Total Phenols,Flavonoids and Antioxidant Activity in Annona muricata and Annona purpurea Callus Culture

Callus cultures of Annona muricata and Annona purpurea were induced in Murashige and Skoog(MS)medium supplemented with different concentrations of 1-naphthylacetic acid(NAA),6-benzyladenine(BA)and 2,4-dichlorophenoxyacetic acid(2,4-D)utilized hypocotyls with explant.The highest percentage of callus formation was the treatment supplemented with 3 mg L-1 NAA for A.muricata(100%)while for A.purpurea in lower percentage(75%).BA stimulated the formation of shoots in all the evaluated concentrations,being the concentration of 2 mg L-1 the one that induced the greater formation of shoots for A.muricata(23 shoots/explant)and A.purpurea(28 shoots/explant).The content of total phenols,flavonoids and antioxidant activity was measured in the callus obtained from both species.The results showed that a higher content of total phenols was quantified in callus of A.purpurea(27.8 mg g-1 dw)compared to A.muricata(23.2 mg g-1 dw).The highest content of total flavonoids was observed in the callus of A.purpurea(8.0μg g-1 dw).Antioxidant activity was determined by the 2,2-diphenyl-1-picrylhydracil radical assay.The concentration required for 50%inhibition(IC50)of the 2,2-diphenyl-1-picrylhydracil radicals were 4.22μg mL-1 in methanolic extracts of callus of A.muricata,while in extracts of callus of A.purpurea was 2.86μg mL-1,in both cases was greater than that found for leaves.Callus culture of the species studied in this work represents an alternative for the production of natural antioxidants.

Coffee Leaf Rust(Hemileia vastatrix)Disease in Coffee Plants and Perspectives by the Disease Control

Coffee Leaf Rust(CLR)is caused by Hemileia vastatrix in Coffea spp.It is one of the most dangerous phytopathogens for coffee plantations in terms of coffee productivity and coffee cup quality.In this review,we resume the problem of CLR in Mexico and the pathogenesis of H.vastatrix.The review abord plant-pathogen interactions which lead a compatible or incompatible interactions and result in CLR disease or resistance,respectively.The review abord Coffea spp.defense response pathways involved in H.vastatrix pathogenicity.Additionally,current measures to control H.vastatrix proliferation and germination were aborded focused on phytosanitary actions,and biological and chemical control.Finally,new trendlines to reduce the impact of CLR as nanoparticles and nanotechnology were analyzed.

Synthesis and Characterization of Green Potassium Nanoparticles from Sideroxylon Capiri and Evaluation of Their Potential Antimicrobial

In the present study,the green synthesis of potassium nanoparticles(K-NPs)was assessed using aqueous extract of Sideroxylon capiri.The potassium nanoparticles were analyzed by UV-visible spectroscopic techniques,X-ray spectrometers of energy dispersive(SEM-EDS)and dynamic light scattering.The results showed high values at 3.5 keV confirming the formation of potassium nanoparticles and the SEM analysis showed an agglomerated particles size between 360 to 200 nm with a spherical morphology.The K-NPs showed an effective antibacterial activity against the test organisms mainly with Bacillus cereus,Enterobacter aerogenes,Fusarium solani and Botrytis cinerea.However further studies about nanotoxicity of K-NPs are needed to confirm their potential in the control of the pathogen microorganisms under field conditions.

Green Synthesis of Bimetallic Nanoparticles From Prosopis juliflora(Sw)DC.,and Its Effect Against Cotton Mealybug,Phenacoccus solenopsis(Hemiptera:Pseudococcidae)

Phenacoccus solenopsis has been recognized as an aggressively invasive species on cotton plants in different countries.This study was conducted to investigate the effect of green synthesized Cu/Zn-nanoparticles using aqueous leaf extract of Prosopis juliflora(mezquite)against P.solenopsis.The scanning electron microscope(SEM)showed bimetallic nanoparticles of Cu/Zn-NPs with spherical shape with varying size of 74.33 nm to 59.46 nm.More than 30%mortality of P.solenopsis was observed with Cu/Zn-nanoparticles(100 ppm)at 96 hours after treatment.Negligible mortality of P.solenopsis was recorded with Cu/Zn solution(100 ppm)and aqueous P.juliflora extracts.The results of the viability test for Cu/Zn-nanoparticles of P.juliflora showed a significant reduction of the cell viability by 50%in insect exposed to Cu/Zn-nanoparticles-P.juliflora.Therefore studies about nanotoxicity of Cu/Zn-NPs of P.juliflora are needed to reveal the mechanism of toxicity this phytonanoparticles in P.solenopsis.

Green Synthesis of Silver Nanoparticles from Abronia villosa as an Alternative to Control of Pathogenic Microorganisms

The aim of this study was to evaluate the antibacterial and antifungal activities of eco-friendly synthesized silver nanoparticles.The silver nanoparticles were synthesized by biological method using aqueous extract of Abronia villosa.Synthesis of silver nanoparticles was confirmed by color change and characterized using UV-visible spectroscopy,scanning electron microscope(SEM),energy dispersive X-ray spectroscopy(EDX),dynamic light scattering(DLS),and zeta potential analysis.The SEM analysis revealed the presence of spherical silver nanoparticles of the size range 21 to 33 nm.Synthesized silver nanoparticles were used to evaluate their antibacterial effects at different concentrations(25,50,75 and 100μg/ml)on gram negative and gram positive bacteria.The biggest halo zone was observed at 75 and 100μg/ml concentrations of silver nanoparticles against both gram positive and gram negative bacteria.Antifungal activity of biosynthesized silver nanoparticles was evaluated against seven different phytopathogenic fungi.AgNPs showed high inhibition of radial growth toward all tested fungi.The highest inhibition of fungal growth by AgNPs was recorded against Macrophomina phaseolina(86.06±0.92%).Biosynthesized AgNPs using plant extract are a promising to use safety for various biomedical and agricultural applications.