Transcriptional analysis of molecular interactions between Pseudomonas fluorescens strain TDK1, Oryza sativa and Cnaphalocrocis medinalis

Rice leaffolder Cnaphalocrocis medinalis is a devastating insect pest posing major threat to rice cultivation. Plant growth-promoting rhizobacteria Pseudomonas fluorescens strain TDK1 was found to induce high degree of resistance in rice plants against leaffolder insect through Induced Systemic Resistance in our previous studies. Thus the present study was aimed to understand the molecular mechanisms involved in P. fluorescens TDK1-mediated host plant resistance against leaffolder infestation on rice. Transcript profiling was done through DD-RT-PCR method in leaffolder-infested rice plants that were treated with and without Pf TDK1. A total of 3500 transcripts were displayed, of which 165 transcripts exhibited differential expression during rice-Pf TDK1-leaffolder interactions. The differential transcripts were 58 in Pf TDK1-treated + leaffolder-challenged, 51 in leaffolderinfested and 56 in Pf TDK1-treated rice leaf sheath tissues. Annotation and mapping of differentially expressed genes onto metabolic pathways revealed the interaction of leaffolder and Pf TDK1 in rice plant at the molecular level. Furthermore, Pf TDK1 induced over-expression of genes found to regulate the diverse metabolic processes by the selective integration of defensive signals in rice plants.