The miRNAomes in Rehmannia glutinosa Roots Exposed to Different Levels of Replanting Disease Pressure

Abstract

To cite this paper: Yang, Y., M. Li and Y. Yi, 2017. The miRNAomes in Rehmannia glutinosa roots exposed to different levels of replanting disease pressure. AbstractRoot development in the medicinal plant Rehmannia glutinosa is severely disordered by replanting disease, which occurs when it is grown in the same soils over consecutive seasons. Following the demonstration of changes to the miRNAome of the R. glutinosa plants in the second year of cultivation, a fuller experiment was organized to track the root miRNAomes over four successive plantings. Four small RNA libraries were generated from the roots of one year's planted (free of replanting disease) and 2-4 years' continuous cultivation (replanting disease) R. glutinosa plants, respectively. Sequencing of these libraries revealed the presence of 18 novel and 344 conserved miRNA families. The abundance of many of the miRNAs varied between the four libraries, consistent with the notion that replanting disease reflects the outcome differential miRNA transcription. A combined bioinformatic and degradome sequencing approach allowed the identification of 69 differentially abundant (DA) miRNA targets, leading to the recognition that particular miRNA/target modules may be important for the expression of the disease. The expression profiles of 28 key miRNAs and their targets implied that the longer years of continuous cultivation was extended, the more severe tendency of these profiles' changes would be. The indication was that the miRNAs-responsive continuous cultivation pressure reprogrammed gene expression patterns, which disordered hormone signaling, repressed core mechanisms, weakened stress tolerance and resulted in forming the disease in R. glutinosa. In conclusion, the key miRNAs involved in important roles of replanting disease and were a crucial basis for exploration in the disease forming repertoire.