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Physiological and molecular characterization of drought responses and identification of candidate tolerance genes in cassava

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Title Physiological and molecular characterization of drought responses and identification of candidate tolerance genes in cassava
 
Creator Turyagyenda, L.F.
Kizito, E.B.
Ferguson, M.
Baguma, Yona K.
Agaba, Morris
Harvey, Jagger J.W.
Osiru, D.S.O.
 
Subject crops
 
Description Cassava is an important root crop to resource-poor farmers in marginal areas, where its production faces drought stress constraints. Given the difficulties associated with cassava breeding, a molecular understanding of drought tolerance in cassava will help in the identification of markers for use in marker-assisted selection and genes for transgenic improvement of drought tolerance. This study was carried out to identify candidate drought-tolerance genes and expression-based markers of drought stress in cassava. One drought-tolerant (improved variety) and one drought-susceptible (farmer-preferred) cassava landrace were grown in the glasshouse under well-watered and water-stressed conditions. Their morphological, physiological and molecular responses to drought were characterized. Morphological and physiological measurements indicate that the tolerance of the improved variety is based on drought avoidance, through reduction of water loss via partial stomatal closure. Ten genes that have previously been biologically validated as conferring or being associated with drought tolerance in other plant species were confirmed as being drought responsive in cassava. Four genes (MeALDH, MeZFP, MeMSD and MeRD28) were identified as candidate cassava drought-tolerance genes, as they were exclusively up-regulated in the drought-tolerant genotype to comparable levels known to confer drought tolerance in other species. Based on these genes, we hypothesize that the basis of the tolerance at the cellular level is probably through mitigation of the oxidative burst and osmotic adjustment. This study provides an initial characterization of the molecular response of cassava to drought stress resembling field conditions. The drought-responsive genes can now be used as expression-based markers of drought stress tolerance in cassava, and the candidate tolerance genes tested in the context of breeding (as possible quantitative trait loci) and engineering drought tolerance in transgenics.
 
Date 2013-03-21
2014-05-23T10:22:56Z
2014-05-23T10:22:56Z
 
Type Journal Article
 
Identifier Turyagyenda, L.F., Kizito, E.B., Ferguson, M., Baguma, Y., Agaba, M., Harvey, J.J.W. and Osiru, D.S.O. 2013. Physiological and molecular characterization of drought responses and identification of candidate tolerance genes in cassava. AoB PLANTS 5: plt007.
2041-2851
https://hdl.handle.net/10568/35659
https://doi.org/10.1093/aobpla/plt007
 
Language en
 
Rights Open Access
 
Publisher Oxford University Press
 
Source AoB PLANTS