Fungal Proliferation Research Articles

Induction and analysis of systemic C. albicans infections in mice.

The human fungal pathogen Candida albicans (C. albicans) causes invasive candidiasis, characterized by fatal organ failure due to disseminated fungal growth and inflammatory damage. To better understand fungal pathogenicity mechanisms and host protective responses, a murine model of invasive candidiasis has been developed in which C. albicans is administered systemically via intravenous injection. In this infection model, all major tissues are seeded within 0-4h. Of all the peripheral organs, the kidneys provide the most favorable niches for fungal proliferation and the morphogenetic switch to a hyphal state. As a consequence, the kidneys are a focal point for analyzing many of the genetic and immunological factors that underlie disease progression. Herein, we describe a number of well-established techniques that allow investigation into specific mechanisms that impact host-pathogen interactions.

From on-site to in-lab: Microscopic observation of fungal proliferation on 17th century mural paintings

The fungal community of biodeteriorated 17th century mural paintings within the nave and altar portion of the old Church of the Holy Ascension (Veliki Krcimir, Nisava District, Serbia) has been studied via an array of microscopic analyses in order to detect actively growing fungi and assess their potential damage to the painted layer and mortar. In situ microscopy, performed with portable microscopes, together with optical and scanning electron microscopy, has revealed impairments of the painted layer in the form of cracks and biopitting, along with surface salt deposits and hidden, symptomless fungal growth. Various structures, such as fully developed fruiting bodies and melanized mycelia, clusters of microcolonial fungi and lichen soredia, as well as a conidial apparatus and numerous conidia in mass have been observed, all attesting to the presence of actively growing fungal community on the surface of the painted layer and in the interspaces between the painted layer and mortar. Based on the observed reproductive structures, the main agents of biodeterioration have been identified as fungi of Chaetomium and Cladosporium genera. The documented deterioration symptoms are most likely due to hyphal penetration and formation of fruiting bodies and other fungal structures.

Effect of Cry Toxins on Xylotrechus arvicola (Coleoptera: Cerambycidae) Larvae

Simple SummaryXylotrechus arvicola is a destructive pest in vineyards (Vitis vinifera) in the main wine-producing areas of the Iberian Peninsula. X. arvicola larvae bore into the grapevine wood-making galleries, thus damaging the plant both directly and indirectly. The susceptibility of X. arvicola larvae to five coleopteran toxic Cry proteins was evaluated under laboratory conditions in order to deepen the knowledge of the effect of these proteins on this insect throughout its biological development. The Cry proteins tested could be applied to control X. arvicola larvae since they were able to kill them and cause serious alterations in the larvae during the remaining months of development that followed. The data presented suggest that these Cry proteins can be used as bioinsecticides against the larvae of this insect, in order to avoid the rapid evolution of resistance against these toxins since not all of the larvae were killed and thus increase vine wood protection.The beetle Xylotrechus arvicola is a destructive pest in vineyards (Vitis vinifera) in the main wine-producing areas of the Iberian Peninsula. X. arvicola larvae bore into the grapevine wood-making galleries, thus damaging the plant both directly and indirectly; the latter through the proliferation of wood fungi, which can invade the inside of the plant, decreasing the quality and quantity of its production. The susceptibility of X. arvicola larvae to five coleopteran toxic Cry proteins (Cry1B, Cry1I, Cry3A, Cry7A, and Cry23/37) was evaluated under laboratory conditions in order to deepen the knowledge of the effect of these proteins on this insect throughout its biological development. Cry7Ab and Cry1Ba were the most effective in controlling X. arvicola larvae due to the significant reduction in larvae survival (32.9 and 25.9 days, respectively), and by causing serious alterations in the larvae during the remaining months of their development. The developmental stage of the prepupal and pupal stages was not affected by the previous ingestion of Cry proteins. The Cry proteins tested could be applied to control X. arvicola larvae since they were able to kill them and cause serious alterations in the larvae during the remaining months of development that followed. The data presented suggest that these Cry proteins can be used as bioinsecticides against the larvae of this insect, applying them only at the moment when the larvae hatch from the egg outside the grapevine wood (this would only be useful and justified if the economic threshold is exceeded) in order to avoid the rapid evolution of resistance against these toxins since not all of the larvae were killed and thus increase vine wood protection.

Ustilago maydis Secreted Endo-Xylanases Are Involved in Fungal Filamentation and Proliferation on and Inside Plants.

Plant pathogenic fungi must be able to degrade host cell walls in order to penetrate and invade plant tissues. Among the plant cell wall degrading enzymes (PCWDEs) produced, xylanases are of special interest since its degradation target, xylan, is one of the main structural polysaccharides in plant cell walls. In the biotrophic fungus Ustilago maydis, attempts to characterize PCWDEs required for virulence have been unsuccessful, most likely due to functional redundancy. In previous high-throughput screening, we found one xylanase to be important for U. maydis infection. Here, we characterize the entire U. maydis endo-xylanase family, comprising two enzymes from the glycoside hydrolase (GH) 10 family, Xyn1 and Xyn2, one from GH11, Xyn11A, and one from GH43, Xyn3. We show that all endo-xylanases except Xyn3 are secreted and involved in infection in a non-redundant manner, suggesting different roles for each xylanase in this process. Taking a closer look inside the plant during the pathogenic process, we observed that all secreted xylanases were necessary for fungal proliferation. Finally, we found that at least Xyn11A accumulated in the apoplast of the infected plant after three days, highlighting the role of these enzymes as important secreted proteins during fungal proliferation inside plant tissues.

In vitro Effects of Prebiotics and Synbiotics on Apis cerana Gut Microbiota.

This study aimed to investigate in vitro effects of the selected prebiotics alone, and in combination with two potential probiotic Lactobacillus strains on the microbial composition of Apis cerana gut microbiota and acid production. Four prebiotics, inulin, fructo-oligosaccharides, xylo-oligosaccharides, and isomalto-oligosaccharides were chosen, and glucose served as the carbon source. Supplementation of this four prebiotics increased numbers of Bifidobacterium and lactic acid bacteria while decreasing the pH value of in vitro fermentation broth inoculated with A. cerana gut microbiota compared to glucose. Then, two potential probiotics derived from A. cerana gut at different dosages, Lactobacillus helveticus KM7 and Limosilactobacillus reuteri LP4 were added with isomalto-oligosaccharides in fermentation broth inoculated with A. cerana gut microbiota, respectively. The most pronounced impact was observed with isomalto-oligosaccharides. Compared to isomalto-oligosaccharides alone, the combination of isomalto-oligosaccharides with both lactobacilli strains induced the growth of Bifidobacterium, LAB, and total bacteria and reduced the proliferation of Enterococcus and fungi. Consistent with these results, the altered metabolic activity was observed as lowered pH in in vitro culture of gut microbiota supplemented with isomalto-oligosaccharides and lactobacilli strains. The symbiotic impact varied with the types and concentration of Lactobacillus strains and fermentation time. The more effective ability was observed with IMO combined with L. helveticus KM7. These results suggested that isomalto-oligosaccharides could be a potential prebiotic and symbiotic with certain lactobacilli strains on A. cerana gut microbiota.

Filamentous fungi occurrence on Molossus molossus (Pallas, 1766) (Chiroptera: Molossidae) present in an Atlantic Forest remnant in Southern Brazil.

The bats usually inhabit shelters with favorable conditions for fungal proliferation, including pathogenic and opportunistic species. The fungal diversity present on bats is little known and the studies are scarce in Brazil, which only a work has been performed in Cerrado and Pantanal biomes. Therefore, the objective of this study was evaluating the occurrence of filamentous fungi on the rostral region of Molossus molossus in an Atlantic Forest remnant of Brazil. The bats were captured with mist nets installed outside a shelter located in the municipality of Treviso, (28°29'23"S and 49°31'23"W), south region of state Santa Catarina. With a swab sterile moistened in saline solution, samples from the rostral region were obtained from all captured M. molossus individuals. The samples were taken to the laboratory for analysis and isolation in different culture media, followed of identification of fungal through the microculture technique. In total, 15 individuals were captured, which five fungal genus and 19 taxa were identified. Among the taxa registered, Aspergillioides sp.2, (47%), Penicillium sp.1 (33%), Chrysonilia sp. (33%), Cladosporium sp. (27%) were classified as little constant. In terms of abundance, Penicillium sp.1 (34%), Aspergillioides sp.2 (21%) and Aspergillus sp.2 (11%) were the most abundant in the samples. The results showed the occurrence of high diversity fungal in the rostral region of M. molossus in the Atlantic Forest, which is higher than observed in others Brazilian biomes. Some fungal genera found may harbor pathogenic and opportunistic species that need to be identified for preventing potential disease well as for bat conservation projects.

Time-Lapse Imaging of Root Pathogenesis and Fungal Proliferation Without Physically Disrupting Roots.

Microscopic observation of root disease onset and progression is typically performed by harvesting different plants at multiple time points. This approach prevents the monitoring of individual encounter sites over time, often mechanically damages roots, and exposes roots to unnatural conditions during observation. Here, we describe a method developed to avoid these problems and its application to study Fusarium oxysporum-Arabidopsis thaliana interactions. This method enabled three-dimensional, time-lapse imaging of both A. thaliana and F. oxysporum as they interact via the use of confocal and multi-photon microscopy and facilitated inquiries about the genetic mechanism underpinning Fusarium wilt.

Antifungal Activity of Biocontrol Agents In Vitro and Potential Application to Reduce Mycotoxins (Aflatoxin B1 and Ochratoxin A).

Food bio-preservatives are requested as substituents of chemical pesticides in food. The aim of this study was to carry out a screening of twenty biocontrol agents (BCAs) for their potential fungicidal activity in vitro. Twenty BCAs were tested against ten pathogenic fungi. Some of the cell-free supernatants (CFS) tested showed in vitro antifungal activity versus pathogenic fungi. The highest fungicidal activity was observed in the fermented CFS of Paenibacillus chibensis CECT 375, Bacillus amyloliquefaciens CECT 493, and Pantoea agglomerans CECT 850, which showed a minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) values of 125 and 250 g/L, respectively. The compounds responsible for the antifungal activity, such as organic and phenolic acids, were determined. Lactic acid, acetic acid, benzoic acid, and phenyllactic acid among others can be related to antifungal activity. HPLC-MS/MS analysis showed a reduction of ochratoxin A (OTA) and aflatoxin B1 (AFB1) up to 26% (Paenibacillus alvei CECT 2) and 55% (Paenibacillus polymyxa CECT 155), respectively. The present study prompts that metabolism products of BCAs are propitious for the bioconservation of food, due to their ability to reduce the proliferation of mycotoxigenic fungi and mycotoxins production.

Macrophage-Derived Osteopontin Influences the Amplification of Cryptococcus neoformans-Promoting Type 2 Immune Response.

A multifunctional glycoprotein, osteopontin (OPN), can modulate the function of macrophages, resulting in either protective or deleterious effects in various inflammatory diseases and infection in the lungs. Although macrophages play the critical roles in mediating host defenses against cryptococcosis or cryptococcal pathogenesis, the involvement of macrophage-derived OPN in pulmonary infection caused by fungus Cryptococcus has not been elucidated. Thus, our current study aimed to investigate the contribution of OPN to the regulation of host immune response and macrophage function using a mouse model of pulmonary cryptococcosis. We found that OPN was predominantly expressed in alveolar macrophages during C. neoformans infection. Systemic treatment of OPN during C. neoformans infection resulted in an enhanced pulmonary fungal load and an early onset of type 2 inflammation within the lung, as indicated by the increase of pulmonary eosinophil infiltration, type 2 cytokine production, and M2-associated gene expression. Moreover, CRISPR/Cas9-mediated OPN knockout murine macrophages had enhanced ability to clear the intracellular fungus and altered macrophage phenotype from pathogenic M2 to protective M1. Altogether, our data suggested that macrophage-derived OPN contributes to the elaboration of C. neoformans-induced type 2 immune responses and polarization of M2s that promote fungal survival and proliferation within macrophages.

Sustainable materials with high insulation capacity obtained from wastes from hemp industry processed by wet-laid

This article reports on the revalorization of hemp waste from the textile industry, focusing on the development of new sustainable materials with high insulating properties. Wet-laid technology was used to manufacture nonwovens with different binding fibers, polylactic acid, and viscose fibers. The characterization of the acoustic insulating capacity was carried out using a Kundt tube, and the thermal insulating performance by measuring the heat transmission resistance ( R) and thermal conductivity ( λ). The results showed that the developed nonwovens have lower thermal conductivity values of about 0.027–0.034 W/(m K), were even lower than those of traditional thermal insulating materials, being the sample with 100 g/m2 of areal density and with a composition of 80% of hemp, 10% of polylactide and 10% of viscose the one with the lowest thermal conductivity (0.027 W/(mK). Their acoustic absorption capacity was around 0.76 at a frequency of 6 kHz, in samples containing high hemp waste (>80 wt%). However, the heterogeneous, discontinuous, and high void density structure that contributes to excellent insulating properties, lead to a decrease in their mechanical properties. This demonstrated that these materials are suitable for substituting traditional materials in insulating applications. Additionally, antifungal tests were carried out. However, hemp nonwovens proved to be inefficient against fungal proliferation.

Hand-foot syndrome and nail disorders secondary to treatment with paclitaxel: Is there a relationship with the presence of fungi?

This study aimed to evaluate the frequency of nail disorders and the presence of fungi on the nails of the hands and feet of patients with hand-foot syndrome secondary to treatment with paclitaxel. Prospective study, carried out from October 2018 to December 2019, which included 81 patients undergoing treatment for breast cancer using paclitaxel and had signs and or symptoms of hand-foot syndrome with or without nail disorders. The data were collected through interviews guided by a structured questionnaire, information from medical records and reports of mycological exams. The average age of women was 54.7 ± 7.4 years. Nail disorders occurred in 69 patients (85.2%), and of these, 43 (62.3%) were positive for fungi. The fungi were yeasts (n = 38; 69%), dermatophytes (n = 15; 27.2%) and non-dermatophyte filamentous fungi (n = 8; 14.5%). Nail disorders were the most frequent manifestations in patients with hand-foot syndrome treated with paclitaxel and occurred in 85.2% of them. It was evidenced that fungi are present on the nails of these patients and can occur in up to 65.28%. The most prevalent fungi were Candida and Trichophyton. The nail lesion was associated with the type of treatment protocol used by the patient. The results of the study point to the need to select safe management alternatives for patients, so they can prevent nail lesions and prevent the proliferation of fungi, consequently reducing negative life impact during treatment.

Mycotoxins in Foods: Occurrence, Challenges and Management in Context of Nepal

Incidence of mycotoxins in principal foods and grains is a major threat to achieving food safety but still remains one of the most underrated and ignored sources for food borne diseases, particularly in less developed countries. Furthermore, food insecurity together with ineffective government regulations and environmental conditions that favor fungal proliferation and toxin production merge together to make the people’s life even harder in countries like Nepal. Apart from wasting huge quantities of food every year, mycotoxins are associated with various acute and chronic health disorders including carcinogenic, mutagenic, estrogenic, digestive, vascular and nervous defects. Staple diets in less developed countries like Nepal are largely based on crops like maize, susceptible to mycotoxins which may ultimately lead to chronic health problems in large population. Although there is an immediate need to address the food safety challenges caused by mycotoxin contamination in cereal grains, studies so far in Nepal has been conducted mainly in aflatoxins in limited commodities only and very less efforts have been made to manage and mitigate the problems caused by mycotoxins in Nepal. Therefore, a thorough control of mycotoxins in overall food chain is essential to safeguard the health of the population which could be achieved by implementing stricter regulations, modern and scientific post-harvest operations, effective monitoring programs and raising necessary awareness among stakeholders. Int. J. Appl. Sci. Biotechnol. Vol 9(3): 152-159.

Extension of Storage Life of Papayas Grown in Puerto Rico by Gamma Radiation Treatments

Shelf-life extension (measured as ripening delay) and the retention of nutrients in irradiated P. R. 965 papayas have been investigated at constant storage temperature and relative humidity. The major findings were: 1. The ripening process in irradiated papayas was delayed up to 7 days by the use of gamma radiation treatments. The maximum delay in ripening was achieved by 25 to 50 Krads treatments, while the 100 Krad treatment showed a slight stimulation of ripening in storage. 2. Some destruction of vitamin C (ascorbic acid) seemed to have been effected by the gamma irradiation, although there were only slight differences between dose levels. 3. The level of total carotenoids was not affected by gamma radiation. During storage, there was a marked increase in these pigments as the papayas ripened. 4. Gamma irradiation inhibited fungal proliferation on papaya fruit even at dosages of 25 Krad. 5. There was no effect observed at the dosages studied on the skin of the fruit which developed its characteristic bright yellow color when ripe.

Storage Mycoflora in Sesame Seed Production in Benue State, Nigeria

Sesame (Sesamum indicum) is usually contaminated with many fungi where some of them are mycotoxigenic causing economic and health problems. This study investigated the percentage composition of fungi contamination of sesame seeds in Benue state Nigeria. Using direct plating technique; the study revealed twelve species of fungi contamination in sesame seed obtained in Benue State. The percentage occurrence of fungal isolates shows that Aspergillus flavus and A. niger were found in all the locations and their occurrence was significantly different (P≤0.05). The percentage contamination of Sesame samples collected from Otukpo LGA has the highest fungal (23.35%) contamination and was significantly higher (P≤0.05) from samples of other places whereas Sesame contamination from Gboko was the least with total percentage of (12.05%). In conclusion, considering the benefits of sesame, it is recommended that several treatments should be applied to reduce the levels of contamination in sesame seeds before consumption utilization such as environmental conditions leading to fungal proliferation (a high temperature, humidity, poor soil fertility, drought and insect damage). Also poor harvesting practices, unsuitable storage conditions, improper transportation, marketing and processing should be discouraged.

Mycotoxins and their alarming reach to cattle: Review

Mycotoxins are metabolites from filamentous fungi founded in environment and food, as pasture and cereals, intended for cattle feeding. Herd mycotoxin contamination is one of the big preoccupations around the world. The incorrect food production and storage, when conditions favor to proliferation of fungi that cause contamination, is problematic. These mycotoxins can cause carcinogenic, neurological and hepatic damages. The purpose of this literature review was to highlight the main mycotoxins, the etiologic agents, and mycotoxicosis that affect cattle. For this purpose, the Scielo, Pubmed and Portal Capes search bases were used, in addition to official websites, using the keywords "mycotoxins", "mycotoxicosis" and "fungal intoxication", with a focus on cattle.

Genipin in an Ex Vivo Corneal Model of Bacterial and Fungal Keratitis.

PurposeTo determine whether genipin (a natural crosslinker) could reduce the colonization and proliferation of bacteria and fungi in an ex vivo model of corneal infection.MethodsThis study, using an ex vivo model of bacterial and fungal keratitis, investigated the antimicrobial efficacy of genipin crosslinking. Excised corneoscleral buttons were wounded by scalpel incision and subsequently infected with Staphylococcus aureus, Pseudomonas aeruginosa, or Candida albicans. After inoculation, corneas were treated with genipin for 24 hours at 37°C. Histologic examinations were carried out, and the number of viable colony-forming units (CFU)/cornea was determined.ResultsGenipin exerts bactericidal action against S. aureus and P. aeruginosa, as well as fungicidal action against C. albicans and significantly reduced the CFU compared to contralateral eyes that received saline treatment (P < 0.05).ConclusionsThese data identify genipin as a novel ocular antimicrobial agent that has the potential to be incorporated into the therapeutic armamentarium against microbial keratitis.Translational RelevanceThis study provided evidence for the antimicrobial and antifungal properties of genipin as an alternative crosslinker that could be used in the management of infectious keratitis.

Evaluation of the influence of UV radiation and sodium hypochlorite on the shelf life of strawberries

It is common to combine methods to increase the shelf life of a raw material or product. In this study, we sought to understand the relationship between ultraviolet (UV) radiation and sodium hypochlorite (NaOCl) in attenuating the proliferation of fungus and its deteriorating effect on strawberries. The UV light intensities of 125, 250 and 400 Watts (W) and sodium hypochlorite were tested in concentrations 0.5, 1.0 and 1.5 ppm. The strawberries were sprayed with sodium hypochlorite solutions and then kept for 1 minute in UV light chambers, to then be stored in transparent sealed plastic containers. The strawberry samples with the longest life were those that were sprayed with 0.5 and 1.0 ppm sodium hypochlorite solution combined with exposure to 125 W UV light. These samples had a shelf-life extension of about five days compared to strawberries without any kind of treatment. Thus, it is possible to state that this combination is efficient in cleaning the fruit without causing damage.

Respiring to infect: Emerging links between mitochondria, the electron transport chain, and fungal pathogenesis.

Fungal pathogens threaten human health both directly as infectious agents and indirectly by limiting crop production, and new approaches are desperately needed to combat fungal diseases [1]. There is a growing appreciation that mitochondrial functions contribute to the ability of fungal pathogens to cause disease and may be promising targets for new therapeutic approaches [2,3]. A number of excellent reviews provide insights into the roles of mitochondria in fungal pathogens; readers are directed to these reviews for information on connections between mitochondria and virulence, antifungal drug resistance and susceptibility, and cell wall synthesis [4–8]. Our intention in this review is to focus on recent studies that highlight mitochondrial connections to virulence, metal homeostasis, the response to stress, and metabolic adaptation, as summarized in Fig 1, for a selected set of fungi that are major agents of human disease: Aspergillus fumigatus, Candida albicans, and Cryptococcus neoformans [9]. A. fumigatus is the causative agent of noninvasive pulmonary infections (aspergillomas and chronic aspergillosis), allergic bronchopulmonary aspergillosis, and invasive pulmonary aspergillosis. C. albicans is a commensal in the human gut but can cause invasive candidiasis of the blood stream and internal organs, as well as diseases involving mucosal surfaces. Infections with C. neoformans generally begin in lung tissue, but the fungus has a propensity to disseminate to the brain to cause meningoencephalitis, a disease that is highly prevalent and often fatal in the HIV/AIDS population. These fungi have aerobic lifestyles dependent on mitochondria, and the involvement of the electron transport chain (ETC) emerges as a common theme in their ability to cause disease (Fig 2) [5,10,11]. Open in a separate window Fig 1 Mitochondrial-associated activities that impact fungal pathogenesis. Mitochondria play key roles in stress responses and metabolic activities (e.g., iron homeostasis and use of carbon sources) relevant to fungal proliferation in mammalian hosts. Recent studies emphasize the prominent participation of the ETC in virulence, and the targets of inhibitors of specific complexes are shown in Fig 2. The phenotypic outcomes of perturbed mitochondrial function include cell surface changes that directly influence evasion of the host immune response. Critically important activities related to drug susceptibility and resistance are the subject of other recent reviews [2–9]. cAMP, cyclic adenosine monophosphate; ETC, electron transport chain; PKA, protein kinase A; ROS, reactive oxygen species.

Induction of Antioxidant Response With Compatible Combination of Mesorhizobium SP. and Pseudomonas SP. Against Fusarium Oxysporum SP. Ciceris in Chickpea

Chickpea (Cicer arietinum L.) is severely affected by Fusarium oxysporum sp. ciceris causing vascular wilt disease accounting about 10% of yield losses. The present study was conducted to assess the potential of compatible dual inoculants of Mesorhizobium sp. and PGPR (rhizospheric and endophytic) in initiating and boosting the antioxidant response towards the phytopathogen in vivo under wilt sick conditions in chickpea. Among the different dual inoculated treatments, LGR191+NE8 (Mesorhizobium sp. + nodule endophyte) showed maximum augmentation in the antioxidants viz., catalase (15.16 U/min/g fresh weight of root), guaiacol peroxidase (2.492mmoles/min/g fresh weight of root) and total phenolics (110.25 tannic acid equivalents/g fresh weight of root) over recommended fungicide (captan). Percent wilt control was highest with LGR191+NE8 (95.77%) followed by LGR1+LPGPR-1 (94.17%) after 120 days of sowing. The results suggested an expanded antioxidant state of the wilt infected plants with the dual inoculation of Mesorhizobium sp. with PGPR (rhizospheric and endophytic) decreasing fungal proliferation sustainably.&#x0D; Bangladesh J. Bot. 50(2): 359-364, 2021 (June)

Mitogen-Activated Protein Kinase MAPKKK7 from Plasmodiophora brassicae Regulates Low-Light-Dependent Nicotiana benthamiana Immunity.

MAPKKK is the largest family of mitogen-activated protein kinase (MAPK) cascades and is known to play important roles in plant pathogen interaction by regulating fungal cell proliferation, growth, and pathogenicity. Thus far, only a few have been characterized because of the functional redundancy of MAPKKKs. In this study, it is interesting that Plasmodiophora brassicae (Pb)MAPKKK7 was clustered into the A3 subgroup of plant MAPKKKs by a phylogenetic analysis and also with the BCK1 and STE groups of fungal MAPKKKs. PbMAPKKK7 function in reactive oxygen species accumulation and cell death in Nicotiana benthamiana was characterized. Agroinfiltration with the PbMAPKKK7 mutated protein kinase domain relieved these changes. Interestingly, the induction of cell death was dependent on light intensity. Transcriptional profiling analysis demonstrated that PbMAPKKK7 was highly expressed during cortex infection stages, indicating its important role in P. brassicae infection. These functional analyses of PbMAPKKK7 build knowledge of new roles of the MAPK cascade pathway in N. benthamiana and P. brassicae interactions.