Root exudation of contrasting drought-stressed pearl millet genotypes conveys varying biological nitrification inhibition (BNI) activity

Ghatak, A and Schindler, F and Bachmann, G and Engelmeier, D and Bajaj, P and Brenner, M and Fragner, L and Varshney, R K and Subbarao, G V and Chaturvedi, P and Weckwerth, W (2021) Root exudation of contrasting drought-stressed pearl millet genotypes conveys varying biological nitrification inhibition (BNI) activity. Biology and Fertility of Soils (TSI). ISSN 0178-2762

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Roots secrete a vast array of low molecular weight compounds into the soil broadly referred to as root exudates. It is a key mechanism by which plants and soil microbes interact in the rhizosphere. The effect of drought stress on the exudation process and composition is rarely studied, especially in cereal crops. This study focuses on comparative metabolic profiling of the exudates from sensitive and tolerant genotypes of pearl millet after a period of drought stress. We employed a combined platform of gas and liquid chromatography coupled to mass spectrometry to cover both primary and secondary metabolites. The results obtained demonstrate that both genotype and drought stress have a significant impact on the concentration and composition of root exudates. The complexity and function of these differential root exudates are discussed. To reveal the potential effect of root exudates on the soil microbial community after a period of drought stress, we also tested for biological nitrification inhibition (BNI) activity. The analysis revealed a genotype-dependent enhancement of BNI activity after a defined period of drought stress. In parallel, we observed a genotype-specific relation of elongated root growth and root exudation under drought stress. These data suggest that the drought stress-dependent change in root exudation can manipulate the microbial soil communities to adapt and survive under harsh conditions.

Item Type: Article
Divisions: Global Research Program - Accelerated Crop Improvement
Uncontrolled Keywords: Root exudates, Pearl millet, Primary metabolites, Secondary metabolites, LC–MS, GC–MS
Subjects: Mandate crops > Millets > Pearl Millet
Others > Genetics and Genomics
Depositing User: Mr Arun S
Date Deposited: 31 Aug 2021 16:29
Last Modified: 31 Aug 2021 16:29
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Acknowledgement: The authors are thankful to Ms. Annapurna Chitikineni, Senior Manager CEGSB ICRISAT, Patancheru, Hyderabad, India, for arranging seeds of pearl millet. We would also like to thank the gardeners Andreas Schröfl and Thomas Joch for excellent plant cultivation in the glasshouse facility of the Molecular Systems Biology (MOSYS), Department of Functional and Evolutionary Ecology, University of Vienna, Vienna, Austria.
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