Authors:M. W. Abbasi, M. Q. Khan, M. J. Zaki, S. S. Shaukat, A. Rauf, N. Ahmed, M. Azeem, and M. Tariq
Bacillus thuringiensis (B.t) is well known for its biocontrol potential against a variety of insects. Nematicidal potential of ten B.t isolates was tested against root-knot nematodes (Meloidogyne javanica (Treub) Chitwood) in vitro, under greenhouse as well as in field conditions. Eggs and second stage juveniles (J2) were exposed to 5 and 25% concentrations of bacterial cell-free aqueous extracts up to 96 h. B.t isolates showed lesser degrees of nematicidal activity at 5% concentration. However, some B.t isolates (B.t-14, B.t-16 and B.t-64) greatly reduced egg hatching and increased J2. All B.t isolates revealed suppressed egg hatching and increased mortality of J2 at 25% concentration. Soil applications with most of the B.t isolates under greenhouse and field conditions significantly improved height and fresh weights of root-knot nematode parasitized okra (Abelmoschus esculentus (L.) Moench). Some isolates, including B.t-64 reduced the number of galls and egg masses. B.t-64 reduced gall formation up to 70% under greenhouse conditions. However, 29% of decrease was observed in field conditions. Similarly, B.t-64 treated plants showed a 56% decreased in eggs/egg mass in a field experiment. Population of root-knot nematodes in the rhizosphere was decreased up to 61% in the field experiment as compared to control.
Authors:A. Bellatreche, S.R. Mnasri, M. Ben Naceur, and S.S.B. Gaouar
Climate change has significantly affected wheat yield. Many studies have suggested that rising temperatures could be harmful to cereals around the world. Thus, the valorization of the desert wheat resources is essential to improve the resistance of this species to climate change. In this context, twenty-eight different local Saharan bread wheat (Triticumaestivum L.) genotypes were described using ten preselected SSR markers. The tested SSRs produced a total number of 20 alleles with an allelic size ranged from 100 pb (WMC261) to 400 pb (WMC257). The allele frequency varied from 0.1 for the allele 230 pb (WMC156) to 1 for the alleles 187 pb, 310 pb (WMC97, WMC168). Likewise, the PIC values ranged from 0 (WMC97, WMC168) to 0.5 (WMC327, WMC233), with an average of 0.34 and the observed heterozygosity (Ho) from 0 to 0.88, with an average of 0.55. The molecular variance (AMOVA) revealed the highest level of intra-population differentiation of local Saharan bread wheat (97%) and the statistical geometric distributions based on PCoA, NJ method and structure analysis confirmed the existence of four major classes of bread wheat. These results substantiate the previous researches based on the morphological markers and contribute for the first time in Algeria to create the genetic fingerprint of the Saharan bread wheat resources and to valorize their drought resistance potential through breeding programs.
Authors:C. Calderón del Cid, R. S. Rezende, A. R. Calor, J. S. Dahora, L. N. de Aragão, M. L. Guedes, A. N. Caiafa, and A. O. Medeiros
Leaf litter breakdown is an important process in riparian ecosystems, regulated by the concomitant fluctuations of allochthonous organic matter input (quality and quantity), the environmental conditions, and the decomposer community. Our objective was to assess the effects of temporal variability of litter quantity and quality over the stream's decomposer community. We hypothesized that the litter effects over the decomposer community would be overruled by Cerrado's harsh environmental conditions. Precipitation fluctuations, especially during dry and rain seasons, did modify the litterfall periodicity, but not the average organic matter entering the system or the litterfall triggers. Fifteen riparian species were identified contributing with organic matter into the stream, however, Richeria grandis contributed with 48% of litter biomass, helping explain the nutritional intra-annual balance given by the litter chemistry, that would be determinant for ecosystem stability. Higher aquatic hyphomycetes sporulation rates and invertebrate density during the dry season suggest that the decomposer community required a more stable environment (consistent low current) in order to colonize and exploit leaf litter. Our results point out that physical fragmentation was the predominant driver of litter breakdown for our system, due to high decomposition rates, litter remaining mass correlated negatively with precipitation, and low decomposer abundance and activity. Invertebrate collectors' abundance was negatively correlated with litter remaining mass and showed no temporal variation, suggesting that this functional group may have benefited from the particulate organic matter produced by physical fragmentation. Therefore, annual temporal variations on Brazilian savanna stream systems may drive the functioning of the ecosystem.
Authors:S. Feranchuk, N. Belkova, U. Potapova, I. Ochirov, D. Kuzmin, and S. Belikov
The methods for data presentation are important in bioinformatics as data processing algorithms. The article describes the software package for the extensive analysis of tables with estimates of bacterial abundance levels in environmental samples. The package was designed to be executed in a distributed hardware environment, with powerful packages in Python in the backend and interactive front-end forms. Most of microbial ecology-specific functionality is implemented by the scikit-bio Python package, together with the other Python packages intended for big data analysis. Interactive visualisation tools are implemented by the D3.js software library, therefore, the software project is named D3b. The package is a suite of tools for the analysis of microbial ecology data implemented as a web-service and as a desktop application. It supports a substantial part of the graphical and analytical descriptions of microbial communities used in scientific publications. Source codes are available at github (sferanchuk/d3b_charts) and the on-line version of the system is accessible at d3b-charts.bri-shur.com.
Avena spp. were artificially inoculated with Fusarium culmorum Sacc. (FC) and F. graminearum Schwabe (FG) causing Fusarium head blight (FHB). This disease is often accompanied by the accumulation of Fusarium mycotoxins mainly deoxynivalenol (DON) in grains. The contaminated grains with this mycotoxin are toxic to their consumers. Genotypes Avena spp. with low DON accumulation in grains can be used as genetic resources suitable for the formation of new resistant varieties of oats against FHB caused by fungi FC and FG. The aim was to find out and to compare the potential for mycotoxin accumulation in grains between genotypes of Avena spp. after artificial inoculation panicles by FC and FG using three spray methods and identify genotypes of Avena (A. abyssinica, A. byzantina, A. canariensis, A. fatua, A. ludoviciana, A. nuda, A. sativa, A. sterilis, A. strigosa) with low toxin accumulation in whole grain. The average accumulations of DON in the grains of Avena spp. gradually increased from the spray inoculation (0.68 mg · kg−1), spray + polyethylene (PE) bag cover 24 hrs (2.75 mg · kg−1) and spray + PE bag/48 hrs. (9.46 mg · kg−1) methods. We found out that after application of each used method, the high DON accumulation in grains was found in A. canariensis, and low DON levels were found in A. byzantine and A. sterilis.
We briefly complement Endrédi et al. (2019) forum paper from terrestrial animal ecological points of view. We discuss the origins of trait-based approach, challenges of trait classifications, and we provide an example of a commonly used trait, body size.
Authors:J. H. Pérez, E. Carneiro, F. G. Gaviria-Ortiz, M. M. Casagrande, and O. H. H. Mielke
Terrestrial ecosystems across the world experience large-scale and widespread urbanization, causing a sharp decline, fragmentation and segregation of natural landscapes. Nevertheless, fragments of natural habitats that are found within the largest cities may still be capable of preserving high species diversity that amount to a large portion of the regional biodiversity. Knowing which variables of the urban landscape promote the conservation of species' assemblages in large cities helps us to implement measures that support biodiversity conservation. We sampled the butterfly assemblages of eight urban forest fragments in Curitiba (Southern Brazil), from September 2015 to April 2016. At each site, richness, diversity and composition of butterflies were estimated and then correlated to nine landscape variables measured at two spatial scales (buffers of 250 and 750m). A total of 298 species were recorded in these fragments, representing 53.7% of all species known to occur in the city. Despite of great difference in the size of the fragments (between 27 and 56.3 ha), there were no significant differences in species richness among the fragments. On the other hand, some significant correlations were observed between landscape variables and butterfly composition other than the fragment itself, such as the paved area and total forested area present around the fragments. These results reinforce the idea that the conservation of natural fragments in urban areas requires public policies that enhance not only the habitat quality of the fragment itself, but also enrichment of the landscape around them.
Authors:N.V. Trubacheeva, E.D. Badaeva, T.S. Osadchaya, and L.A. Pershina
Wild barley, Hordeum marinum subsp. gussoneanum (2n = 28) is a valuable source of genes that determine resistance to abiotic stresses. These resistance traits might be transferred to wheat due to the crossability of wild barley with bread wheat. The availability of reliable and rapid methods for the identification of H. marinum subsp. gussoneanum chromatin in a wheat background would facilitate the development of introgression wheat genotypes. For this purpose, we evaluated the applicability of eighty-seven H. vulgare EST markers for studying bread wheat – H. marinum subsp. gussoneanum substitution and addition lines. Of all of the markers studied, forty-three (49%) were amplified in H. marinum ssp. gussoneanum and wheat introgression lines. The identification of wild barley chromosomes using EST markers confirmed the GISH and C-banding data. Thus, it was established that the H. vulgare EST markers can be successfully used to identify the chromosomes of the H. marinum subsp. gussoneanum in introgression lines of wheat.
Authors:P. Alfaya, J. G. Casanovas, J. Lobón-Rovira, B. Matallanas, A. Cruz, P. Arana, and G. Alonso
Iberian lynx distribution is currently restricted to the south of the Iberian Peninsula. Nevertheless, there is evidence of the presence of several small groups in the peninsular centre that have been forgotten by management and conservation actions. In this research, we gathered evidences of Iberian lynx presence along 21 transects located in the southwest of the Madrid province. In these transects lynx DNA was identified in 47 scats, which scientifically proves the presence of the species in that location. Using these locations (presence-only data) we built a maximum entropy model (MaxEnt) to estimate the suitability of the study area for the species. Our results show the existence of an almost continuous area that is approximately 744 km2 that is suitable for the Iberian lynx. Seventy-eight percent of this area is within the Natura 2000 network and, therefore, it falls under regulations to preserve and restore habitat types, flora and fauna. This study shows the suitability of this territory has for the Iberian lynx.
Shoots of ten day old seedlings of nineteen wheat genotypes were evaluated for proline metabolism, H2O2, thiobarbituric acid reactive substances (TBARS) and 2,2 diphenyl-picrylhydrazyl (DPPH) radical scavenging activity under water deficit, water withholding and salinity stress conditions. Principle component analysis demarcated four groups: i.e. drought tolerant (Excalibar, Krichauff, Babax, Drysdale, Gladius and C306), salt tolerant (Kharchia, Type11, Krl 1-4 and Krl 19), low stress tolerant (C273, C518 and C591) and susceptible (HD2967, PBW621, WH1105, HD3086, PBW660 and PBW175). Salt stress treatment affected the length, fresh weight and dry weight of seedlings of all studied genotypes in comparison to water deficit and water withholding condition which may be due to higher contents of TBARS. Shoots of salt and drought tolerant genotypes possessed higher proline content and DPPH radical scavenging activity alongwith reduced content of TBARS in parallel with decreased H2O2 content under water stress conditions. The activities of proline synthesizing enzymes i.e. pyrroline-5-carboxylate synthetase (P5CS) and pyrroline-5-carboxylate reductase (P5CR) were significantly higher than proline degrading enzyme viz. proline dehydrogenase (PDH) under water stress as compared to salinity stress conditions. Overall, results indicated that P5CS, P5CR and PDH activities led to higher build up of proline under water stress, which might play a significant role in improving membrane stability by increasing radical scavenging activity and finally imparting stress tolerance in specific wheat genotypes.