Induced resistance in sweet orange against Xanthomonas citri subsp. citri by hexanoic acid (original) (raw)
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Induction of Resistance against Citrus Canker through Chemicals and Plant Activators
Advances in Zoology and Botany, 2018
The objective of present study was to evaluate the effect of copper hydroxide and flare at three concentrations (0.1, 0.2 and 1%) and naphthalene acetic acid, salicylic acid, copper hydroxide alone and in combination (Flare + salicylic acid) at 0.75, 1 and 1.5% concentration against Xanthomonas axonopodis pv. citri in lab and greenhouse conditions respectively. Results showed that in lab condition maximum inhibition of bacterial growth was expressed by combination of flare and copper hydroxide, followed by Flare, copper hydroxide over control while in case of greenhouse experiment minimum disease incidence was expressed by combination of Flare + salicylic acid after 5, 10 and 15 days interval followed by flare, salicylic acid, naphthalene acetic acid and Cu(OH) 2 as compared to control.
2019
The glasshouse and laboratory experiments were conducted to evaluate the enzymatic activity of the antioxident enzymes viz; Phenylalanine ammonia lyase (PAL), Catalase (CAT) and Peroxidase (PO) against X. axonopodis pv. citri for different treatments at, Department of Plant Pathology, College of Agriculture, G.B.P.U.A. &T., Pantnagar. Experiment was laid out in Completely Randomized Design (CRD) in glass house comprising ten treatment combinations replicated thrice, where the pretreatment of citrus plants with Pant bioagent 2, Pant bioagent 3, L-methionine, GABA and Salicylic acid induced the levels of plant defense and thus induced disease resistance against X. axonopodispv.citri. These compounds can be used as effective alternative compounds to copper bactericides for the management of citrus canker.
American Journal of Plant Sciences, 2017
Citrus canker is a perilous disease caused by Xanthomonas axonopodis pv. citri (Xac) which is hardly manageable. Till now, chemicals used against Xac either proved less effective against the disease or hazardous for environment. In this study, we investigated how phytohormones such as Salicylic acid (SA, 3 mM), Jasmonic acid (JA, 0.3 mM), 3-indolacetonitrile (IAN, 0.6 mM), Nicotinic acid (NA, 5 mM), Folic acid (FA, 0.5 mM) influenced canker disease. Disease severity and lesion diameter were significantly mitigated by exogenous application of these phytohormones compared with water (control) accompanied by the increase of latent period. However, these phytohormones did not show any in vitro antimicrobial properties against Xac. Concomitant with boosted resistance, phytohormones treated leaves showed the higher level of phenyl ammonia lyase (PAL) activity. Besides, total phenolic compounds (TPC) and potassium contents were also higher in phytohormone treated plants compared with control. Phytohormones showed the significant and better performance on disease mitigation than control among which, SA showed the highest performance while JA and INA showed the moderate performance. However, NA and FA showed the lowest performance. This result recommended that application of some phytohormones had elicited some biochemical and physiological events which induced the resistance against Xac.
Phytohormone-Induced Resistance against Xanthomonas axonopodis PV. citri in Citrus aurantifolia
Citrus canker is a perilous disease caused by Xanthomonas axonopodis pv. ci-tri (Xac) which is hardly manageable. Till now, chemicals used against Xac either proved less effective against the disease or hazardous for environment. In this study, we investigated how phytohormones such as Salicylic acid (SA, 3 mM), Jasmonic acid (JA, 0.3 mM), 3-indolacetonitrile (IAN, 0.6 mM), Nico-tinic acid (NA, 5 mM), Folic acid (FA, 0.5 mM) influenced canker disease. Disease severity and lesion diameter were significantly mitigated by exogen-ous application of these phytohormones compared with water (control) accompanied by the increase of latent period. However, these phytohormones did not show any in vitro antimicrobial properties against Xac. Concomitant with boosted resistance, phytohormones treated leaves showed the higher level of phenyl ammonia lyase (PAL) activity. Besides, total phenolic compounds (TPC) and potassium contents were also higher in phytohormone treated plants compared with control. Phytohormones showed the significant and better performance on disease mitigation than control among which, SA showed the highest performance while JA and INA showed the moderate performance. However, NA and FA showed the lowest performance. This result recommended that application of some phytohormones had elicited some biochemical and physiological events which induced the resistance against Xac.
Frontiers in Plant Science, 2022
Citrus canker is a destructive disease caused by Xanthomonas citri subsp. citri, which affects all commercial sweet orange (Citrus sinensis [L.] Osbeck) cultivars. Salicylic acid (SA) and systemic-acquired resistance (SAR) have been demonstrated to have a crucial role in mediating plant defense responses against this phytopathogen. To induce SAR, SA is converted to methyl salicylate (MeSA) by an SA-dependent methyltransferase (SAMT) and translocated systemically to prime noninfected distal tissues. Here, we generated sweet orange transgenic plants (based on cvs. Hamlin and Valencia) overexpressing the SAMT gene from Citrus (CsSAMT) and evaluated their resistance to citrus canker. We obtained four independent transgenic lines and confirmed their significantly higher MeSA volatilization compared to wild-type controls. Plants overexpressing CsSAMT showed reduced symptoms of citrus canker and bacterial populations in all transgenic lines without compromising plant development. One representative transgenic line (V44SAMT) was used to evaluate resistance response in primary and secondary sites. Without inoculation, V44SAMT modulated CsSAMT, CsNPR1, CsNPR3, and CsWRKY22 expression, indicating that this plant is in a primed defense status. The results demonstrate that MeSA signaling prompts the plant to respond more efficiently to pathogen attacks and induces immune responses in transgenic plants at both primary and secondary infection sites.
European Journal of Plant Pathology, 2012
Streptomycin has been tested as an alternative to copper bactericides, which are routinely used for the control of citrus canker (Xanthomonas citri subsp. citri, Xcc) in citrus producing areas where the disease is endemic. A major concern is that excessive use of copper as a bactericide may lead to development of copperresistant strains of Xcc. In this study, we developed a semi-selective medium to recover copper or streptomycin-resistant strains of Xcc from citrus leaves. The newly developed semi-selective medium was used to monitor the effect of a 21-day-interval copper or streptomycin spray program on Xcc for three consecutive seasons and on citrus epiphytic bacterial populations for two seasons in a commercial grapefruit grove. Although, no copper-or streptomycin-resistant strains of Xcc were isolated after three seasons, we observed a significant increase over time in the frequency of citrus epiphytic bacteria resistant to these chemicals. Overall, the proportion of epiphytic bacteria resistant to streptomycin on treated and untreated leaves was proportionally lower than the copper-resistant bacterial population. When application of each bactericide was suspended for the season, the proportion of bactericide-resistant bacteria in the epiphytic population decreased to that of the non-treated bacterial population. Availability of an alternative bactericide, such as streptomycin, to integrate into a copperbased program would reduce the amount of each bactericide sprayed in citrus orchards and possibly lower the selection pressure for bacterial resistance to these chemicals.
Resistance evaluation of sweet orange (Citrus sinensis) cultivars to Xanthomonas citri subsp. citri
Citrus canker, caused by the bacterium Xanthomonas citri subsp. citri, is responsible for significant economic losses of citrus in Brazil and elsewhere. The disease occurs in all regions of commercial production of sweet orange (C. sinensis L. Osbeck). Compared to chemical control, deploying canker-resistant cultivars is a viable and economical alternative for management of the disease. The objectives of this study were to compare the resistance to citrus canker of 14 genotypes of sweet orange, and to verify the levels of various enzymes involved in the canker resistance response, specifically peroxidase, catalase, and superoxide dismutase. The 14 genotypes included were Hamlin, Vermelha, Pera EEL, Pera IAC, Pera Bianchi/CC, Pera Ipiguá, Pera IAC 2000/1, Pera Ovale Siracusa, Pera Ovale, Pera IAC 2000/2, Pera M5, Pera Arapongas, Pera 58 and Pera 59. The varieties were evaluated under greenhouse conditions, through inoculation of leaves with X. citri subsp. citri, strain Xcc 306. Afte...
Plant Gene, 2018
Citrus, one of the most valuable fruit crops around the world, are severely damaged by biotic stress and huge economical losses are caused by pathogen infections. Non-host response is an essential plant defense mechanism against pathogen attack, however is still not completely characterized and is poorly studied in non-model plants. In previous reports, we characterized C. sinensis non-host response to Xanthomonas campestris pv. vesicatoria (Xcv), in comparison to infection caused by Xanthomonas citri subsp. citri (Xcc). This was described as a hypersensitive response with structural and physiological modifications, and transcriptional reprogramming of pathogen related proteins and transcription factors, among others. Phytohormones serve as key regulators in plant response to stress, by means of interconnected complex pathways. Here, we study the participation of phytohormone pathways during Citrus non-host response to Xcv. Our results indicate a decrease in abscisic acid, cytokinins, gibberellins, brassinosteroids, auxins and nitric oxide, an increase in ethylene and salicylic acid, constant levels of jasmonic acid, whereas polyamine levels change in a very specific pattern. The present work provides a first broad approach to hormone participation during non-host response in a non-model plant of the Citrus genus, also representative of woody plants.
Tropical Plant Pathology, 2020
Drench applications of systemic acquired resistance (SAR) inducing compounds acibenzolar-s-methyl (ASM) and thiamethoxam (THIA) may contribute for the control of citrus canker, caused by Xanthomonas citri subsp. citri. Here, we report the results of a 3-year field experiment on the effect of drench applications of two SAR-inducing compounds, applied alone or in combination with copper oxychloride (CuOX) foliar sprays, on citrus canker control, as well as tree growth and yield, of Natal sweet orange trees under Brazilian subtropical conditions. Leaf disease incidence, tree defoliation, and citrus leaf miner (Phyllocnistis citrella) attack were evaluated every 30 days for 16 months. Soil applications of ASM or THIA combined with foliar sprays of CuOX highly reduced citrus canker incidence on leaves. Effective control of the disease, comparable to regular foliar sprays of cupric bactericides, was obtained with two to four drench applications of SAR-inducing compounds. No differences among the treatments were observed in regard to tree height and canopy volume, and fruit yield of the young citrus trees. Soil applications of SAR-inducing compounds proved to be an important measure for the integrate management of citrus canker under the Brazilian subtropical conditions. Keywords Systemic acquired resistance. Xanthomonas citri subsp. citri. Citrus leaf miner. Copper in bacterial disease management. Neonicotinoid insecticide