grade III (Re-growth of root galls on the tumor) 1
The lateral roots of 3-year-old P. notoginseng plants, which healthy or infected by RKNs to different severity were collected. According to the numbers of root galls, the P. notoginseng were divided into garde 0 (Healthy and no root gall), and four disease grade I (There are a few root galls), grade II (Most roots have root galls on them), grade III (Re-growth of root galls on the tumor), grade IV (Root galls interconnected into masses). Three independent biological replicates were conducted in this study.