Changes in photosynthetic metabolism induced by tobamovirus infection in Nicotiana benthamiana studied in vivo by thermoluminescence.
* In thylakoids from Nicotiana benthamiana infected with the pepper mild mottle virus (PMMoV), a decreased amount of the PsbP and PsbQ proteins of photosystem II and different proteins of the Calvin cycle have been previously observed. We used thermoluminescence to study the consequences in vivo. * Measurements on unfrozen discs from symptomatic and asymptomatic leaves of plants infected by two tobamovirus PMMoV-S and PMMoV-I strains were compared with homologous samples in control plants. * Thermoluminescence emission did not reveal noticeable alteration of PSII electron transfer activity in infected symptomatic leaves. In these leaves, the relative intensity of the 'afterglow' emission indicated an increase of the NADPH + ATP assimilatory potential, contrasting with its decrease in asymptomatic leaves. High-temperature thermoluminescence, as a result of peroxides, increased in symptomatic and asymptomatic leaves. * In young infected leaves, PSII activity is preserved, producing a high assimilatory potential. Older asymptomatic leaves export more nutrients towards young infected leaves. This depresses their assimilatory potential and weakens their defence mechanisms against reactive oxygen species, resulting in higher peroxide content.
Sajnani
Carlota
C
Department of Biochemistry, Cell and Molecular Biology of Plants, Estación Experimental del Zaidin, CSIC, c/Profesor Albareda 1, 18008 Granada, Spain.
Zurita
Jorge L
JL
Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla-CSIC, Avda. Américo Vespucio 49, 41092 Sevilla, Spain.
Roncel
Mercedes
M
Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla-CSIC, Avda. Américo Vespucio 49, 41092 Sevilla, Spain.
Ortega
José M
JM
Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla-CSIC, Avda. Américo Vespucio 49, 41092 Sevilla, Spain.
Barón
Matilde
M
Department of Biochemistry, Cell and Molecular Biology of Plants, Estación Experimental del Zaidin, CSIC, c/Profesor Albareda 1, 18008 Granada, Spain.
Ducruet
Jean-Marc
JM
Service de Bioénergétique, INRA/CEA Saclay, 91191 Gif-sur-Yvette cedex, France.
D008027:Light; D015227:Lipid Peroxidation; D009249:NADP / Q000378:metabolism; D010084:Oxidation-Reduction; D010545:Peroxides / Q000378:metabolism; D010788:Photosynthesis; D045332:Photosystem II Protein Complex / Q000378:metabolism; D010935:Plant Diseases / Q000821:virology*; D018515:Plant Leaves / Q000378:metabolism / Q000821:virology; D013696:Temperature; D013816:Thermodynamics; D013819:Thermoluminescent Dosimetry / Q000379:methods; D014026:Nicotiana / Q000378:metabolism* / Q000821:virology*; D017898:Tobamovirus / Q000472:pathogenicity*
D010545:Peroxides; D045332:Photosystem II Protein Complex; D009249:NADP