Efficient virus-induced gene silencing in Cynodon dactylon and Zoysia japonica using rice tungro bacilliform virus vectors

- Two PDS genes were cloned from Cynodon dactylon and Zoysia japonica.
- Agroinfiltration of pRTBV-MVIGS-PDS cause leaf white streak symptoms in Cynodon dactylon and Zoysia japonica.
- PDS gene expression was significantly down-regulated in leaves with streaking phenotypes.

Cynodon dactylon and Zoysia japonica are two important warm-season turfgrass species with multiple utilizations. Genetic transformations of Cynodon dactylon and Zoysia japonica are extremely difficult, which severely restrict the gene functional studies and molecular breeding research of the two grasses. By contrast, virus-induced gene silencing (VIGS) presents an effective and rapid alternative method to create targeted gene knock-outs for gene functional studies in plants. In this study, we tested the efficiency of modified rice tungro bacilliform virus (RTBV) vector in silencing Cynodon dactylon and Zoysia japonica phytoene desaturase (PDS) gene through agroinfiltration. The agroinfiltrated leaves of two Cynodon dactylon and two Zoysia japonica cultivars all showed white streaks typical for PDS gene silencing at 21 days post agroinfiltration. In Cynodon dactylon and Zoysia japonica plants displaying white streak leaf symptoms, PDS gene expression in leaves were all significantly lower than that of control and mock-infected plants. These results indicated that RTBV-VIGS system is efficient in Cynodon dactylon and Zoysia japonica.