The Mechanism of Sesame Resistance Against Macrophomina Phaseolina Was Revealed via Comparison of Transcriptomes of Resistant and Susceptible Sesame Genotypes

Abstract

Background: Sesame (sesamum indicum) charcoal rot, a destructive fungal disease caused by Macrophomina phaseolina (Tassi) Goid (MP), is a great threat to the yield and quality of sesame. However, there is a lack of information revealing gene-for-gene relationship between sesame and MP, and the molecular mechanism in the interaction is not yet clear. The aim of this study is to interpret the molecular mechanism of sesame resistance against MP in disease-resistant (DR) and disease-susceptible (DS) genotypes based on transcriptomes, which is the first report on the interaction between sesame and MP from the transcriptomes.Results: A set of core genes that function in sesame disease resistance were revealed in our investigation by comparative transcriptomics, which preferentially associate with GO terms such as ribosome-related processes, fruit ripening, regulation of jasmonic acid mediated signaling pathway and cell-cell signaling. In addition, 52 potential resistance-related genes differentially and persistently expressed all through were obtained in sesame. Furthermore, we preliminarily studied the immune response mechanism of sesame against MP and found that auxin signal pathway shows negative regulation in the process. Also, the most highlighted pathway JA/ET signal transduction plays a negative regulatory role in sesame resistance against MP. Finally, a JAZ gene (LOC105168467) and an ERF transcription factor (LOC105171710) that may be related to disease resistance were screened. Conclusions: In our investigation, the mechanism of resistance against MP from the transcriptomes were illustrated, which is a complex bioprocess involved in many phytohormones and disease resistance-related genes. The findings not only shed more light on mechanism of interaction between sesame and MP, but also help us identify key genes and transcription factors (TFs) associated with charcoal rot resistance in sesame.