Induction Of Defense-related Enzymes Research Articles

Potential biocontrol agents involved in induction of defense related enzymes in brinjal (solanum melongena l.) Against phomopsis blight caused by phomopsis vexans

Phomopsis blight, caused by Phomopsis vexans (P. vexans) in brinjal plants is one of the main diseases in India. In order to manage this malady, we initially screened seed samples of 14 cultivars obtained from seed suppliers for the disease incidence. Based on the disease incidence and severity, the samples were categorized as resistant and susceptible cultivars of brinjal. It was established that MEBH-9' was a sensitive cultivar, while the Kolar local was resistant to the disease. Two ideal strains of Rhizosphere colonizing bacteria (RCB), Pseudomonas putida strain Has-1/c (HM229805), and Phylloplane Colonizing Bacteria (PCB), Bacillus subtilis strain Br/ph-33 (KJ867501), previously characterized as potential plant growth-promoting rhizobacteria, were tested for their potential biocontrol of this disease. Both susceptible and resistant cultivars' seedlings were treated with different combinations of PCB and RCB, PCB alone, RCB alone, and challenge inoculated with P. vexans. In order to ascertain whether there was signalling between defense enzyme activation and plant protection after PCB and RCB treatment, defense enzymes were quantified. Brinjal plants treated with PCB+RCB combination and challenge inoculated with P. vexans showed a significant increase in the activity of Phenylalanine ammonia-lyase (PAL), Peroxidase (POX), Lipoxygenase (LOX), Polyphenol oxidase (PPO), Catalase, Chitinase, β -1,3-glucanase, and Hydrogen peroxide (H2O2) content. The current study reveals that the defense enzymes and PR-proteins are gradually induced and accumulated, which enhance the resistance in brinjal plants against P. vexans-causing fruit rot disease.

Cultivating a greener future: Exploiting trichoderma derived secondary metabolites for fusarium wilt management in peas

This study aimed to identify efficient Trichoderma isolate(s) for the management of Fusarium wilt in peas. Four different pea germplasms (Sarsabz, Pea-09, Meteor and Supreme) were evaluated for resistance against Fusarium oxysporum in pot assay. Resistant germplasm exhibits a varying range of disease severity (23%) and percent disease index (21%), whereas susceptible and highly susceptible germplasm exhibit maximum disease severity (44–79%) and percent disease index (47–82%). The susceptible germplasm Meteor was selected for in vivo experiment. Five different Trichoderma spp. (Trichoderma koningii, T. hamatum, T. longibrachiatum, T. viride, and T. harzianum) were screened for the production of hydrolytic extracellular enzymes under in vitro. In-vitro biocontrol potential of Trichoderma spp. was assayed by percentage inhibition of dry mass of Fusarium oxysporum pisi (FOP) with Trichoderma spp. metabolite filtrate concentrations. Maximum growth inhibition was observed by T. harzianum (50–89%). T. harzianum metabolites in filtrate conc. (40%, 50%, and 60%) exhibited maximum reduction in biomass and were thus used for in vivo management of the disease. The pot experiment for in-vivo management also confirmed the maximum inhibition of FOP by T. harzianum metabolites filtrate at 60% by reducing disease parameters and enhancing growth, yield, and physiochemical and stress markers. Trichoderma strains led to an increase in chlorophyll and carotenoids (34-26%), Total phenolic 55%, Total protein content 60%, Total Flavonoid content 36%, and the increasing order of enzyme activities were as follows: CAT > POX > PPO > PAL in all treatments. These strains demonstrate excellent bio-control of Fusarium wilt in pea via induction of defense-related enzymes. The present work will help use Trichoderma species in disease management programme as an effective biocontrol agent against plant pathogens.

Induction of defense-related enzymes and enhanced disease resistance in rice against Sarocladium oryzae by Bacillus cereus RBS-57

Bacillus species have been identified as effective bioagents and plant growth boosters in rice. Currently, there is limited research on the effectiveness of Bacillus strains in managing the sheath rot disease of rice caused by Sarocladium oryzae, a significant threat to rice-cultivating areas in India. The aim of this study was to evaluate the efficacy of Bacillus spp. to control the sheath rot disease and promote growth in rice plants. We investigated the in vitro antagonistic activity and growth-promoting potential of eighty-four Bacillus spp. against S. oryzae. Ten efficient strains were carefully selected and analyzed at the molecular level based on their capacity for antagonism and growth promotion. A PCR study of the potential strains has revealed the presence of lipopeptide genes that produce bacilysin, bacillomycin, iturin, surfactin, subtilin, subtilosin and fengycin. Among the strains, RBS-57 had the highest mycelial growth inhibition (74.44 %) of the pathogen as well as the highest number of antibiotic genes (6). The efficacy of talc and liquid formulations of Bacillus strains BS-5, RBS-57, and RBS-3 was further tested against sheath rot disease. Results indicated that a combined application of seed treatment + seedling dip + foliar spray of RBS-57 liquid formulation under pot culture conditions, showed a considerable reduction in the incidence of sheath rot disease, followed by BS-5 and RBS-3. Similarly, a significant increase in the plant growth attributes and yield was observed with RBS-57, when compared to the other treatments. Enzymatic activities such as PO, PPO, PAL, CAT and SOD were induced in the rice sheath by B. cereus (RBS-57) treatment. Real-time expression analysis was performed to validate the fold changes in defense enzymes and reactive oxygen species. The effectiveness of RBS-57 liquid formulation in reducing disease incidence was demonstrated when applied as a combination of seed treatment @ 10 ml/l + seedling dip @ 10 ml/l + foliar spray @ 10 ml/l. Moreover, higher defense enzyme activities, maximum plant growth promotion and higher yield were reported with RBS-57 treatment. This study has the potential to be exploited to manage sheath rot disease in an eco-friendly and sustainable manner.

Biocontrol efficacy and induced defense mechanisms of indigenous Trichoderma strains against Fusarium wilt [F. udum (Butler)] in pigeonpea

This study aimed to identify efficient Trichoderma isolate(s) for the management of Fusarium wilt in pigeonpea. In vitro and in vivo (greenhouse) experiments were conducted to evaluate 17 Trichoderma isolate(s) for their anti-pathogenic activity, induction of plant biochemical functions, disease suppression, and plant growth traits comparing with standard Trichoderma strains. Among the indigenous isolates, IIPRTh-31 (T. asperellum) and IIPRTh-33 (T. afroharzianum) had a higher mycelia growth inhibition in vitro [membrane assay (>74%), binary assay (>65%)]. Seed treatment with IIPRTh-31 and IIPRTh-33 isolates led to an increase in peroxidase (173–244%), polyphenol oxidase (48–80%), phenylalanine ammonia–lyase (147–178%) activities in pigeonpea plants over control and reduced disease incidence by 78–85%. Hence, IIPRTh-31, and IIPRTh-33 strains demonstrate excellent bio-control of Fusarium wilt in pigeonpea via induction of defense-related enzymes. These isolates have been registered (Registration No. NAIMCC-R-5, NAIMCC-R-6) and used for talc-based bio-formulations for field application.

Trichoderma reesei induces defense-related biochemical markers associated with resistance to Fusarium dieback in tea crop

Tea crop is an important source of non-alcoholic beverages worldwide with several health benefits. However, its production is significantly inhibited by both biotic and abiotic stresses. Among biotic stresses, Fusarium dieback, caused by Fusarium solani, is a prevalent disease of tea crop, which limits crop production in eastern and northeast India. Disease mitigation with microbial bioagents is considered a viable and eco-friendly alternative to synthetic fungicides. In this study, we explored the efficiency of Trichoderma reesei TRPATH01 in the reduction of Fusarium dieback and stimulation of various defensive enzymes in tea crop against F. solani through a tri-trophic interface. A total 16 isolates of Trichoderma species isolated from rhizospheric tea soils were characterized. Further, dual culture test revealed that amongst the 16 isolates screened, isolate TRPATH01 possessed highest growth inhibition (82.6%) of F. solani FSNKT. Morpho-molecular characterizations of the isolate TRPATH01 showed that it was T. reesei. Further, 2% and 5% dosage of T. reesei TRPATH01, each with spore density 2 × 106 spores/ml controlled 66.6% to 74.4% of Fusarium dieback under nursery conditions over positive control inoculated with only pathogen. In addition, tea plants applied with T. reesei TRPATH01 possessed enhanced stem diameter, shoot height, fresh weight of root and shoot at inoculation after 60 days under nursery conditions compared with controls. Furthermore, induction of defense-related enzymes viz., peroxidase, phenolics, polyphenol oxidase, chitinase, phenylalanine ammonia lyase, and β-1, 3-glucanase due to antagonist were investigated. Overall, the accumulation of defensive enzymes was superior in plants sprayed with T. reesei TRPATH01 followed by F. solani FSNKT inoculation compared to both positive and negative controls. The outcomes of this study suggests that induction of defense-related enzymes by T. reesei TRPATH01 is potentially a prevailing management approach for Fusarium dieback, and it may offer a mitigation prospect for its eco-friendly and sustainable use in tea gardens.

Defense responses in cowpea elicited by entomopathogenic fungi against <i>Aphis craccivora</i> Koch

Use of entomopathogenic fungi for controlling the aphids is well attempted and further substantiation of interaction of entomopathogenic fungus in cowpea plants against aphid were studied in detail. Bioassays were performed with five fungal isolates against cowpea aphid Aphis craccivora Koch. The results revealed that the isolate Beauveria bassiana (NBAIR) recorded the highest mortality of 94.67% at 120 hr (at 5 days after treatment- DAT). The foliar application of its crude formulation @ 108 spores ml-1 had significant influence on the induction of defense related enzymes and components against A. craccivora infestation in cowpea. Resistant mechanism mediated by entomopathogenic fungi in cowpea against A. craccivora showed sustained and timely induction/ accumulation of defense enzymes. On 4 DAT the enzymes viz., peroxidases, polyphenol oxidases, phenylalanine ammonia lyase, chitinase, catalase and phenolics revealed maximum activity.

Biocontrol Potential of Endophytic Fungi for the Eco-Friendly Management of Root Rot of Cuminum cyminum Caused by Fusarium solani

Root rot disease of Cuminum cyminum caused by Fusarium solani is one of the most destructive diseases threatening cumin production. The present study investigates the biocontrol potential of some endophytes against F. solani and their effect on the induction of defense-related enzymes in a greenhouse. The results herein presented illustrate the strong biocontrol potential of three (out of twelve) endophytes. During the in vitro assay, three isolates demonstrated strong mycelial growth inhibition of F. solani: isolates 3, 4, and 9, with 87%, 65%, and 80% reductions, respectively, with respect to the control (100%). These isolates were identified as Trichoderma harzianum, T. longibrachiatum, and Chaetomium globosum, which produce siderophore and indole-3-acetic acid (IAA). Cumin seed priming with the culture filtrates of T. harzianum, C. globosum, and T. longibrachiatum positively affected the seed germination, as a higher germination (%) of culture filtrate-treated seeds was observed followed by infected and healthy control/untreated seeds. In the greenhouse, the application of T. harzianum, T. longibrachiatum, and C. globosum caused a reduction in disease severity (67.7%, 58.1%, and 59.3%, respectively) on cumin plants, with a lower disease severity (20%, 26%, and 25%, respectively) recorded in treated plants compared to the infected control (62%). Furthermore, a significant increase in defense-related enzymes in culture filtrate-treated cumin plants was recorded. Higher peroxidase (PO), polyphenoloxidase (PPO), and phenylalanine ammonia-lyase (PAL) activity, and a higher content of phenolic compounds, were found in culture filtrate-treated plants. These results indicate that the culture filtrates of these bioagents not only increased seed germination, but also protected the plants from F. solani infection by acting as important elements of the cellular antioxidant system in plants upon infection, conferring the biocontrol potential of C. globosum and Trichoderma species toward mitigating the root rot disease of cumin plants in a greenhouse.

Induction of Defense-Related Enzymes and Pathogenesis-Related Proteins Imparts Resistance to Barley Genotypes Against Spot Blotch Disease

Spot blotch caused by Bipolaris sorokiniana is a major foliar disease of barley affecting its productivity worldwide. The barley cultivar with complete resistance to this pathogen is not yet identified. In the present study, leaves of six barley genotypes namely PL 807, BH 946, DWRUB 52, BL 1338, BL 1369 and PL 426 inoculated with Bipolaris sorokiniana were evaluated for levels of H2O2, malondialdehyde, antioxidative enzymes, non-enzymatic antioxidants, pathogenesis-related (PR) proteins and β-glucan. The disease score was assessed at flag leaf (F) and one leaf lower to the flag leaf (F1) at two growth stages, i.e. GS 55 and GS 87. The genotype BL 1369 showed moderately resistant nature, PL 807, DWRUB 52 and BL 1338 moderately susceptible whereas other genotypes remained susceptible in response to this pathogen. During GS 87 stage, maximum increase of catalase (CAT), ascorbate peroxidase (APX), glutathione reductase (GR), phenylalanine ammonia lyase (PAL), tyrosine ammonia lyase (TAL) and polyphenol oxidase (PPO) activities along with concomitant decrease of H2O2 content in the infected F1 leaves of BL 1369 may contribute towards its moderately resistant character. However, downregulation of APX and GR enzymes in PL 426, BH 946 and DWRUB 52 may be responsible for their sensitivity towards this pathogen. Although on fungal inoculation, chitinase activity increased in all the genotypes except DWRUB 52 and BL 1338 but maximum increase was reported in BL 1369. β-glucanase activity also increased significantly in both the leaf tissues of BL 1369. It showed positive correlation with chitinase in the flag leaf at 1% level of significance. The β-glucan content decreased in DWRUB 52 and PL 426 upon fungal infection while it increased in BL 1338 and BL 1369 which further pointed out towards resistant character of BL 1369 as the cell wall is a physical barrier which constitutes the first line defence against pathogen attack.

Effect of Ethanol Vapor Treatment on the Growth of Alternaria alternata and Botrytis cinerea and Defense-Related Enzymes of Fungi-Inoculated Blueberry During Storage.

The aim of the present study was to investigate the effects of ethanol vapor on the inhibition of Alternaria alternata and Botrytis cinerea in postharvest blueberry and the induction of defense-related enzymes (DREs) activities in fungi-inoculated blueberries stored at 0±0.5°C for 16days. Results indicated that ethanol vapor markedly inhibited the mycelial growth of A. alternata and B. cinerea in a dose-dependent manner, with inhibition rates of 9.1% (250μlL−1), 36.4% (500μlL−1), and 5.5% (1,000μlL−1) on A. alternata and 14.2% (250μlL−1), 44.7% (500μlL−1), and 76.6% (1,000μlL−1) on B. cinerea, respectively. Meanwhile, ethanol vapor also enhanced the activities of DREs in fungi-inoculated blueberries, including β-1,3-glucanase (GLU), chitinase (CHI), phenylalnine ammonialyase (PAL), peroxidase (POD), and polyphenol oxidase (PPO). In particular, 500μlL−1 ethanol vapor increased the activities of DREs by 84.7% (GLU), 88.0% (CHI), 37.9% (PAL), 85.5% (POD), and 247.0% (PPO) in A. alternata-inoculated blueberries and 103.8% (GLU), 271.1% (CHI), 41.1% (PAL), 148.3% (POD), and 74.4% (PPO) in B. cinerea-inoculated blueberries, respectively. But, the activity of PPO was decreased by 55.2 and 31.9% in 500μlL−1 ethanol-treated blueberries inoculated with A. alternata and B. cinerea, respectively, after 8days of storage. Moreover, the surface structure and ultrastructure of 500μlL−1 ethanol-treated blueberry fruit cells were more integrated than those of other treatments. The findings of the present study suggest that ethanol could be used as an activator of defense responses in blueberry against Alternaria and Botrytis rots, by activating DREs, having practical application value in the preservation of postharvest fruit and vegetables.

Induction of defense-related enzymes and enhanced disease resistance in maize against Fusarium verticillioides by seed treatment with Jacaranda mimosifolia formulations

Fusarium verticillioides is an important fungal pathogen of maize, causing stalk rot and severely affecting crop production. The aim of this study was to characterize the protective effects of formulations based on Jacaranda mimosifolia leaf extracts against F. verticillioides in maize. We compared different seed treatments comprising J. mimosifolia extracts, chemical fungicide (mefenoxam) and salicylic acid to modulate the defense system of maize host plants. Both aqueous and methanolic leaf extracts of J. mimosifolia (1.2% w/v) resulted in 96–97% inhibition of mycelial growth of F. verticillioides. While a full-dose (1.2%) extract of J. mimosifolia provided significant protective effects on maize plants compared to the inoculated control, a half-dose (0.6% w/v) application of J. mimosifolia in combination with half-strength mefenoxam was the most effective treatment in reducing stalk rot disease in pot and field experiments. The same seed treatment significantly upregulated the expression of genes in the leaves encoding chitinase, glucanase, lipid transfer protein, and pathogenesis-related proteins PR-1, PR-5 and PR-10, 72 h after inoculation. This treatment also induced the activities of peroxidase, polyphenol oxidase, protease, acid invertase, chitinase and phenylalanine ammonia lyase. We conclude that seed pre-treatment with J. mimosifolia extract with half-strength chemical mefenoxam is a promising approach for the management of stalk rot in maize.

Biocontrol potential of Bacillus subtilis RH5 against sheath blight of rice caused by Rhizoctonia solani.

The sheath blight disease of rice caused by Rhizoctonia solani is widely prevalent and one of the most destructive diseases, affecting rice cultivation and loss worldwide. In the present study, a set of twenty Bacillus isolates from saline soil of Uttar Pradesh were tested for their biocontrol activity against R. solani with the aim to obtain a potential strain for the control of sheath blight disease toward ecofriendly and sustainable agriculture. The results of dual-culture assay and scanning electron microscopic studies showed that the strain RH5 exhibited significant antagonistic activity (84.41%) against the fungal pathogen R. solani. On the basis of 16S rDNA sequencing analysis, the potential biocontrol strain RH5 was identified as Bacillus subtilis. Furthermore, the strain RH5 was characterized by different plant growth-promoting (PGP) activities and induction of defense-related enzymes in rice plants against R. solani. The strain RH5 posses various PGP attributes (indole acetic acid, siderophore, hydrogen cyanide production and phosphate, Zn, K solubility), hydrolytic enzymatic (chitinase, protease, cellulase, xylanase) activity, and presence of antimicrobial peptide biosynthetic genes (bacylisin, surfactin, and fengycin), which support the strain for efficient colonization of hyphae and its inhibition. Finally, the results of the greenhouse study confirmed that strain RH5 significantly increased plant growth and triggered resistance in rice plants through the production of defense-related antioxidant enzymes.

A Biostimulant Preparation of Brown Seaweed Ascophyllum nodosum Suppresses Powdery Mildew of Strawberry.

Strawberry, an important fruit crop, is susceptible to a large number of pathogens that reduce fruit quality and productivity. In this study, the effect of a biostimulant prepared from Ascophyllum nodosum extract (ANE) (0.1%, 0.2%, and 0.3%) was evaluated on powdery mildew progression under greenhouse and field conditions. In the greenhouse, application of 0.2% ANE showed maximum reduction in powdery mildew progression as compared to the control. Forty-eight hour post-inoculation, foliar spray of 0.2% ANE reduced spore germination by 75%. Strawberry leaves sprayed with ANE showed higher total phenolic and flavonoid content in response to powdery mildew infection. Furthermore, application of ANE elicited defense response in strawberry plants by induction of defense-related enzymes, such as phenylalanine ammonia lyase, polyphenol oxidase, and peroxidase activity. In field conditions, foliar spray of 0.2% ANE showed a reduction of 37.2% of natural incidence of powdery mildew infection as compared to the control. ANE sprayed plant also reduces the severity of powdery mildew infection under natural conditions. These results indicate that application of ANE induces the strawberry plant’s active defense against powdery mildew infection by induction of secondary metabolism and regulating the activities of defense-related enzymes.

Antioxidant Enzyme Activities and Secondary Metabolite Profiling of Oil Palm Seedlings Treated with Combination of NPK Fertilizers Infected with Ganoderma boninense.

Oil palm (Elaeis guineensis Jacq) is one of the major sources of edible oil. Reducing the effect of Ganoderma, main cause of basal stem rot (BSR) on oil palm, is the main propose of this study. Understanding the oil palm defense mechanism against Ganoderma infection through monitoring changes in the secondary metabolite compounds levels before/after infection by Ganoderma under different fertilizing treatment is required. Oil palm requires macro- and microelements for growth and yield. Manipulating the nutrient for oil palm is a method to control the disease. The 3-4-month-old oil palm seedlings were given different macronutrient treatments to evaluate induction of defense related enzymes and production of secondary metabolite compounds in response to G. boninense inoculation. The observed trend of changes in the infected and uninfected seedlings was a slightly higher activity for β-1,3-glucanases, chitinase, peroxidase, and phenylalanine ammonia-lyase during the process of pathogenesis. It was found that PR proteins gave positive response to the interaction between oil palm seedlings and Ganoderma infection. Although the responses were activated systematically, they were short-lasting as the changes in enzymes activities appeared before the occurrence of visible symptoms. Effect of different nutrients doses was obviously observed among the results of the secondary metabolite compounds. Many identified/unidentified metabolite compounds were presented, of which some were involved in plant cell defense mechanism against pathogens, mostly belonging to alkaloids with bitter-tasting nitrogenous-compounds, and some had the potential to be used as new markers to detect basal stem rot at the initial step of disease.

Biocontrol of Bacterial Leaf Blight of Rice and Profiling of Secondary Metabolites Produced by Rhizospheric Pseudomonas aeruginosa BRp3.

Xanthomonas oryzae pv. oryzae (Xoo) is widely prevalent and causes Bacterial Leaf Blight (BLB) in Basmati rice grown in different areas of Pakistan. There is a need to use environmentally safe approaches to overcome the loss of grain yield in rice due to this disease. The present study aimed to develop inocula, based on native antagonistic bacteria for biocontrol of BLB and to increase the yield of Super Basmati rice variety. Out of 512 bacteria isolated from the rice rhizosphere and screened for plant growth promoting determinants, the isolate BRp3 was found to be the best as it solubilized 97 μg/ mL phosphorus, produced 30 μg/mL phytohormone indole acetic acid and 15 mg/ L siderophores in vitro. The isolate BRp3 was found to be a Pseudomonas aeruginosa based on 16S rRNA gene sequencing (accession no. HQ840693). This bacterium showed antagonism in vitro against different phytopathogens including Xoo and Fusarium spp. Strain BRp3 showed consistent pathogen suppression of different strains of BLB pathogen in rice. Mass spectrometric analysis detected the production of siderophores (1-hydroxy-phenazine, pyocyanin, and pyochellin), rhamnolipids and a series of already characterized 4-hydroxy-2-alkylquinolines (HAQs) as well as novel 2,3,4-trihydroxy-2-alkylquinolines and 1,2,3,4-tetrahydroxy-2-alkylquinolines in crude extract of BRp3. These secondary metabolites might be responsible for the profound antibacterial activity of BRp3 against Xoo pathogen. Another contributing factor toward the suppression of the pathogen was the induction of defense related enzymes in the rice plant by the inoculated strain BRp3. When used as an inoculant in a field trial, this strain enhanced the grain and straw yields by 51 and 55%, respectively, over non-inoculated control. Confocal Laser Scanning Microscopy (CLSM) used in combination with immunofluorescence marker confirmed P. aeruginosa BRp3 in the rice rhizosphere under sterilized as well as field conditions. The results provide evidence that novel secondary metabolites produced by BRp3 may contribute to its activity as a biological control agent against Xoo and its potential to promote the growth and yield of Super Basmati rice.

Induction of Defense-related Enzymes by Bacillus amyloliquefaciens DSBA-11 in Resistant and Susceptible Cultivars of Tomato Against Bacterial Wilt Disease

Induction of Defense-related Enzymes by Bacillus amyloliquefaciens DSBA-11 in Resistant and Susceptible Cultivars of Tomato Against Bacterial Wilt Disease

Induction of defense-related enzymes in patchouli inoculated with virulent Ralstonia solanacearum

800x600 800x600 Background: Defense-related anti-oxidative response is a vital defense mechanism of plant against pathogen invasion. Ralstonia solanacearum is an important phytopathogen. Bacterial wilt caused by R. solanacearum is the most destructive disease and causes severe losses in patchouli, an important aromatic and medicinal plant in Southeast Asia. The present study evaluated the defense response of patchouli inoculated with virulent R. solanacearum . Results: Results showed that the basic enzymatic activities differed not only between the leaves and stems, but also between the upper and lower parts of the same organ of patchouli. POD, SOD, PPO and PAL enzymatic activities were significantly elevated in leaves and stems from patchouli inoculated with R. solanacearum as compared to control. The variation magnitude and rate of POD, PPO and PAL activities were more obvious than SOD in patchouli inoculated with R. solanacearum . PAGE isoenzymatic analysis showed that there were one new POD band and two new SOD bands elicited, and at least two isoformic POD bands and two SOD bands were observably intensified as compared to the corresponding control. Conclusion: Our results suggest that not only the defensive enzymatic activities were elevated, but also the new isoenzymatic isoforms were induced in patchouli inoculated with R. solanacearum . Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:Tabla normal; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:Times New Roman,serif;}

Evaluation of Abiotic and Biotic Elicitors for Induction of Defense Related Enzymes in Pea against U. Viciae-Fabae (Pers.) J. Schrot

Evaluation of Abiotic and Biotic Elicitors for Induction of Defense Related Enzymes in Pea against U. Viciae–Fabae (Pers.) J. Schrot Total of fifteen elicitors tested alone/or in combination for induction of defense related enzymes in pea against U. viciae–fabae (Pers.) J. Schrot results in significant induction of total phenols, peroxidase, polyphenol oxidase and phenylalanine ammonia lyase in all the treatment as compare to control. Salicylic acid, Pseudomonas fluorescens, salicylic acid + Pseudomonas fluorescens were found most effective in induction of total phenols and peroxidase at 72 hrs after spray of elicitors. Polyphenol oxidase induction was found significantly high in oxalic acid, Pseudomonas fluorescens + Trichoderma harzianum and chitosan + Pseudomonas fluorescens at 72 hrs after spray of elicitors. Among all the treatments, maximum induction of Phenylalanine ammonia lyase activity was found in oxalic acid, Trichoderma harzianum + Pseudomonas fluorescens and isonicotinic acid + Trichoderma harzianum after 48hrs of spray of elicitors. Effect of different elicitors on percent disease index (PDI) 20 days after inoculation with uredospores of U. viciae– fabae showed least PDI in salicylic acid, Trichoderma harzianum + Pseudomonas fluorescens and chitosan + Pseudomonas fluorescens treated plants....

PGPM-induced defense-related enzymes in aerobic rice against rice leaf blast caused by Pyricularia oryzae

Rice blast caused by Pyricularia oryzae is the most devastative disease especially under aerobic cultivation systems. The bio-efficacy of plant growth-promoting microorganisms: Pseudomonas aeruginosa (UPMP1), Corynebacterium agropyri (UPMP7), Enterobacter gergoviae (UPMP9) and Bacillus amyloliquefaciens (UPMS3), Trichoderma harzianum (UPMT1) and Trichoderma virens (UPMT2) in induction of defense-related enzymes against Pyricularia oryzae was evaluated in rice cultivated under aerobic conditions. Under dual culture plate testing, all PGPMs indicated antagonism against P. oryzae with percentage inhibition radial growth (PIRG) which ranged from 51.69–81.97 %. The bio-efficacy of the respective PGPM in induction of defense-related enzymes in rice seedlings was evaluated based on individual inoculation before challenged inoculation with P. oryzae under greenhouse conditions. Inoculation of all PGPMs significantly reduced rice leaf blast severity at day eight after P. oryzae inoculation. The reduction in rice leaf blast disease severity was associated to the increase of peroxidase (PO), polyphenol oxidase (PPO) and phenylalanine ammonia-lyase (PAL) activities in rice seedlings when pre-inoculated with PGPMs. The highest leaf blast disease reduction (59.17 %) occurred with rice seedlings pre-inoculated with C. agropyri (UPMP9), followed by P. aeruginosa (UPMP1) (40.65 %), T. harzianum (UPMT1) (42.23 %), T. virens (UPMT2) (20.85 %), E. gergoviae (UPMP9) (17.84 %) and B. amyloliquefaciens (UPMS3). The high efficiency of PGPM in leaf blast disease suppression was associated with significant increase in total microbial activity (FDA hydrolysis) in rhizosphera soil (4.80–7.86 μg/g/0.5 h) compared to the control (2.25 μg/g/0.5 h). Thus, the application of PGPM is a potential alternative approach in rice leaf blast disease management of aerobic rice.

Defense related enzyme induction in coconut by endophytic bacteria (EPC 5)

Endophytic bacteria Bacillus subtilis (EPC 5) was isolated and tested in vitro along with Pseudomonas fluorescens (Pf1) and the fungus Trichoderma viride (Tv1) against Ganoderma lucidum (Leys) Karst, the causal agent of basal stem rot on coconut palm. The endophytic bacterial strains namely EPC 5 and EPC 8 showed higher vigor index (germination percentage, root and shoot length) and more inhibition against G. lucidum over un-inoculated control. These strains were confirmed as Bacillus subtilis by biochemical tests, cloning and sequencing of internal transcribed spacer (ITS) region. The Bacillus subtilis (EPC 5) along with Pseudomonas fluorescens (Pf1) and Trichoderma viride (Tv1) has been tried as bioconsortia against basal stem rot disease under greenhouse conditions. The soil application of bioconsortia enriched with farm yard manure (FYM) enhanced the coconut saplings growth under greenhouse conditions and showed higher induction of defense related enzymes like peroxidase, polyphenol oxidase, phenylalanine ammonia lyase and phenols when challenged with pathogen.

In vitro inhibition and in vivo induction of defense response against Penicillium expansum in sweet cherry fruit by postharvest applications of Bacillus cereus AR156

The biocontrol effect of Bacillus cereus AR156 on blue mold decay caused by Penicillium expansum in harvested sweet cherry fruit and the possible mechanisms were investigated. The results indicated that B. cereus AR156 treatment significantly reduced disease incidence and development. The treatment significantly enhanced activities of chitinase and β-1, 3-glucanase in the fruit. B. cereus AR156 damaged the plasma membrane integrity of P. expansum spores and caused the leakage of protein and sugar of the pathogen mycelia in vitro. The results indicated that the efficacy of B. cereus AR156 on controlling blue mold decay in cherry fruit may be related to the direct fungitoxic property against the pathogen, and the induction of defense-related enzymes in the fruit.