Five-year survey uncovers extensive diversity and temporal fluctuations among fusarium head blight pathogens of wheat and barley in Brazil

We conducted a five-year survey (2011–2015) of barley and wheat fields in Paraná state, Brazil, obtaining 754 Fusarium isolates from spikes with fusarium head blight (FHB)-symptoms. Multilocus genotyping and TEF-1α gene sequence analyses confirmed the dominance of the F. graminearum species complex (FGSC, 75.7%), but F. poae (11.5%), as well as F. avenaceum and related members of the F. tricinctum species complex (FTSC, 8.1%) appeared as substantial contributors to FHB. Within the FGSC, F. graminearum of the 15-ADON genotype was dominant (63%), followed by F. meridionale of the NIV genotype (23.1%), F. cortaderiae of the NIV (7%) or 3-ADON (2.6%) genotypes, and F. austroamericanum (3.8%) of the 3-ADON genotype. Substantial variation in pathogen composition was observed across years, with F. poae and F. meridionale frequencies significantly elevated in some years. Most F. poae strains produced DAS, diANIV, and butenolide, but not neosolaniol, T-2, or HT-2. All FTSC species produced moniliformin. Enniatin production was widespread among FTSC species, with the single F. acuminatum strain found to be the strongest producer of enniatins. Our findings confirm FGSC as a major contributor to FHB and expand considerably our knowledge of the presence, frequency, and conditions under which other pathogens may emerge, altering the spectrum of toxins that may accumulate in grain.     

Integrating species and successional classes for wood production in a mixed forest restoration system in a neotropical region

As forests in neotropical regions,particularly in developing countries,are devastated,interventions to restore biodiversity and its ecological functions are nee...     

Target and non-target site mechanisms of fungicide resistance and their implications for the management of crop pathogens

Fungicides are indispensable for high-quality crops, but the rapid emergence and evolution of fungicide resistance have become the most important issues in modern agriculture. Hence, the sustainability and profitability of agricultural production have been challenged due to the limited number of fungicide chemical classes. Resistance to site-specific fungicides has principally been linked to target and non-target site mechanisms. These mechanisms change the structure or expression level, affecting fungicide efficacy and resulting in different and varying resistance levels. This review provides background information about fungicide resistance mechanisms and their implications for developing anti-resistance strategies in plant pathogens. Here, our purpose was to review changes at the target and non-target sites of quinone outside inhibitor (QoI) fungicides, methyl-benzimidazole carbamate (MBC) fungicides, demethylation inhibitor (DMI) fungicides, and succinate dehydrogenase inhibitor (SDHI) fungicides and to evaluate if they may also be associated with a fitness cost on crop pathogen populations. The current knowledge suggests that understanding fungicide resistance mechanisms can facilitate resistance monitoring and assist in developing anti-resistance strategies and new fungicide molecules to help solve this issue. © 2023 Society of Chemical Industry.     

Sulfated Glucan from the Green Seaweed Caulerpa sertularioides Inhibits Adipogenesis through Suppression of Adipogenic and Lipogenic Key Factors

Sulfated polysaccharides (SPS) from seaweeds have great biochemical and biotechnological potential. This study aimed to investigate the effect of SPS isolated from the seaweed Caulerpa sertularioides on adipogenic differentiation as a possible alternative treatment for obesity. The SPS-rich extract from the seaweed C. sertularioides was fractioned into three SPS-rich fractions (F0.5; F0.9; and F1.8) chemically characterized. Among these four samples, only F0.9 showed a significant inhibitory effect on adipogenesis of 3T3-L1 preadipocytes. Ten SPS-rich fractions were isolated from F0.9 through ion-exchange chromatography. However, only the fraction (CS0.2) containing a sulfated glucan was able to inhibit adipogenesis. CS0.2 reduces lipid accumulation and inhibits the expression of key adipogenic (PPARγ, C/EBPβ, and C/EBPα) and lipogenic markers (SREBP-1c, Fabp4, and CD36). The data points to the potential of sulfated glucan from C. sertularioides for the development of functional approaches in obesity management.     

Effect of Temperature on Texture of Corn Tortilla With and Without Antistaling Agents

Tortilla stiffening should occur between ‐23 to 57°C, showing a maximum rate near the midpoint of this range (17°C). Starch recrystallization below the glass transition temperature (T_g = ‐23°C) in corn tortillas is minimal due to lack of molecular mobility. The objective of this study was to determine the effect of storage temperature (‐20 to 21°C) on the stiffening rate of corn tortillas with or without additives (carboxy‐methylcellulose [CMC] and maltogenic amylase). Tortilla pliability, stiffness, and energy dissipated obtained by stress relaxation, and amylopectin recrystallization determined by differential scanning calorimetry (DSC) showed a second‐order polynomial relationship with temperature. Tortillas became stiff faster during refrigerated storage (3–10°C). Adding 0.25% CMC and 1,650 AU of amylase maintained tortilla softness and flexibility, both at room temperature and under refrigeration for at least three weeks.     

Development and agronomic performance of common bean lines simultaneously resistant to anthracnose, angular leaf spot and rust

The common bean is affected by several pathogens that can cause severe yield losses. Here we report the introgression of resistance genes to anthracnose, angular leaf spot and rust in the 'carioca-type' bean cultivar 'Rudá'. Initially, four backcross (BC) lines were obtained using 'TO', 'AB 136', 'Ouro Negro' and 'AND 277' as donor parents. Molecular fingerprinting was used to select the lines genetically closer to the recurrent parent. The relative genetic distances between 'Rudá' and the BC lines varied between 0.0% and 1.99%. The BC lines were intercrossed and molecular markers linked to the resistance genes were used to identify the plants containing the genes of interest. These plants were selfed to obtain the F₂, F₃ and F₄ plants which were selected based on the presence of the molecular markers mentioned and resistance was confirmed in the F₄ generation by inoculation. Four F_4:7 pyramid lines with all the resistance genes showed resistance spectra equivalent to those of their respective donor parents. Yield tests showed that these lines are as productive as the best 'carioca-type' cultivars.     

Characterization of Open-Pollinated Maize Varieties from Rio Grande do Sul State

Journal of Crop Science and Biotechnology - The morphological characterization allows one to estimate and evaluate the genetic distance among different varieties, identifying heterotrophic groups...     

Rates of Chlorimuron Applied in Glyphosate-Tolerant and Sulfonylurea-Tolerant Soybean

Susceptibility to chlorimuron varies according to soybean genotype. STS® (sulfonylurea-tolerant soybean) presents a high tolerance to some sulfonylureas; this feature is determined by semi-dominants alleles, Als1 and Als2. Experiments were conducted in the field for four seasons with two cultivars for season to evaluate the selectivity of chlorimuron rates in post-emergency (V4) of glyphosate-tolerant and sulfonylurea-tolerant soybean. Data analysis made it possible to infer that there was no significant effect on the productivity of the cultivars when they received application in post-emergency, of chlorimuron at the doses used (0, 15, 30, 45, 60, 75, and 90 g ai ha^-1). The maximum recommended rate for non-STS cultivars of chlorimuron is 20 g ai ha^-1, or 4.5 times less than the maximum rate employed in this study. The soybean cultivars CD 250 RR/STS, CD 236 RR/STS, CD 2630 RR/STS, and BMX Turbo RR/STS were tolerant to the application, in post-emergency (V4) of the herbicide chlorimuron, until the rate of 90 g ai ha^-1.     

Search for molecular markers linked to Liriomyza trifolii resistance in tomato

Resistance to many arthropods, including Liriomyza species, is known to be present in accessions of Lycopersicon hirsutum (f. typicum or f. glabratum). From the cross L. esculentum cv. Moneymaker and L. hirsutum f. glabratum G1561 100 F₂ plants were screened in a no-choice test for resistance to Liriomyza trifolii. The Bulked Segregant Analysis approach was used to find Random Amplified Polymorphic DNA markers linked to resistance. Two markers were located on chromosome 2. Restriction Fragment Length Polymorphisms constructed a more detailed genetic linkage map for part of chromosome 2. Kruskal-Wallis analysis showed that this chromosome harbored a Quantitative Trait Locus (QTL) for number of pupae, number of mines and damage. At least one major QTL is essential for resistance and this QTL is located on chromosome 2 nearby the location of the tomato probe TG451. This revised version was published online in July 2006 with corrections to the Cover Date.     

Tolerance of potentially diazotrophic bacteria to adverse environmental conditions and plant growth-promotion in sugarcane

Sugarcane is one of the crops responsible for the high consumption of fertilizers in Brazil. To minimize this demand a sustainable alternative is to increase the studies to evaluate the beneficial effects of the relationship between plants/microorganisms, mainly plant growth-promoting bacteria. The objectives of this study were: a) to evaluate potentially diazotrophic bacteria isolates from sugarcane in adverse environmental conditions; b) inoculate these bacteria in sugarcane to evaluate their ability in plant growth-promotion. The study was carried in the Northeast of Brazil. Bacterial genera Burkholderia sp., Pantoea sp., Stenotrophomonas sp. and Enterobacter sp. were evaluated in different culture medium and later the bacterial isolates were inoculated in sugarcane evaluating the plant growth-promotion. Stenotrophomonas sp. and Pantoea sp. were tolerant to salinity and to different sources of carbon in acid medium and too tolerated high concentrations of pesticides and produced quorum sensing molecules (QS), but did not increase the dry matter production of sugarcane. Burkholderia sp. and Enterobacter sp. were more sensitive to salinity and pest control, but were more effective in plant growth-promotion. The tolerance of the bacteria to the adverse environmental conditions interfered negatively in the ability to plant growth-promotion.