Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 6 de 6
Filter
Add more filters










Database
Language
Publication year range
1.
J Plant Physiol ; 300: 154298, 2024 Sep.
Article in English | MEDLINE | ID: mdl-38924905

ABSTRACT

Seed inoculation with entomopathogenic fungi (EPF) causes plant-mediated effects against arthropod herbivores, but the responses vary among EPF isolates. We used a wheat model system with three isolates representing Beauveria bassiana and Metarhizium spp. causing either negative or positive effects against the aphid Rhopalosiphum padi. Activities of six carbohydrate enzymes increased in plants showing biomass build-up after EPF inoculations. However, only aldolase activity showed positive correlation with R. padi numbers. Plants inoculated with M. robertsii hosted fewest aphids and showed increased activity of superoxide dismutase, implying a defense strategy of resistance towards herbivores. In M. brunneum-inoculated plants, hosting most R. padi, activities of catalase and glutathione reductase were increased suggesting enhanced detoxification responses towards aphids. However, M. brunneum simultaneously increased plant growth indicating that this isolate may cause the plant to tolerate herbivory. EPF seed inoculants may therefore mediate either tolerance or resistance towards biotic stress in plants in an isolate-dependent manner.


Subject(s)
Aphids , Beauveria , Herbivory , Triticum , Animals , Triticum/microbiology , Triticum/enzymology , Aphids/physiology , Beauveria/physiology , Metarhizium/physiology , Plant Defense Against Herbivory
2.
Front Microbiol ; 14: 1197770, 2023.
Article in English | MEDLINE | ID: mdl-37293220

ABSTRACT

Entomopathogenic fungi have been well exploited as biocontrol agents that can kill insects through direct contact. However, recent research has shown that they can also play an important role as plant endophytes, stimulating plant growth, and indirectly suppressing pest populations. In this study, we examined the indirect, plant-mediated, effects of a strain of entomopathogenic fungus, Metarhizium brunneum on plant growth and population growth of two-spotted spider mites (Tetranychus urticae) in tomato, using different inoculation methods (seed treatment, soil drenching and a combination of both). Furthermore, we investigated changes in tomato leaf metabolites (sugars and phenolics), and rhizosphere microbial communities in response to M. brunneum inoculation and spider mite feeding. A significant reduction in spider mite population growth was observed in response to M. brunneum inoculation. The reduction was strongest when the inoculum was supplied both as seed treatment and soil drench. This combination treatment also yielded the highest shoot and root biomass in both spider mite-infested and non-infested plants, while spider mite infestation increased shoot but reduced root biomass. Fungal treatments did not consistently affect leaf chlorogenic acid and rutin concentrations, but M. brunneum inoculation via a combination of seed treatment and soil drenching reinforced chlorogenic acid (CGA) induction in response to spider mites and under these conditions the strongest spider mite resistance was observed. However, it is unclear whether the M. brunneum-induced increase in CGA contributed to the observed spider mite resistance, as no general association between CGA levels and spider mite resistance was observed. Spider mite infestation resulted in up to two-fold increase in leaf sucrose concentrations and a three to five-fold increase in glucose and fructose concentrations, but these concentrations were not affected by fungal inoculation. Metarhizium, especially when applied as soil drench, impacted the fungal community composition but not the bacterial community composition which was only affected by the presence of spider mites. Our results suggest that in addition to directly killing spider mites, M. brunneum can indirectly suppress spider mite populations on tomato, although the underlying mechanism has not yet been resolved, and can also affect the composition of the soil microbial community.

3.
Vaccines (Basel) ; 11(1)2022 Dec 28.
Article in English | MEDLINE | ID: mdl-36679915

ABSTRACT

The study aimed to determine the reasons for polio vaccine hesitancy among parents of persistently missed children (PMCs) in the high-risk areas of Karachi, Pakistan. A cross-sectional survey of parents of PMCs was conducted in April 2019 in 34 high-risk union councils of Karachi. PMCs were randomly selected from the polio program database, and further information was collected on a questionnaire by trained staff using face-to-face interviews with parents of PMCs. A total of 325 participants were included in the study. Among refusals, 112 (37.3%) had no trust in vaccine quality, followed by 45 (15.0%) who were afraid of side effects, 42 (14.0%) whose elders did not allow polio vaccination, 39 (13.0%) who refused due to the influence of negative social media videos, and 20 (6.7%) who had no trust in polio teams. We concluded that misconception is still a big challenge, and the program needs to strive for community acceptance. Low levels of trust in vaccines and teams as well as fear of OPV side effects were among the main reason for vaccine hesitancy. The participant communities recommended involving famous medical doctors, religious influencers, and TV or sports stars to enhance knowledge and acceptance of polio vaccination.

4.
J Chem Ecol ; 47(4-5): 476-488, 2021 May.
Article in English | MEDLINE | ID: mdl-33740175

ABSTRACT

Entomopathogenic fungi (EPF) can be experimentally established in several plant species as endophytes. Ecological effects of EPF inoculations on plant growth and plant-herbivore interactions have been demonstrated, potentially by altering plant physiological responses. However, the role of these responses in plant-fungus-herbivore tripartite interactions has not been well elucidated. Steroidal glycoalkaloids (SGAs) are plant specialized metabolites with bioactive properties against arthropod herbivores. Here, the effects of seed treatments by three EPF isolates, representing Beauveria bassiana, Metarhizium brunneum, and M. robertsii, on population growth of two-spotted spider mites (Tetranychus urticae Koch) were evaluated on tomato (Solanum lycopersicum). The levels of two SGAs, α-tomatine and dehydrotomatine, were determined in tomato leaves by LC-MS with and without T. urticae infestations after EPF inoculations. Interestingly, the population growth of T. urticae was significantly highest with M. brunneum and lowest with M. robertsii and B. bassiana at 15 days after infestation. Overall there was a significant negative correlation between SGAs content and the number of T. urticae. The levels of SGAs were significantly induced by T. urticae presence in all treatments, while only M. robertsii showed significantly higher levels of SGAs than M. brunneum and control in one of two experiments. Contrastingly, the effects on SGAs accumulation and population growth of T. urticae did not directly correlate with EPF endophytic colonization patterns of the inoculated plants. This study suggests a link between ecological effects and physiological responses mediated by EPF inoculations and T. urticae infestation with potential implications for plant protection.


Subject(s)
Alkaloids/chemistry , Plant Extracts/chemistry , Plant Leaves/chemistry , Solanum lycopersicum/chemistry , Solanum lycopersicum/metabolism , Animals , Beauveria/metabolism , Biological Evolution , Crops, Agricultural/microbiology , Crops, Agricultural/parasitology , Female , Gas Chromatography-Mass Spectrometry , Herbivory , Metarhizium/metabolism , Pest Control, Biological , Plant Extracts/metabolism , Plant Leaves/metabolism , Population Growth , Seeds/metabolism , Tetranychidae
5.
BMC Public Health ; 21(1): 44, 2021 01 06.
Article in English | MEDLINE | ID: mdl-33407294

ABSTRACT

BACKGROUND: Inactivated Polio Vaccine (IPV) campaign was conducted in February 2019 in Karachi where needle-free injectors were introduced for the administration of the fractional dose of IPV (fIPV) on a large scale. This study aimed to determine the impact of needle-free injectors on vaccination coverage. METHODS: In four towns of Karachi, fIPV was given using needle-free injectors "PharmaJet Tropis ID". Whereas, in six towns full dose of IPV was administered to children of 4-59 months of age. Cluster surveys through rapid convenience assessment method were conducted after the completion of vaccination activity. RESULTS: A total of 33,815 households' data was analyzed. Among these, 27,650 (82.8%) children were vaccinated. In fIPV areas, 85.3% of children were vaccinated compared to 79.5% in full dose IPV areas. A comparison of reasons for unvaccinated showed that 1.6% of parents do not give importance to vaccination in fIPV areas compared to 4.2% in full IPV areas (p-value < 0.0001). More children were not vaccinated due to fear of injection 1.8% in full IPV areas compared to 0.7% in fIPV areas (p-value < 0.0001). The source of campaign information shows that more frequent mobile miking 3.1% was observed in fIPV areas compared to 0.4% in full IPV areas (p-value < 0.0001). CONCLUSIONS: Our analysis supports the fractional dose of IPV in mass campaigns to achieve good vaccination coverage especially using needle-free injectors "PharmaJet Tropis ID" and vigorous social mobilization activities are expedient in accomplishing high coverage.


Subject(s)
Poliomyelitis , Poliovirus , Child , Humans , Infant , Injections, Intradermal , Mass Drug Administration , Pakistan , Poliomyelitis/prevention & control , Poliovirus Vaccine, Inactivated , Vaccination
6.
New Phytol ; 229(3): 1715-1727, 2021 02.
Article in English | MEDLINE | ID: mdl-33006149

ABSTRACT

Entomopathogenic fungi (EPF) can display a plant-associated lifestyle as endophytes. Seed application of EPF can affect insect herbivory above ground, but the mechanisms behind this are not documented. Here we applied three EPF isolates, Beauveria bassiana, Metarhizium brunneum and M. robertsii, as seed inoculation of wheat and bean, and evaluated the effects on population growth of aphids, Rhopalosiphum padi and Aphis fabae, respectively. In wheat and bean leaves, we quantified benzoxazinoids and flavonoids, respectively, in response to EPF inoculation and aphid infestation to elucidate the role of specific plant secondary metabolites (PSMs) in plant-fungus-herbivore interactions. Inoculations of wheat and bean with M. robertsii and B. bassiana reduced aphid populations compared with control treatments, whereas M. brunneum unexpectedly increased the populations of both aphids. Concentrations of the majority of PSMs were differentially altered in EPF-treated plants infested with aphids. Changes in aphid numbers were associated with PSMs regulation rather than EPF endophytic colonisation capacity. This study links the effects of EPF seed inoculations against aphids with unique PSM accumulation patterns in planta. The understanding of PSM regulation in tri-trophic interactions is important for the future development of EPF for pest management.


Subject(s)
Aphids , Beauveria , Animals , Metarhizium , Pest Control, Biological , Seeds
SELECTION OF CITATIONS
SEARCH DETAIL
...