Elimination of five sugarcane viruses from sugarcane using in vitro culture of axillary bud and apical meristem

Authors: Cheong, Eun; Mock, Raymond; Li, Ruhui

Submitted to: Plant Cell Tissue and Organ Culture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/4/2011
Publication Date: 1/13/2012
Citation: Cheong, E.J., Mock, R.G., Li, R. 2012. Elimination of five sugarcane viruses from sugarcane using in vitro culture of axillary bud and apical meristem. Plant Cell Tissue And Organ Culture. 109:439-445.

Interpretive Summary: Sugarcane is an important group of tall grasses grown for sugar and biofuel production. Many viruses including Sugarcane mosaic virus (SCMV), Sorghum mosaic virus (SrMV), Sugarcane yellow leaf virus, Sugarcane streak mosaic virus (SCSMV), and Fiji disease virus infect sugarcane and cause yield (sugar content or biomass) reduction. Therefore, imported sugarcane plants infected with any of the viruses must remain in the U.S. quarantine until the virus is eliminated. A virus elimination method involving two steps was developed in this study. A cane stalk with a node containing an axillary bud is first cultured in sterile water to generate a shoot. The active growing tip (meristem) from the shoot and the top of a plant (apical meristem) is then cultured on an agar medium to generate a virus-free plant. The procedure worked to eliminate the above five viruses from singly-infected plants as well as both SCMV and SCYLV from a mixed-infection in a plant. This is the first report of the application of the same method for eliminating five different viruses from different sugarcane cultivars. It also represents the first application of the meristem culture for elimination of SrMV and SCSMV. The method is a novel technique for the harvest and use of axillary meristems, which provide a greater probability for eradication from any given sugarcane plant. This technique has the potential for routine use in programs that import and ship pathogen-free sugarcane material worldwide.

Technical Abstract: Procedures were developed for the in vitro elimination of Sugarcane mosaic virus (SCMV), Sorghum mosaic virus (SrMV), Sugarcane streak mosaic virus (SCSMV), Sugarcane yellow leaf virus (SCYLV) and Fiji disease virus (FDV) from infected sugarcane. In vitro shoot regeneration, elongation and virus elimination through meristem tissue culture originating from both apical and axillary shoots were compared. The average rates of regeneration and elongation from apical meristem tissues were 91% and 66%, respectively, with the virus-free rate among elongated shoots ranging from 61-92%. Mature axillary buds were cultivated in vitro to produce axillary shoots, from which meristem tissues were excised and cultured. These meristem tissues regenerated (77-100%) and elongated (55-88%) in culture medium at approximately the same rate as the apical meristems. The average virus elimination rate was 90% among elongated shoots derived from mature axillary buds. All five viruses can be eliminated by meristem tissue culture from both apical and axillary shoots using a standardized procedure. The overall average efficiency of virus-free plant production was 45 % and 58 % from apical and axillary shoots, respectively. There were no significant differences for shoot induction or virus elimination when the meristems were harvested from either the apical or the axillary shoots. This is the first report of SrMV or SCSMV elimination from sugarcane, as well as elimination of any mixed virus infections. This new method of harvesting meristems from axillary buds greatly expands the amount of material available for therapeutic treatments and thereby increases the probability of eliminating viruses from infected sugarcane.