Increase In Total Peroxidase Activity Research Articles

Fungal penetration associated with recognition, signaling and defence-related genes and peroxidase activity during the resistance response of coffee to Colletotrichum kahawae

Resistant and susceptible coffee varieties were used aiming to unveil genes and proteins putatively involved in the resistance response to Colletotrichum kahawae. Gene expression analysis revealed a stronger induction of recognition, signaling and cell wall modification genes in the resistant variety during fungal penetration. It was also observed the increase of total peroxidase activity and the induction of lignin-forming anionic peroxidase-like gene which was further supported by the increase of an anionic isoenzyme. Peroxidases localized in the walls of host cells at infection sites can be related with cell wall lignification. Altogether, these defence responses contribute to restricting fungal growth.

Agronomic application of olive mill wastewater: Effects on maize production and soil properties

This study investigates the effect of direct amendment of olive mill wastewater (OMW) on the fertility of soil, described as poor in the area of Marrakech (semi-arid region) in Morocco. The treated plots were amended with untreated OMW generated by a traditional extraction process at the amount of 10 L/m2/year during two consecutive years. Results of these two years treatments with crude OMW at relatively high dose reveal an important increase in soil physicochemical characteristics, namely electric conductivity (EC), Na+, K+, phosphorus, nitrogen, organic matter and soluble phenolic compounds. EC of treated soil was enhanced from 0.34 to 2.91 mS/cm as compared to the control soil. After spreading OMW in soil, the amounts of its nutritive elements increased by 81% for nitrogen, 66% for phosphorus and 88% for potassium. The accumulation of phenolic compounds and the increase of total peroxidase activity in plants provide evidence of their protective role against the physiological stress induced by OMW. However, this enrichment in mineral and nutritive elements decreased three months after OMW application, revealing OMW biodegradation in the studied calcareous soil. In parallel, an increase in the contents of the soluble phenolic compounds on the upper layer of soil was denoted and maize plants growth was efficiently raised. Significant amelioration was obtained notably in terms of fresh and dry weight of leaves, leaves area, spikes fresh and dry weight, 100 seeds weight and straw yield (37, 54, 27, 24, 14 and 9% respectively). Along with the correct choice of convenient soils notably calcareous ones and tolerant crops such as maize, this method could constitute an efficient approach for avoiding problems attributed to the uncontrolled disposal of these effluents and an effective strategy to regenerate degraded soils and represents an economical alternative that provides a local fertilizer.

Host responses in Norway spruce roots induced to the pathogen Ceratocystis polonica are evaded or suppressed by the ectomycorrhizal fungus Laccaria bicolor

The outcome of a compatible mycorrhizal interaction is different from that in a compatible plant-pathogen interaction; however, it is not clear what mechanisms are used to evade or suppress the host defence. The aim of this work is to reveal differences between the interaction of Norway spruce roots to the pathogen Ceratocystis polonica and the ectomycorrhizal Laccaria bicolor, examine if L.bicolor is able to evade inducing host defence responses typically induced by pathogens, and test if prior inoculation with the ectomycorrhizal fungus affects the outcome of a later challenge with the pathogen. The pathogen was able to invade the roots and caused extensive necrosis, leading to seedling death, with or without prior inoculation with L.bicolor. The ectomycorrhizal L.bicolor colonised primary roots of the Norway spruce seedlings by partly covering, displacing and convoluting the cells of the outer root cortex, leaving the seedlings healthy. We detected increased total peroxidase activity, and staining indicating increased lignification in roots as a response to C.polonica. In L.bicolor inoculated roots there was no increase in total peroxidase activity, but an additional highly acidic peroxidase isoform appeared that was not present in healthy roots, or in roots invaded by the pathogen. Increased protease activity was detected in roots colonised by C.polonica, but little protease activity was detected in L.bicolor inoculated roots. These results suggest that the pathogen efficiently invades the roots despite the induced host defence responses, while L.bicolor suppresses or evades inducing such host responses in this experimental system.

Transcriptome analysis of various flower and silique development stages indicates a set of class III peroxidase genes potentially involved in pod shattering in Arabidopsis thaliana.

BackgroundPlant class III peroxidases exist as a large multigenic family involved in numerous functions suggesting a functional specialization of each gene. However, few genes have been linked with a specific function. Consequently total peroxidase activity is still used in numerous studies although its relevance is questionable. Transcriptome analysis seems to be a promising tool to overcome the difficulties associated with the study of this family. Nevertheless available microarrays are not completely reliable for this purpose. We therefore used a macroarray dedicated to the 73 class III peroxidase genes of A. thaliana to identify genes potentially involved in flower and fruit development.ResultsThe observed increase of total peroxidase activity during development was actually correlated with the induction of only a few class III peroxidase genes which supports the existence of a functional specialization of these proteins. We identified peroxidase genes that are predominantly expressed in one development stage and are probable components of the complex gene networks involved in the reproductive phase. An attempt has been made to gain insight into plausible functions of these genes by collecting and analyzing the expression data of different studies in plants. Peroxidase activity was additionally observed in situ in the silique dehiscence zone known to be involved in pod shattering. Because treatment with a peroxidase inhibitor delayed pod shattering, we subsequently studied mutants of transcription factors (TF) controlling this mechanism. Three peroxidases genes -AtPrx13, AtPrx30 and AtPrx55- were altered by the TFs involved in pod shatter.ConclusionsOur data illustrated the problems caused by linking only an increase in total peroxidase activity to any specific development stage or function. The activity or involvement of specific class III peroxidase genes needs to be assessed. Several genes identified in our study had not been linked to any particular development stage or function until now. Notably AtPrx13, which is one of the peroxidase genes not present on commercially available microarrays. A systematic survey of class III peroxidase genes expression is necessary to reveal specific class III peroxidase gene functions and the regulation and evolution of this key multifunctional enzyme family. The approach used in this study highlights key individual genes that merit further investigation.

Overexpression of a pepper ascorbate peroxidase-like 1 gene in tobacco plants enhances tolerance to oxidative stress and pathogens

In order to determine the role of ascorbate peroxidase, an antioxidant enzyme, in the cellular responses to oxidative stress and pathogens, transgenic tobacco plants were generated, using the Capsicum annuum ascorbate peroxidase-like 1 gene ( CAPOA1), under the control of the CaMV 35S promoter. High levels of CAPOA1 gene expression were observed in the transgenic plants, with a 2-fold increase in total peroxidase activity. The constitutive expression of CAPOA1 in the tobacco exhibited no morphological abnormalities, while significantly increased growth was observed in transgenic plants, as compared to control plants. The CAPOA1 -overexpressed plants exhibited increased tolerance to methyl viologen-mediated oxidative stress, and also enhanced resistance to the oomycete pathogen, Phytophthora nicotianae. However, the transgenic plants were not found to be resistant to the bacterial pathogen, Pseudomonas syringae pv. tabaci, but were weakly resistant to Ralstonia solanacearum. Our results suggested that the overproduction of ascorbate peroxidase increased peroxidase activity that enhances active oxygen scavenging system, leading to oxidative stress tolerance and oomycete pathogen resistance.

Changes in phenol content and peroxidase activity during in vitro organogenesis in Xanthosoma sagittifolium L.

Direct plant regeneration, multiple shoot formation and callogenesis were induced from cocoyam shoot tips cultured in vitro. At different stages of culture, phenol content, peroxidase activity and acidic soluble isoperoxidase patterns were analysed in plantlets. Results showed that phenol content of plantlets cultured on auxin-free media decreased with time, while it increased in those cultured on media supplemented with an auxin. Each form of morphogenesis induced with a growth regulator was preceded by an increase in total peroxidase activity. On hormone-free medium, organogenesis occurred (single shoot development and rhizogenesis), but there was no increase in total peroxidase activity. The appearance of isoperoxidase A2 was associated with root initiation, while the disappearance of isoperoxidase A5 and the appearance of isoperoxidase A6 preceded multiple shoot formation. These results indicate that total peroxidase activity was not a proper marker for organogenesis in cocoyam. Each form of morphogenetic differentiation is associated with an alteration of the acidic isoperoxidase pattern. These enzymes can be used as biochemical markers for rooting and multiple shoot initiation in cocoyam.

Disease development and enhanced susceptibility of wounded pepper roots to Phytophthora capsici

Greenhouse experiments were conducted to determine disease progression of phytophthora root rot on nonwounded and wounded pepper plants (Capsicum annuum) and to determine whether susceptibility to Phytophthora capsici decreases with wound aging. Two isolates of P. capsici were used in this study, one less aggressive than the other. Trimming the roots immediately prior to inoculation with either isolate increased susceptibility significantly (P ≤ 0·05) compared with plant roots that were not trimmed. Both isolates caused a higher level of disease severity on disturbed/trimmed than on disturbed/nontrimmed roots. Disease also occurred earlier with the more aggressive isolate on both wounded and nonwounded roots. Disease severity was three to four times more severe on plants treated with the aggressive isolate (NM6011) than on those inoculated with the less aggressive isolate (NM6040), regardless of root treatment. In separate experiments, pepper roots were wounded and allowed to age for up to 5 days before inoculation. Resistance to P. capsici increased as the wounds aged, resulting in significantly (P ≤ 0·001) lower disease severity on plants with 3‐ and 5‐day‐old wounds than on those inoculated at the time of wounding and the nondisturbed/nontrimmed controls. Wounding of the roots followed by immediate inoculation with zoospores resulted in significantly higher levels of attachment than when roots were inoculated with zoospores 48 h after wounding. The 48‐h postwounding inoculation treatment showed the same amount of zoospore attachment as nonwounded roots. Increase in plant resistance correlated (P ≤ 0·01) with an increase in total peroxidase activity. Isoelectric focusing‐polyacrylamide gel electrophoresis (IEF‐PAGE) indicated increased band intensity of three acidic and one basic isozyme as wounds aged. These data suggest that wound repair plays a role in decreasing infection and resultant disease symptoms of pepper to P. capsici.

Expression of theShpx2peroxidase gene ofStylosanthes humilisin transgenic tobacco leads to enhanced resistance toPhytophthora parasiticapv.nicotianaeandCercospora nicotianae

Abstract Previous research indicated that the constitutive expression of a pathogen-inducible peroxidase gene (Shpx6a) from Stylosanthes humilis in transgenic plants resulted in enhanced resistance to fungal pathogens ( Kazan, K., Goulter, K.C., Way, H.M. and Manners, J.M. (1998) Expression of a pathogenesis-related peroxidase of Stylosanthes humilis in transgenic tobacco and canola and its effect on disease development. Plant Sci. 136, 207-217). We have now investigated another pathogen-inducible peroxidase gene of S. humilis, termed Shpx2, which is highly divergent from Shpx6a. Constitutive expression of the Shpx2 cDNA was obtained in tobacco using the 35S CaMV promoter, and up to a 12-fold increase in total peroxidase activity was observed in the leaves of transgenic plants compared to nontransgenic controls. Disease development was evaluated after inoculations in T(1) and T(2) transgenic lines expressing Shpx2. Lesion expansion was significantly (P < 0.05) reduced by up to 25% and 50% on leaves and stems, respectively, of transgenic plants expressing high levels of peroxidase compared to nontransgenic controls, following inoculation with Phytophthora parasitica pv. nicotianae, the cause of black shank disease. In addition, plant survival and recovery were greatly enhanced in transgenic plants following stem inoculations of plants with this plant pathogen. A significant (55%, P < 0.05) reduction in lesion number was observed in transgenic plants with high levels of peroxidase activity following inoculation with the fungus Cercospora nicotianae, the cause of frog-eye disease. No significant differences in disease development were observed between the lines expressing Shpx2 and controls following inoculation with the bacterium Pseudomonas syringae pv. tabaci, the cause of wildfire disease. These results provide evidence for a role for this peroxidase gene in plant defence, and suggest that diverse peroxidase genes may be employed as components of strategies aimed at the engineering of disease resistance.

Agrobacterium-mediated transformation of poplar using a disarmed binary vector and the overexpression of a specific member of a family of poplar peroxidase genes in transgenic poplar cell

An efficient method was established for transformation of the poplar hybrid Populus kitakamiensis ( Populus sieboldii × Populus gradidentata) using a binary disarmed strain of Agrobacterium tumefaciens LBA4404 and Ti-binary vectors. The frequency of transformation of poplar leaf segments reached as high as 60%. In transgenic poplar plants, the gene for β-glucuronidase ( gus) was expressed at high levels under the control of the cauliflower mosaic virus 35S (CaMV35S) promoter. Poplars possess a number of peroxidase isozymes whose pattern of expression is tissue-specific, developmentally regulated and influenced by environmental factors. We altered the expressin of a peroxidase isozyme by introducing an identified genomic gene for a peroxidase ( prxA1) under the control of the CaMV35S promoter. Transgenic poplars obtained by introducing the chimeric peroxidase gene (CaMV35S promoter- prxA1) were shown to have an increase in total peroxidase activity that was accounted for by the specific overproduction of the peroxidase isozyme (PrxA1). From this study, the anionic peroxidase isozyme encoded by the identified genomic gene, prxA1, was demonstrated to be the anionic peroxidase isozyme with a pI of 4.4 among various isozymes of poplar peroxidase. On the basis of this assignment, we characterized the tissue-specific and UV-light-inducible regulation of expression of this isozyme.

Increased Activity of a Cationic Peroxidase Associated with an Incompatible Interaction Between Xanthomonas oryzae pv oryzae and Rice (Oryza sativa)

Rice (Oryza sativa L.) cultivar Cas 209 carries the gene Xa-10 for resistance to race 2 of Xanthomonas oryzae pv oryzae, the bacterial blight pathogen. When seedling leaves of Cas 209 plants were infiltrated with bacterial cell suspensions of strain PXO86(Rif) (race 2, incompatible), total peroxidase activity in extracts from extracellular spaces increased almost threefold between 16 and 24 hours after inoculation. The increase in total peroxidase activity in extracellular extracts was correlated with the appearance of a 43-kilodalton peroxidase isoenzyme with an isoelectric point of 8.6. Increases in the activities of two anionic peroxidase isoenzymes also were associated with the incompatible interaction. Later during the interactions, total peroxidase activities increased in both compatible (cv Cas 209 infiltrated with race 1, PXO61(Sm)) and control (Cas 209 infiltrated with water) treatments, but final activity levels were less than that observed in the incompatible combination. Similarly, the cationic peroxidase was detected in all three treatments by 48 hours after infiltration, but at reduced levels in compatible and water-infiltrated control treatments relative to the incompatible combination. Accumulation of this peroxidase in extracellular spaces thus may play a role in the defense response in cultivar Cas 209.

Fungal elicitor-mediated responses in pine cell cultures

A tissue culture system has been developed to examine phenylpropanoid metabolism induced in pine tissues by an ectomycorrhizal symbiont. An elicitor preparation from the ectomycorrhizal fungus Thelephora terrestris Fr. induced enhanced phenolic metabolism in suspension cultured cells of Pinus banksiana Lamb., as indicated by tissue lignification and accumulation of specific methanol-extractable compounds in the cells. Induction of lignification was observed as early as 12 h after elicitation. The activity of phenylalanine ammonia-lyase (PAL, EC 4.3.1.5), the entry-point enzyme into phenylpropanoid metabolism, also increased within the same time-frame in elicited cells. Significant increases in PAL activity were evident by 6 h after elicitation, and, by 12 h after elicitation, PAL activity in elicited cells was ten times greater than that in the corresponding controls. Lignification of the elicited tissue was also accompanied by an increase in the activity of other enzymes associated with lignin synthesis, including caffeic acid O-methyl transferase (EC 2.1.1.46), hydroxycinnamate:CoA ligase (EC 6.2.1.12), cinnamyl alcohol dehydrogenase (EC 1.1.1.-), coniferin βglucosidase (EC 3.2.1.21) and peroxidase (EC 1.11.1.7). The increase in total peroxidase activity was associated with a change in the pattern of soluble peroxidase isoforms. The pine cell culture-ectomycorrhizal elicitor system provides a good model for molecular analysis of the process of lignification in an economically important softwood species.

Peroxidase Isoenzymes and Leaf Senescence in Sunflower, Helianthus annuus L

Changes in the activities of acid phosphatase (EC 3.1.3.2) and peroxidase (EC 1.11.1.7) have been measured during development of the first leaves of sunflower seedlings. Acid phosphatase activity increased to a maximum early during expansion growth. This maximum activity coincided with the maximal leaf content of free amino acids (23 days after seed imbibition). Acid phosphatase activity declined throughout subsequent leaf development and senescence. Peroxidase activity remained low until after 30 days, then a 10-fold increase in activity occurred between 30 and 35 days, coincident with a fall in leaf chlorophyll content. Seven anionic isoenzymes of peroxidase were resolved when leaf extracts were analysed by pore-gradient polyacrylamide gel electrophoresis. Only two of these were prominent in young leaves: isoenzymes 2 (MW 42,000) and 7 (MW 81,000). The increase in total peroxidase activity in senescing leaves was brought about by increases in the activities of isoenzymes 1, 2, 3 and 6, of MW 40,000, 42,000, 46,000 and 68,000 daltons respectively.

Regulation und Bedeutung der Peroxidase-Muster�nderungen in spro�differenzierenden Kalluskulturen von Nicotiana tabacum L.

Peroxidase activity and isoenzyme pattern were studied during dedifferentiation of tobacco stem-sections leading to callus formation and during redifferentiation of tobacco callus leading to formation of shoots. These processes are both accompanied by an increase in total peroxidase activity and by characteristic changes in isoenzyme pattern. The isoenzyme pattern of tobacco callus differs from that of tobacco stem-tissue. The plantlets differentiated from the callus show the same pattern as seedlings do. During the differentiation process, before any buds are visible, the callus shows a peroxidase pattern that is determined by a reduction of fast-migrating anodic isoenzymes and by an increase of activity in all the other peroxidase isoenzymes. The formation of this pattern is independent of the growth regulators responsible for the differentiation: only the kind of differentiation itself determines the pattern. By artificial inhibition of callus growth it is possible to induce an isoenzyme pattern very similar to that of differentiation; the fast-migrating anodic enzymes are reduced in activity but the others are not increased as they are during differentiation. Therefore the question arises whether there are two independent processes taking place in differentiating callus. The one process, inhibition of growth in the cells that do not differentiate, is accompanied by a reduction of fast-migrating anodic isoenzymes. The other process, formation of meristemoids in the callus, is accompanied by a sharp rise in peroxidase activity of the other anodic and cathodic isoenzymes.

Hormonal Control of Isoperoxidases in Lentil Embryonic Axis

Detachment of the cotyledons from the lentil (Lens culinaris Med.) embryonic axis causes in the latter an increase in total peroxidase activity which is shown to be due to enhancement of specific cathodic isoperoxidases. Kinetin treatment of attached or detached axes promotes activity of essentially the same cathodic isoperoxidases. In addition kinetin enhances the activity of two anodic peroxidases and represses specifically that of a cathodic one. Abscisic acid inhibits the production of all isoenzymes in the presence or absence of kinetin. Cytokinin and abscisic acid actions are discussed in relation to the nature of a wounding hormone and the role of natural inhibitors in cotyledons during germination. Indoleacetic acid stimulates the activity of certain isoenzymes which are also stimulated by kinetin, whereas in others the effects of the two hormones are different. Specific inverse effects of indoleacetic acid and kinetin are demonstrated on the two most cathodic isoperoxidases. Indoleacetic acid-kinetin interactions on the cathodic isoperoxidases have been found in the literature and are discussed as a possible mechanism for explaining interactions of the two regulators on growth and other physiological processes.