Cargando…

Systemic Uptake of Oxytetracycline and Streptomycin in Huanglongbing-Affected Citrus Groves after Foliar Application and Trunk Injection

Huanglongbing (HLB), which is caused by the phloem-limited bacterium ‘Candidatus Liberibacter asiaticus,’ is an economically important disease of citrus in many regions of the world. Due to the significant damage caused by the HLB disease in recent years, the use of antibiotics was recommended for t...

Descripción completa

Detalles Bibliográficos
Autores principales: Vincent, Christopher I., Hijaz, Faraj, Pierre, Myrtho, Killiny, Nabil
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2022
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9405128/
https://www.ncbi.nlm.nih.gov/pubmed/36009961
http://dx.doi.org/10.3390/antibiotics11081092
_version_ 1784773804742934528
author Vincent, Christopher I.
Hijaz, Faraj
Pierre, Myrtho
Killiny, Nabil
author_facet Vincent, Christopher I.
Hijaz, Faraj
Pierre, Myrtho
Killiny, Nabil
author_sort Vincent, Christopher I.
collection PubMed
description Huanglongbing (HLB), which is caused by the phloem-limited bacterium ‘Candidatus Liberibacter asiaticus,’ is an economically important disease of citrus in many regions of the world. Due to the significant damage caused by the HLB disease in recent years, the use of antibiotics was recommended for the therapy of this destructive disease. Products with active ingredients oxytetracycline and streptomycin have been approved for the control of the HLB via foliar application. However, previous work raised questions about the efficacy of foliar delivery of antibiotics in the field. In this study, we examined the effects of a variety of adjuvants on the uptake of oxytetracycline and streptomycin using the foliar application. We also compared the efficiency of foliar application of oxytetracycline and streptomycin with trunk injection. The ‘Ca. L. asiaticus’ titers in citrus plants were measured using quantitative PCR, and the levels of antibiotics were determined using the ELISA assay. Our results include extremely low levels of oxytetracycline and streptomycin in leaves that were covered during foliar application, indicating that neither streptomycin nor oxytetracycline was successfully systemically delivered by foliar application even after being mixed with adjuvants. Likewise, the ‘Ca. L. asiaticus’ titer0 was not affected by any of the foliar applications. High levels of streptomycin were detected in leaves that were exposed to direct foliar application, indicating that streptomycin was adsorbed or bound to citrus leaves. On the other hand, the trunk injection of oxytetracycline resulted in high levels of this antibiotic in leaves and significantly reduced the level of ‘Ca. L. asiaticus’ titer in citrus trees. Unfortunately, the trunk injection of streptomycin resulted in low levels of streptomycin in citrus leaves and did not affect the ‘Ca. L. asiaticus’ titer, indicating that streptomycin was either bound in the xylem of citrus trees or it was not applied in sufficient quantity required for the inhibition of ‘Ca. L. asiaticus.’ Taken together, our current results demonstrated that foliar application of oxytetracycline and streptomycin did not effectively deliver antibiotics in citrus despite using adjuvants. Our results also suggested that oxytetracycline could be more effective against the HLB pathogen than streptomycin, which is possibly due to differences between the two in systemic movement in citrus trees.
format Online
Article
Text
id pubmed-9405128
institution National Center for Biotechnology Information
language English
publishDate 2022
publisher MDPI
record_format MEDLINE/PubMed
spelling pubmed-94051282022-08-26 Systemic Uptake of Oxytetracycline and Streptomycin in Huanglongbing-Affected Citrus Groves after Foliar Application and Trunk Injection Vincent, Christopher I. Hijaz, Faraj Pierre, Myrtho Killiny, Nabil Antibiotics (Basel) Article Huanglongbing (HLB), which is caused by the phloem-limited bacterium ‘Candidatus Liberibacter asiaticus,’ is an economically important disease of citrus in many regions of the world. Due to the significant damage caused by the HLB disease in recent years, the use of antibiotics was recommended for the therapy of this destructive disease. Products with active ingredients oxytetracycline and streptomycin have been approved for the control of the HLB via foliar application. However, previous work raised questions about the efficacy of foliar delivery of antibiotics in the field. In this study, we examined the effects of a variety of adjuvants on the uptake of oxytetracycline and streptomycin using the foliar application. We also compared the efficiency of foliar application of oxytetracycline and streptomycin with trunk injection. The ‘Ca. L. asiaticus’ titers in citrus plants were measured using quantitative PCR, and the levels of antibiotics were determined using the ELISA assay. Our results include extremely low levels of oxytetracycline and streptomycin in leaves that were covered during foliar application, indicating that neither streptomycin nor oxytetracycline was successfully systemically delivered by foliar application even after being mixed with adjuvants. Likewise, the ‘Ca. L. asiaticus’ titer0 was not affected by any of the foliar applications. High levels of streptomycin were detected in leaves that were exposed to direct foliar application, indicating that streptomycin was adsorbed or bound to citrus leaves. On the other hand, the trunk injection of oxytetracycline resulted in high levels of this antibiotic in leaves and significantly reduced the level of ‘Ca. L. asiaticus’ titer in citrus trees. Unfortunately, the trunk injection of streptomycin resulted in low levels of streptomycin in citrus leaves and did not affect the ‘Ca. L. asiaticus’ titer, indicating that streptomycin was either bound in the xylem of citrus trees or it was not applied in sufficient quantity required for the inhibition of ‘Ca. L. asiaticus.’ Taken together, our current results demonstrated that foliar application of oxytetracycline and streptomycin did not effectively deliver antibiotics in citrus despite using adjuvants. Our results also suggested that oxytetracycline could be more effective against the HLB pathogen than streptomycin, which is possibly due to differences between the two in systemic movement in citrus trees. MDPI 2022-08-12 /pmc/articles/PMC9405128/ /pubmed/36009961 http://dx.doi.org/10.3390/antibiotics11081092 Text en © 2022 by the authors. https://creativecommons.org/licenses/by/4.0/Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Vincent, Christopher I.
Hijaz, Faraj
Pierre, Myrtho
Killiny, Nabil
Systemic Uptake of Oxytetracycline and Streptomycin in Huanglongbing-Affected Citrus Groves after Foliar Application and Trunk Injection
title Systemic Uptake of Oxytetracycline and Streptomycin in Huanglongbing-Affected Citrus Groves after Foliar Application and Trunk Injection
title_full Systemic Uptake of Oxytetracycline and Streptomycin in Huanglongbing-Affected Citrus Groves after Foliar Application and Trunk Injection
title_fullStr Systemic Uptake of Oxytetracycline and Streptomycin in Huanglongbing-Affected Citrus Groves after Foliar Application and Trunk Injection
title_full_unstemmed Systemic Uptake of Oxytetracycline and Streptomycin in Huanglongbing-Affected Citrus Groves after Foliar Application and Trunk Injection
title_short Systemic Uptake of Oxytetracycline and Streptomycin in Huanglongbing-Affected Citrus Groves after Foliar Application and Trunk Injection
title_sort systemic uptake of oxytetracycline and streptomycin in huanglongbing-affected citrus groves after foliar application and trunk injection
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9405128/
https://www.ncbi.nlm.nih.gov/pubmed/36009961
http://dx.doi.org/10.3390/antibiotics11081092
work_keys_str_mv AT vincentchristopheri systemicuptakeofoxytetracyclineandstreptomycininhuanglongbingaffectedcitrusgrovesafterfoliarapplicationandtrunkinjection
AT hijazfaraj systemicuptakeofoxytetracyclineandstreptomycininhuanglongbingaffectedcitrusgrovesafterfoliarapplicationandtrunkinjection
AT pierremyrtho systemicuptakeofoxytetracyclineandstreptomycininhuanglongbingaffectedcitrusgrovesafterfoliarapplicationandtrunkinjection
AT killinynabil systemicuptakeofoxytetracyclineandstreptomycininhuanglongbingaffectedcitrusgrovesafterfoliarapplicationandtrunkinjection