Mosaic Virus / Q000276:immunology / Q000528:radiation effects*