Plant Pathology (2012) 61, 658-664

M.C.G. Gasparoto, H.D. Coletta-Filho, R.B. Bassanezi, S.A. Lopes, S.A. Lourenço and L. Amorim (2012)
Influence of temperature on infection and establishment of ´Candidatus Liberibacter americanus' and `Candidatus Liberibacter asiaticus' in citrus plants
Plant Pathology 61 (4), 658-664
Abstract: The objectives of this work were (i) to determine the influence of temperature on infection of citrus by `Candidatus Liberibacter asiaticus' and `Candidatus Liberibacter americanus', the two bacterial species associated with citrus huanglongbing (HLB) in Brazil, and (ii) to determine the influence of temperature on citrus colonization by `Ca. L. asiaticus', which has taken over from `Ca. L. americanus' as the predominant species in Brazil since 2008. Two experiments were carried out with graft-inoculated Valencia oranges on Rangpur lime rootstocks. Immediately after inoculation the plants were maintained for 423 days in growth chambers under the following night/day temperature conditions: 17/22, 22/27 or 27/32°C, with a dark/light photoperiod of 8/16 h. Infection and colonization of plants were determined using quantitative PCR (qPCR). `Candidatus Liberibacter americanus' did not infect the plants maintained at 27/32°C; however, infection by `Ca. L. asiaticus' occurred at all studied temperatures. Two months after inoculation, `Ca. L. asiaticus' was distributed throughout the inoculated plants, with mean Ct values in the range of 30-31 for leaves and 25-28 for roots. Over time, `Ca. L. asiaticus' reached the highest titres in mature leaves (mean Ct value = 26·7) of citrus plants maintained at 22/27°C. `Candidatus Liberibacter asiaticus' colonization of citrus plants was negatively affected by the daily temperature regime of 27/32°C (mean Ct value in mature leaves = 33·6).
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Lilian Amorim, Renato B. Bassanezi

Research topic(s) for pests/diseases/weeds:
general biology - morphology - evolution
environment - cropping system/rotation

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Liberibacter asiaticus	Citrus (genus)
	Liberibacter americanus	Citrus (genus)