Identification of Rhizobia Isolated from Nodules of Mexican Commercial Soybean Varieties

Rhizobia, crucial for nitrogen fixation in leguminous plants, play a vital role in soybean cultivation. This study, conducted in Mexico, a major soybean importer, aimed to identify bacteria from nodules of five soybean varieties in high-production regions. Multilocus sequence analysis (MLSA) was employed for enhanced species resolution. The study identified six Bradyrhizobium species: Bradyrhizobium japonicum USDA 110, Bradyrhizobium japonicum USDA 6, Bradyrhizobium elkanii USDA 76, Bradyrhizobium neotropicale, Bradyrhizobium lablabi, and Bradyrhizobium icense. Bradyrhizobium japonicum USDA 110 predominated in the soils, displaying symbiotic preference for the Huasteca 400 variety. However, phylogenetic analysis didn't reveal a clear association between strains, soil, and soybean variety. This research sheds light on the diversity of rhizobia in Mexican soybean cultivation, contributing to the understanding of symbiotic relationships in soybean production systems.

In vitro Mutagenesis for the Improvement of Agave Genus

Biotechnological techniques provide a viable alternative to help improve and increase the production of plant species of agricultural and economic importance,which have been affected over the years by climate change,increasing their susceptibility to pests and/or diseases,generating losses in production as well as a decrease in their regenerative and genetic diversity.The application of biotechnological techniques such as in vitro mutagenesis offers a viable option for the generation of crops that are resistant to the different factors caused by abiotic and biotic stress.In vitro mutagenesis has been used in an efficient way to generate genetic changes in different plant species.However,these methods have not been studied thoroughly in crops of agro-industrial interest,such as agave,which represents an economic resource of national importance and are considered as endemic species of Mexico.Therefore,this literary review aimed to focus on the studies that have been used for the genetic improvement of this species via mutagenesis techniques in plants in the agave genus.Therefore,the objective was to set a precedent for future genetic studies that aim to obtain more productive regenerants for various industries,such as food and pharmaceutical.It is also of great interest to compile information from basic research that helps understand and elucidate a model of possible defense mechanisms that are activated in the Agave genus.

Effects of Plant Extracts and Beauveria bassiana on the Activity of Defense-Related Enzymes in Solanum lycopersicum L.during Interaction with Fusarium oxysporum f.sp.lycopersici

The objective to this work was to evaluate the enzymatic activity in the culture of Solanum lycopersicum L.infected with Fusarium oxysporum after the combined application of Beauveria bassiana and plant extracts.Solanum lycopersicum plantlets were transplanted 15 days after the emergency.Five days after transplanting,Beauveria bassiana spores were applied at a concentration of 1×10^(7)spores mL^(−1)onto soil(along with A.indica(N)and P.auritum(H)leaf extracts)where S.lycopersicum plants were planted.Eight days after transplanting,spores of F.oxysporum strain were applied at a concentration of 1×10^(6)spores mL^(−1)to soil where S.lycopersicum plants were growing.The development of S.lycopersicum plants was monitored for 114 days,whereby a randomized complete block treatment design was used,the roots of the plants were crushed with liquid nitrogen,after which UV/VIS spectrophotometry was used to determine protein concentration,as well as the activity ofβ-1,3-glucanases,peroxidases(POX,EC1.11.1.7),catalase and chitinases.The treatments combining B.bassiana and A.indica and P.auritum extracts,had a significant difference in enzymatic activity levels,thus contributing to better defense mechanisms and a greater protection to S.lycopersicum plants in the presence of F.oxysporum.The application of B.bassiana and plant extracts to the ground mitigated damage caused by F.oxysporum on S.lycopersicum plants.

The best of both worlds:mastering nerve regeneration combining biological and nanotechnological tools

Over the last decade,remarkable developments in nanotechnology have powered medical research,unveiling new approaches for the solution of public health issues such as the treatment of traumatic peripheral neuropathies.

Antifungal Potential of Beauveria bassiana on Solanum lycopersicum L. Infected with Fusarium oxysporum f. sp. lycopersici

The objective of this work was to evaluate the effect of Beauveria bassiana(Bb 1205)on controlling Fusarium oxysporum f.sp.lycopersici(Fol 17108)in tomato plants in greenhouse conditions.Inoculation of Bb 1205 was the most promising among the agronomic variables and expression of the activity of the enzymesβ-1,3-glucanases and chitinases.Inoculation of Bb 1205 occurred at a concentration of 1×108 conidia·mL−1,which was administered onto the leaves,directly into the soil and via injection.Infection with Fol 17108 occurred with 1×106 spores·mL−1,which were added directly to the soil.Spectrophotometry was used for measuring agronomic parameters,namely activity of chitinases andβ-1,3-glucanases in foliage and roots.When Bb 1205 was added to the soil,the chlorophyll index and aerial part length showed significant differences.In addition,it was determined that root length,fresh weight of foliage,flower,and fruit count increased 82 days after inoculation(dai).Chitinase activity induced by Bb 1205 in leaves and roots of tomato plants infected with Fol 17108 was observed when injected into the stem at 32 dai(41.8 and 11.6-fold,respectively).Inoculation on the foliage showed a 10-fold increase ofβ-1,3-glucanases in the roots after 82 dpi.As for leaves,a 3.8-fold increase was found when the stem was inoculated.In the different in vivo applications,Bb 1205 activated its defenses by expressing the chitinase enzymes andβ-1,3-glucanase,thus reducing the damage caused by Fol 17108,demonstrating increase plant growth thereafter.

Effect of Water Stress Induced by Polyethylene Glycol on Growth, Proline Accumulation in Agave americana L.

The effect of water deficit was determined on both in vitro and soil seedling as well as in cells in suspension of Agave americana L.In order to do the establishment of cells,the formation of callus was induced;for it two auxins were evaluated:2,4-dichlorophenoxyacetic acid(2,4-D)and 4-mino-3,5,6-trichloropicolinic acid(picloram)at three concentrations(0.25,0.5 and 0.75 mg L−1)in three explants(leaf,root and meristems)cultured in MS semisolid medium.The callogenesis response was related to the type and section of the explant,as well as the regulator used,and a cell suspension was established using 0.5 mg L−1 naphthaleneacetic acid(NAA)+0.5 mg L−1 Benzylaminopurine(BAP).Seedlings were exposed to polyethyleneglycol(15%and 30%w/v)with a water potential of−0.87 and−2.67 MPa,respectively,under soil conditions.Water stress was applied through restricted irrigation.Fresh weight,root system growth,and chlorophyll concentration were some of the parameters that were affected by the effect of water deficit on A.americana L.Chlorophyll concentration values were significantly decreased by 15 at 30%PEG(19.6 SPAD units)compared to the control treatment.In in vitro plants,the highest concentration of proline was found in the roots,being the treatment with 30%polyethylene glycol where the highest concentration of this osmoregulator was obtained(62.5 mg g−1 DW).Under restricted irrigation conditions,an increase in proline concentration was observed both in the aerial part(2.2μg 100 g−1 DW)and in the root system(1.8μg 100 g−1 DW).However,the concentrations found were approximately ten times greater,less than those found under in vitro conditions.Therefore,the accumulation of proline can be considered an indicator of stress in Agave Americana L.growth in vitro.

Selection and Analysis of Polymorphisms in Somaclonal Variants of Agave americana Resistant to Fusarium oxysporum via an Ethyl Methanesulphonate Treatment

Agave americana L.callus were exposed to different concentrations of ethyl methanesulphonate(EMS)0,15,30,45 and 60 mM and to different times of exposure(2 and 4 h).The viability and capacity of shoot formation were shown to be affected when the callus were exposed to high concentrations(30–60 mM).Only the callus exposed to 15 mM EMS presented shoot formation;the exposure time of two hours produced the largest quantity of shoots regenerated per callus(21 shoots/callus).In order to generate somaclonal variants resistant to Fusarium oxysporum,a selection pressure was applied through of a culture filtrate(CF)of 100 ppm of the fungus.This was made in callus obtained in the treatment with 15 mM EMS during 2 h of exposure.The CF caused oxidation and necrosis in 71.25%of the callus;however,they were capable of generating shoots(3.5 shoots/callus).Molecular markers type RAPD,ISSR and DAMD were used to evaluate the genetic variation arising from the mutations caused by EMS on control plants and 16-month-old somaclonal variants.The polymorphic information content(PIC)for each one of the initiating groups was:0.28(DAMD),0.09(ISSR)and 0.14(RAPD).DAMD revealed a greater percentage of polymorphism than RAPD and ISSR.Polymorphic bands were detected in the somaclonal variants.This indicated that the EMS caused genetic variation in the regenerated plants conferring resistance to them against Fusarium oxysporum.

Ultrastructural Analysis of the Ontogenetic Development of Shoot Induced from Embryonic Axes of Costa Rican Bean Varieties (<i>Phaseolus vulgaris</i>L.) under <i>in Vitro</i>Conditions by Scanning Electronic Microscopy

Common bean (Phaseolus vulgaris L.) is an economic important crop and one of the major grain legumes for human consumption in Latin America, Africa and Asia. A morphological study of shoot induced from embryonic axes development in four Costa Rican bean varieties (Brunca, Huetar, Guaymi and Bribri) cultivated on MS media with or without 5 mg·L–1 de N6-benzylaminopurine (BAP) by scanning electron microscopy (SEM) was developed in the present work. Micrographs showed similarities and differences in the ultrastructure of the apical dome, epidermal surface, stomata and different types of trichomes in the varieties cultivated on organogenesis media. Genotypes with advantageous morphological characteristics for genetic transformation, in particular an exposed apical dome, were identified. This work will contribute to the optimization of the in vitro regeneration of four common bean varieties.

Encapsulation of Immature Somatic Embryos of Coffea arabica L.for in Vitro Preservation

The present study aimed to develop a protocol for somatic embryogenesis and encapsulation of coffee embryos(Coffea arabica L.),for the conservation of genotypes with characteristics of commercial interest.Somatic embryos were induced from leaf explants in Murashige and Skoog medium(MS)supplemented with 1 mg·L^(−1) of 2,4-dichlorophenoxiacetic acid(2,4-D)combined with 2 mg·L^(−1) of benzyladenine(BA).Somatic embryos(SE)at the globular stage were encapsulated in a sodium alginate matrix;two treatments were tested:MS+5 mg·L^(−1) BA+1 mg·L^(−1) NAA+3%(w/v)alginate,and MS+7 mg·L^(−1) BA+5.7 mg·L^(−1) indoleacetic acid(IAA)+3%(w/v)alginate.Alginate was complexed with 100 mM calcium chloride(CaCl_(2)).Viability of the encapsulated SE was determined by staining with 0.01%fluorescein diacetate(FDA)after 0,15,30,and 45 days of storage at 4℃.Embryo viability was 100%in both treatments.

Morphometric and Biochemical Changes in Agave americana L.Plantlets Induced By Ethyl Methanesulfonate

A.americana L.is a crop with very little genetic variability.In order to evaluate the effect of ethyl methanesulfonate(EMS)to induce variability in in vitro plantlets of A.americana,different explants(meristems,leaves and roots)were evaluated for the production of callus.MS medium supplemented with ANA(2.68μM)and BAP(2.68μM)was used.Callus obtained from apical meristem were treated with 15 mM EMS for two hours after which shoot formation was induced using 2,4-D(0.11μM)and BAP(44μM).The EMS induced variations in the morphometric and morphological parameters of the plantlets obtained,with 60%of the plantlets presenting differences such as dwarfism and different leaf forms,without the presence of spines,as well as an increase in fructan content of 30%with respect to the control plantlets.PAL was increased and this activity is related with higher anthocyanins concentration in A.americana L.plantlets.

Renin-angiotensin system blockade: Effect on renal mRNA expression in 5/6 nephrectomized rats

The aim of this study was to determinate the gene expression levels of angiotensinogen, angiotensin converting enzyme, renin, (pro)renin receptor, and the final rennin-angiotensin system (RAS) products Angiotensin (Ang) II and Ang 1-7 inthe remnant kidney of 5/6 nephrectomized rats and its response to RAS pharmacological blockade. Male Wistar rats were divided into five groups: sham operated (SO), 5/6 nephrectomized (NFX), NFX + captopril (50 mg/ kg/day), NFX + losartan (10 mg/kg/day), and NFX + aliskiren (10 mg/kg/day). Animals were followed up for 60 days and protein urine excretion was measured. Systolic blood pressure, renal tissue RAS mRNA expression levels, plasma Ang II, and plasma Ang 1-7 were evaluated at day 60 after nephrectomy. Blood pressure and urine protein were increased after 5/6 nephrectomy. Ang II levels were increased 9.4 fold, whereas Ang 1-7 decreased 72.9% in NFX animals compared with SO rats. 5/6 nephrectomy increased renal angiotensinogen and (pro)renin receptor mRNA expression but down-regulated renin mRNA expression. RAS blockade restored the systolic blood pressure to normal values and slowed down urinary protein excretion, and also prevented changes in Ang II and Ang 1-7. RAS blockade reduced (pro)renin receptor, ACE, and AGT mRNA expression in the remnant kidney. However, renin mRNA expression increased compared with NFX rats. In conclusion these results suggest that inhibition of Ang II synthesis by RAS blockade is associated with renal regulation of RAS mRNA expression and this may be through a mechanism related with the Ang II/Ang 1-7 balance.

Cryopreservation of Seeds and Embryos of Jatropha curcas L.

Jatropha curcas is a species with a variety of uses. It is grown primarily for oil for biodiesel, but also has agronomic and medicinal applications. Two methods were evaluated for cryopreservation of seeds and zygotic embryos of J. curcas: desiccation followed by rapid immersion of seeds and embryos in liquid nitrogen (LN, -196°C), and vitrification of zygotic embryos. Prior to cryo-preservation, seeds were manually scarified and the moisture content (MC) of seeds and embryos was determined. Explants were disinfected after cryopreservation. Seed germination after LN exposure was 100%. Plantlet development was better in sand substrate than that in vitro. Survival of zygotic embryos after cryopreservation was also 100%, without significant differences between treatments. Optimal development (100%) and plantlet length (51.77 mm) were observed with embryos dried for 60 min to 9.4% MC under laminar flow prior to cryopreservation. Zygotic embryos subjected to the vitrification procedure did not withstand LN exposure. Survival data for non-cryopreserved embryos after each step of the vitrification procedure provided information about embryo tolerance to cryoprotectants.

Inhibition of Acinetobacter baumannii Biofilm Formation by Methanolic Extract of Nothoscordum bivalve

Acinetobacter baumannii is one of the most prevalent pathogens in nosocomial infections and has been cause of concern in recent years because, it has presented multiresistance to antibiotics and besides can form biofilms on biotic and abiotic surfaces like tissues and medical devices. Therefore, the search for new alternatives of natural origin to inhibit biofilm formation is being conducted. In the present investigation, sub-lethal concentrations (5.61 mg/mL, 3.74 mg/mL and 1.87 mg/mL) of methanolic extract of Nothoscordum bivalve were evaluated, showing biofilm formation inhibition up to 40.8%, in one nosocomial isolated of A. baumannii by the microtiter biofilm formation assay using crystal violet. On the other hand, the concentrations of 5.61 mg/mL and 3.74 mg/mL, caused an overexpression (up to 15.4 times) in the genes involved in the formation of biofilm (abaI, bap and csuE);due to this, the interaction of the extract with the bacteria was analyzed by scanning electron microscopy (SEM) and cellular damage was observed in the structure and stability of biofilm.

Rice straw recycling: A sustainable approach for ensuring environmental quality and economic security

One of the major challenges in Asian countries is the effective management of rice straw.To ensure food security for their ever-growing population,Asian countries grow more rice,leading to increasing rice straw generation.Burning of rice straw,a common practice,is detrimental to both environmental and human health.However,if managed effectively,rice straw has the potential to safeguard the sustainability of agricultural ecosystems and to uplift the economic security of the population depending on rice farming.Judicious management of rice straw involving minimum soil disturbance along with retention of residues alters the soil carbon cycle through reduced carbon emissions and increased levels of total soil organic carbon.Several alternative uses of rice straw,such as production of livestock feed,bioethanol,biochar,biogas,electricity,mushroom,and paper,can add prosperity to rice farmers’life by fetching extra income.It is evident that efficient management of rice straw is of enormous economic value.Therefore,it is essential to create awareness among the different rice stakeholders of these alternative economic avenues associated with rice straw.This review is an attempt to provide effective options for sustainable rice straw management and rice straw value chains for harnessing its economic potential.It further identifies gaps in our understanding of the effects of rice straw on ecological sustainability,particularly concerning the multifaceted connections between the diverse mechanisms of rice agro-ecosystems,which may greatly influence food security in the 21st century.

Dietary carbohydrate-to-protein ratio influences growth performance,hepatic health and dynamic of gut microbiota in atlantic salmon(Salmo salar)

Atlantic salmon(Salmo salar)fed a carbohydrate-rich diet exhibit suboptimal growth performance,along with other metabolic disturbances.It is well known that gut microbes play a pivotal role in influencing metabolism of the host,and these microbes can be modified by the diet.The main goal of the present study was to determine the effect of feeding graded levels of digestible carbohydrates to Atlantic salmon on the distal intestine digesta microbiota at 3 sampling times(i.e.,weeks 4,8 and 12),during a 12-week trial.A low carbohydrate-to-high protein diet(LC/HP,0%wheat starch),a medium carbohydrate-tomedium protein diet(MC/MP,15%wheat starch)or a high carbohydrate-to-low protein diet(HC/LP,30%wheat starch)was fed to triplicate fish tanks(27 to 28 fish per tank).We performed an in-depth characterization of the distal intestine digesta microbiota.Further,growth parameters,liver histology and the expression of genes involved in hepatic neolipogenesis in fish were measured.Fish fed a HC/LP diet showed greater hepatosomatic and viscerosomatic indexes(P=0.026 and P=0.018,respectively),lower final weight(P=0.005),weight gain(P=0.003),feed efficiency(P=0.033)and growth rate(P=0.003)compared with fish fed the LC/HP diet.Further,feeding salmon a high digestible carbohydrate diet caused greater lipid vacuolization,steatosis index(P=0.007)and expression of fatty acid synthase(fas)and delta-6 fatty acyl desaturase(d6fad)(P=0.001 and P=0.001,respectively)in the liver compared with fish fed the LC/HP diet.Although,the major impact of feeding a carbohydrate-rich diet to Atlantic salmon in beta diversity of distal intestine digesta microbiota was observed at week 4(HC/LP vs MC/MP and HC/LP vs LC/HP;P=0.007 and P=0.008,respectively)and week 8(HC/LP vs MC/MP;P=0.04),no differences between experimental groups were detected after 12 weeks of feeding.Finally,at the end of the trial,there was a negative correlation between lactic acid bacteria(LAB)members,including Leuconostoc and Lactobacillus,with hepatic steatosis level,the hepatosomatic and viscerosomatic indexes as well as the expression of fas and d6fad.Weissella showed negative correlation with hepatic steatosis level and the hepatosomatic index.Finally,further research to explore the potential use of LAB as probiotics to improve liver health in carnivorous fish fed fatty liver-induced diet is warranted.

Maize seed coatings and seedling sprayings with chitosan and hydrogen peroxide:their influence on some phenological and biochemical behaviors

Objective:To evaluate the effect of chitosan(CH) and hydrogen peroxide(H2O2) seed coatings and seedling sprinklings on two different maize varieties by measuring their phenology,the H2O2 presence,the catalase(CAT) activity,and the protein quantity.Methods:Seven groups of ten seeds for each maize variety were treated with CH(2%(20 g/L) and 0.2%(2 g/L)) or H2O2(8 mmol/L) by coating,sprinkling,or both.Germination and seedling growth were measured.One month after germination,the presence of H2O2 in seedlings in the coated seed treatments was evaluated.Protein content and CAT activity were determined under all treatments.Results:H2O2 seed coating enhanced the germination rate and increased seedling and stem length in the quality protein maize(QPM) variety.Seedlings had a higher emergence velocity under this treatment in both varieties.CH and H2O2 sprinklings did not have an effect on seedling phenology.Exogenous application of H2O2 promoted an increase of endogenous H2O2.CH and H2O2 seedling sprinkling increased the protein content in both maize varieties,while there was no significant effect on the CAT activity of treated seeds and seedlings.Conclusions:CH and H2O2 enhance some phenological and biochemical features of maize depending on their method of application.