当前位置： SCI文献检索 > PHYTOPATHOLOGY期刊下所有文献 > The in Planta Effective Concentration of Oxytetracycline Against 'Candidatus Liberibacter asiaticus' for Suppression of Citrus Huanglongbing.

The in Planta Effective Concentration of Oxytetracycline Against 'Candidatus Liberibacter asiaticus' for Suppression of Citrus Huanglongbing.

Abstract：

:Huanglongbing (HLB) or greening currently is the most devastating citrus disease worldwide. The fastidious phloem-colonizing bacterium 'Candidatus Liberibacter asiaticus' (CLas) is the causal agent of citrus HLB in Florida. Bactericides containing the active ingredient oxytetracycline (OTC) have been used in foliar spray to control citrus HLB in Florida since 2016. However, the minimum concentration of OTC required to suppress CLas in planta remains unknown. We developed a new method for evaluating the effects of OTC treatment on CLas titers in infected plants and determined the relationship between OTC residue levels and control levels achieved for CLas using mathematical modeling in greenhouse and field experiments. In both greenhouse and field, OTC spray did not reduce the titers of CLas, and it produced undetectable or mild levels of OTC residue in leaves within 7 days post-application (DPA). In greenhouse, OTC injection at 0.05 g per tree decreased CLas titers to an undetectable level (cycle threshold value ≥ 36.0) from 7 to 30 DPA and produced a residue level of OTC at 0.68 to 0.73 µg/g of fresh tissue over this period. In the field, OTC injection at 0.50 g per tree resulted in the decline of CLas titers by 1.52 log reduction from 14 to 60 DPA, with residue levels of OTC at 0.27 to 0.33 µg/g of fresh tissue. In both trials, a first-order compart model of OTC residue dynamics in leaves of trunk-injected trees was specified for estimating the retention of effective concentrations. Furthermore, nonlinear modeling revealed significant positive correlations between OTC residue levels in leaves and the control levels for CLas achieved. The results suggested that the minimum concentrations of OTC required to suppress CLas populations in planta to below the detection limit are 0.68 and 0.86 µg/g and that the minimum concentrations of OTC required for initial inhibition of CLas growth in planta are ∼0.17 and ∼0.215 µg/g in leaf tissues under greenhouse and field conditions, respectively. This finding highlights that a minimum concentration of OTC should be guaranteed to be delivered to target CLas in infected plants for effective control of citrus HLB.

journal_name

Phytopathology

journal_title

Phytopathology

authors

Li J,Pang Z,Duan S,Lee D,Kolbasov VG,Wang N

doi

10.1094/PHYTO-06-19-0198-R

subject

Has Abstract

pub_date

2019-12-01 00:00:00

pages

2046-2054

issue

eissn

0031-949X

issn

1943-7684

journal_volume

109

pub_type

杂志文章

在线工具

The in Planta Effective Concentration of Oxytetracycline Against 'Candidatus Liberibacter asiaticus' for Suppression of Citrus Huanglongbing.