A novel cotton miR7814 targeting GhCNL2 regulates plant defense against Verticillium dahliae infection
1Zhengzhou Research Base, National Key Laboratory of Cotton Bio-breeding and Integrated Utilization, School of Agricultural Sciences, Zhengzhou University, Zhengzhou, China; The State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.
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Summary
A novel microRNA, ghr-miR7814, targets the GhCNL2 gene to regulate plant immunity against Verticillium dahliae. Suppressing ghr-miR7814 enhances disease resistance, possibly through reactive oxygen species and salicylic acid pathways.
Area of Science:
- Plant Molecular Biology
- Plant-Pathogen Interactions
- Gene Regulation
Background:
- MicroRNAs (miRNAs) post-transcriptionally regulate plant resistance (R) genes, including those encoding NBS-LRR proteins.
- The specific resistance mechanisms of miRNA-targeted R gene pairs are not fully understood.
- Understanding these interactions is crucial for developing disease-resistant crops.
Purpose of the Study:
- To investigate the function of a novel miRNA, ghr-miR7814, in regulating plant resistance against Verticillium dahliae infection.
- To elucidate the targeting mechanism of ghr-miR7814 on the GhCNL2 gene.
- To explore the molecular pathways involved in ghr-miR7814-mediated plant defense.
Main Methods:
- GUS reporter assays and 5'-RLM RACE to confirm miRNA-target interaction.
- Virus-induced gene silencing (VIGS) and overexpression assays to study gene function.
- Gene expression analysis of defense-related and biosynthesis genes (e.g., GhPR1, GhICS1).
- DAB staining to assess reactive oxygen species (ROS) levels.
Main Results:
- ghr-miR7814 directly targets and cleaves GhCNL2 mRNA post-transcriptionally.
- Knockdown of ghr-miR7814 enhanced plant resistance to V. dahliae, while overexpression reduced it.
- GhCNL2 knockdown reduced plant resistance and altered the expression of defense genes (GhPR1, GhPR3, GhPR5, GhPDF1.2).
- ROS and salicylic acid (SA) biosynthesis pathways were implicated, with altered H2O2 content and SA-related gene expression in GhCNL2 knockdown plants.
Conclusions:
- The novel ghr-miR7814 negatively regulates plant resistance to V. dahliae by targeting GhCNL2.
- This regulatory pathway likely involves the induction of ROS and SA biosynthesis.
- Findings provide insights into miRNA-mediated plant defense mechanisms against fungal pathogens.