Establishment of a Virus-Induced Gene Silencing System in Abelmoschus manihot L

Abelmoschus manihot L. (Jinhuakui, JHK) is widely cultivated for its pharmacological properties owing to its high flavonoid content and is commonly used as a garden landscape plant. However, the absence of an efficient genetic transformation system poses significant challenges for functional gene studies in this species. Virus-induced gene silencing (VIGS) is a well-established technique for exploring plant gene functions; however, this technique has not been applied to JHK. Here, a tobacco rattle virus (TRV)-VIGS system was successfully developed for the first time in JHK using the gene encoding phytoene desaturase (AmPDS) as a marker gene. This study investigated the impact of various Agrobacterium infection methods on the efficiency of AmPDS silencing. The results demonstrated that administering two injections-the first on the day of complete cotyledon expansion and the second 14 days later-using pTRV1 and pTRV2-AmPDS cultures resuspended to an OD₆₀₀ of 1.0 and via the backside of the blade-led to significant photobleaching in the cotyledons 2 days after the second injection. Subsequent analyses revealed a marked reduction in both chlorophyll content and AmPDS expression. These findings suggest that a VIGS system was successfully developed in JHK, thus providing a rapid and effective method for studying gene function in this species and facilitating future research in JHK genetics.