The stationary life of plants has led to the evolution of a complex gridded antioxidant defence system constituting numerous enzymatic components, playing a crucial role in overcoming various stress ...conditions. Mainly, these plant enzymes are superoxide dismutase (SOD), catalase (CAT), peroxidase (POX), glutathione peroxidase (GPX), glutathione reductase (GR), glutathione S-transferases (GST), ascorbate peroxidase (APX), monodehydroascorbate reductase (MDHAR), and dehydroascorbate reductase (DHAR), which work as part of the antioxidant defence system. These enzymes together form a complex set of mechanisms to minimise, buffer, and scavenge the reactive oxygen species (ROS) efficiently. The present review is aimed at articulating the current understanding of each of these enzymatic components, with special attention on the role of each enzyme in response to the various environmental, especially abiotic stresses, their molecular characterisation, and reaction mechanisms. The role of the enzymatic defence system for plant health and development, their significance, and cross-talk mechanisms are discussed in detail. Additionally, the application of antioxidant enzymes in developing stress-tolerant transgenic plants are also discussed.
The
species has diverse ecological functions ranging from saprophytes, endophytes, and animal and plant pathogens. Occasionally, they are isolated from dead and alive insects. However, research on ...fusaria-insect associations is very limited as fusaria are generalized as opportunistic insect-pathogens. Additionally, their phytopathogenicity raises concerns in their use as commercial biopesticides. Insect biocontrol potential of
is favored by their excellent soil survivability as saprophytes, and sometimes, insect-pathogenic strains do not exhibit phytopathogenicity. In addition, a small group of fusaria, those belonging to the
species complex, act as insect mutualists assisting in host growth and fecundity. In this review, we summarize mutualism and pathogenicity among fusaria and insects. Furthermore, we assert on
entomopathogenicity by analyzing previous studies clearly demonstrating their natural insect-pathogenicity in fields, and their presence in soils. We also review the presence and/or production of a well-known insecticidal metabolite beauvericin by different
species. Lastly, some proof-of-concept studies are also summarized, which demonstrate the histological as well as immunological changes that a larva undergoes during
pathogenesis. These reports highlight the insecticidal properties of some
spp., and emphasize the need of robust techniques, which can distinguish phytopathogenic, mutualistic and entomopathogenic fusaria.
Entomopathogenic fungi (EPF) are the natural enemies of insect-pests. However, EPF recoveries can be influenced by the soil habitat-type(s) incorporated and/or the bait-insect(s) used.
...Galleriamellonella
(GM) as bait-insect, i.e. ‘
Galleria
-bait’, is arguably the most common methodology, which is sometimes used solely, to isolate EPF from soils. Insect baiting using
Tenebriomolitor
(TM) has also been employed occasionally. Here 183 soils were used to estimate the functional diversity of EPF in Portuguese Douro vineyards (cultivated habitat) and adjacent hedgerows (semi-natural habitat), using the TM bait method. Moreover, to study the effect of insect baiting on EPF recovery, 81 of these 183 soil samples were also tested for EPF occurrences using the GM bait method. Twelve species were found in 44.26% ± 3.67% of the total of 183 soils. Clonostachysroseaf.rosea was found in maximum soils (30.05% ± 3.38%), followed by
Beauveriabassiana
(12.57% ± 2.37%),
Purpureocilliumlilacinum
(9.29% ± 2.14%) and
Metarhiziumrobertsii
(6.01% ± 1.75%).
Beauveriapseudobassiana
(
P
< 0.001), C.roseaf.rosea (
P
= 0.006) and
Cordycepscicadae
(
P
=0.023) were isolated significantly more from hedgerows, highlighting their sensitivities towards agricultural disturbances.
Beauveriabassiana
(
P
= 0.038) and
M.robertsii
(
P
= 0.003) were isolated significantly more using GM and TM, respectively. Principal component analysis revealed that
M.robertsii
was associated both with TM baiting and cultivated habitats, however,
B.bassiana
was slightly linked with GM baiting only. Ecological profiles of
B.bassiana
and
P.lilacinum
were quite similar while
M.robertsii
and C.roseaf.rosea were relatively distant and distinct. To us, this is the first report on (a)
C.cicadae
isolation from Mediterranean soils, (b)
Purpureocilliumlavendulum
as an EPF worldwide; and (c) significant recoveries of
M.robertsii
using TM over GM. Overall, a ‘
Galleria
-
Tenebrio
-bait method’ is advocated to study the functional diversity of EPF in agroecosystems.
Cryptococcus flavescens and C. terrestris are phenotypically indistinguishable sister species that belong to the order Tremellales (Tremellomycetes, Basidiomycota) and which may be mistaken for C. ...laurentii based on phenotype. Phylogenetic separation between C. flavescens and C. terrestris was based on rDNA sequence analyses, but very little is known on their intraspecific genetic variability or propensity for sexual reproduction. We studied 59 strains from different substrates and geographic locations, and used a multilocus sequencing (MLS) approach complemented with the sequencing of mating type (MAT) genes to assess genetic variation and reexamine the boundaries of the two species, as well as their sexual status. The following five loci were chosen for MLS: the rDNA ITS-LSU region, the rDNA IGS1 spacer, and fragments of the genes encoding the largest subunit of RNA polymerase II (RPB1), the translation elongation factor 1 alpha (TEF1) and the p21-activated protein kinase (STE20). Phylogenetic network analyses confirmed the genetic separation of the two species and revealed two additional cryptic species, for which the names Cryptococcus baii and C. ruineniae are proposed. Further analyses of the data revealed a high degree of genetic heterogeneity within C. flavescens as well as evidence for recombination between lineages detected for this species. Strains of C. terrestris displayed higher levels of similarity in all analysed genes and appear to make up a single recombining group. The two MAT genes (STE3 and SXI1/SXI2) sequenced for C. flavescens strains confirmed the potential for sexual reproduction and suggest the presence of a tetrapolar mating system with a biallelic pheromone/receptor locus and a multiallelic HD locus. In C. terrestris we could only sequence STE3, which revealed a biallelic P/R locus. In spite of the strong evidence for sexual recombination in the two species, attempts at mating compatible strains of both species on culture media were unsuccessful.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Animals are frequently used as model systems for determination of safety and efficacy in pharmaceutical research and development. However, significant quantitative and qualitative differences exist ...between humans and the animal models used in research. This is as a result of genetic variation between human and the laboratory animal. Therefore the development of a system that would allow the assessment of all molecular differences between species after drug exposure would have a significant impact on drug evaluation for toxicity and efficacy. Here we describe a cross-species microarray methodology that identifies and selects orthologous probes after cross-species sequence comparison to develop an orthologous cross-species gene expression analysis tool. The assumptions made by the use of this orthologous gene expression strategy for cross-species extrapolation is that; conserved changes in gene expression equate to conserved pharmacodynamic endpoints. This assumption is supported by the fact that evolution and selection have maintained the structure and function of many biochemical pathways over time, resulting in the conservation of many important processes. We demonstrate this cross-species methodology by investigating species specific differences of the peroxisome proliferator-activator receptor (PPAR) α response in rat and human.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Entomopathogenic bacteria and fungi are quite frequently found in soils and insect cadavers. The first step in utilizing these microbes as biopesticides is to isolate them, and several culture media ...and insect baiting procedures have been tested in this direction. In this work, the authors review the current techniques that have been developed so far, in the last five decades, and display brief protocols which can be adopted for the isolations of these entomopathogens. Among bacteria, this review focuses on
spp. and bacteria from the class Bacilli. Among fungi, the review focuses those from the order Hypocreales, for example, genera
,
,
,
, and
. The authors chose these groups of entomopathogenic bacteria and fungi based on their importance in the microbial biopesticide market.
Entomopathogenic fungi (EPF) contribute to different ecosystem services. However, factors affecting their natural occurrences in soil remain poorly understood. In a previous study, 81 soil samples ...were subjected to insect baiting using
and
to isolate EPF from Portuguese vine farms. Here, soils yielding any of the four common EPF, i.e.,
,
,
, and
f.
, were correlated with their chemical properties.
was negatively affected by higher available P (
= 0.02), exchangeable K-ions (
= 0.016) and positively affected by higher soil pH_H
O (
= 0.021). High exchangeable K-ions inhibited
(
= 0.011) and promoted
f.
(
= 0.03). Moreover, high available K also suppressed
(
= 0.027).
was inhibited by higher organic matter content (
= 0.009), higher C:N (
= 0.017), total N (
= 0.007), and exchangeable Mg-ions (
= 0.026), and promoted by higher exchangeable Na-ions (
= 0.003). Nonetheless, mean comparisons and principal component analysis suggested that higher soil pH and exchangeable Ca-ions have contrasting effects on EPF occurrences, as they promote
and inhibit
. Herbicides did not seem to affect EPF presence. Overall, this study is among the first reports on the effects of soil chemistry on EPF other than
, and will facilitate biological pest management approaches.
exhibits insect pathogenicity-however, generalized concerns of releasing phytopathogens within agroecosystems marred its entomopathogenicity-related investigations. In a previous study, soils were ...sampled from Douro vineyards and adjacent hedgerows. In this study, 80 of those soils were analyzed for their chemical properties and were subsequently co-related with the abundance of entomopathogenic
, after insect baiting of soils with
and
larvae. The soil chemical properties studied were organic matter content; total organic carbon; total nitrogen; available potassium; available phosphorus; exchangeable cations, such as K⁺, Na⁺, Ca
, and Mg
; pH; total acidity; degree of base saturation; and effective cation exchange capacity. Entomopathogenic
was found in 48 soils, i.e., 60% ± 5.47%, of the total soil samples. Out of the 1280 insect larvae used, 93, i.e., 7.26% ± 0.72%, were found dead by entomopathogenic
. Stepwise deletion of non-significant variables using a generalized linear model was followed by a generalized linear mixed model (GLMM). A higher C:N (logarithmized) (
< 0.001) and lower exchangeable K⁺ (logarithmized) (
= 0.008) were found significant for higher fungal abundance. Overall, this study suggests that entomopathogenic
is robust with regard to agricultural changes, and GLMM is a useful statistical tool for count data in ecology.
Fusarium verticillioides (Sacc.) Nirenberg (Fv) causes rots in maize around the world and produces mycotoxins that contaminate grains, making this species a significant health concern for both ...animals and humans. One of the best approaches to address rots is to identify highly tolerant or resistant genotypes that can be used for genetic improvement. The aim of the study was to evaluate dose-response assays to tolerance or resistance for Fv rots throughout the maize life cycle. These tests assessed the effects of Fv during post-germination development and the seedling (V2) stage by seed infection, the plantlet (V4) stage by substrate infection, and in the reproductive phase in maize stalks (R2 stage) and ears (R6 stage) by R1 stage inoculation. In all assays, the doses were effective at distinguishing contrasting phenotypes. Severity, root fresh weight, and aerial length were the most informative parameters at the V2 and V4 stages. Evaluation of the stalk necrosis area between and within the internodes of susceptible genotypes revealed significant differences among doses, and a positive correlation between necrosis and conidia concentration was observed in internodes. Injecting eight million conidia in the ear was sufficient for selecting different phenotypes. A total of 85% of the genotypes conserved their same capacity to respond to Fv infection throughout the maize life cycle, so that screening at the early vegetative stage (e.g., V2) could be useful for distinguishing contrasting phenotypes in the reproductive stage. Implementing these screening assays in a maize breeding program could be valuable for classifying the degrees of resilience of maize germplasms to Fv rots. This global screening has the potential to be employed to select against other Fusarium species.
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