Arbuscular mycorrhizal fungi can contribute to maintain antioxidant and carbon metabolism in nodules of Anthyllis cytisoides L. subjected to drought

• Published in: Journal of plant physiology 2005-01, Vol.162 (1), p.27-35
• Main Authors: Goicoechea, Nieves, Merino, Silvia, Sánchez-Díaz, Manuel
• Format: Article
• Language: English
• Subjects: Anthyllis; Anthyllis cytisoides; Antioxidant; antioxidant activity; antioxidants; Antioxidants - metabolism; Arbuscular mycorrhizal fungi; Biological and medical sciences; carbon; Carbon - metabolism; drought; Fabaceae - metabolism; Fabaceae - microbiology; Fabaceae - physiology; Fundamental and applied biological sciences. Psychology; Glomus fasciculatum; hydroxybutyrate dehydrogenase; isocitrate dehydrogenase; leaf water potential; leghemoglobin; malate dehydrogenase; Mycorrhizae - physiology; mycorrhizal fungi; Parasitism and symbiosis; peroxidase; phosphoenolpyruvate carboxylase; Plant physiology and development; plant proteins; Plant Roots - metabolism; Plant Shoots - metabolism; plant-water relations; reactive oxygen species; root nodules; Soil compaction; soil water content; Symbiosis; Symbiosis - physiology; Time Factors; vesicular arbuscular mycorrhizae; Water - metabolism; Water deficit; water stress
• ISSN: 0176-1617; 1618-1328
• DOI: 10.1016/j.jplph.2004.03.011

The symbiosis legume–arbuscular mycorrhizal fungi–nitrogen fixing bacteria is of relevant interest in Mediterranean regions where Anthyllis cytisoides L. grows. In these areas, nitrogen is one of the nutrients that most limits plant growth. In addition, the long periods of water deficit decrease the diffusion rate of phosphorus and, consequently, also decrease the biological nitrogen fixation. It is well known that mycorrhizal fungi can improve phosphorus uptake and, recently, some authors have found that antioxidant activities in mycorrhizal plants can delay drought-induced nodule senescence. The objective of our work was to evaluate weather mycorrhizal fungi could preserve the nodule metabolism in A. cytisoides subjected to drought. Results showed that a low soil water content associated with an enhancement of soil compaction accelerated the senescence of nodules in both non-mycorrhizal and mycorrhizal plants. However, while total soluble protein, leghaemoglobin (Lb) content, as well as carbon and antioxidant metabolism significantly decreased in nodules from non-mycorrhizal A. cytisoides subjected to drought, nodules from stressed mycorrhizal plants maintained Lb levels, showed greater rates of carbon metabolism, and exhibited higher enzymatic activities related to the removal of reactive oxygen species. In addition to the greater activity of antioxidant enzymes, other mechanisms related or unrelated to enhanced nodule water status could also be implied in the better nodule functioning observed in mycorrhizal plants under stressful conditions.