Serial transcriptome analysis reveals genes associated with late blight resistance in potato cultivar qingshu 9

Abstract

The late blight caused by Phytophthora infestans (P. infestans) has been a major constraint for worldwide sustainable potato production. Chinese potato cultivar Qingshu 9 has shown excellent field performance against late blight. To understand the mechanism underlying its resistance, the transcriptomic dynamics of Qingshu 9 infected with P. infestans was systematically investigated to identify the resistance-related genes. In total, 2027 shared differentially expressed genes (DEGs) were identified when infected with P. infestans at 24, 48 and 72 h post-inoculation. Based on k-mean cluster analysis, the DEGs showed four types of expression patterns, suggesting their divergent functions in response to P. infestans infection. KEGG enrichment analysis showed that the significantly enriched DEGs were involved in the biosynthesis of secondary metabolites, plant–pathogen interaction, and photosynthesis. Furthermore, 980 transcription factor genes belonging to 68 families were found in the DEGs, of which AP2-EREBP and MYB genes were the most abundant. Moreover, many genes related to disease resistance showed differential expression during infection. Finally, the expression of nine DEGs was validated by quantitative real-time PCR. These results provide valuable information for understanding late resistance in potato cultivar Qingshu 9.