Effect of ectomycorrhizal colonization and drought on reactive oxygen species metabolism of Nothofagus dombeyi roots.
Infection with ectomycorrhizal fungi can increase the ability of plants to resist drought stress through morphophysiological and biochemical mechanisms. However, the metabolism of antioxidative enzyme activities in the ectomycorrhizal symbiosis remains poorly understood. This study investigated biomass production, reactive oxygen metabolism (hydrogen peroxide and malondialdehyde concentration) and antioxidant enzyme activity (superoxide dismutase, catalase, ascorbate peroxidase and glutathione reductase) in pure cultures of the ectomycorrhizal fungi Descolea antartica Sing. and Pisolithus tinctorius (Pers.) Coker & Couch, and non-mycorrhizal and mycorrhizal roots of Nothofagus dombeyi (Mirb.) roots under well-watered conditions and drought conditions (DC). The studied ectomycorrhizal fungi regulated their antioxidative enzyme metabolism differentially in response to drought, resulting in cellular damage in D. antartica but not in P. tinctorius. Ectomycorrhizal inoculation and water treatment had a significant effect on all parameters studied, including relative water content of the plant. As such, N. dombeyi plants in symbiosis experienced a lower oxidative stress effect than non-mycorrhizal plants under DC. Additionally, ectomycorrhizal N. dombeyi roots showed a greater antioxidant enzyme activity relative to non-mycorrhizal roots, an effect which was further expressed under DC. The association between the non-specific P. tinctorius and N. dombeyi had a more effective reactive oxygen species (ROS) metabolism than the specific D. antartica-N. dombeyi symbiosis. We conclude that the combination of effective ROS prevention and ROS detoxification by ectomycorrhizal plants resulted in reduced cellular damage and increased plant growth relative to non-mycorrhizal plants under drought.
Alvarez
Maricel
M
Instituto de Botánica, Universidad Austral de Chile, Casilla 567, Valdivia, Chile. malvarez@uni-bremen.de
Huygens
Dries
D
Fernandez
Carlos
C
Gacitúa
Yessy
Y
Olivares
Erick
E
Saavedra
Isabel
I
Alberdi
Miren
M
Valenzuela
Eduardo
E
D001487:Basidiomycota / Q000254:growth & development*; D018533:Biomass; D015169:Colony Count, Microbial; D055864:Droughts; D029962:Fagaceae / Q000378:metabolism* / Q000382:microbiology*; D006861:Hydrogen Peroxide / Q000378:metabolism; D008315:Malondialdehyde / Q000378:metabolism; D025282:Mycelium / Q000201:enzymology; D038821:Mycorrhizae / Q000254:growth & development*; D018517:Plant Roots / Q000254:growth & development / Q000382:microbiology; D018520:Plant Shoots / Q000254:growth & development / Q000382:microbiology; D017382:Reactive Oxygen Species / Q000378:metabolism*; D012987:Soil / Q000032:analysis; D014867:Water
D017382:Reactive Oxygen Species; D012987:Soil; D014867:Water; D008315:Malondialdehyde; D006861:Hydrogen Peroxide