Trans-species microRNA loci in the parasitic plant Cuscuta campestris have a U6-like snRNA promoter

Trans-Species Mobility of RNA Interference between Plants and Associated Organisms

Trans-species RNA interference (RNAi) occurs naturally when small RNAs (sRNAs) silence genes in species different from their origin. This phenomenon has been observed between plants and various organisms including fungi, animals and other plant species. Understanding the mechanisms used in natural cases of trans-species RNAi, such as sRNA processing and movement, will enable more effective development of crop protection methods using host-induced gene silencing (HIGS). Recent progress has been made in understanding the mechanisms of cell-to-cell and long-distance movement of sRNAs within individual plants. This increased understanding of endogenous plant sRNA movement may be translatable to trans-species sRNA movement. Here, we review diverse cases of natural trans-species RNAi focusing on current theories regarding intercellular and long-distance sRNA movement. We also touch on trans-species sRNA evolution, highlighting its research potential and its role in improving the efficacy of HIGS.

The role of small RNAs in resistant melon cultivar against Phelipanche aegyptiaca parasitization

Bidirectional trans-kingdom RNA silencing, a pivotal factor in plant-pathogen interactions, remains less explored in plant host-parasite dynamics. Here, using small RNA sequencing in melon root systems, we investigated microRNA (miRNA) expression variation in resistant and susceptible cultivars pre-and post-infection by the parasitic plant, broomrape. This approach revealed 979 known miRNAs and 110 novel miRNAs across 110 families. When comparing susceptible (F0) and resistant (R0) melon lines with broomrape infection (F25 and R25), 39 significantly differentially expressed miRNAs were observed in F25 vs. F0, 35 in R25 vs. R0, and 5 in R25 vs. F25. Notably, two miRNAs consistently exhibited differential expression across all comparisons, targeting genes linked to plant disease resistance. This suggests their pivotal role in melon's defense against broomrape. The target genes of these miRNAs were confirmed via degradome sequencing and validated by qRT-PCR, ensuring reliable sequencing outcomes. GO and KEGG analyses shed light on the molecular functions and pathways of these differential miRNAs. Furthermore, our study unveiled four trans-kingdom miRNAs, forming a foundation for exploring melon's resistance to broomrape.

microRNAs: Key Regulators in Plant Responses to Abiotic and Biotic Stresses via Endogenous and Cross-Kingdom Mechanisms

Dramatic shifts in global climate have intensified abiotic and biotic stress faced by plants. Plant microRNAs (miRNAs)-20-24 nucleotide non-coding RNA molecules-form a key regulatory system of plant gene expression; playing crucial roles in plant growth; development; and defense against abiotic and biotic stress. Moreover, they participate in cross-kingdom communication. This communication encompasses interactions with other plants, microorganisms, and insect species, collectively exerting a profound influence on the agronomic traits of crops. This article comprehensively reviews the biosynthesis of plant miRNAs and explores their impact on plant growth, development, and stress resistance through endogenous, non-transboundary mechanisms. Furthermore, this review delves into the cross-kingdom regulatory effects of plant miRNAs on plants, microorganisms, and pests. It proceeds to specifically discuss the design and modification strategies for artificial miRNAs (amiRNAs), as well as the protection and transport of miRNAs by exosome-like nanovesicles (ELNVs), expanding the potential applications of plant miRNAs in crop breeding. Finally, the current limitations associated with harnessing plant miRNAs are addressed, and the utilization of synthetic biology is proposed to facilitate the heterologous expression and large-scale production of miRNAs. This novel approach suggests a plant-based solution to address future biosafety concerns in agriculture.

The Non-Coding RNA Journal Club: Highlights on Recent Papers-13

We are delighted to share with you our thirteenth Journal Club and highlight some of the most interesting papers published recently [...].