Enhanced agrobacterium transformation platform with morphogenic regulators for plant regeneration

Overview

This offering combines a multi-pronged improvement of Agrobacterium as a plant transformation vector with advanced morphogenic regulator delivery to address one of the most persistent bottlenecks in plant biotechnology: regenerating transformed plants from recalcitrant species. The platform integrates auxotrophic Agrobacterium strains, RecA inactivation, reduced hypersensitive response, and SacB-based negative selection into a single optimized strain. Complementing this, morphogenic regulators and signal transduction modulators are delivered transiently via functionalized carbon nanotubes, enabling enhanced regeneration without stable integration. The combined approach targets improved transformation efficiency, reduced tissue necrosis, and broader applicability across difficult-to-transform crops.

Technical specifications

Engineered Agrobacterium strain features:

• Auxotrophism (cysteine auxotroph in C58 background) to attenuate bacterial overgrowth post-transformation
• RecA inactivation to stabilize large binary vectors carrying complex trait cassettes
• SacB negative selection enabling clean removal of Agrobacterium during post-transformation sucrose exposure
• Non-necrotic strain background (sequenced from the Michelmore lab) to reduce hypersensitive plant response
• Ti-megaplasmid eviction and replacement with the well-characterized EHA105 helper plasmid
• Salicylate hydroxylase expression to degrade salicylic acid and further suppress hypersensitive response, monitored via a luminol-based duckweed plate assay

Morphogenic regulator delivery:

• Morphogenic regulator genes (including BBM, LEC2, and Clavata3 suppressors) cloned from cacao, Dioscorea (yam), Brachypodium, hemp, and tomato
• Regulator coding sequences compacted onto a minimized E. coli plasmid to reduce DNA payload size
• Functionalized carbon nanotube delivery for transient, non-integrating enhancement of plant regeneration
• Compatible with standard Agrobacterium-mediated transformation workflows

Technology readiness level

The platform is at an early-to-mid stage of development. Individual components have been validated: auxotrophic attenuation was demonstrated in prior published work, the non-necrotic strain and C58 cysteine auxotroph have been sequenced, and morphogenic regulators such as BBM and LEC2 have shown enhanced regeneration in highly recalcitrant cacao. RecA/SacB homologous recombination tools and megaplasmid eviction systems have been obtained from collaborating labs. Remaining work includes completing the redesigned knockin vector at the RecA locus, swapping helper plasmids, validating hypersensitive response reduction with the luminol assay, and demonstrating carbon nanotube-mediated transient delivery of morphogenic regulators in a recalcitrant species such as yam. The platform is not yet commercially deployed and will require further validation before licensing or co-development partnerships.