Application of virus-induced gene silencing in Andrographis paniculata, an economically important medicinal plant

Kalmegh [Andrographis paniculata (Burm.f.) Wall. ex Nees] is one of the most studied medicinal plants for pharmaceutical properties and phytochemistry. However, functional genomics studies in kalmegh are so far limited due to the unavailability of a robust tool for gene silencing. Here, we tested the application of virus-induced gene silencing (VIGS) in kalmegh using the well-known Tobacco rattle virus (TRV)-based vectors and achieved targeted silencing of phytoene desaturase (ApPDS) which is essential in plants for carotenoid biosynthesis that protects chlorophyll from photooxidation. ApPDS silencing in kalmegh leaves developed a typical photobleaching phenotype. The silencing of ApPDS was confirmed by analysing ApPDS transcript level and determining chlorophyll content in the leaves of VIGS seedlings. The analysis revealed similar to 30% reduction in chlorophyll content, and 40 to 60% reduction in ApPDS transcript level in the leaves of VIGS seedlings. These findings clearly demonstrated the applicability of VIGS in kalmegh using TRV-based vectors. The VIGS protocol presented in this study might be useful for studying gene function related to medicinal and agricultural traits in kalmegh.

Automated summary

The study successfully applied virus-induced gene silencing technology to achieve targeted silencing of phytoene desaturase in kalmegh, resulting in a typical photobleaching phenotype. This provides a useful method for studying gene functions related to medicinal and agricultural traits in kalmegh.