Iron toxicity in rice is still an under-researched topic

Iron (Fe) toxicity is a major stress to rice in many lowland environments worldwide. Due to excessive uptake of Fe2+ by the roots and its acropetal translocation into the leaves, toxic oxygen radicals may form and damage cell structural components, thus impairing physiological processes. The typical visual symptom is the “bronzing” of the rice leaves, leading to substantial yield losses, particularly when toxicity occurs during early vegetative growth stages. The problem is best addressed through genotype improvement, i.e., tolerant cultivars. However, the time of occurrence and the severity of symptoms and yield responses vary widely among soil types, years, seasons, and genotypes. Cultivars resistant in one system may fail when transferred to another. Better targeting of varietal improvement requires selection tools improving our understanding of the resistance mechanisms and strategies of rice in the presence of excess iron. We have developed screening tools for iron toxicity responses in rice genotypes. We have worked on a method speeding up measurements of tissue Fe2+ concentrations and we have been investigating effects of bacteria present in the rhizosphere on the symptom responses of rice genotypes.

Iron toxicity

PhD

 People

Katrin Engel
 

MSc

"Mechanistische Bewertung von Eisentoxizitätsresistenz bei Nassreis im Feldanbau im Mekong Delta, Vietnam"
Diplomarbeit 2007, Sabine Stürz [Germany].

"Physiological mechanisms of iron toxicity in lowland rice"
Master of Science Thesis 2006, Tam Aung [Myanmar].

"Developing a Standardized Procedure to Screen Lowland Rice (Oryza sativa ) Seedlings for Tolerance to Iron Toxicity"
Master of Science Thesis 2003, Dilys Kpongor [Ghana].

Funds

Projects

Phenotyping of lowland rice for iron toxicity resistance - AfricaRice 2009-2010

Evaluation of adaptation mechanisms of paddy rice to iron toxic conditions - DFG 2008-2010

Paper

Publications

Becker, M., Asch, F., 2005 
Iron toxicity in rice -  conditions and management concepts. J. Plant Nutri. Soil Sci. 168, 558-573.

Asch, F., Becker, M., Kpongor, D. S., 2005 
A quick and efficient screen for resistance to iron toxicity in lowland rice. J. Plant Nutri. Soil Sci. 168, 764-773.

Poster

Engel, K., Becker, M., Asch, F. 2009. "Efficiency of Adaptation Mechanisms of Rice to Diverse Conditions of Iron Toxicity". Tropentag 2009, October 6-8, University of Hamburg, Germany.

Engel, K., Becker, M., Asch, F. 2008
"Adaptation mechanisms in rice cultivars of different origin to iron toxic conditions". Tropentag 2008, October 7-9, University of Hohenheim, Stuttgart

Stürz, S., Asch, F., Becker, M. 2007. 
"Field validation of a quick screening method for iron toxicity in lowland rice". Tropentag 2007, October 9-11, University of Kassel-Witzenhausen, Witzenhausen.

Asch, F., Aung, T., Becker, M. 2007. 
"Root iron plaque formation as resistance mechanism to iron toxicity in lowland rice". Tropentag 2007, October 9-11,University of Kassel-Witzenhausen, Witzenhausen.

Ripken, C., Asch, F., Becker, M., Wimmer, M. 2005.
"A low cost miniature method to determine iron content in samples suitable for small research laboratories". 
Deutscher Tropentag 2005, October 11-13, University of Hohenheim, Stuttgart.

 Iron toxicity and root associated bacteria

MSc

 People

"Effects of rhizobacteria on root iron plaque formation in rice subjected to iron toxicity"
Master of Science Thesis, Sunilda Terré [Spain]

Paper

Publications

Dimpka, C., Weinand, T., Asch, F., 2009
Plant–rhizobacteria interactions alleviate abiotic stress conditions. Plant, Cell, and Environment 32, 1682-1694.

Poster

Terre, S.,  Asch, F., Becker, M. 2009. 
"Influence of Bacillus spp. on iron plaque formation at the root surface of lowland rice". Tropentag 2009, October 6-8, University of Hamburg, Hamburg.

Terre, S.,  Asch, F., Padgham, J., Becker, M. 2007. 
"Influence of root zone bacteria on root iron sequestration in rice subjected to iron toxicity". Tropentag 2007, October 9-11, University of Kassel-Witzenhausen, Witzenhausen.

Asch, F., Padgham, J. 2005.
"Root associated bacteria suppress symptoms of iron toxicity in lowland rice"
Deutscher Tropentag 2005, October 11-13, University of Hohenheim, Stuttgart.