biologia plantarum

Biologia plantarum 70:109-118, 2026 | DOI: 10.32615/bp.2026.013

Study on Agrobacterium-mediated transient expression in Viola plants

Duli WANG¹, Yuting CAI¹, Jindi LI¹, Ting JI¹, Jie ZHANG¹, Yi RU², Yuanyuan ZENG¹, Hanqing FENG^{1, *}, Qiaoxia LI^{1, *}

¹ College of Life Science, Northwest Normal University, 730070 Lanzhou, P.R. China

² Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Science, 730046 Lanzhou, P.R. China

Background: The Viola plants have important value for theoretical and applied research. Agrobacterium-mediated transient expression enables rapid target protein production in plants, yet this system remains poorly established in Viola.

Aims: To establish an efficient Agrobacterium-mediated transient expression system in Viola.

Methods: By employing two types of A. tumefaciens strains (EHA105 and LBA4404) and green fluorescent protein (GFP) as a reporter, we demonstrated the transient expression in the leaves of four Viola species, including Viola philippica, V. prionantha, V. tricolor, and V. dissecta. Results: GFP transient expression peaked at 4 dpi in all four Viola species. Agrobacterium at OD₆₀₀ = 0.3 yielded optimal expression, and strain EHA105 was superior to LBA4404; V. philippica showed the highest GFP accumulation. In the optimal system, exogenous indole-3-acetic acid (IAA) improves GFP transient expression with maximum promotion at 50 ng/mL, while methyl jasmonate (MeJA) has no facilitating effect. This system enables transient expression of FMDV VP1, whose expression is also markedly increased by 50 ng/mL IAA.

Conclusions: This study successfully established a transient expression system for Viola and identified factors affecting Agrobacterium-mediated transient expression efficiency in this genus.

Keywords: Agrobacterium-mediated transient expression, auxin, Viola, VP1.

Received: April 17, 2026; Revised: June 16, 2026; Accepted: June 30, 2026; Published online: July 20, 2026  Show citation