Background: Late blight is a serious disease in potato caused by Phytophthora infestans.
To date only few miRNA have been discovered which are related to late blight disease of potato during
host pathogen interaction. Recent studies showed that miRNA, an important gene expression regulator,
plays a very important role in host-pathogen interaction by silencing genes either by destructing
or blocking of translation of mRNA.
Method: Homology search was performed between non-redundant mature miRNA sequences from
miRBase database and Solanum tuberosum EST sequences from NCBI database. Screening of the potential
miRNA was done after secondary structure prediction. The target related to late blight disease
of respective miRNA was functionally annotated. To identify the relationship between the predicted
and mature miRNAs, multiple sequence alignment and evolutionary relationships were established.
Results and Conclusion: 34 Candidate miRNA related to late blight disease of potato were identified
which were associated to five target genes. These miRNAs were linked with Avr3a, INF1, INF2b
genes which are elicitin like protein and triggers a hypersensitive response to host cell. Mapping of
target sequences showed similarity with Solanum lycopersicum NRC1 gene of chr.1, which are reported
as a casual protein required for Pto-mediated cell death and resistance in N. benthamiana.
NRC1 are considered as a RX-CC_like domain-containing protein which shows similarity with coiledcoil
domain of the potato virus X resistance protein (RX) in Solanum tuberosum. RX recognizes
pathogen effector proteins and triggers a response that may be as severe as localized cell death thereby
providing resistance against potato virus X.