RESULTS: In this experiment, thick and short hairy roots were induced at all induction sites of C. annuum while thin, elongated hairy roots appeared mostly at wound sites of C. frutescens. Overall, the hairy root induction percentages of C. frutescens were higher compared with C. annuum. Hairy root initiation was observed earliest using radicles (1st week), followed by cotyledons (2nd week), and hypocotyls (3rd week). Cotyledon explants of both species had the highest induction frequency with all strains compared with the other explants types. Strains ATCC 13333 and ATCC 15834 were the most favourable for C. frutescens while ATCC 43056 and ATCC 43057 were the most favourable for C. annuum. The interactions between the different explants and strains showed significant differences with p-values < 0.0001 in both Capsicum species.
CONCLUSIONS: Both Capsicum species were amenable to A. rhizogenes infection and hairy root induction is recommended for use as an alternative explants in future plant-based studies.
RESULTS: We have devised a method to introduce Agrobacterium suspensions into plant leaves with greater reproducibility. Using a decommissioned dissecting microscope as an armature, a syringe body with the bacterial suspension is mounted to the nosepiece. Gentle, even pressure is applied by rotating the focus knob. The treatment force is measured using a basic kitchen scale. The development of the Standardized Pressure Agrobacterium Infiltration Device (SPAID) provides a means to deliver consistent amounts of bacterial suspensions into plant tissues with the goal of increasing reproducibility between replicates and laboratories.