A SET domain-containing protein involved in cell wall integrity signaling and peroxisome biogenesis is essential for appressorium formation and pathogenicity of Colletotrichum gloeosporioides

The chromatin modulator Set5 plays important regulatory roles in both cell growth and stress responses of Saccharomyces cerevisiae. However, its function in filamentous fungi remains poorly understood. Here, we report the pathogenicity-related gene CgSET5 discovered in a T-DNA insertional mutant M285 of Colletotrichum gloeosporioides. Bioinformatic analysis revealed that CgSET5 encodes a SET domain-containing protein that is a homolog of the budding yeast S. cerevisiae Set5. CgSET5 is important for hyphae growth and conidiation and is necessary for appressorium formation and pathogenicity. CgSet5 regulates appressorium formation in a mitogen-activated protein kinase-independent manner. Inactivation of CgSET5 resulted in a significant reduction in chitin content within the cell wall, indicating CgSet5 plays a vital role in cell wall integrity. CgSet5 is involved in peroxisome biogenesis. We identified CgSet5 as the histone H4 methyltransferase, which methylates the critical H4 lysine residues 5 and 8 in C. gloeosporioides. We carried out a yeast two-hybrid screen to find CgSet5 interacting partners. We found CgSet5 putatively interacts with an inorganic pyrophosphatase named CgPpa1, which co-localized in the cytoplasm with CgSet5. Finally, CgPpa1 was found to strongly interact with CgSet5 in vivo during appressorium formation by bimolecular fluorescence complementation assays. These data corroborate a complex control function of CgSet5 acting as a core pathogenic regulator, which connects cell wall integrity and peroxisome biogenesis in C. gloeosporioides

The phosphorylation landscape of infection-related development by the rice blast fungus

Many of the world’s most devastating crop diseases are caused by fungal pathogens that elaborate specialized infection structures to invade plant tissue. Here, we present a quantitative mass-spectrometry-based phosphoproteomic analysis of infection-related development by the rice blast fungus Magnaporthe oryzae, which threatens global food security. We mapped 8,005 phosphosites on 2,062 fungal proteins following germination on a hydrophobic surface, revealing major re-wiring of phosphorylation-based signaling cascades during appressorium development. Comparing phosphosite conservation across 41 fungal species reveals phosphorylation signatures specifically associated with biotrophic and hemibiotrophic fungal infection. We then used parallel reaction monitoring (PRM) to identify phosphoproteins regulated by the fungal Pmk1 MAPK that controls plant infection by M. oryzae. We define 32 substrates of Pmk1 and show that Pmk1-dependent phosphorylation of regulator Vts1 is required for rice blast disease. Defining the phosphorylation landscape of infection therefore identifies potential therapeutic interventions for the control of plant diseases

scripts to biuld seurat dataset and trajectory analysis

scripts deployed to build the Seurat single-cell RNA-seq to study plant response to fungal infectio

Endurance assessment of Eichhornia crassipes (Mart.) Solms, in heavy metal contaminated site–A case study

In this study, the ability to hyper accumulate heavy metals from contaminated site by water hyacinth (Eichhornia crassipes) was monitored. The heavy metal-contaminated habitat was validated by X-ray diffraction and energy dispersive X-ray elemental spectrometry analysis of the soil samples. Heavy metal contamination in soil and water; accumulation in foliar, root and bulb tissue samples were determined by atomic absorption spectroscopy and were monitored as a function of accumulation in different tissues. Significant differences were recorded in the bioaccumulation capability of heavy metals by different tissue. Discrete variation in protein profile of leaves and high expression of alcohol dehydrogenase (ADH), peroxidase (POX) and altered regulation of esterase (EST) in root tissue was observed in contaminated site grown Eichhornia. The high metal accumulation efficiency of water hyacinth due to the biomass production suggests this species as reliable organic biomarker for heavy metal contamination

Endurance assessment of Eichhornia crassipes (Mart.) Solms, in heavy metal contaminated site–A case study

In this study, the ability to hyper accumulate heavy metals from contaminated site by water hyacinth (Eichhornia crassipes) was monitored. The heavy metal-contaminated habitat was validated by X-ray diffraction and energy dispersive X-ray elemental spectrometry analysis of the soil samples. Heavy metal contamination in soil and water; accumulation in foliar, root and bulb tissue samples were determined by atomic absorption spectroscopy and were monitored as a function of accumulation in different tissues. Significant differences were recorded in the bioaccumulation capability of heavy metals by different tissue. Discrete variation in protein profile of leaves and high expression of alcohol dehydrogenase (ADH), peroxidase (POX) and altered regulation of esterase (EST) in root tissue was observed in contaminated site grown Eichhornia. The high metal accumulation efficiency of water hyacinth due to the biomass production suggests this species as reliable organic biomarker for heavy metal contamination.Department of Biotechnology, Ministry of Science and Technology, Government of Indi

Cell-type-specific responses to fungal infection in plants revealed by single-cell transcriptomics

Pathogen infection is a dynamic process. Here, we employ single-cell transcriptomics to investigate plant response heterogeneity. By generating an Arabidopsis thaliana leaf atlas encompassing 95,040 cells during infection by a fungal pathogen, Colletotrichum higginsianum, we unveil cell-type-specific gene expression, notably an enrichment of intracellular immune receptors in vasculature cells. Trajectory inference identifies cells that had different interactions with the invading fungus. This analysis divulges transcriptional reprogramming of abscisic acid signaling specifically occurring in guard cells, which is consistent with a stomatal closure dependent on direct contact with the fungus. Furthermore, we investigate the transcriptional plasticity of genes involved in glucosinolate biosynthesis in cells at the fungal infection sites, emphasizing the contribution of the epidermis-expressed MYB122 to disease resistance. This work underscores spatially dynamic, cell-type-specific plant responses to a fungal pathogen and provides a valuable resource that supports in-depth investigations of plant-pathogen interactions

Endurance assessment of <i>Eichhornia crassipes</i> (Mart.) Solms, in heavy metal contaminated site–A case study

<p>In this study, the ability to hyper accumulate heavy metals from contaminated site by water hyacinth (<i>Eichhornia crassipes</i>) was monitored. The heavy metal-contaminated habitat was validated by X-ray diffraction and energy dispersive X-ray elemental spectrometry analysis of the soil samples. Heavy metal contamination in soil and water; accumulation in foliar, root and bulb tissue samples were determined by atomic absorption spectroscopy and were monitored as a function of accumulation in different tissues. Significant differences were recorded in the bioaccumulation capability of heavy metals by different tissue. Discrete variation in protein profile of leaves and high expression of alcohol dehydrogenase (ADH), peroxidase (POX) and altered regulation of esterase (EST) in root tissue was observed in contaminated site grown <i>Eichhornia</i>. The high metal accumulation efficiency of water hyacinth due to the biomass production suggests this species as reliable organic biomarker for heavy metal contamination.</p

The Biology of Invasive Growth by the Rice Blast Fungus Magnaporthe oryzae

This introductory chapter describes the life cycle of Magnaporthe oryzae, the causal agent of rice blast disease. During plant infection, M. oryzae forms a specialized infection structure called an appressorium, which generates enormous turgor, applied as a mechanical force to breach the rice cuticle. Appressoria form in response to physical cues from the hydrophobic rice leaf cuticle and nutrient availability. The signaling pathways involved in perception of surface signals are described and the mechanism by which appressoria function is also introduced. Re-polarization of the appressorium requires a septin complex to organize a toroidal F-actin network at the base of the cell. Septin aggregation requires a turgor-dependent sensor kinase, Sln1, necessary for re-polarization of the appressorium and development of a rigid penetration hypha to rupture the leaf cuticle. Once inside the plant, the fungus undergoes secretion of a large set of effector proteins, many of which are directed into plant cells using a specific secretory pathway. Here they suppress plant immunity, but can also be perceived by rice immune receptors, triggering resistances. M. oryzae then manipulates pit field sites, containing plasmodesmata, to facilitate rapid spread from cell to cell in plant tissue, leading to disease symptom development

Pathogen protein modularity enables elaborate mimicry of a host phosphatase

Pathogens produce diverse effector proteins to manipulate host cellular processes. However, how functional diversity is generated in an effector repertoire is poorly understood. Many effectors in the devastating plant pathogen Phytophthora contain tandem repeats of the “(L)WY” motif, which are structurally conserved but variable in sequences. Here, we discovered a functional module formed by a specific (L)WY-LWY combination in multiple Phytophthora effectors, which efficiently recruits the serine/threonine protein phosphatase 2A (PP2A) core enzyme in plant hosts. Crystal structure of an effector-PP2A complex shows that the (L)WY-LWY module enables hijacking of the host PP2A core enzyme to form functional holoenzymes. While sharing the PP2A-interacting module at the amino terminus, these effectors possess divergent C-terminal LWY units and regulate distinct sets of phosphoproteins in the host. Our results highlight the appropriation of an essential host phosphatase through molecular mimicry by pathogens and diversification promoted by protein modularity in an effector repertoire

Appressorium-mediated plant infection by Magnaporthe oryzae is regulated by a Pmk1-dependent hierarchical transcriptional network

Rice blast is a devastating disease caused by the fungal pathogen Magnaporthe oryzae that threatens rice production around the world. The fungus produces a specialized infection cell, called the appressorium, that enables penetration through the plant cell wall in response to surface signals from the rice leaf. The underlying biology of plant infection, including the regulation of appressorium formation, is not completely understood. Here we report the identification of a network of temporally coregulated transcription factors that act downstream of the Pmk1 mitogen-activated protein kinase pathway to regulate gene expression during appressorium-mediated plant infection. We show that this tiered regulatory mechanism involves Pmk1-dependent phosphorylation of the Hox7 homeobox transcription factor, which regulates genes associated with induction of major physiological changes required for appressorium development—including cell-cycle control, autophagic cell death, turgor generation and melanin biosynthesis—as well as controlling a additional set of virulence-associated transcription factor–encoding genes. Pmk1-dependent phosphorylation of Mst12 then regulates gene functions involved in septin-dependent cytoskeletal re-organization, polarized exocytosis and effector gene expression, which are necessary for plant tissue invasion. Identification of this regulatory cascade provides new potential targets for disease intervention