Symbiont-mediated drought stress tolerance in faba bean
Devika Talwar
Collaborators: Jakob Santner, Linbo Wu (both Justus Liebig University Giessen, Germany), Susanne Baldermann (University of Bayreuth, Germany), Hanna Tietgen (Norddeutsche Pflanzenzucht Innovation GmbH, Germany)
Background: The legume crop faba bean (Vicia faba) is a rich source of protein for food and feed and is cultivated world-wide. In addition to its high nutritional value, it can be invaluable in sustainable crop rotations leaving surplus nitrogen in the soil due to its root symbiosis with N2 fixing, nodulating bacteria. However, the low biotic and abiotic stress resilience of present faba bean cultivars results in low yield stability and production. For these reasons, faba bean grows on only 0.7% of the arable land in Germany (FAOSTAT). The development of more resilient faba bean cultivars is therefore most important. Drought stress is a major constraint in yield stability of faba beans by affecting flower development and reproduction. It can further reduce the size and activity of the N2 fixing nodules in grain legumes. In addition to enhancing nutrient supply, beneficial microbes can protect plants against stress. This phenomenon resembles plant systemic immunity in response to a prior stress and is defined as priming, representing a genetically determined plant process that induces higher tolerance against stresses. To access this still untapped beneficial potential of microbes requires the analysis of the interactions of below-ground plant-microbe interactions under stress. Priming can be induced by the endophytic fungus Serendipita indica in plants. Upon root colonisation, S. indica provides systemic (leaf) and local (root) resistance against diseases and tolerance against abiotic stresses, including drought stress tolerance in a broad range of legumes. As a clearly determined genetic trait, we aim to identify gene candidates that mediate priming-induced protection against drought stress in faba bean.
Project: Phenotyping of S. indica induced priming will be conducted under control and drought conditions in a panel of extreme faba bean cultivars. Phenotypic assessments will include various vegetative and reproductive traits, physiological parameters, and hormone metabolism. Transcriptome and microbiome analyses will complement phenotyping to investigate transcriptional and microbiome signatures associated with genotype-specific differences in symbiont-mediated drought tolerance. Key regulators of symbiosis-driven drought resilience will be anticipated using phenotypic, transcriptomic and microbiome data. The findings will promote symbiosis-based approaches for sustainable faba bean production and will further support marker development and breeding strategies for drought resilient faba bean genotypes.
Lab tools / techniques: Serendipita indica cultivation and plant inoculation, greenhouse drought stress experiments, plant phenotyping, physiological measurements (photosynthetic efficiency, stomatal conductance), qRT-PCR, RNA sequencing (RNA-seq), 16S rRNA amplicon sequencing, microbiome analysis, gene network analyses
Relevant publications:
Bond, D. A., Jellis, G. J., Rowland, G. G., Le Guen, J., Robertson, L. D., Khalil, S. A., & Li-Juan, L. (1993). Present status and future strategy in breeding faba beans (Vicia faba L.) for resistance to biotic and abiotic stresses. Euphytica, 73(1), 151-166.
Jensen, E. S., Peoples, M. B., & Hauggaard-Nielsen, H. (2010). Faba bean in cropping systems. Field crops research, 115(3), 203-216.
Khan, H. R., Paull, J. G., Siddique, K. H. M., & Stoddard, F. L. (2010). Faba bean breeding for drought-affected environments: A physiological and agronomic perspective. Field Crops Research, 115(3), 279-286.
Lagunas, B., Richards, L., Sergaki, C., Burgess, J., Pardal, A. J., Hussain, R. M. F., Richmond, B. L., Baxter, L., Roy, P., Pakidi, A., Stovold, G., Vázquez, S., Ott, S., Schäfer, P., & Gifford, M. L. (2023). Rhizobial nitrogen fixation efficiency shapes endosphere bacterial communities and Medicago truncatula host growth. Microbiome 11, 146.
Liu, B., Jing, D., Liu, F., Ma, H., Liu, X., & Peng, L. (2021). Serendipita indica alleviates drought stress responses in walnut (Juglans regia L.) seedlings by stimulating osmotic adjustment and antioxidant defense system. Applied Microbiology and Biotechnology, 105(23), 8951-8968.
Qiang, X., Weiss, M., Kogel, K.-H. & Schäfer, P. (2012). Piriformospora indica—a mutualistic basidiomycete with an exceptionally large plant host range. Molecular Plant Pathology, 13, 508-518.