In semi-arid regions, water stress during seed germination and early seedling growth is the highest cause of crop loss. In nature, some seeds (for example, chia and basil) produce a mucilage-based hydrogel that creates a germination-promoting microenvironment by retaining water, regulating nutrient entry and facilitating interactions with beneficial microorganisms. Inspired by this strategy, a two-layered biopolymer-based seed coating has been developed to increase germination and water-stress tolerance in semi-arid, sandy soils. Seeds are coated with a silk/trehalose inner layer containing rhizobacteria and a pectin/carboxymethylcellulose outer layer that reswells upon sowing and acts as a water jacket. Using Phaseolus vulgaris (common bean) cultured under water-stress conditions in an experimental farm in Ben Guerir, Morocco, the proposed seed coating effectively delivered rhizobacteria to form root nodules, resulted in plants with better health and mitigated water stress in drought-prone marginal lands. A programmable seed coating technology has the potential to increase seed germination and water-stress tolerance in semi-arid, sandy soils.
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We acknowledge M. Lara for R. tropici CIAT 899-GFP from Universidad Nacional Autonoma de Mexico, OCP S.A. and the Université Mohammed VI Polytechnique–MIT Research Program. This work was partially supported by the Office of Naval Research (Award No. N000141812258), the National Science Foundation (Award No. CMMI‐1752172) and the MIT Paul M. Cook Career Development Professorship. Schematics in Fig. 1a,b were created with BioRender.com.
B.M. and A.T.Z. are co-inventors in a patent application (US Patent application no. 63/036,088) that describes the coating technology reported in this study. B.M. is co-founder of Mori, Inc., a company that develops silk-based edible coatings to extend the shelf life of food. All other authors have no competing interests.
Peer review information Nature Food thanks David Britt, Haihua Xiao and Maximino Manzanera for their contribution to the peer review of this work.
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Zvinavashe, A.T., Laurent, J., Mhada, M. et al. Programmable design of seed coating function induces water-stress tolerance in semi-arid regions. Nat Food 2, 485–493 (2021). https://doi.org/10.1038/s43016-021-00315-8
Nature Food (2021)