Differential responses in pear and quince genotypes induced by Fe deficiency and bicarbonate

• Published in: Journal of plant physiology 2009-07, Vol.166 (11), p.1181-1193
• Main Authors: Donnini, Silvia, Castagna, Antonella, Ranieri, Annamaria, Zocchi, Graziano
• Format: Article
• Language: English
• Subjects: bicarbonates; Bicarbonates - pharmacology; Biological and medical sciences; Blotting, Western; Chlorosis; Cydonia oblonga; electron transport chain; enzyme activity; ferric chelate reductase; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation, Plant - drug effects; Gene Expression Regulation, Plant - genetics; genetic variation; Genotype; H-transporting ATP synthase; iron; Iron - deficiency; Iron - metabolism; metal tolerance; oxidoreductases; pears; photosynthesis; Photosynthesis - drug effects; physiological response; Plant physiology and development; plant pigments; plant proteins; plant response; Pyrus - drug effects; Pyrus - genetics; Pyrus - metabolism; Pyrus communis; quinces; Rosaceae - drug effects; Rosaceae - genetics; Rosaceae - metabolism; thylakoids
• ISSN: 0176-1617; 1618-1328
• DOI: 10.1016/j.jplph.2009.01.007

Most of the studies carried out on Fe deficiency condition in arboreous plants have been performed, with the exception of those carried out on plants grown in the field, in hydroponic culture utilizing a total iron depletion growth condition. This can cause great stress to plants. By introducing Fe deficiency induced by the presence of bicarbonate, we found significant differences between Pyrus communis L. cv. Conference and Cydonia oblonga Mill. BA29 and MA clones, characterized by different levels of tolerance to chlorosis. Pigment content and the main protein–pigment complexes were investigated by HPLC and protein gel blot analysis, respectively. While similar changes in the structural organization of photosystems (PSs) were observed in both species under Fe deficiency, a different reorganization of the photosynthetic apparatus was found in the presence of bicarbonate between tolerant and susceptible genotypes, in agreement with the photosynthetic electron transport rate measured in isolated thylakoids. In order to characterize the intrinsic factors determining the efficiency of iron uptake in a tolerant genotype, the main mechanisms induced by Fe deficiency in Strategy I species, such as Fe 3+-chelate reductase (EC 1.16.1.7) and H +-ATPase (EC 3.6.3.6) activities, were also investigated. We demonstrate that physiological and biochemical root responses in quince and pear are differentially affected by iron starvation and bicarbonate supply, and we show a high correlation between tolerance and Strategy I activation.