Biology subjects

Brugidou, C.

Publications and source records attributed to Brugidou, C..

4 recordsLinked to original sources

bioRxiv2023

Rice yellow mottle virus is a suitable amplicon vector an efficient production of an anti-leishmianiasis vaccine in Nicotiana benthamiana leaves.

The suitability of rice yellow mottle virus RYMV as a gene expression vector in plant was assessed using a construct carrying promastigote surface antigen (PSA) C-terminal coding sequence of the parasite protozoan Leishmania. RYMV ORF1 encoding P1 protein has been deleted from the RYMV native genome. The C-terminal PSA gene was substituted for the viral coat protein. PSA is present at the surface of the parasite and displays vaccine properties against canine and human leishmaniosis. RYMV-based vector allowed PSA expression in Nicotiana benthamiana. Q-pcr analysis showed that chimeric RYMV carrying PSA gene is able to replicate in N. benthamiana leaves. P19 silencing suppressor in combination with the lacked viral vector ORF encoding RYMV Coat Protein (CP) enhanced significantly RYMV tool replication in N. benthamiana. RYMV CP played a key role on viral RNA stabilization and acts as a weak silencing suppressor. The original RYMV-based expression vector allowed PSA protein expression enhancement in N. benthamiana without any symptoms. RYMV-based vector could be suitable for functional genomic studies in monocots by VIGS (Viral Induced Gene Silencing) technology.

bioengineering↗

bioRxiv2023

Dynamics of the rice yellow mottle disease in western Burkina Faso: epidemic monitoring, spatio-temporal variation of viral diversity and pathogenicity in a disease hotspot

The rice yellow mottle virus (RYMV) is a model in plant virus molecular epidemiology and phylogeography, with the reconstruction of historical introduction routes at the scale of the African continent. However, information on patterns of viral prevalence and viral diversity over multiple years at local scale remain scarce, in spite of potential implications for crop protection. Here we describe a five-years monitoring of RYMV prevalence in six sites from western Burkina Faso. This study confirmed one irrigated site as a disease hotspot, and found two rainfed lowland sites with occasional high prevalence levels. Within studied field, a pattern of disease aggregation was evidenced at a five-meter distance, as expected for a mechanically transmitted virus. Next, we monitored RYMV genetic diversity in the irrigated disease hotspot site, revealing a high viral diversity, with the current coexistence of various distinct genetic groups at the site-scale (irrigated perimeter of ca. 520 ha), and also within various specific fields (25 meters side). One genetic lineage, named S1bzn, is the most recently introduced group and increased in frequency over the studied period. Its genome results from a recombination between two other lineages. Finally, experimental work evidenced no differences between three rice varieties cultivated in Burkina Faso in terms of resistance level, and no statistical effect of RYMV genetic group on symptom expression and viral load. We found however, that infection outcome depended on the specific RYMV isolate, with various isolates from the lineage S1bzn found to be particularly aggressive, including one accumulating at highest level. Overall, this study documents a case of high viral prevalence and high viral diversity, with the co-occurrence of divergent genetic lineages at small geographic scale. A recently introduced lineage, that includes viral isolates with high symptoms and accumulation in controlled conditions, could be recently rising though natural selection. Following up the monitoring of RYMV genetic and pathogenic diversity in the area is required to confirm this trend and further understand the factors driving the maintenance of viral diversity at local scale.

evolutionary biology↗

bioRxiv2021

An atypical class of non-coding small RNAs produced in rice leaves upon bacterial infection

Non-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.

molecular biology↗

bioRxiv2020

An original structural fold underlies the multitask P1, a silencing suppressor encoded by the Rice yellow mottle virus

ABSTRACTThe Rice Yellow Mottle sobemovirus (RYMV) belongs to the most damaging pathogens devastating rice fields in Africa. P1, a key protein for RYMV, was reported as a potent RNAi suppressor counteracting RNA silencing in plant reporter systems. Here we describe the complete 3D structure and dynamics of P1. Its N-terminal region contains ZnF1, a structural CCCC-type zinc finger strongly affine to zinc and a prominent short helix, rendering this region poorly amenable to structural changes. P1 C-terminal region contains ZnF2, an atypical HCHC-type ZnF that does not belong to any existing class of Zn finger proteins. ZnF2 appeared much less affine to zinc and more sensitive to oxidizing environments than ZnF1, and may serve as a sensor of plant redox status. The structure helped us to identify key residues essential for RYMV infectivity and spread in rice tissues through their participation in P1 oligomerization and folding. Altogether, our results provide the first complete structure of an antiviral silencing suppressor encoded by a virus infecting rice and highlight P1 structural and dynamical properties that may serve RYMV functions to infect and invade its host plant.Competing Interest StatementThe authors have declared no competing interest.View Full Text

pathology↗