Functional mechanisms of drought tolerance in subtropical maize (Zea mays L.) identified using genome-wide association mapping

Thirunavukkarasu, N and Hossain, F and Arora, K and Sharma, R and Shiriga, K and Mittal, S and Mohan, S and Namratha, P M and Dogga, S and Rani, T S and Katragadda, S and Rathore, A and Shah, T and Mohapatra, T and Gupta, H S (2014) Functional mechanisms of drought tolerance in subtropical maize (Zea mays L.) identified using genome-wide association mapping. BMC Genomics, 15 (1182). 01-12. ISSN 1471-2164

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Background Earlier studies were focused on the genetics of temperate and tropical maize under drought. We identified genetic loci and their association with functional mechanisms in 240 accessions of subtropical maize using a high-density marker set under water stress. Results Out of 61 significant SNPs (11 were false-discovery-rate-corrected associations), identified across agronomic traits, models, and locations by subjecting the accessions to water stress at flowering stage, 48% were associated with drought-tolerant genes. Maize gene models revealed that SNPs mapped for agronomic traits were in fact associated with number of functional traits as follows: stomatal closure, 28; flowering, 15; root development, 5; detoxification, 4; and reduced water potential, 2. Interactions of these SNPS through the functional traits could lead to drought tolerance. The SNPs associated with ABA-dependent signalling pathways played a major role in the plant’s response to stress by regulating a series of functions including flowering, root development, auxin metabolism, guard cell functions, and scavenging reactive oxygen species (ROS). ABA signalling genes regulate flowering through epigenetic changes in stress-responsive genes. ROS generated by ABA signalling are reduced by the interplay between ethylene, ABA, and detoxification signalling transductions. Integration of ABA-signalling genes with auxin-inducible genes regulates root development which in turn, maintains the water balance by regulating electrochemical gradient in plant. Conclusions Several genes are directly or indirectly involved in the functioning of agronomic traits related to water stress. Genes involved in these crucial biological functions interacted significantly in order to maintain the primary as well as exclusive functions related to coping with water stress. SNPs associated with drought-tolerant genes involved in strategic biological functions will be useful to understand the mechanisms of drought tolerance in subtropical maize.

Item Type: Article
Divisions: RP-Grain Legumes
CRP: CGIAR Research Program on Grain Legumes
CGIAR Research Program on Dryland Cereals
Uncontrolled Keywords: Genome-wide SNPs; Association mapping; Functional mechanisms; Candidate SNPs; Water stress; Drought tolerance; Maize
Subjects: Others > Maize
Depositing User: Mr Ramesh K
Date Deposited: 05 Oct 2015 10:24
Last Modified: 19 Oct 2016 09:54
Official URL:
Acknowledgement: We thank the breeders from different breeding centres in India and from CIMMYT for providing the seeds, and the National Agricultural Innovation Project (NAIP, Component IV) and the ICAR Network Project on Transgenics in Crop Plants (Maize Functional Genomics Component) for funding the study.
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