Effects of Plant Growth Regulators On Transient Expression of Foreign Genes In Nicotiana Benthamiana L. Leaves

Abstract Background: In the last decades, autonomously replicating expression vectors based on plant geminivirus has been widely used as one of the most effective expression vectors in plant transient expression. Compared with those non-replicating expression vectors, autonomously replicating expression vectors based on plant geminivirus have many advantages. By using the bean yellow dwarf virus-derived expression vector and green fluorescent protein as a reporter, we investigated the effects of α-naphthalene acetic acid, gibberellins, and 6-benzyladenine, as three common plant growth regulators, on the efficiency of plant transient expression and biomass during the process of transient expression in Nicotiana benthamiana L. leaves. Results: With the increase of α-naphthalene acetic acid, gibberellins, 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 plant growth regulators treatment). 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 19%, compared to the controls. Gibberellins at 0.1 to 0.4 mg/L can enhance the level of transient expression of green fluorescent protein, which peaked at 0.2 mg/L gibberellins and was increased about 25%. However, the 6-benzyladenine application led to decrease in the level of transient expression of green fluorescent protein. Conclusions: The moderate concentration of appropriate plant growth regulators could be beneficial to the expression of foreign proteins from the Agrobacterium-mediated transient expression system in plants. Thus, appropriate plant growth regulators could be considered as an exogenous component to be applied in recombinant protein production by plant-based transient expression systems.