Chengyu Gao, Binsen Zhao, Jian Zhang, Xuan Du, Jie Wang, Yan Guo, Yanting He, Hao Feng*, Lili Huang*,Adaptive regulation of miRNAs/milRNAs in tissue specific interaction between apple and Valsa mali ,Horticulture Research, 2024,https://doi.org/10.1093/hr/uhae094.

Abstract

In plant-pathogen interactions, pathogens display tissue specificity, infecting and causing disease in particular tissues. However, the involvement of microRNAs/microRNA-like RNAs (miRNAs/milRNAs) in tissue-specific regulation during plant-pathogen interactions remains largely unexplored. This study investigates the differential expression of miRNAs/milRNAs, as well as their corresponding target genes, in interactions between  Valsa mali  ( Vm ) and different apple tissues. The results demonstrated that both apple miRNAs and  Vm  milRNAs exhibited distinct expression profiles when  Vm  infected bark and leaves, with functionally diverse corresponding target genes. Furthermore, one apple miRNA (Mdo-miR482a) and one  Vm  milRNA (Vm-milR57) were identified as exhibiting tissue-specific expression in interactions between  Vm  and apple bark or leaves. Mdo-miR482a was exclusively up-regulated in response to  Vm  infection in bark, and target a nucleotide-binding leucine-rich repeat (NLR) gene of apple. When Mdo-miR482a was transiently over-expressed or silenced, the resistance was significantly reduced or improved. Similarly, transient expression of the NLR gene also showed an increase in resistance. Vm-milR57 could target two essential pathogenicity-related genes of  Vm . During  Vm  infection in bark, the expression of Vm-milR57 was down-regulated to enhance the expression of the corresponding target gene to improve the pathogenicity. The study is the first to reveal tissue-specific characteristics of apple miRNAs and  Vm  milRNAs in interactions between  Vm  and different apple tissues, providing new insights into adaptive regulation in tissue-specific interactions between plants and fungi.