Small RNAs in Plant Immunity and Virulence of Filamentous Pathogens

2021 ◽  
Vol 59 (1) ◽  
Author(s):  
Yongli Qiao ◽  
Rui Xia ◽  
Jixian Zhai ◽  
Yingnan Hou ◽  
Li Feng ◽  
...  

Gene silencing guided by small RNAs governs a broad range of cellular processes in eukaryotes. Small RNAs are important components of plant immunity because they contribute to pathogen-triggered transcription reprogramming and directly target pathogen RNAs. Recent research suggests that silencing of pathogen genes by plant small RNAs occurs not only during viral infection but also in nonviral pathogens through a process termed host-induced gene silencing, which involves trans-species small RNA trafficking. Similarly, small RNAs are also produced by eukaryotic pathogens and regulate virulence. This review summarizes the small RNA pathways in both plants and filamentous pathogens, including fungi and oomycetes, and discusses their role in host–pathogen interactions. We highlight secondary small interfering RNAs of plants as regulators of immune receptor gene expression and executors of host-induced gene silencing in invading pathogens. The current status and prospects of small RNAs trafficking at the host–pathogen interface are discussed. Expected final online publication date for the Annual Review of Phytopathology, Volume 59 is August 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Xiaoyu Yang ◽  
Chenjiang You ◽  
Xufeng Wang ◽  
Lei Gao ◽  
Beixin Mo ◽  
...  

Abstract Background Small RNAs (sRNAs) including microRNAs (miRNAs) and small interfering RNAs (siRNAs) serve as core players in gene silencing at transcriptional and post-transcriptional levels in plants, but their subcellular localization has not yet been well studied, thus limiting our mechanistic understanding of sRNA action. Results We investigate the cytoplasmic partitioning of sRNAs and their targets globally in maize (Zea mays, inbred line “B73”) and rice (Oryza sativa, cv. “Nipponbare”) by high-throughput sequencing of polysome-associated sRNAs and 3′ cleavage fragments, and find that both miRNAs and a subset of 21-nucleotide (nt)/22-nt siRNAs are enriched on membrane-bound polysomes (MBPs) relative to total polysomes (TPs) across different tissues. Most of the siRNAs are generated from transposable elements (TEs), and retrotransposons positively contributed to MBP overaccumulation of 22-nt TE-derived siRNAs (TE-siRNAs) as opposed to DNA transposons. Widespread occurrence of miRNA-mediated target cleavage is observed on MBPs, and a large proportion of these cleavage events are MBP-unique. Reproductive 21PHAS (21-nt phasiRNA-generating) and 24PHAS (24-nt phasiRNA-generating) precursors, which were commonly considered as noncoding RNAs, are bound by polysomes, and high-frequency cleavage of 21PHAS precursors by miR2118 and 24PHAS precursors by miR2275 is further detected on MBPs. Reproductive 21-nt phasiRNAs are enriched on MBPs as opposed to TPs, whereas 24-nt phasiRNAs are nearly completely devoid of polysome occupancy. Conclusions MBP overaccumulation is a conserved pattern for cytoplasmic partitioning of sRNAs, and endoplasmic reticulum (ER)-bound ribosomes function as an independent regulatory layer for miRNA-induced gene silencing and reproductive phasiRNA biosynthesis in maize and rice.


Author(s):  
Antonio Cuadrado

Neurodegenerative diseases are characterized by the loss of homeostatic functions that control redox and energy metabolism, neuroinflammation, and proteostasis. The transcription factor nuclear factor erythroid 2–related factor 2 (NRF2) is a master controller of these functions, and its overall activity is compromised during aging and in these diseases. However, NRF2 can be activated pharmacologically and is now being considered a common therapeutic target. Many gaps still exist in our knowledge of the specific role that NRF2 plays in specialized brain cell functions or how these cells respond to the hallmarks of these diseases. This review discusses the relevance of NRF2 to several hallmark features of neurodegenerative diseases and the current status of pharmacological activators that might pass through the blood-brain barrier and provide a disease-modifying effect. Expected final online publication date for the Annual Review of Pharmacology and Toxicology, Volume 62 is January 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.


Science ◽  
2015 ◽  
Vol 348 (6230) ◽  
pp. 120-123 ◽  
Author(s):  
Xinyan Zhang ◽  
Ying Zhu ◽  
Xiaodan Liu ◽  
Xinyu Hong ◽  
Yang Xu ◽  
...  

Plant immunity against foreign gene invasion takes advantage of posttranscriptional gene silencing (PTGS). How plants elaborately avert inappropriate PTGS of endogenous coding genes remains unclear. We demonstrate in Arabidopsis that both 5′-3′ and 3′-5′ cytoplasmic RNA decay pathways act as repressors of transgene and endogenous PTGS. Disruption of bidirectional cytoplasmic RNA decay leads to pleiotropic developmental defects and drastic transcriptomic alterations, which are substantially rescued by PTGS mutants. Upon dysfunction of bidirectional RNA decay, a large number of 21- to 22-nucleotide endogenous small interfering RNAs are produced from coding transcripts, including multiple microRNA targets, which could interfere with their cognate gene expression and functions. This study highlights the risk of unwanted PTGS and identifies cytoplasmic RNA decay pathways as safeguards of plant transcriptome and development.


2021 ◽  
Author(s):  
Ganna Reshetnyak ◽  
Jonathan M. Jacobs ◽  
Florence Auguy ◽  
Coline Sciallano ◽  
Lisa Claude ◽  
...  

ABSTRACTNon-coding small RNAs (sRNA) act as mediators of gene silencing and regulate plant growth, development and stress responses. Early insights into plant sRNAs established a role in antiviral defense and they are now extensively studied across plant-microbe interactions. Here, sRNA sequencing discovered a class of sRNA in rice (Oryza sativa) specifically associated with foliar diseases caused by Xanthomonas oryzae bacteria. Xanthomonas-induced small RNAs (xisRNAs) loci were distinctively upregulated in response to diverse virulent strains at an early stage of infection producing a single duplex of 20-22nt sRNAs. xisRNAs production was dependent on the Type III secretion system, a major bacterial virulence factor for host colonization. xisRNA loci overlap with annotated transcripts sequences often encoding protein kinase domain proteins. A number of the corresponding rice cis-genes have documented functions in immune signaling and some xisRNA loci coincide with the coding sequence of a conserved kinase motif. xisRNAs exhibit features of small interfering RNAs and their biosynthesis depend on canonical components OsDCL1 and OsHEN1. xisRNA induction possibly mediates post-transcriptional gene silencing but they do not broadly suppress cis-genes expression on the basis of mRNA-seq data. Overall, our results identify a group of unusual sRNAs with a potential role in plant-microbe interactions.


2021 ◽  
Vol 72 (1) ◽  
Author(s):  
Zane Duxbury ◽  
Chih-hang Wu ◽  
Pingtao Ding

Nucleotide-binding domain leucine-rich repeat receptors (NLRs) play important roles in the innate immune systems of both plants and animals. Recent breakthroughs in NLR biochemistry and biophysics have revolutionized our understanding of how NLR proteins function in plant immunity. In this review, we summarize the latest findings in plant NLR biology and draw direct comparisons to NLRs of animals. We discuss different mechanisms by which NLRs recognize their ligands in plants and animals. The discovery of plant NLR resistosomes that assemble in a comparable way to animal inflammasomes reinforces the striking similarities between the formation of plant and animal NLR complexes. Furthermore, we discuss the mechanisms by which plant NLRs mediate immune responses and draw comparisons to similar mechanisms identified in animals. Finally, we summarize the current knowledge of the complex genetic architecture formed by NLRs in plants and animals and the roles of NLRs beyond pathogen detection. Expected final online publication date for the Annual Review of Plant Biology, Volume 72 is May 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.


Author(s):  
Seung-Oh Seo ◽  
Yong-Su Jin

A growing human population is a significant issue in food security owing to the limited land and resources available for agricultural food production. To solve these problems, sustainable food manufacturing processes and the development of alternative foods and ingredients are needed. Metabolic engineering and synthetic biology can help solve the food security issue and satisfy the demand for alternative food production. Bioproduction of food ingredients by microbial fermentation is a promising method to replace current manufacturing processes, such as extraction from natural materials and chemical synthesis, with more ecofriendly and sustainable operations. This review highlights successful examples of bioproduction for food additives by engineered microorganisms, with an emphasis on colorants and flavors that are extensively used in the food industry. Recent strain engineering developments and fermentation strategies for producing selected food colorants and flavors are introduced with discussions on the current status and future perspectives. Expected final online publication date for the Annual Review of Food Science and Technology, Volume 13 is March 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.


2019 ◽  
Vol 20 (11) ◽  
pp. 2816 ◽  
Author(s):  
Chen Zhu ◽  
Ting Liu ◽  
Ya-Nan Chang ◽  
Cheng-Guo Duan

Small RNAs represent a class of small but powerful agents that regulate development and abiotic and biotic stress responses during plant adaptation to a constantly challenging environment. Previous findings have revealed the important roles of small RNAs in diverse cellular processes. The recent discovery of bidirectional trafficking of small RNAs between different kingdoms has raised many interesting questions. The subsequent demonstration of exosome-mediated small RNA export provided a possible tool for further investigating how plants use small RNAs as a weapon during the arms race between plant hosts and pathogens. This review will focus on discussing the roles of small RNAs in plant immunity in terms of three aspects: the biogenesis of extracellular small RNAs and the transportation and trafficking small RNA-mediated gene silencing in pathogens.


Parasitology ◽  
2019 ◽  
Vol 147 (8) ◽  
pp. 855-864
Author(s):  
Collette Britton ◽  
Roz Laing ◽  
Eileen Devaney

AbstractSmall RNAs are important regulators of gene expression. They were first identified in Caenorhabditis elegans, but it is now apparent that the main small RNA silencing pathways are functionally conserved across diverse organisms. Availability of genome data for an increasing number of parasitic nematodes has enabled bioinformatic identification of small RNA sequences. Expression of these in different lifecycle stages is revealed by small RNA sequencing and microarray analysis. In this review we describe what is known of the three main small RNA classes in parasitic nematodes – microRNAs (miRNAs), Piwi-interacting RNAs (piRNAs) and small interfering RNAs (siRNAs) – and their proposed functions. miRNAs regulate development in C. elegans and the temporal expression of parasitic nematode miRNAs suggest modulation of target gene levels as parasites develop within the host. miRNAs are also present in extracellular vesicles released by nematodes in vitro, and in plasma from infected hosts, suggesting potential regulation of host gene expression. Roles of piRNAs and siRNAs in suppressing target genes, including transposable elements, are also reviewed. Recent successes in RNAi-mediated gene silencing, and application of small RNA inhibitors and mimics will continue to advance understanding of small RNA functions within the parasite and at the host–parasite interface.


Reproduction ◽  
2009 ◽  
Vol 137 (6) ◽  
pp. 901-911 ◽  
Author(s):  
Zuping He ◽  
Maria Kokkinaki ◽  
Disha Pant ◽  
G Ian Gallicano ◽  
Martin Dym

Small RNA molecules (small RNAs), including small interfering RNAs (siRNAs), microRNAs (miRNAs), and piwi-interacting RNAs (piRNAs), have recently emerged as important regulators of gene expression at the post-transcriptional or translation level. Significant progress has recently been made utilizing small RNAs in elucidating the molecular mechanisms regulating spermatogenesis. Spermatogenesis is a complex process that involves the division and eventual differentiation of spermatogonial stem cells into mature spermatozoa. The process of spermatogenesis is composed of several phases: mitotic proliferation of spermatogonia to produce spermatocytes; two meiotic divisions of spermatocytes to generate haploid round spermatids; and spermiogenesis, the final phase that involves the maturation of early-round spermatids into elongated mature spermatids. A number of miRNAs are expressed abundantly in male germ cells throughout spermatogenesis, while piRNAs are only present in pachytene spermatocytes and round spermatids. In this review, we first address the synthesis, mechanisms of action, and functions of siRNA, miRNA, and piRNA, and then we focus on the recent advancements in defining the small RNAs in the regulation of spermatogenesis. Concerns pertaining to the use of siRNAs in exploring spermatogenesis mechanisms and open questions in miRNAs and piRNAs in this field are highlighted. The potential applications of small RNAs to male contraception and treatment for male infertility and testicular cancer are also discussed.


2021 ◽  
Vol 42 (1) ◽  
Author(s):  
Roger D. Peng ◽  
Stephanie C. Hicks

Advances in computing technology have spurred two extraordinary phenomena in science: large-scale and high-throughput data collection coupled with the creation and implementation of complex statistical algorithms for data analysis. These two phenomena have brought about tremendous advances in scientific discovery but have raised two serious concerns. The complexity of modern data analyses raises questions about the reproducibility of the analyses, meaning the ability of independent analysts to recreate the results claimed by the original authors using the original data and analysis techniques. Reproducibility is typically thwarted by a lack of availability of the original data and computer code. A more general concern is the replicability of scientific findings, which concerns the frequency with which scientific claims are confirmed by completely independent investigations. Although reproducibility and replicability are related, they focus on different aspects of scientific progress. In this review, we discuss the origins of reproducible research, characterize the current status of reproducibility in public health research, and connect reproducibility to current concerns about replicability of scientific findings. Finally, we describe a path forward for improving both the reproducibility and replicability of public health research in the future. Expected final online publication date for the Annual Review of Public Health, Volume 42 is April 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.


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