Biology subjects

Norvienyeku, J.

Publications and source records attributed to Norvienyeku, J..

5 recordsLinked to original sources

bioRxiv2023

Transposon elements shape population divergence of rice blast fungus Magnaporthe oryzae

Dynamic transposition of transposable elements (TEs) in fungal pathogens have significant impact on genome stability, gene expression, and virulence to the host. In Magnaporthe oryzae, genome plasticity resulting from TE insertion is a major driving force leading to the rapid evolution and diversification of this fungus. Despite their importance in M. oryzae population evolution and divergence, our understanding of TEs in this context remains limited. Here we conducted a genome-wide analysis of TE transposition dynamics in the 11 most abundant TE families in M. oryzae populations. Our results show that these TEs have specifically expanded in recently isolated M. oryzae rice populations, with the presence/absence polymorphism of TE insertions highly concordant with population divergence on Geng/Japonica and Xian/Indica rice cultivars. Notably, the genes targeted by clade-specific TEs showed clade-specific expression patterns and are involved in the pathogenic process, suggesting a transcriptional regulation of TEs on targeted genes. Our study provides a comprehensive analysis of TEs in M. oryzae populations and demonstrates a crucial role of recent TE bursts in adaptive evolution and diversification of the M. oryzae rice-infecting lineage. IMPORTANCEM. oryzae is the causal agent of the destructive blast disease, which caused massive loss of yield annually worldwide. The fungus diverged into distinct clades during adaptation toward two rice subspecies, Xian/indica and Geng/japonica. Although the role of TEs in the adaptive evolution was well established, mechanisms underlying how TEs promote the population divergence of M. oryzae remains largely unknown. In this study, we reported that TEs shape the population divergence of M. oryzae by differentially regulating gene expression between Xian/Indica-infecting and Geng/Japonica-infecting populations. Our results revealed a TE insertion mediated gene expression adaption that led to the divergence of M. oryzae population infecting different rice subspecies.

genomics↗

bioRxiv2023

COP9 signalosome complex subunit-7-mediated regulation of cAMP levels contributes to autophagic degradation and pathogenesis of rice blast fungus Magnaporthe oryzae

O_LIPhoto-dependent processes, including circadian rhythm, autophagy, ubiquitination, neddylation/deneddylation, and metabolite biosynthesis, profoundly influence microbial pathogenesis. Although a photomorphogenesis signalosome (COP9/CSN) has been identified, the mechanism by which this large complex contributes to pathophysiological processes in filamentous fungi remains unclear. C_LIO_LIHere, we identified eight CSN complex subunits in the rice blast fungus Magnaporthe oryzae and functionally characterized the translocon subunits containing a nuclear export or localization signal (NES/NLS). C_LIO_LITargeted gene replacement of these CSN subunits, including MoCSN3, MoCSN5, MoCSN6, MoCSN7, and MoCSN12, attenuated vegetative growth and conidiation in M. oryzae and rendered non-pathogenic deletion strains. MoCSN7 deletion significantly suppressed arachidonic acid catabolism, compromised cell wall integrity, subverted photo-dependent ubiquitination, and abolished photo-responsiveness. Surprisingly, we also discovered that MoCSN subunits, particularly MoCsn7, are required for the cAMP-dependent regulation of autophagic flux. C_LIO_LITherefore, MoCSN significantly contributes to morphological, physiological, and pathogenic differentiation in M. oryzae by fostering cross-talk between multiple pathways. C_LI

pathology↗

bioRxiv2022

The protein phosphatases MoPtc1 and MoPtc2 are induced during pathogen-host interactions and play synergistic roles in regulating MAPK pathways in Magnaporthe oryzae

Reversible protein phosphorylation is essential in cellular signal transduction. The rice blast fungus Magnaporthe oryzae, contains six putative type 2c protein phosphatases namely; MoPtc1, MoPtc2, MoPtc5, MoPtc6, MoPtc7 and MoPtc8 respectively. In this study, we carried out transcription expression analysis and found that MoPtc1, MoPtc2 and MoPtc7 are significantly induced during pathogen-host interactions. Subsequent deletions of MoPtc1 or MoPtc2 not only resulted in increased sensitivity to cell wall stress mediated by Congo red but also increased phosphorylation of Mps1-MAPK. By immunoblot analysis, we found that deletion of both MoPtc1 and MoPtc2 resulted in overstimulation of both the HOG1 and Pmk1 pathways in M. oryzae. We also demonstrate that MoPtc1 is recruited directly to Osm1 by the adaptor protein MoNbp2 to inactivate the Osm1 during hypoosmotic stress unlike in budding yeast. Finally, we show that type 2c protein phosphatases are localized in different cellular compartments in the life cycle of Magnaporthe oryzae. Taken together type 2C protein phosphatases MoPtc1 and MoPtc2 play synergistic roles in regulating MAPK signaling pathways in M. oryzae. This work expands our understanding of the MAPK signaling regulation circuits in M. oryzae and the essential roles of type 2C phosphatases in fine-tuning phosphorylation levels of MAPK during fungal development.

molecular biology↗

bioRxiv2019

Bayogenin 3-O-Cellobioside is a novel non-cultivar specific anti-blast metabolite produced in rice in response to Pyricularia oryzae infection

Rice cultivars from japonica and indica lineage possess differential resistance against blast fungus on an account genetic divergence. Whether different rice cultivars also show distinct metabolomic changes in response to P. oryzae, and their role in host resistance, are poorly understood. Here, we examine the responses of six different rice cultivars from japonica and indica lineage challenged with P. oryzae. Both susceptible and resistant rice cultivars expressed several metabolites exclusively during P. oryzae infection, including the saponin Bayogenin 3-O-cellobioside. Bayogenin 3-O-cellobioside level in infected rice directly correlated with their resistant attributes. These findings reveal, for the first time to our knowledge that besides oat, other grass plants including rice produces protective saponins. Our study provides insight into the role of pathogen-mediated metabolomics-reprogramming in host immunity. The correlation between Bayogenin 3-O-Cellobioside levels and blast resistance suggests that engineering saponin expression in cereal crops represents an attractive and sustainable disease control strategy.

biochemistry↗

bioRxiv2018

Comparative genomic analysis revealed rapid differentiation in the pathogenicity-related gene repertoires between Pyricularia oryzae and Pyricularia penniseti isolated from a Pennisetum grass

BackgroundsPyricularia is a multispecies complex that could infect and cause severe blast disease on diverse hosts, including rice, wheat and many other grasses. Although the genome size of this fungal complex is small [~40 Mbp for Pyricularia oryzae (syn. Magnaporthe oryzae), and ~45 Mbp for P. grisea], the genome plasticity allows the fungus to jump and adapt to new hosts. Therefore, deciphering the genome basis of individual species could facilitate the evolutionary and genetic study of this fungus. However, except for the P. oryzae subgroup, many other species isolated from diverse hosts, such as the Pennisetum grasses, remain largely uncovered genetically.\n\nResultsHere, we report the genome sequence of a pyriform-shaped fungal strain P. penniseti P1609 isolated from a Pennisetum grass (JUJUNCAO) using PacBio SMRT sequencing technology. We performed a phylogenomic analysis of 28 Magnaporthales species and 5 non-Magnaporthales species and addressed P1609 into a Pyricularia subclade that is distant from P. oryzae. Comparative genomic analysis revealed that the pathogenicity-related gene repertoires were fairly different between P1609 and the P. oryzae strain 70-15, including the cloned avirulence genes, other putative secreted proteins, as well as some other predicted Pathogen-Host Interaction (PHI) genes. Genomic sequence comparison also identified many genomic rearrangements.\n\nConclusionTaken together, our results suggested that the genomic sequence of the P. penniseti P1609 could be a useful resource for the genetic study of the Pennisetum-infecting Pyricularia species.

genomics↗