Enhanced resistance to citrus canker in transgenic sweet orange expressing the sarcotoxin IA gene

During the development of a citrus fruit, many cycles of infection by Xanthomonas citri subsp. citri may occur leading to the development of a range of characteristics of citrus canker lesions scattered across the fruit surface. This study aimed to determine whether the size of the lesions, their distance from the peduncle, and the number and time of appearance of the lesions on fruit of sweet orange were associated with premature fruit drop. A multiple linear regression analysis revealed a negative relationship between the fruit detachment force and the lesion diameter, the proximity of the nearest lesion to the peduncle and the number of lesions. A survival analysis demonstrated that these characteristics significantly influenced the probability and the time that a cankered fruit remained attached to the tree. More than 90% of dropped fruit had large lesions (>5 mm) but not all fruit with large lesions dropped before harvest. Approximately 50% of the harvested fruit had lesions >5 mm. On the harvested fruit remaining on the tree, although large, the lesions had a smaller diameter, were located farther from the peduncle, and were less numerous than those observed on dropped fruit. Small canker lesions neither reduced the detachment force nor the survival of fruit in the tree. The earlier a fruit expressed canker symptoms, the higher the probability the fruit developed large lesions near the peduncle and/or developed lesions in greater numbers. This study provides a better understanding on the relationship between the time of appearance of lesions of citrus canker on fruit and premature fruit drop. This information defines the critical period for fruit protection and may be used to improve disease management.

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Enhanced resistance to citrus canker in transgenic mandarin expressing Xa21 from rice

Transgenic Research ◽

10.1007/s11248-018-0065-2 ◽

2018 ◽

Vol 27 (2) ◽

pp. 179-191 ◽

Cited By ~ 18

Author(s):

Ahmad A. Omar ◽

Mayara M. Murata ◽

Hesham A. El-Shamy ◽

James H. Graham ◽

Jude W. Grosser

Keyword(s):

Citrus Canker ◽

Enhanced Resistance

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Enhanced Resistance to Bacterial Diseases of Transgenic Tobacco Plants Overexpressing Sarcotoxin IA, a Bactericidal Peptide of Insect

The Journal of Biochemistry ◽

10.1093/oxfordjournals.jbchem.a022304 ◽

1999 ◽

Vol 125 (3) ◽

pp. 431-435 ◽

Cited By ~ 38

Author(s):

M. Ohshimax ◽

I. Mitsuhara ◽

M. Okamoto ◽

S. Sawano ◽

K. Nishiyama ◽

...

Keyword(s):

Transgenic Tobacco ◽

Transgenic Tobacco Plants ◽

Tobacco Plants ◽

Bacterial Diseases ◽

Sarcotoxin Ia ◽

Enhanced Resistance

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Relative contribution of windbreak, copper sprays and leafminer control for citrus canker management and prevention of crop loss in sweet orange trees

Plant Disease ◽

10.1094/pdis-10-20-2153-re ◽

2020 ◽

Author(s):

Franklin Behlau ◽

José Belasque Junior ◽

RUI LEITE ◽

Armando Bergamin-Filho ◽

Tim Gottwald ◽

...

Keyword(s):

Sweet Orange ◽

Disease Incidence ◽

Citrus Canker ◽

Control Measures ◽

Disease Suppression ◽

Additional Contribution ◽

Crop Losses ◽

Rangpur Lime ◽

Relative Contribution ◽

Orange Trees

The management of citrus canker, caused by Xanthomonas citri subsp. citri, has been widely studied in endemic areas due to the importance of the disease in several citrus producing countries. A set of control measures is well-established, but no study has investigated the efficiency of each measure individually and their combination for disease suppression. This study comprised a 3-year field study to assess the relative contribution of three measures for the control of citrus canker and reduction of crop losses. Windbreak (Wb), copper sprays (Cu), and leafminer control (Lc) were assessed in eight different combinations in a split-split plot design. The orchard was composed of ‘Valencia’ sweet orange trees grafted onto ‘Rangpur’ lime. Casuarina cunninghamiana trees were used as Wb. Cu and Lc sprays were performed every 21 days throughout the year. Individually, Cu showed the highest contribution for canker control, followed by Wb. Lc had no effect on reducing citrus canker. Wb+Cu showed the highest efficiency for control of the disease. This combination reduced the incidence of diseased trees by ~60%, and the incidence of diseased leaves and fruit by ≥ 90% and increased the yield in 2.0 to 2.6-fold in comparison with the unmanaged plots. Cu sprays were important for reducing disease incidence and crop losses, whereas Wb had an additional contribution in minimizing the incidence of cankered, non-marketable fruit. The results indicated that the adoption of these measures of control may depend on the characteristics of the orchard and destination of the production.

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EVALUATION OF SUSCEPTIBILITY OF 'PERA' SWEET ORANGE GENOTYPES TO CITRUS CANKER UNDER FIELD AND GREENHOUSE CONDITIONS

Acta Horticulturae ◽

10.17660/actahortic.2015.1065.62 ◽

2015 ◽

pp. 511-516

Author(s):

Aline M.O. Gonçalves-Zuliani ◽

William M.C. Nunes ◽

Carlos A. Zanutto ◽

José Croce Filho ◽

Paula T.R. Nocchi

Keyword(s):

Sweet Orange ◽

Citrus Canker

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Increased Resistance Against Citrus Canker Mediated by a Citrus Mitogen-Activated Protein Kinase

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi-04-13-0122-r ◽

2013 ◽

Vol 26 (10) ◽

pp. 1190-1199 ◽

Cited By ~ 15

Author(s):

Maria Luiza Peixoto de Oliveira ◽

Caio Cesar de Lima Silva ◽

Valéria Yukari Abe ◽

Marcio Gilberto Cardoso Costa ◽

Raúl Andrés Cernadas ◽

...

Keyword(s):

Hydrogen Peroxide ◽

Sweet Orange ◽

Plant Immunity ◽

Gene Promoter ◽

Citrus Canker ◽

Hypersensitive Reaction ◽

Mitogen Activated Protein Kinase ◽

Defense Gene Expression ◽

Defense Gene ◽

Mitogen Activated Protein

Mitogen-activated protein kinases (MAPK) play crucial roles in plant immunity. We previously identified a citrus MAPK (CsMAPK1) as a differentially expressed protein in response to infection by Xanthomonas aurantifolii, a bacterium that causes citrus canker in Mexican lime but a hypersensitive reaction in sweet oranges. Here, we confirm that, in sweet orange, CsMAPK1 is rapidly and preferentially induced by X. aurantifolii relative to Xanthomonas citri. To investigate the role of CsMAPK1 in citrus canker resistance, we expressed CsMAPK1 in citrus plants under the control of the PR5 gene promoter, which is induced by Xanthomonas infection and wounding. Increased expression of CsMAPK1 correlated with a reduction in canker symptoms and a decrease in bacterial growth. Canker lesions in plants with higher CsMAPK1 levels were smaller and showed fewer signs of epidermal rupture. Transgenic plants also revealed higher transcript levels of defense-related genes and a significant accumulation of hydrogen peroxide in response to wounding or X. citri infection. Accordingly, nontransgenic sweet orange leaves accumulate both CsMAPK1 and hydrogen peroxide in response to X. aurantifolii but not X. citri infection. These data, thus, indicate that CsMAPK1 functions in the citrus canker defense response by inducing defense gene expression and reactive oxygen species accumulation during infection.

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