Identification of critical stage responding to consecutive monoculture obstacle in Rehmannia glutinosa L.

Rehmannia glutinosa L. ( R. glutinosa ) is one of the most common traditional Chinese medicines, whose productivity and quality, however, are seriously impacted by replanting disease, also known as consecutive monoculture obstacle. Little is known about R. glutinosa ’s critical responsive stage to consecutive monoculture. There were two parts to this study: first, we analyzed different gene expression profiles in root of R. glutinosa between first-year planting (FP) and second-year replanting (SP) in five development stages (stage I to V) using Illumina sequencing to interpret the stage that most dramatically responding to consecutive monoculture; second, applying tissue culture technique, the harm of consecutive monoculture in a sterile condition was simulated and the medium was added with the soil extracts from FP and SP soil. The results showed that a significant difference in gene expression appeared at stage I under consecutive monoculture. Using a calcium indicator, the fluo-3 fluorescence to detect calcium distribution in the root tip of seedlings cultured in medium, the results revealed that after being cultured for 10 days, the SP fluorescence intensity of the seedlings was significantly higher than that of FP while crown position was particularly prominent. The evidence from gene expression profiling and tissue culture reached agreement that early stage of R. glutinosa growth was the critical stage to perceive consecutive monoculture stress. The results are of great significance to study the molecular mechanism of consecutive monoculture, which is expected to await a quick and accurate evaluation of land feasibility to plant R. glutinosa .