Novel MicroRNAs and their Functional Targets from Phytophthora infestans and Phytophthora cinnamomi

Background: Even though miRNAs play vital roles in developmental biology by regulating the translation of mRNAs, they are poorly studied in oomycetes, especially in the plant pathogen Phytophthora. Objective: The study aimed to predict and identify the putative miRNAs and their targets in Phytophthora infestans and Phytophthora cinnamomi. Methods: The homology-based comparative method was used to identify the unique miRNA sequences in P. infestans and P. cinnamomi with 148,689 EST and TSA sequences of these species. Secondary structure prediction of sRNAs for the 76 resultant sequences has been performed with the MFOLD tool, and their targets were predicted using psRNATarget. Result: Novel miRNAs, miR-8210 and miR-4968, were predicted from P. infestans and P. cinnamomi, respectively, along with their structural features. The newly identified miRNAs were identified to play important roles in gene regulation, with few of their target genes predicted as transcription factors, tumor suppressor genes, stress-responsive genes, DNA repair genes, etc. Conclusion: The miRNAs and their targets identified have opened new interference and editing targets for the development of Phytophthora resistant crop varieties.