Genome-wide identification of Sclerotinia sclerotiorum small RNAs and their endogenous targets

Abstract Background Several phytopathogens produce small non-coding RNAs of approximately 18–30 nucleotides (nt) which post-transcriptionally regulate gene expression. Commonly called small RNAs (sRNAs), these small molecules were also reported to be present in the necrotrophic pathogen Sclerotinia...

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Main Authors: Roshan Regmi, Toby E. Newman, Yuphin Khentry, Lars G. Kamphuis, Mark C. Derbyshire
Format: Article
Language:English
Published: BMC 2023-10-01
Series:BMC Genomics
Subjects:
Online Access:https://doi.org/10.1186/s12864-023-09686-7
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author Roshan Regmi
Toby E. Newman
Yuphin Khentry
Lars G. Kamphuis
Mark C. Derbyshire
author_facet Roshan Regmi
Toby E. Newman
Yuphin Khentry
Lars G. Kamphuis
Mark C. Derbyshire
author_sort Roshan Regmi
collection DOAJ
description Abstract Background Several phytopathogens produce small non-coding RNAs of approximately 18–30 nucleotides (nt) which post-transcriptionally regulate gene expression. Commonly called small RNAs (sRNAs), these small molecules were also reported to be present in the necrotrophic pathogen Sclerotinia sclerotiorum. S. sclerotiorum causes diseases in more than 400 plant species, including the important oilseed crop Brassica napus. sRNAs can further be classified as microRNAs (miRNAs) and short interfering RNAs (siRNAs). Certain miRNAs can activate loci that produce further sRNAs; these secondary sRNA-producing loci are called ‘phased siRNA’ (PHAS) loci and have only been described in plants. To date, very few studies have characterized sRNAs and their endogenous targets in S. sclerotiorum. Results We used Illumina sequencing to characterize sRNAs from fungal mycelial mats of S. sclerotiorum spread over B. napus leaves. In total, eight sRNA libraries were prepared from in vitro, 12 h post-inoculation (HPI), and 24 HPI mycelial mat samples. Cluster analysis identified 354 abundant sRNA clusters with reads of more than 100 Reads Per Million (RPM). Differential expression analysis revealed upregulation of 34 and 57 loci at 12 and 24 HPI, respectively, in comparison to in vitro samples. Among these, 25 loci were commonly upregulated. Altogether, 343 endogenous targets were identified from the major RNAs of 25 loci. Almost 88% of these targets were annotated as repeat element genes, while the remaining targets were non-repeat element genes. Fungal degradome reads confirmed cleavage of two transposable elements by one upregulated sRNA. Altogether, 24 milRNA loci were predicted with both mature and milRNA* (star) sequences; these are both criteria associated previously with experimentally verified miRNAs. Degradome sequencing data confirmed the cleavage of 14 targets. These targets were related to repeat element genes, phosphate acetyltransferases, RNA-binding factor, and exchange factor. A PHAS gene prediction tool identified 26 possible phased interfering loci with 147 phasiRNAs from the S. sclerotiorum genome, suggesting this pathogen might produce sRNAs that function similarly to miRNAs in higher eukaryotes. Conclusions Our results provide new insights into sRNA populations and add a new resource for the study of sRNAs in S. sclerotiorum.
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spelling doaj.art-b68df58f880141e9b49eeea2f9d565542023-11-26T12:26:17ZengBMCBMC Genomics1471-21642023-10-0124111510.1186/s12864-023-09686-7Genome-wide identification of Sclerotinia sclerotiorum small RNAs and their endogenous targetsRoshan Regmi0Toby E. Newman1Yuphin Khentry2Lars G. Kamphuis3Mark C. Derbyshire4Centre for Crop and Disease Management, School of Molecular and Life Sciences, Curtin UniversityCentre for Crop and Disease Management, School of Molecular and Life Sciences, Curtin UniversityCentre for Crop and Disease Management, School of Molecular and Life Sciences, Curtin UniversityCentre for Crop and Disease Management, School of Molecular and Life Sciences, Curtin UniversityCentre for Crop and Disease Management, School of Molecular and Life Sciences, Curtin UniversityAbstract Background Several phytopathogens produce small non-coding RNAs of approximately 18–30 nucleotides (nt) which post-transcriptionally regulate gene expression. Commonly called small RNAs (sRNAs), these small molecules were also reported to be present in the necrotrophic pathogen Sclerotinia sclerotiorum. S. sclerotiorum causes diseases in more than 400 plant species, including the important oilseed crop Brassica napus. sRNAs can further be classified as microRNAs (miRNAs) and short interfering RNAs (siRNAs). Certain miRNAs can activate loci that produce further sRNAs; these secondary sRNA-producing loci are called ‘phased siRNA’ (PHAS) loci and have only been described in plants. To date, very few studies have characterized sRNAs and their endogenous targets in S. sclerotiorum. Results We used Illumina sequencing to characterize sRNAs from fungal mycelial mats of S. sclerotiorum spread over B. napus leaves. In total, eight sRNA libraries were prepared from in vitro, 12 h post-inoculation (HPI), and 24 HPI mycelial mat samples. Cluster analysis identified 354 abundant sRNA clusters with reads of more than 100 Reads Per Million (RPM). Differential expression analysis revealed upregulation of 34 and 57 loci at 12 and 24 HPI, respectively, in comparison to in vitro samples. Among these, 25 loci were commonly upregulated. Altogether, 343 endogenous targets were identified from the major RNAs of 25 loci. Almost 88% of these targets were annotated as repeat element genes, while the remaining targets were non-repeat element genes. Fungal degradome reads confirmed cleavage of two transposable elements by one upregulated sRNA. Altogether, 24 milRNA loci were predicted with both mature and milRNA* (star) sequences; these are both criteria associated previously with experimentally verified miRNAs. Degradome sequencing data confirmed the cleavage of 14 targets. These targets were related to repeat element genes, phosphate acetyltransferases, RNA-binding factor, and exchange factor. A PHAS gene prediction tool identified 26 possible phased interfering loci with 147 phasiRNAs from the S. sclerotiorum genome, suggesting this pathogen might produce sRNAs that function similarly to miRNAs in higher eukaryotes. Conclusions Our results provide new insights into sRNA populations and add a new resource for the study of sRNAs in S. sclerotiorum.https://doi.org/10.1186/s12864-023-09686-7Small RNAsmiRNAsGene regulationRepeat elements
spellingShingle Roshan Regmi
Toby E. Newman
Yuphin Khentry
Lars G. Kamphuis
Mark C. Derbyshire
Genome-wide identification of Sclerotinia sclerotiorum small RNAs and their endogenous targets
BMC Genomics
Small RNAs
miRNAs
Gene regulation
Repeat elements
title Genome-wide identification of Sclerotinia sclerotiorum small RNAs and their endogenous targets
title_full Genome-wide identification of Sclerotinia sclerotiorum small RNAs and their endogenous targets
title_fullStr Genome-wide identification of Sclerotinia sclerotiorum small RNAs and their endogenous targets
title_full_unstemmed Genome-wide identification of Sclerotinia sclerotiorum small RNAs and their endogenous targets
title_short Genome-wide identification of Sclerotinia sclerotiorum small RNAs and their endogenous targets
title_sort genome wide identification of sclerotinia sclerotiorum small rnas and their endogenous targets
topic Small RNAs
miRNAs
Gene regulation
Repeat elements
url https://doi.org/10.1186/s12864-023-09686-7
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