Mycorrhizal fungi symbiosis as strategy against oxidative stress in soybean plants.

MARINA BRESSANO; MARIELA CURETTI; LORENA GIACHERO; SILVINA VARGAS GIL; MARTA CABELLO; GUILLERMO MARCH; DANIEL DUCASSE; CELINA LUNA

JOURNAL OF PLANT PHYSIOLOGY

ELSEVIER GMBH

Año: 2010 vol. 167 p. 1622 - 1627

0176-1617

Oxidative stress responses generated by paraquat (PQ), an herbicide that triggers an oxidative stress reactionin leaves, were studied in non-arbuscular mycorrhizal (non-AM) and in arbuscular mycorrhizal (AM)soybean plants inoculated with Glomus mosseae (Gm) or Glomus intraradices (Gi). Some oxidative stresssymptoms were evident in non-AM after 6 d of PQ application on leaves. Oxidative damage, measuredas malondialdehyde content (MDA), was significantly higher, and although no changes were evident intotal catalase (CAT, EC 1.11.1.6) and total superoxide dismutase (SOD, EC 1.15.1.1) activity, total ascorbateperoxidase (APX, EC 1.11.1.11) activity was significantly reduced. These effects were correlatedwith a significant decrease in growth parameters. By contrast, in both AM plants, foliar MDA contentwas reduced or unaltered and, interestingly, after PQ stress, its level was unchanged and significantlylower than in PQ non-AM plants. Unlike PQ stress in non-AM plants, total APX activity was unaltered orinduced byAMplants, while total SOD activity was unchanged and no consistent effects were detected intotal CAT activity. All these events coincided with no changes or a significant increase in growth parameters.Since oxidative stress is a common phenomenon triggered by several environmental stresses, theseresults highlight the importance of mycorrhizal fungi in oxidative stress regulation as a general strategyto protect plants from abiotic and biotic stress.