scholarly journals Hybrid de novo genome-reassembly reveals new insights on pathways and pathogenicity determinants in rice blast pathogen Magnaporthe oryzae RMg_Dl

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Bhaskar Reddy ◽  
Aundy Kumar ◽  
Sahil Mehta ◽  
Neelam Sheoran ◽  
Viswanathan Chinnusamy ◽  
...  

AbstractBlast disease incited by Magnaporthe oryzae is a major threat to sustain rice production in all rice growing nations. The pathogen is widely distributed in all rice paddies and displays rapid aerial transmissions, and seed-borne latent infection. In order to understand the genetic variability, host specificity, and molecular basis of the pathogenicity-associated traits, the whole genome of rice infecting Magnaporthe oryzae (Strain RMg_Dl) was sequenced using the Illumina and PacBio (RSII compatible) platforms. The high-throughput hybrid assembly of short and long reads resulted in a total of 375 scaffolds with a genome size of 42.43 Mb. Furthermore, comparative genome analysis revealed 99% average nucleotide identity (ANI) with other oryzae genomes and 83% against M. grisea, and 73% against M. poe genomes. The gene calling identified 10,553 genes with 10,539 protein-coding sequences. Among the detected transposable elements, the LTR/Gypsy and Type LINE showed high occurrence. The InterProScan of predicted protein sequences revealed that 97% protein family (PFAM), 98% superfamily, and 95% CDD were shared among RMg_Dl and reference 70-15 genome, respectively. Additionally, 550 CAZymes with high GH family content/distribution and cell wall degrading enzymes (CWDE) such endoglucanase, beta-glucosidase, and pectate lyase were also deciphered in RMg_Dl. The prevalence of virulence factors determination revealed that 51 different VFs were found in the genome. The biochemical pathway such as starch and sucrose metabolism, mTOR signaling, cAMP signaling, MAPK signaling pathways related genes were identified in the genome. The 49,065 SNPs, 3267 insertions and 3611 deletions were detected, and majority of these varinats were located on downstream and upstream region. Taken together, the generated information will be useful to develop a specific marker for diagnosis, pathogen surveillance and tracking, molecular taxonomy, and species delineation which ultimately leads to device improved management strategies for blast disease.

2020 ◽  
Author(s):  
Sarmina Dangol ◽  
Raksha Singh ◽  
Khoa Nam Nguyen ◽  
Yafei Chen ◽  
Juan Wang ◽  
...  

ABSTRACTMitogen-activated protein kinase (MAPK) signaling is required for plant cell death responses to invading microbial pathogens. Ferric ions and reactive oxygen species (ROS) accumulate in rice (Oryza sativa) tissues undergoing cell death during Magnaporthe oryzae infection. Here, we report that rice MAP kinase (OsMEK2 and OsMPK1) signaling cascades are involved in iron- and ROS-dependent ferroptotic cell death responses of rice to M. oryzae infection. OsMEK2 interacted with OsMPK1 in the cytoplasm, and OsMPK1 moved from the cytoplasm into the nucleus to bind to the OsWRKY90 transcription factor. OsMEK2 expression may trigger OsMPK1-OsWRKY90 signaling pathways in the nucleus. Avirulent M. oryzae infection in ΔOsmek2 mutant rice did not trigger iron and ROS accumulation and lipid peroxidation, and also downregulated OsMPK1, OsWRKY90, OsRbohB, and OsPR-1b expression. However, OsMEK2 overexpression induced ROS-and iron-dependent cell death in rice during M. oryzae infection. The downstream MAP kinase (OsMPK1) overexpression induced ROS- and iron-dependent ferroptotic cell death in the compatible rice-M. oryzae interaction. These data suggest that the OsMEK2-OsMPK1-OsWRKY90 signaling cascade is involved in the ferroptotic cell death in rice. The small-molecule inducer erastin triggered iron- and lipid ROS-dependent, but OsMEK2-independent, ferroptotic cell death in ΔOsmek2 mutant plants during M. oryzae infection. Disease-related cell death was lipid ROS-dependent and iron-independent in the ΔOsmek2 mutant plants. These combined results suggest that OsMEK2 and OsMPK1 expression positively regulates iron- and ROS-dependent ferroptotic cell death via OsMEK2-OsMPK1-OsWRKY90 signaling pathways, and blast disease (susceptibility)-related cell death was ROS-dependent but iron-independent in rice-M. oryzae interactions.


2021 ◽  
Vol 43 (3) ◽  
pp. 2177-2188
Author(s):  
Hakjoon Choi ◽  
Wan Seok Kang ◽  
Jin Seok Kim ◽  
Chang-Su Na ◽  
Sunoh Kim

Scutellaria L. (family Lamiaceae) includes approximately 470 species found in most parts of the world and is commonly known as skullcaps. Scutellaria L. is a medicinal herb used as a folk remedy in Korea and East Asia, but it is difficult to identify and classify various subspecies by morphological methods. Since Scutellaria L. has not been studied genetically, to expand the knowledge of species in the genus Scutellaria L., de novo whole-genome assembly was performed in Scutellaria indica var. tsusimensis (H. Hara) Ohwi using the Illumina sequencing platform. We aimed to develop a molecular method that could be used to classify S.indica var. tsusimensis (H. Hara) Ohwi, S. indica L. and three other Scutellaria L. species. The assembly results for S.indica var. tsusimensis (H. Hara) Ohwi revealed a genome size of 318,741,328 bp and a scaffold N50 of 78,430. The assembly contained 92.08% of the conserved BUSCO core gene set and was estimated to cover 94.65% of the genome. The obtained genes were compared with previously registered Scutellaria nucleotide sequences and similar regions using the NCBI BLAST service, and a total of 279 similar nucleotide sequences were detected. By selecting the 279 similar nucleotide sequences and nine chloroplast DNA barcode genes, primers were prepared so that the size of the PCR product was 100 to 1000 bp. As a result, a species-specific primer set capable of distinguishing five species of Scutellaria L. was developed.


2016 ◽  
Vol 106 (11) ◽  
pp. 1359-1365 ◽  
Author(s):  
Emmanuel M. Mgonja ◽  
Elias G. Balimponya ◽  
Houxiang Kang ◽  
Maria Bellizzi ◽  
Chan Ho Park ◽  
...  

Rice blast disease is emerging as a major constraint to rice production in Africa. Although a traditional gene-tagging strategy using biparental crosses can effectively identify resistance (R) genes or quantitative trait loci (QTL) against Magnaporthe oryzae, the mapping procedure required is time consuming and requires many populations to investigate the genetics of resistance. In this report, we conducted a genome-wide association study (GWAS) to rapidly map rice genes conferring resistance against eight M. oryzae isolates from four African countries. We inoculated 162 rice cultivars, which were part of the rice diversity panel 1 (RDP1) and were previously genotyped with the 44,000 single-nucleotide polymorphism (SNP) chip, with the eight isolates. The GWAS identified 31 genomic regions associated with blast resistance (RABR) in the rice genome. In addition, we used polymerase chain reaction analysis to confirm the association between the Pish gene and a major RABR on chromosome 1 that was associated with resistance to four M. oryzae isolates. Our study has demonstrated the power of GWAS for the rapid identification of rice blast R or QTL genes that are effective against African populations of M. oryzae. The identified SNP markers associated with RABR can be used in breeding for resistance against rice blast in Africa.


2020 ◽  
Vol 15 ◽  
Author(s):  
Dicle Yalcin ◽  
Hasan H. Otu

Background: Epigenetic repression mechanisms play an important role in gene regulation, specifically in cancer development. In many cases, a CpG island’s (CGI) susceptibility or resistance to methylation are shown to be contributed by local DNA sequence features. Objective: To develop unbiased machine learning models–individually and combined for different biological features–that predict the methylation propensity of a CGI. Methods: We developed our model consisting of CGI sequence features on a dataset of 75 sequences (28 prone, 47 resistant) representing a genome-wide methylation structure. We tested our model on two independent datasets that are chromosome (132 sequences) and disease (70 sequences) specific. Results: We provided improvements in prediction accuracy over previous models. Our results indicate that combined features better predict the methylation propensity of a CGI (area under the curve (AUC) ~0.81). Our global methylation classifier performs well on independent datasets reaching an AUC of ~0.82 for the complete model and an AUC of ~0.88 for the model using select sequences that better represent their classes in the training set. We report certain de novo motifs and transcription factor binding site (TFBS) motifs that are consistently better in separating prone and resistant CGIs. Conclusion: Predictive models for the methylation propensity of CGIs lead to a better understanding of disease mechanisms and can be used to classify genes based on their tendency to contain methylation prone CGIs, which may lead to preventative treatment strategies. MATLAB and Python™ scripts used for model building, prediction, and downstream analyses are available at https://github.com/dicleyalcin/methylProp_predictor.


Genes ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 246
Author(s):  
Xiaomeng Chen ◽  
Rui Li ◽  
Yonglin Wang ◽  
Aining Li

An emerging poplar canker caused by the gram-negative bacterium, Lonsdalea populi, has led to high mortality of hybrid poplars Populus × euramericana in China and Europe. The molecular bases of pathogenicity and bark adaptation of L. populi have become a focus of recent research. This study revealed the whole genome sequence and identified putative virulence factors of L. populi. A high-quality L. populi genome sequence was assembled de novo, with a genome size of 3,859,707 bp, containing approximately 3434 genes and 107 RNAs (75 tRNA, 22 rRNA, and 10 ncRNA). The L. populi genome contained 380 virulence-associated genes, mainly encoding for adhesion, extracellular enzymes, secretory systems, and two-component transduction systems. The genome had 110 carbohydrate-active enzyme (CAZy)-coding genes and putative secreted proteins. The antibiotic-resistance database annotation listed that L. populi was resistant to penicillin, fluoroquinolone, and kasugamycin. Analysis of comparative genomics found that L. populi exhibited the highest homology with the L. britannica genome and L. populi encompassed 1905 specific genes, 1769 dispensable genes, and 1381 conserved genes, suggesting high evolutionary diversity and genomic plasticity. Moreover, the pan genome analysis revealed that the N-5-1 genome is an open genome. These findings provide important resources for understanding the molecular basis of the pathogenicity and biology of L. populi and the poplar-bacterium interaction.


2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Huihui Li ◽  
Mingzhe Xie ◽  
Yan Wang ◽  
Ludong Yang ◽  
Zhi Xie ◽  
...  

AbstractriboCIRC is a translatome data-oriented circRNA database specifically designed for hosting, exploring, analyzing, and visualizing translatable circRNAs from multi-species. The database provides a comprehensive repository of computationally predicted ribosome-associated circRNAs; a manually curated collection of experimentally verified translated circRNAs; an evaluation of cross-species conservation of translatable circRNAs; a systematic de novo annotation of putative circRNA-encoded peptides, including sequence, structure, and function; and a genome browser to visualize the context-specific occupant footprints of circRNAs. It represents a valuable resource for the circRNA research community and is publicly available at http://www.ribocirc.com.


Foods ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1649
Author(s):  
Hyang-Lan Eum ◽  
Seung-Hyun Han ◽  
Eun-Jin Lee

Improved methods are needed to extend the shelf life of strawberry fruits. The objective of this study was to determine the postharvest physiological mechanism of high-CO2 treatment in strawberries. Harvested strawberries were stored at 10 °C after 3 h of exposure to a treatment with 30% CO2 or air. Pectin and gene expression levels related to cell wall degradation were measured to assess the high-CO2 effects on the cell wall and lipid metabolism. Strawberries subjected to high-CO2 treatment presented higher pectin content and firmness and lower decay than those of control fruits. Genes encoding cell wall-degrading enzymes (pectin methylesterase, polygalacturonase, and pectate lyase) were downregulated after high-CO2 treatment. High-CO2 induced the expression of oligogalacturonides, thereby conferring defense against Botrytis cinerea in strawberry fruits, and lowering the decay incidence at seven days after its inoculation. Our findings suggest that high-CO2 treatment can maintain strawberry quality by reducing decay and cell wall degradation.


2020 ◽  
Vol 12 (6) ◽  
pp. 905-910 ◽  
Author(s):  
Ruoyu Liu ◽  
Kun Wang ◽  
Jun Liu ◽  
Wenjie Xu ◽  
Yang Zhou ◽  
...  

Abstract Cold seeps, characterized by the methane, hydrogen sulfide, and other hydrocarbon chemicals, foster one of the most widespread chemosynthetic ecosystems in deep sea that are densely populated by specialized benthos. However, scarce genomic resources severely limit our knowledge about the origin and adaptation of life in this unique ecosystem. Here, we present a genome of a deep-sea limpet Bathyacmaea lactea, a common species associated with the dominant mussel beds in cold seeps. We yielded 54.6 gigabases (Gb) of Nanopore reads and 77.9-Gb BGI-seq raw reads, respectively. Assembly harvested a 754.3-Mb genome for B. lactea, with 3,720 contigs and a contig N50 of 1.57 Mb, covering 94.3% of metazoan Benchmarking Universal Single-Copy Orthologs. In total, 23,574 protein-coding genes and 463.4 Mb of repetitive elements were identified. We analyzed the phylogenetic position, substitution rate, demographic history, and TE activity of B. lactea. We also identified 80 expanded gene families and 87 rapidly evolving Gene Ontology categories in the B. lactea genome. Many of these genes were associated with heterocyclic compound metabolism, membrane-bounded organelle, metal ion binding, and nitrogen and phosphorus metabolism. The high-quality assembly and in-depth characterization suggest the B. lactea genome will serve as an essential resource for understanding the origin and adaptation of life in the cold seeps.


BMC Genetics ◽  
2014 ◽  
Vol 15 (1) ◽  
pp. 24 ◽  
Author(s):  
Samuel G Younkin ◽  
Robert B Scharpf ◽  
Holger Schwender ◽  
Margaret M Parker ◽  
Alan F Scott ◽  
...  

Author(s):  
Shahid Khan ◽  
Neeta Raj Sharma

Objective: In vitro analysis of Allium sativum and Allium ampeloprasum was performed to evaluate their antifungal potential against Alternaria triticina (ITCC 5496), causative agent of leaf blight in wheat and Magnaporthe oryzae (ITCC 6808), causative agent of blast disease in rice.Methods: Ethanol extracts of A. ampeloprasum and A. sativum were prepared by crushing their bulb in liquid nitrogen and then immersing them in 90% ethanol and 100% ethanol separately. The antifungal activity test was determined by quantitative assay using 96-well microtiter plate and results were statistically analyzed using GraphPad Prism v. 5.03.Results: A. triticina and M. oryzae showed above 90% and 95% growth inhibition, respectively against the ethanol extracts of A. ampeloprasum. Conversely, growth inhibition of either fungus remained mostly below 35% against ethanol extracts of A. sativum at all tested concentrations.Conclusion: Ethanol extracts of A. ampeloprasum have relatively higher antifungal potential than ethanol extracts of A. sativum and could be considered as a natural alternative to chemical fungicides.Keywords: Allium sativum, Allium ampeloprasum, Alternaria triticina, Magnaporthe oryzae.


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