Title : Unveiling the Role of Exosome-Like Nanoparticle (ELN) miRNAs in plant-pathogen interaction using the tomato–fusarium pathosystem
Abstract:
Tomato is one of the most widely cultivated vegetable crops around the world. However, their yield is often poor due to their vulnerability to various phytopathogens. One of the most destructive diseases affecting tomatoes is Fusarium wilt caused by Fusarium oxysporum f. sp. lycopersici (FOL). Our research is focused on the role of secreted extracellular vesicles or Exosome-like nanoparticles (ELNs) in plant-pathogen interaction. The ELNs contain various biomolecules and facilitate cell-to-cell communication by transferring them between cells. The pathosystem of tomato and Fusarium was confirmed through microscopy.
The infected seedlings were used to isolate ELNs using a differential centrifugation procedure and characterized using standard procedures. Our studies proved that ELNs from infected tomato seedlings significantly inhibited the spore germination of F. oxysporum under in vitro conditions. Sequencing of ELN microRNAs (miRNAs) isolated from 20 days post-infected seedlings revealed 27 differentially expressed miRNAs, among them, five were novel. The miRNAs, miR482b, miR5300, miR171a, miR156E-3p, and miR394a were expressed on the fifth day, while miR396b was expressed on the tenth day, miR166C-3p and miR9470 on the fifteenth day, and miR6023a on the twentieth day.
The investigation on the expression of miRNA target genes at various post-infection time points indicated a differential expression pattern matching with the abundance of target miRNAs at the specific time points (5, 10, 15, and 20 days). This study suggested that the transcript levels of defense genes are downregulated after the fifth day, likely due to the upregulation of miRNAs that target these transcripts. These new findings demonstrate, that ELNs carry and distribute miRNAs that target defence genes in infected plants, thereby negatively impacting plant's defence mechanisms.
