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.

中文翻译：

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miRNA/milRNA 在苹果和 Valsa mali 组织特异性相互作用中的适应性调节

在植物-病原体相互作用中，病原体表现出组织特异性，在特定组织中感染并引起疾病。然而，微小RNA/微小RNA样RNA（miRNA/milRNA）在植物-病原体相互作用过程中参与组织特异性调节的作用在很大程度上仍未被探索。本研究调查了 Valsa mali (Vm) 与不同苹果组织之间相互作用中 miRNA/milRNA 及其相应靶基因的差异表达。结果表明，当Vm感染树皮和叶子时，苹果miRNA和Vm milRNA都表现出不同的表达谱，并具有功能多样的相应靶基因。此外，一种苹果 miRNA (Mdo-miR482a) 和一种 Vm milRNA (Vm-milR57) 被鉴定为在 Vm 与苹果树皮或叶子之间的相互作用中表现出组织特异性表达。 Mdo-miR482a 专门针对树皮中的 Vm 感染而上调，并针对苹果的核苷酸结合富含亮氨酸重复序列 (NLR) 基因。当Mdo-miR482a短暂过表达或沉默时，耐药性显着降低或改善。同样，NLR基因的瞬时表达也显示出耐药性的增加。 Vm-milR57可以靶向Vm的两个必需致病性相关基因。 Vm感染树皮时，Vm-milR57的表达下调，从而增强相应靶基因的表达，从而提高致病性。该研究首次揭示了Vm与不同苹果组织相互作用中苹果miRNA和Vm milRNA的组织特异性特征，为植物与真菌之间组织特异性相互作用的适应性调节提供了新的见解。