Peroxidase Isozymes Research Articles

Genetic Variation of Hampala Fish (Hampala macrolepidota) Population in PB. Soedirman Reservoir and Serayu River

Panglima Besar Soedirman waters reservoir and the Serayu River in Banjarnegara Regency, Central Java is one of the habitats of hampala fish . Hampala fish is a member of the Cyprinidae family, which has economic value but is fully captured from the wild. The study on the genetic diversity using approaches of isozyme analysis needed to support conservation and domestication of the fish in this area. This study was aimed at the genetic variation of the hampala fish population in PB. Soedirman water reservoir and the Serayu River in Banjarnegara Regency based on esterase (EST), acid phosphatase (ACP), peroxidase (PER), and aspartate aminotransferase (AAT). Visualization of the isozyme was carried out employing horizontal electrophoretic technique with potato starch. From the results of this study it can be concluded that the hampala fish from the reservoir of PB. Soedirman, Serayu River area before reservoir and after reservoir, all of which are in Banjarnegara Regency, can visualized isozymes EST, ACP, and AAT well, except PER isozyme. This finding can be used as based information on population genetics and finally can be used for conservation of this fish. The results of this study are expected to be utilized to evaluate the potential genetic condition of hampala fish, which is the basis for conservation strategy and domestication.

Enhanced pest resistance and increased phenolic production in maize callus transgenically expressing a maize chalcone isomerase -3 like gene

Significant losses in maize production are due to damage by insects and ear rot fungi. A gene designated as chalcone isomerase 3-like (CI3), located in a quantitative trait locus for resistance to Fusarium ear rot fungi, was cloned from a Fusarium ear rot resistant inbred and transgenically expressed in maize callus. Transformants were often more resistant to feeding by the corn earworm and fall armyworm compared to glucuronidase (GUS) callus transformant controls. The transformed callus was also more resistant to colonization by the mycotoxin producing ear rot fungi Fusarium graminearum, Fusarium proliferatum, and Fusarium verticillioides. Chemical analysis unexpectedly indicated increased production of several phenolic compounds, instead of flavonoids, compared to GUS controls. The levels of one of these, a glucosylated ferulic acid, were significantly correlated with the degree of growth inhibition of F. graminearum. Increased levels of a peroxidase isozyme previously associated with pest resistance also occurred in these CI3 transformants. The production of phenolics and higher levels of a peroxidase suggests this gene product is behaving as a fatty acid binding protein and enhancing transport of fatty acids involved in the production of jasmonic acid, which can induce the biosynthesis of resistance molecules. Breeding for enhanced expression of this gene can potentially contribute to resistance to both insects and plant pathogenic fungi, thereby contributing to sustainable production and better quality food.

Salicylic Acid Attenuates the Adverse Effects of Salinity on Growth and Yield and Enhances Peroxidase Isozymes Expression more Competently than Proline and Glycine Betaine in Cucumber Plants

Foliar applications of osmoprotectants could be a valuable tool to counteract the deleterious effects of salinity and protect plant cells from oxidative damage. Some of the known osmoprotectants used in this field are salicylic acid, proline, and/or glycine betaine but there is no available empirical research exists to figure out which of these chemicals is the most effective in reducing the adverse effects of salt stress. To compare the ameliorating effects of foliar application of these osmoprotectants on growth, some physiological and biochemical parameters, and productivity of cucumber plants under NaCl stress (0, 50, or 100 mM), a factorial experiment was carried out during 2015 and 2016 seasons at the Experimental Farm of Horticulture Department, Faculty of Agriculture, Ain Shams University, Qalubia Governorate, Egypt. Increasing NaCl levels reduced plant growth parameters, leaf relative water content, leaf membrane stability, chlorophyll contents, some macro-nutrients content and yield and the lowest values were recorded with the use of 100 mM of sodium chloride treatment. Foliar application of salicylic acid at 1 mM, proline at 10 mM, or glycine betaine at 10 mM to cucumber plants ameliorated the harmful effects of NaCl stress on the vegetative growth and yield through enhancing both leaf relative water content and leaf membrane stability. In addition, these treatments improved both chlorophyll contents, and nutrient content, altogether resulted in a significant reduction in sodium (Na+) and chloride (Cl−) accumulation toxicity. Moreover, the expression of cucumber peroxidase isozymes was analyzed in cucumber leaves 1, 3 and 7 days after the second application. Native polyacrylamide gel electrophoresis analysis indicated that exogenous applications led to the differential regulation of peroxidase enzyme. In conclusion, salicylic acid was the most effective in attenuating the negative effects of the salt stress and in up-regulating peroxidase enzyme expression followed by proline and by glycine betaine. Peroxidase enzyme appeared to function as one of the main molecular mechanisms underlying the resistance response of cucumber to salinity.

Purification and Characterization of Lignin Peroxidase Isozymes from Humicola grisea (Traaen) and Its Application in Bioremediation of Textile Dyes

PEROXIDASES have numerous important applications in industries and biodegradation of organopollutants , so there is a need to explore more and more sources of enzymes with different characteristics. In the present study, lignin peroxidases (LiPs) producing by fungus Humicola grisea were extracted and purified using gel filtration and ion exchange chromatography. Protein and heme protein were eluted in different peaks about 6 of these peaks had LiP activity and this is an indication that LiP in H. grisea was isoenzymes. Four of these isoenzymes were characterized regarding their molecular mass, optimum temperature and optimum pH for activity, substrate concentration and effect of some metal ions. The four purified isoenzymes have maximum activities at different temperatures, where optimum temperature for H2 and H4 isoenzyme were at 60 oC, and the optimum temperatures for H1 and H3 were at 40 oC and 30 oC, respectively. The maximum activities of the four isoenzymes were within the acidic range. The different LiP isoenzymes showed different Km and Vmax values representing the varied affinity of the four isoenzymes using veratryl alcohol as a substrate. Km values for H1, H2, H3 and H4 were 5.26, 5.0, 1.3 and 1.4, respectively. While Vmax values for the same isoenzymes were 1.25, 0.8, 0.87 and 1.1, respectively.

Biochemical Markers and Genetic Improvement in some Tomato Genotypes under Drought Stress Conditions

This study was conducted at the Experimental Farm of Maryout Research Station; Desert Research Center,Alexandria Governorate, in addition to the Genetic and Cytological Laboratory of Desert Research Center, Matarya,Cairo, Egypt; during summer growing seasons from 2012/2013 and 2013/2014, in order to evaluate some tomatogenotypes under drought stress conditions. The tolerant parent UC82B, susceptible parents, Peto82, Super Marmande andSuper Strain B with their crosses and reciprocal crosses were used. The results showed that there was unique band 35KDawas found in hybrid UC82B×Super Strain B due to it represent specialized mechanism in the tolerant genotypes underdrought stress conditions as well as a unique band 42 KDa which was represented in hybrid Super Marmande×UC82B. Inaddition, the results of peroxidaseis ozymes indicated that the unique band associated with line of UC82B. This bandcould be considered as a distinguished marker for the tolerant line of UC82B under drought stress conditions. Also, theresults of polyphenoloxidase isozymes indicated that there are four common monomorphic bands were mentioned at thebands of 1, 2, 5 and 6 with molecular weight. These common bands could consider as markers for positive identificationof previously mentioned genotypes under drought stress conditions. On the other hand, a unique band 4 associated withline LA3772) of UC82B. This band could be considered as a distinguished marker for the tolerant line of UC82B underdrought stress conditions. Moreover, the phylogenetic tree indicated that one cluster included the hybrids SuperMarmande×UC82B and reciprocal hybrid Super Marmande×UC82B and UC82B in sup cluster as a tolerant parentalgenotype.

Peroxidase actvity, its isozymes and deterioration of pearl millet [Pennisetum glaucum(L.) R. BR.] flour during storage

Development of off odour and flavour is an old and unresolved problem associated with pearl millet flour during storage and is the major hindrance for their consumer acceptability. In this study role of peroxidase, lipids and phenolics in deterioration of quality of pearl millet in control and stored flour of high (HHB 94) and low (ICMA 94222 x 78/71) rancid genotype was determined. Fat content, fat acidity, free fatty acids, total phenols, C-glycosylflavones content and peroxidase activity of HHB 94 were higher than that of ICMA 94222 x 78/71. Storage of flour for 8 days of these two genotypes showed significant increase in fat acidity and free fatty acids. Storage had no effect on C-glycosylflavones content whereas peroxidase activity reduced significantly with storage time. Isozyme profile showed that pearl millet grains had 3 isozymes of peroxidase and banding pattern was similar in both HHB 94 and ICMA 94222 x 78/71. While banding intensity represented that ICMA 94222 x 78/711 had lesser peroxidase activity as compared to HHB 94. The result suggested that peroxidase activity, fat acidity and free fatty acid value were usually correlated.

三棱角油菜两类角果的酯酶同工酶和过氧化物酶同工酶比较分析

本文以3个甘蓝型三棱角油菜为材料，在油菜花角期对各材料长度分别为1 cm、3 cm以及5 cm三个不同发育阶段的幼嫩三棱角果(三室)和普通角果(两室)的酯酶(EST)和过氧化物酶(POD)同工酶进行聚丙烯酰胺垂直板凝胶电泳和酶谱的比较分析，以研究三室角果与两室角果在EST和POD同工酶水平上的异同性。研究结果表明：1) 同一材料相同发育阶段三室角果和两室角果的EST同工酶，其带型表现一致，无明显差异，但个别同工酶的酶活性有一定的差异；同一材料相同发育阶段两者的POD同工酶，其带型也表现一致，只是少数同工酶的酶活性有一定的差异。2) 同一材料在三个不同发育阶段的三室角果或两室角果的EST同工酶带型无明显差异，POD同工酶带型也无明显差异，但酶活性存在一定的差异。3) 对EST同工酶和POD同工酶而言，角果越小，酶活性越强，即随着角果的生长发育其酶活性表现为减弱的趋势。4) 3个材料的EST同工酶酶谱比较而言，14ds67与14ds72的酶谱相似程度较高，带型一致，而14ds78的酶谱与前两者的差异较大，说明三棱角材料14ds67和14ds72的亲缘关系较近，而14ds78与前两者的亲缘关系较远。然而，3个材料的POD同工酶酶谱相比较无明显差异，酶带的一致性较好，只是少数条带的酶活性有一定的差异。5) POD同工酶酶谱的酶带数目明显少于相应材料的EST同工酶酶谱的酶带数目，而且迁移快的条带为强带。因此，三室角果与两室角果分别在EST同工酶酶谱和POD同工酶酶谱水平上表现出较强的一致性。 To study the differences of Esterase (EST) and Peroxidase (POD) isozymeograms between triquetrum-siliques (tri-loculus) and ordinary siliques (bi-loculus) of triquetrum-silique materials in Bras- sica napus L., the enzyme spectrums of young siliques of length of 1 cm, 3 cm and 5 cm from 3 selfing populations were analyzed by the polyacrylamide vertical board gel electrophoresis in flowering and silique stage of rapeseed. The results show that: 1) There were no obvious differences in EST isozyme patterns between tri-loculus siliques and bi-loculus siliques in the same developmental stages for the same materials, but there were certain differences in enzyme activity for individual isozymes. In POD isozyme patterns, tri-loculus siliques and bi-loculus siliques were also similar, but there were certain differences in enzyme activity for a few isozymes. 2) The patterns of EST isozymeograms had no significant difference to the siliques in 3 developmental stages for the same materials, the patterns of POD isozymeograms had also no significant difference, but there were some differences in enzyme activity for them. 3) On EST and POD isozymeograms, the smaller the siliques were, the stronger the enzyme activity would be, i.e., the enzyme activity showed a decreasing trend along with the growing and developing of the siliques. 4) Isozyme spectrums of EST isozymeograms of 3 materials in contrast, 14ds67 and 14ds72 had high similarity, and the patterns were consistent, but 14ds78 had greatly difference with the former two. So 14ds67 and 14ds72 had close genetic relationship, and 14ds78 was far away in genetic relationship with the former two. However, isozyme spectrums of POD isozymeograms of 3 materials had no obvious difference, and the enzyme patterns with good consistency, just a few enzyme patterns had certain differences in enzyme activity. 5) The number of bands of POD isozymeograms was significantly less than that of EST isozymeograms for the same materials, and the bands moved fastest were highest in enzyme activity in the enzyme spectrums of POD isozymeograms. Therefore, there are strong consistency in EST isozyme zymogram and POD isoenzyme zymogram, respectively, between tri-loculus siliques and bi-loculus siliques in the same developmental stages for the same materials.

Subcellular extraction and enzyme characterisation of polyphenol oxidase and peroxidase in Cinnamon myrtle

Polyphenol oxidase (PPO) and peroxidase (POD) from Backhousia myrtifolia leaf and floral tissues were characterised. PPO from both tissues showed maximum activity at pH 6.0 and 10.0 at 25 °C, whereas POD activity optima were at pH 5.0 and 9.0 at 25 °C for leaf tissues. The same pH optima for POD activity were evident at 20 °C for floral tissues. With regard to substrate specificity, B. myrtifolia PPOs were of both monophenolase (tyrosine) and diphenolase (l-DOPA) types. POD activity was highest when catechol was used as a substrate for oxidisation. K m ranged from 0.6 to 1.0 mM with l-DOPA as the substrate for PPO, and from 0.1 to 0.4 mM with H2O2 and constant catechol (10 mM) as substrates for POD. In both tissues types, glutathione was a non-competitive inhibitor to PPO at the lower concentrations of 0.1–1 mM, but was uncompetitive at the higher concentrations of 10.0 mM. Sodium azide at concentrations ranging from 0.005 to 0.5 mM was a competitive inhibitor to POD. Subcellular extraction methods showed that PPO and POD were localised in the membrane fraction. Cationic native PAGE performed for both enzymes was only able to detect PPO activity. Using Western blot analyses, low molecular weight PPO isozymes from leaf tissue were identified (<10 kDa). Five POD isozymes (20–80 kDa) were detected in both tissue types. These ‘isoform’ patterns were investigated by two-dimensional gel electrophoresis (2DGE). PPOs were mainly neutral (pI 6–7), while POD isoforms had acidic, neutral and alkaline forms.

Improvement of catalytic performance of lignin peroxidase for the enhanced degradation of lignocellulose biomass based on the imbedded electron-relay in long-range electron transfer route.

BackgroundAlthough lignin peroxidase is claimed as a key enzyme in enzyme-catalyzed lignin degradation, in vitro enzymatic degradation of lignin was not easily observed in lab-scale experiments. It implies that other factors may hinder the enzymatic degradation of lignin. Irreversible interaction between phenolic compound and lignin peroxidase was hypothesized when active enzyme could not be recovered after the reaction with degradation product (guaiacol) of lignin phenolic dimer.ResultsIn the study of lignin peroxidase isozyme H8 from white-rot fungi Phanerochaete chrysosporium (LiPH8), W251 site was revealed to make the covalent coupling with one moiety of monolignolic radical (guaiacol radical) by LC-MS/MS analysis. Hypothetical electron-relay containing W251 residue was newly suggested based on the observation of repressed radical coupling and remarkably lower electron transfer rate for W215A mutant. Furthermore, the retardation of the suicidal radical coupling between the W251 residue and the monolignolic radical was attempted by supplementing the acidic microenvironment around the W251 residue to engineer radical-robust LiPH8. Among many mutants, mutant A242D showed exceptional catalytic performances by yielding 21.1- and 4.9-fold higher increases of kcat and kcat/KM values, respectively, in the oxidation of non-phenolic model lignin dimer.ConclusionsA mechanism-based suicide inhibition of LiPH8 by phenolic compounds was firstly revealed and investigated in this work. Radical-robust LiPH8 was also successfully engineered by manipulating the transient radical state of radical-susceptible electron-relay. Radical-robust LiPH8 will play an essential role in degradation of lignin, which will be consequently linked with improved production of sugars from lignocellulose biomass.Electronic supplementary materialThe online version of this article (doi:10.1186/s13068-016-0664-1) contains supplementary material, which is available to authorized users.

Physiological and oxidative stress responses of baldcypress in response to elevated salinity: linking and identifying biomarkers of stress in a keystone species

Globally, saltwater intrusion associated with sea level rise is threatening the vitality of coastal freshwater wetland communities. In the current study, we investigated the impacts of salinity stress on Baldcypress (Taxodium distichum (L.) Rich), a tree common to coastal freshwater wetlands within the southeastern USA. Salinity-induced responses of saplings and adult trees were assessed in a greenhouse and field-based study, respectively. In the greenhouse study, saplings maintained under mesohaline conditions (8 g L−1) for 10 weeks exhibited a predictable physiological response characterized by decreased maximum quantum yield of photosystem II (Fv/Fm) and increased non-photochemical quenching. Changes in photochemistry were concomitant with increases in leaf sodium, hydrogen peroxide, and free proline content compared to saplings maintained in freshwater. A strong negative correlation existed between Fv/Fm and leaf hydrogen peroxide content. Salinity-stressed saplings also exhibited decreased activity of a low molecular weight peroxidase isozyme within leaf tissue. Taken together, the evidence suggests that H2O2 was maintained at marginally elevated levels in leaf tissue to elicit a physiological response. Adult trees sampled in situ displayed similar stress responses to elevated salinity as saplings from the greenhouse study. Specifically, trees sampled at a basin swamp exhibited decreased Fv/Fm and increased non-photochemical quenching, lipid peroxidation, and free proline content in leaf tissue compared to trees at other sites. Thus, coupling chlorophyll fluorescence parameters with stable biomarkers show promise in detecting sub-lethal salinity stress for plants in situ.

Physiological and Biochemical Responses of Vicia Faba Plants to Foliar Application of Zinc and Iron

Iron (Fe) and zinc (Zn) are essential nutrients for plant growth and development. Therefore, a pot experiment was conducted to examine the role of Zn and Fe on vegetative growth, photosynthetic pigments, soluble sugars, soluble protein, nitrate reductase (NR), ascorbate peroxidase (APX), catalase (CAT), minerals content, amino acid composition fraction, isozymes, and protein electrophoresis in faba bean plants foliar sprayed with FeSO4 and ZnSO4. The results revealed that foliar spray with 1 or 3 g/L of FeSO4 and ZnSO4 significantly increased all the abovementioned parameters compared to control plants. The activity of esterase increased with increasing concentration of Fe and Zn as compared to control plants. The most pronounced increase was found in plants treated with 3 g/L ZnSO4. Three bands of peroxidase isozyme were exhibited with different densities and intensities in all treatments. Three types of modification were observed in the protein patterns of faba bean leaves. Some protein bands disappeared, while other increased and synthesis of a new set of proteins was induced. It could be concluded that foliar spray with the two concentrations (1 or 3 g/L) of ZnSO4 and FeSO4 helped faba bean plants to overcome the deficiency in these minerals by producing antioxidant enzymes. Improved faba bean growth through adequate Fe and Zn foliar spray is likely a promising strategy to improve Vicia faba plants.

Transcriptional reprogramming of genes related to ascorbate and glutathione biosynthesis, turnover and translocation in aphid-challenged maize seedlings

Aphids are pierce-sucking insects that severely affect redox homeostasis in the host tissues. Reduced ascorbate (AsA) and glutathione (GSH) serve as multifunctional molecules involved in constituting sophisticated plant defense responses to aphids' herbivory. This survey aimed to decipher transcriptional responses of forty-one genes associated with AsA and GSH biosynthesis, turnover and translocation in maize (Zea mays L.) seedlings infested with two hemipterans' species: bird cherry-oat aphid (Rhopalosiphum padi L.) and grain aphid (Sitobion avenae F). Cereal aphids' attack substantially stimulated the expression of fifteen maize genes – encoding l-galactose dehydrogenase (GalDH), l-galactono-1,4-lactone dehydrogenase (GLDH), ascorbate oxidase (AO), glutamate–cysteine ligase (GCL), glutathione synthetase (GS), two isozymes of glutathione peroxidase (GPX1, GPX3), five isoforms of glutathione transferase (GST9, GST11, GST16, GST31, GST38) and three GSH transporters (ABCC2, ABCC6, GT1). Transcriptional alternations of these genes were dependent on maize genotype, insect species, duration of infestation and aphids' abundance. Specific patterns of genes' expression as well as total activity of the corresponding enzymes in insect-challenged maize seedlings (cvs Ambrozja and Tasty Sweet, which are relatively resistant and susceptible, respectively) highlighted the molecular background of crucial part of the complex antioxidative responses of maize model plant toward cereal aphids' colonization.

Effects of jinggangmycin on peroxidase and esterase isozymes and phytotoxin from Rhizoctonia solani AG-1 IA, the causal agent of rice sheath blight. Pirinç kabuğu yanığı nedeni Rhizoctonia solani AG-1 IA tarafından üretilen peroksidaz, esteraz izozimleri ve fitotoksinler üzerinde jinggangmycin etkisi

Abstract Objective: To explore the effects of jinggangmycin on the pathogenicity of rice sheath blight. Methods: The effects of jinggangmycin on peroxidase and esterase isozymes from Rhizoctonia solani Kuhn AG-1 IA were compared using non-denaturing polyacrylamide gel electrophoresis (PAGE). Rs-toxins were obtained from the improved Richard medium amended with jinggangmycin at different concentrations. Subsequently, bioassays of Rs-toxin, including virulence to rice tissues, seedling wilting and inhibition to the seed germination were conducted. Results: The results of PAGE showed that when the jinggangmycin concentration increased to 50 μg/mL, two of peroxidase isozyme bands became apparently weaker compared with the controls, indicating that jinggangmycin could considerably weaken the activity of the peroxidase isozyme. In addition, three extra bands of esterase isozyme were induced by jinggangmycin when the concentration increased to 50 μg/mL, indicating that jinggangmycin could affect the metabolism of esterase isozyme. The bioassays of Rs-toxin showed that jinggangmycin could weaken the virulence of Rs-toxin in rice tissues. Conclusion: It was concluded that the control role of jinggangmycin in rice sheath blight might be due to the effects of jinggangmycin on the peroxidase and esterase isozymes and Rs-toxin virulence.

Higher Activities of Defense-Associated Enzymes may Contribute to Greater Resistance of Manchurian Ash to Emerald Ash Borer Than A closely Related and Susceptible Congener.

Emerald ash borer (EAB) is an invasive beetle native to Asia that infests and kills ash (Fraxinus spp.) in North America. Previous experiments indicated that larvae feeding on co-evolved, resistant Manchurian ash (F. mandshurica) have increased antioxidant and quinone-protective enzyme activities compared to larvae feeding on susceptible North American species. Here, we examined mechanisms of host-generated oxidative and quinone-based stress and other putative defenses in Manchurian ash and the closely related and chemically similar, but susceptible, black ash (F. nigra), with and without exogenous application of methyl jasmonate (MeJA) to induce resistance mechanisms. Peroxidase activities were 4.6-13.3 times higher in Manchurian than black ash, although both species appeared to express the same three peroxidase isozymes. Additionally, peroxidase-mediated protein cross-linking activity was stronger in Manchurian ash. Polyphenol oxidase, β-glucosidase, chitinase, and lipoxygenase activities also were greater in Manchurian ash, but only lipoxygenase activity increased with MeJA application. Phloem H2O2 levels were similar and were increased by MeJA application in both species. Lastly, trypsin inhibitor activity was detected in methanol and water extracts that were not allowed to oxidize, indicating the presence of phenolic-based trypsin inhibitors. However, no proteinaceous trypsin inhibitor activity was detected in either species. In response to MeJA application, Manchurian ash had higher trypsin inhibitor activity than black ash using the unoxidized water extracts, but no treatment effects were detected using methanol extracts. Based on these results we hypothesize that peroxidases, lignin polymerization, and quinone generation contribute to the greater resistance to EAB displayed by Manchurian ash.

MOLECULAR GENETIC DIVERSITY AND EFFICIENT PLANT REGENERATION SYSTEM VIA SOMATIC EMBRYOGENESIS IN SWEET POTATO (Ipomoea batatas (L.) Lam.)

Somatic embryogenesis and plant regeneration at high frequency have been restricted to few sweet potato varieties. For enhancing and accelerating somatic embryogenesis from stem segments of the Egyptian sweet potato cultivar Abees were investigated using three different phytohormones; 2,4-dichlorophenoxy-acetic acid (2,4-D), benzyleaminopurine (BAP) and indole acetic acid (IAA). The phytohormone BAP was found to be the best for the induction of embryogenic calli and most studied traits. Data analysis showed a significant variation in three different tissue culture media for all parameters, expect root induction percentage. Two different isozymes; peroxidase (PRX) and α naphthyl acetate esterase (EST) were used and analyzed to determine the genetic variability among the regenerated plants. The two analyzed isozymes successively showed polymorphic variations among the parent and 98 sweet potato plants regenerated from the three different callus induction media. Peroxidase isozyme produced seven polymorphic bands showing genetic variation as compared to the control (Abees cultivar), while esterase isozyme produced only three polymorphic bands. The regenerated plants exhibited somaclonal variations that can be utilized for selection of desired traits in sweet potato. On the other hand, five RAPD primers were used for assessment of genetic diversity in the somaclonal variants compared with control. A total of 68 RAPD loci were amplified with molecular size range of 300–3000 bp with 13.6 loci per each primer. Out of the 68 loci scored, 26 loci (38.24%) were found to be polymorphic and the polymorphism% ranged between 18.18% for (OPB-05) and 75% for (OPB-07). Moreover, all primers produced positive and negative unique DNA bands, except OPB-05 for negative unique bands and OPB-07 for positive unique bands. The same result was confirmed by the cluster and principal coordinate analyses for the positions of somaclonal variant no. 4 which showed high diversity from the parental cultivar.

Specific peroxidases differentiate Brachypodium distachyon accessions and are associated with drought tolerance traits.

Brachypodium distachyon (Brachypodium) is a model system for studying cereal, bioenergy, forage and turf grasses. The genetic and evolutionary basis of the adaptation of this wild grass species to drought stress is largely unknown. Peroxidase (POD) may play a role in plant drought tolerance, but whether the allelic variations of genes encoding the specific POD isoenzymes are associated with plant response to drought stress is not well understood. The objectives of this study were to examine natural variation of POD isoenzyme patterns, to identify nucleotide diversity of POD genes and to relate the allelic variation of genes to drought tolerance traits of diverse Brachypodium accessions. Whole-plant drought tolerance and POD activity were examined in contrasting ecotypes. Non-denaturing PAGE and liquid chromatography-mass spectrometry were performed to detect distinct isozymes of POD in 34 accessions. Single nucleotide polymorphisms (SNPs) were identified by comparing DNA sequences of these accessions. Associations of POD genes encoding specific POD isoenzymes with drought tolerance traits were analysed using TASSEL software. Variations of POD isoenzymes were found among accessions with contrasting drought tolerance, while the most tolerant and susceptible accessions each had their own unique POD isoenzyme band. Eight POD genes were identified and a total of 90 SNPs were found among these genes across 34 accessions. After controlling population structure, significant associations of Bradi3g41340.1 and Bradi1g26870.1 with leaf water content or leaf wilting were identified. Brachypodium ecotypes have distinct specific POD isozymes. This may contribute to natural variations of drought tolerance of this species. The role of specific POD genes in differentiating Brachypodium accessions with contrasting drought tolerance could be associated with the general fitness of Brachypodium during evolution.

Effect of Dimethyl Sulphate on the Growth, Induction of Mutations and Their Identification by Peroxidase Isozyme in Tecoma stans

Effect of Dimethyl Sulphate on the Growth, Induction of Mutations and Their Identification by Peroxidase Isozyme in Tecoma stans

Growth and biochemical analysis of evergreen haloxeric tree species Salvadora oleoides and Salvadora persica under NaCl stress

In vitro growth, development, total soluble proteins and peroxidase profiles of Salvadoraoleoides and Salvadora persica under NaCl stress were analysed in the present investigation. The plants are evergreen haloxeric tree species of family Salvadoraceae. Shoot apex from natural plants were initially used for screening of NaCl tolerance on MS culture medium. Shoot apex of S. oleoides and S. persica could survive optimally up to 200 and 100 mM NaCl. Axillary buds from nodal shoot segments of S. oleoides and S. persica were activated on 6 and 4 μM BAP, and were used further for extraction of total soluble proteins and peroxidases. Total soluble proteins were increased up to 150 mM NaCl in S. oleoides, but decline above 50 mM NaCl in S. persica. Peroxidase activity remained almost constant in S. oleoides at all the concentrations and duration of NaCl, but increased at 100 mM NaCl during fourth week of treatment in S. persica. Eleven peroxidase isozymes were observed in zymogram of S. oleoides. Isozymes P1, P2, P3, and P4 were slightly appeared, but P6 isozyme was lacking in S. persica. The P5 isozyme was more prominent in S. persica than S. oleoides. Isozyme P9 of S. persica was visible during the first week of NaCl treatment, but disappeared in the fourth week. Molecular biology of these plants can be useful further for the understanding of stress tolerance mechanisms for prospects.

Isozyme analysis based genetic fidelity assessment of micropropagated banana plants

Isozyme studies of micropropagated and mother plants of banana cvs. Matti, Ney Poovan, Kechulepa, Dwarf Cavendish, Malbhog, Champa, B.B. Battisa and FHIA-1 were done to test their genetic fidelity. The banding patterns as revealed by electrophoretic variations were evaluated with respect to isozymes of acid phosphatase, catalase, esterase and peroxidase as markers. The genetic fidelity of micropropagated plants and the relationship of the different cultivars were determined by dendrogram using numerical taxonomy and multivariate analysis system(NTSYS). A clustered dendrogram was prepared by unweighted pair group method using averages (UPGAMA) method. At 87% similarity, the micropropagated and mother plants were clustered in four groups reflecting their genomic constitution. Cvs. Matti (AA) and Dwarf Cavendish (AAA) with similar ‘A’ genome were categorized in Cluster I. Cluster II comprised of cvs. Ney Poovan (AB), B.B. Battisa (ABB) and FHIA-1(AAAB) with genomic constitution of both ‘A’ and ‘B’ type. Cvs. Champa (AAB) and Malbhog (AAB) with similar genome were grouped inCluster III. Cluster IV contained the cv. Kechulepa (BB) having only ‘B’ genome. However, there was no somaclonal variation among the micropropagated plants and they showed 100% genetic similarity. Thus, the isozyme studies could be a reliable marker for testing the genetic fidelity of micropropagated plants and for evaluating the diversity among the banana germplasm.

Analysis of defense-related enzymes and metabolites induced by lansiumamide B against Ralstonia solanacearum in tobacco

In this study we investigated the ability of lansiumamide B to protect tobacco against bacterial wilt caused by Ralstonia solanacearum. The results of pot experiments indicated that lansiumamide B profoundly reduced the disease severity of bacterial wilt, with the control efficiency on tobacco bacterial wilt at 87.28% and 77.75% at 15 and 30 days, respectively. The activities of antioxidative enzymes, such as peroxidase (POD) and superoxide dismutase (SOD) were enhanced after treatment with lansiumamide B. The activity of phenylalanine ammonium lyase (PAL) and polyphenol oxidase (PPO) were also increased, which plays an important role in protecting the plant against pathogenic bacteria attack. The isozymes analysis results showed that the expressions of POD and PPO isozymes were enhanced after treatment with lansiumamide B. Detection of metabolites showed that the relative contents of resistance-related substances, such as Myo-inositol, Nicotine, Propanedioic acid, Lactic acid, Glycerol acid, Malic acid, L-threonic acid, D-lyxose, Ribitol, Tetradecanol, L-arabinose, Ribonic acid, Shikimic acid, Tartaric acid, 1, 2, 3-Propanetricarboxylic acid, L-arabitol and Octadecanoic acid in the groups of inoculation, BTH, and lansiumamide B were higher compared to solvent control. These results suggested that lansiumamide B might attenuate the harmful effects of Ralstonia solanacearum on tobacco plants.