Induction of defence related biochemical responses by different treatments (elicitors, bioagents, antibiotics and chemicals) in citrus against Xanthomonas axonopodis pv. citri (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.
Induced resistance in sweet orange against Xanthomonas citri subsp. citri by hexanoic acid
Crop Protection, 2015
Citrus canker, caused by Xanthomonas citri subsp. citri, is a serious and wide-spread disease of citrus, causing losses in fruit yield and quality. There are no highly effective citrus canker disease control measures. Repeated spray applications of copper are often employed to protect fruit from bacterial infection with consequences for copper phytotoxicity and accumulation in the soil. Alternatively, innate plant defense mechanisms can be enhanced by plant treatments with specific natural and synthetic inducers for control of bacterial diseases. In this study, hexanoic acid applied as a soil drench or foliar spray on 9-month-old potted citrus trees reduced lesions on leaves by 50% compared with control plants. Disease-reducing activity lasted up to 50 days after application. Induction of resistance mediated by hexanoic acid was demonstrated by enhanced expression of Pathogenesis-related (PR) genes and callose deposition in treated and infected plants. These findings indicated that hexanoic acid applications trigger a defensive response in the plants. The application of this natural compound may have potential for management of citrus canker in conjunction with other disease control measures and may reduce the frequency or rate of copper bactericides.
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.
Elucidation of Physio-Biochemical Changes in Citrus spp. Incited by Xanthomonas citri pv. citri
Horticulturae
India is one of the leading citrus−producing countries, next to China and Brazil. Despite the sizeable production, especially of lemons and limes, India contributes meagerly to the world’s citrus market. Of the various factors responsible for the restricted quantum of citrus export, citrus canker (Xanthomonas citri pv. citri) is one of the leading serious causes and directly impacts the appearance of the fruits. Considering the extent of damage, the present study aimed to understand the impact of Xanthomonas citri pv. citri (Xcc) on the physio−biochemical responses in contrasting Citrus spp. Two genotypes, each of three citrus species, namely Citrus aurantifolia (Pusa Udit and ALC−35), C. limon (Kagzi Kalan and Konkan Seedless), and C. paradisi (Redblush and Marsh Seedless), were artificially inoculated with Xcc (108 to 109 cfu/ mL) by the pinprick method. The physio−biochemical changes in the host were evaluated after 48 h post inoculation (hpi). The chlorophyll content (total, a, ...
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.
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...
Citrus canker (X. axonopodis pv. citri) widespread bacterial disease which limits citrus productivity and causes quality deterioration. Citrus canker is mostly a leaf-spotting and fruit rind-blemishing disease, but under highly favorable conditions, infections cause defoliation, shoot dieback, and fruit drop. Citrus rootstocks exert a high degree of influence to scions in fruit production and plant susceptibility to diseases including citrus canker. Keeping in view the importance of citrus rootstock present study was planned to evaluate the performance of citrus rootstocks against citrus canker and antibiotics response to control X. axonopodis pv. citri. Eleven exotic citrus rootstocks were selected to evaluate against canker which was inoculated by grafting. Disease index was observed after 9 months of inoculation. Five different commercially available antibiotics were selected for the Invitro treatment, applied at 300, 400 and 500ppm. Inhibition zone was observed at four time points (24, 48, 72 and 96 hours). Kirumakki showed maximum resistance followed by Rangpur Poona nucellar and X639 while Rough lemon was highly susceptible. In Invitro evaluation maximum inhibition zone was expressed by Kanamycin sulphate at 500 ppm followed by Streptomycin sulphate. Lincomycin showed minimum inhibition zone as compared with control (Distilled water, No inhibition). Biochemical analysis exhibited that the disease index (%) decrease with increase of total phenolics contents and total protein contents. Whereas disease index had increasing trend with TSS. This study concludes that according to rootstocks evaluation Kirumakki and Rangpur Poona nucellar showed resistant performance while, on other hand Kanamycin Sulphate having maximum inhabitation against canker.
Pak. J. Phytopathol, 2007
Fifteen citrus cultivars were screened for the sources of resistance against citrus canker disease incited by Xanthomonas axonopodis pv. citri in a field trial conducted at research area of plant pathology department for two years i.e. 2005-07. Citrus sinensis cv. jaffa exhibited resistant response while Citrus paradise, Citrus sinensis cv. blood red, Citrus limonia cv. mayer lemon showed highly susceptible expression. Citrus sinensis cv. valentia late, Citrus reticulate cv. feutral's early showed moderately resistant while Citrus reticulate cv. malta, Citrus limettioides, Citrus limonia cv. china lemon, Citrus sinensis cv. musambi were found moderately susceptible towards canker disease. No citrus cultivar was found immune.