Endogenous soybean peptide overexpression: an alternative to protect plants against root-knot nematodes

Background Root-knot nematodes (RKNs) pose a worldwide threat to agriculture of many crops including cucumber. Genetic transformation (GT) has emerged as a powerful tool for exploration of plant-RKN interactions and genetic improvement of RKN resistance. However, it is usually difficult to achieve a highly efficient and stable GT protocol for most crops due to the complexity of this process. Results Here we firstly applied the hairy root transformation system in exploring root-RKN interactions in cucumber plants and developed a rapid and efficient tool transformation using Rhizobium rhizogenes strain K599. A solid-medium-based hypocotyl-cutting infection (SHI) method, a rockwool-based hypocotyl-cutting infection (RHI) method, and a peat-based cotyledon-node injection (PCI) method was evaluated for their ability to induce transgenic roots in cucumber plants. The PCI method generally outperformed the SHI and RHI methods for stimulating more transgenic roots and evaluating the phenotype of roots during nematode parasitism. Using the PCI method, we generated the CRISPR/Cas9-mediated malate synthase (MS) gene (involved in biotic stress responses) knockout plant and the LATERAL ORGAN BOUNDARIES-DOMAIN 16 (LBD16, a potential host susceptibility gene for RKN) promoter-driven GUS expressing plant. Knockout of MS in hairy roots resulted in effective resistance against RKNs, while nematode infection induced a strong expression of LBD16-driven GUS in root galls. This is the first report of a direct link between these genes and RKN performance in cucumber. Conclusion Taken together, the present study demonstrates that the PCI method allows fast, easy and efficient in vivo studies of potential genes related to root-knot nematode parasitism and host response.

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A novel soybean hairy root system for gene functional validation

Pereira

Arraes

Martins

et al. 2023

PLoS ONE

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Agrobacterium rhizogenes-mediated transformation has long been explored as a versatile and reliable method for gene function validation in many plant species, including soybean (Glycine max). Likewise, detached-leaf assays have been widely used for rapid and mass screening of soybean genotypes for disease resistance. The present study combines these two methods to establish an efficient and practical system to generate transgenic soybean hairy roots from detached leaves and their subsequent culture under ex vitro conditions. We demonstrated that hairy roots derived from leaves of two (tropical and temperate) soybean cultivars could be successfully infected by economically important species of root-knot nematodes (Meloidogyne incognita and M. javanica). The established detached-leaf method was further explored for functional validation of two candidate genes encoding for cell wall modifying proteins (CWMPs) to promote resistance against M. incognita through distinct biotechnological strategies: the overexpression of a wild Arachis α-expansin transgene (AdEXPA24) and the dsRNA-mediated silencing of an endogenous soybean polygalacturonase gene (GmPG). AdEXPA24 overexpression in hairy roots of RKN-susceptible soybean cultivar significantly reduced nematode infection by approximately 47%, whereas GmPG downregulation caused an average decrease of 37%. This novel system of hairy root induction from detached leaves showed to be an efficient, practical, fast, and low-cost method suitable for high throughput in root analysis of candidate genes in soybean.

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Endogenous soybean peptide overexpression: an alternative to protect plants against root-knot nematodes

Cited by 5 publications

References 46 publications

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Peat-based hairy root transformation using Rhizobium rhizogenes as a rapid and efficient tool for easily exploring potential genes related to root-knot nematode parasitism and host response

A novel soybean hairy root system for gene functional validation

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