Transcriptome changes in resistant and susceptible rose in response to powdery mildew

Rose is one of the most important ornamental crops worldwide and powdery mildew (Podosphaera pannosa (Wallr.: Fr.) de Bary) is the major disease of rose when grown in polyhouse or open field. Understanding of plant-pathogen interaction is important to develop strategies for disease management. We profiled transcriptomes of powdery mildew-resistant rose line IIHRR13-4 and susceptible cultivar Konfetti using Illumina NGS platform to understand the molecular mechanism of resistance to powdery mildew in the rose line IIHRR13-4. Profiles of samples were collected at 0 hr after inoculation (hai), 36 hai and 72 hai from susceptible cultivar Konfetti (SCON0, SCON3 and SCON7) and 0 hai and 36 hai from resistant line IIHRR13-4 (RPMR0 and RPMR3). The high-quality reads were aligned to reference genome of Rosa chinensis. The transcripts of rose-powdery mildew interaction were analysed for functions and involvement in disease resistance. Expression of receptor-like kinases, putative disease resistance genes (RLKs, NBS-LRR, NB-ARC, RPP13), WRKY transcription factors and PR proteins was observed in the transcripts library and was found up-regulated in IIHRR13-4 samples. Differentially expressed genes coding for metabolic and cellular process, response to abiotic stress response, defence response and other biosynthetic processes were identified in the transcripts. Gene ontology term enrichment and pathway analysis revealed that transcriptome of IIHRR13-4 was enriched with transcripts coding for plant hormone signal transduction and plant-pathogen interaction compared to transcripts of susceptible cultivar Konfetti. The transcriptome profiling proved that different defence mechanisms including hypersensitive responses were elicited as systemic acquired resistance in rose line IIHRR13-4 when infected by powdery mildew pathogen.

Automated summary

The study profiled the transcriptomes of powdery mildew-resistant rose line IIHRR13-4 and susceptible cultivar Konfetti, revealing the molecular mechanism of disease resistance in IIHRR13-4, including the up-regulation of receptor-like kinases, putative disease resistance genes, WRKY transcription factors, and PR proteins. Differentially expressed genes involved in metabolic processes, cellular responses, defense responses, and biosynthetic processes were identified in IIHRR13-4, indicating enrichment of transcripts related to plant hormone signal transduction and plant-pathogen interactions compared to susceptible cultivar Konfetti. The transcriptome analysis demonstrated the activation of defense mechanisms, including hypersensitive responses, in rose line IIHRR13-4 when infected with powdery mildew.