RESUMEN
BACKGROUND: In the last decades, replicating expression vectors based on plant geminivirus have been widely used for enhancing the efficiency of plant transient expression. By using the replicating expression vector derived from bean yellow dwarf virus and green fluorescent protein as a reporter, we investigated the effects of α-naphthalene acetic acid, gibberellins3, and 6-benzyladenine, as three common plant growth regulators, on the plant biomass and efficiency of transient expression during the process of transient expression in Nicotiana benthamiana L. leaves. RESULTS: With the increase of the concentration of α-naphthalene acetic acid, gibberellins3, and 6-benzyladenine (from 0.1 to 1.6 mg/L), the fresh weight, dry weight, and leaf area of the seedlings increased first and then returned to the levels similar to the controls (without chemical treatment). The treatment with α-naphthalene acetic acid at 0.2 and 0.4 mg/L can enhance the level of transient expression of green fluorescent protein, which peaked at 0.4 mg/L α-naphthalene acetic acid and was increased about by 19%, compared to the controls. Gibberellins3 at 0.1-0.4 mg/L can enhance the level of transient expression of green fluorescent protein, which peaked at 0.2 mg/L gibberellins3 and was increased by 25%. However, the application of 6-benzyladenine led to decrease in the level of transient expression of green fluorescent protein. CONCLUSIONS: The appropriate plant growth regulators at moderate concentration could be beneficial to the expression of foreign genes from the Agrobacterium-mediated transient expression system in plants. Thus, appropriate plant growth regulators could be considered as exogenous components that are applied for the production of recombinant protein by plant-based transient expression systems.