Response of Citrus Germplasm Seedlings to Candidatus Liberibacter Asiaticus Infection under Controlled Greenhouse Conditions
Huanglongbing (HLB) is a major disease of citrus associated with phloem-limited bacteria in the genus Candidatus Liberibacter that affects all known citrus species and relatives, with many commercial cultivars being greatly damaged. Testing cultivar tolerance to HLB in field conditions is difficult...
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| Format: | Article |
| Language: | English |
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American Society for Horticultural Science (ASHS)
2024-01-01
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| Series: | HortScience |
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| Online Access: | https://journals.ashs.org/hortsci/view/journals/hortsci/59/3/article-p278.xml |
| _version_ | 1797305418898210816 |
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| author | Rayane Barcelos Bisi Ute Albrecht Kim D. Bowman |
| author_facet | Rayane Barcelos Bisi Ute Albrecht Kim D. Bowman |
| author_sort | Rayane Barcelos Bisi |
| collection | DOAJ |
| description | Huanglongbing (HLB) is a major disease of citrus associated with phloem-limited bacteria in the genus Candidatus Liberibacter that affects all known citrus species and relatives, with many commercial cultivars being greatly damaged. Testing cultivar tolerance to HLB in field conditions is difficult because of the erratic spread of the bacteria, scion and rootstock interactions, and influence of many biotic and abiotic factors on the tree response to the disease. This study aimed to validate the effect of CLas infection on different citrus species and hybrids thought to have different levels of tolerance to the disease using CLas graft inoculation under controlled greenhouse conditions. Young potted seedlings from 12 different citrus germplasm selections were graft-inoculated with CLas or mock-inoculated. Plants were monitored periodically during 18 months for canopy growth, HLB and nutritional leaf symptoms, and leaf CLas titers. The leaf nutrient content was measured at the end of the experiment. Roots were also assessed at 18 months after inoculation (mai) for CLas titers and biomass distribution. There were significant differences in most analyzed variables of healthy and infected plants. Some plants of all cultivars were successfully infected; however, overall, the CLas transmission rate was low and inconsistent. Ct values of roots were generally higher than those in leaves at 18 mai. HLB symptoms were not observed on seedlings until 1 year after inoculation; at 18 mai, infected trees of all cultivars were HLB symptomatic. Significant shoot and root biomass reductions (44%–75%) in infected ‘Cleopatra’, ‘Duncan’, ‘Olinda Valencia’, ‘Sunburst’, and ‘Valencia 1-14-19’, considered susceptible to HLB, were measured. These cultivars also showed more severe HLB symptoms than the presumed tolerant cultivars such as Microcitrus inodora, Rich 16-6 trifoliate orange, and US-897. This study provides new knowledge of the efficacy and value of greenhouse screening of citrus germplasm for response to HLB to support the development of new cultivars with improved HLB tolerance or resistance. |
| first_indexed | 2024-03-08T00:25:37Z |
| format | Article |
| id | doaj.art-42850a6edc404d289c31e8aa5f215dcc |
| institution | Directory Open Access Journal |
| issn | 2327-9834 |
| language | English |
| last_indexed | 2024-03-08T00:25:37Z |
| publishDate | 2024-01-01 |
| publisher | American Society for Horticultural Science (ASHS) |
| record_format | Article |
| series | HortScience |
| spelling | doaj.art-42850a6edc404d289c31e8aa5f215dcc2024-02-15T16:45:14ZengAmerican Society for Horticultural Science (ASHS)HortScience2327-98342024-01-01593https://doi.org/10.21273/HORTSCI17514-23Response of Citrus Germplasm Seedlings to Candidatus Liberibacter Asiaticus Infection under Controlled Greenhouse ConditionsRayane Barcelos Bisi0Ute Albrecht1Kim D. Bowman2Southwest Florida Research and Education Center, University of Florida Institute of Food and Agricultural SciencesSouthwest Florida Research and Education Center, University of Florida Institute of Food and Agricultural SciencesUS Horticultural Research Laboratory, US Department of AgricultureHuanglongbing (HLB) is a major disease of citrus associated with phloem-limited bacteria in the genus Candidatus Liberibacter that affects all known citrus species and relatives, with many commercial cultivars being greatly damaged. Testing cultivar tolerance to HLB in field conditions is difficult because of the erratic spread of the bacteria, scion and rootstock interactions, and influence of many biotic and abiotic factors on the tree response to the disease. This study aimed to validate the effect of CLas infection on different citrus species and hybrids thought to have different levels of tolerance to the disease using CLas graft inoculation under controlled greenhouse conditions. Young potted seedlings from 12 different citrus germplasm selections were graft-inoculated with CLas or mock-inoculated. Plants were monitored periodically during 18 months for canopy growth, HLB and nutritional leaf symptoms, and leaf CLas titers. The leaf nutrient content was measured at the end of the experiment. Roots were also assessed at 18 months after inoculation (mai) for CLas titers and biomass distribution. There were significant differences in most analyzed variables of healthy and infected plants. Some plants of all cultivars were successfully infected; however, overall, the CLas transmission rate was low and inconsistent. Ct values of roots were generally higher than those in leaves at 18 mai. HLB symptoms were not observed on seedlings until 1 year after inoculation; at 18 mai, infected trees of all cultivars were HLB symptomatic. Significant shoot and root biomass reductions (44%–75%) in infected ‘Cleopatra’, ‘Duncan’, ‘Olinda Valencia’, ‘Sunburst’, and ‘Valencia 1-14-19’, considered susceptible to HLB, were measured. These cultivars also showed more severe HLB symptoms than the presumed tolerant cultivars such as Microcitrus inodora, Rich 16-6 trifoliate orange, and US-897. This study provides new knowledge of the efficacy and value of greenhouse screening of citrus germplasm for response to HLB to support the development of new cultivars with improved HLB tolerance or resistance.https://journals.ashs.org/hortsci/view/journals/hortsci/59/3/article-p278.xmlcitrus breedingcitrus greeninghuanglongbingmicrocitrusponcirus trifoliata |
| spellingShingle | Rayane Barcelos Bisi Ute Albrecht Kim D. Bowman Response of Citrus Germplasm Seedlings to Candidatus Liberibacter Asiaticus Infection under Controlled Greenhouse Conditions HortScience citrus breeding citrus greening huanglongbing microcitrus poncirus trifoliata |
| title | Response of Citrus Germplasm Seedlings to Candidatus Liberibacter Asiaticus Infection under Controlled Greenhouse Conditions |
| title_full | Response of Citrus Germplasm Seedlings to Candidatus Liberibacter Asiaticus Infection under Controlled Greenhouse Conditions |
| title_fullStr | Response of Citrus Germplasm Seedlings to Candidatus Liberibacter Asiaticus Infection under Controlled Greenhouse Conditions |
| title_full_unstemmed | Response of Citrus Germplasm Seedlings to Candidatus Liberibacter Asiaticus Infection under Controlled Greenhouse Conditions |
| title_short | Response of Citrus Germplasm Seedlings to Candidatus Liberibacter Asiaticus Infection under Controlled Greenhouse Conditions |
| title_sort | response of citrus germplasm seedlings to candidatus liberibacter asiaticus infection under controlled greenhouse conditions |
| topic | citrus breeding citrus greening huanglongbing microcitrus poncirus trifoliata |
| url | https://journals.ashs.org/hortsci/view/journals/hortsci/59/3/article-p278.xml |
| work_keys_str_mv | AT rayanebarcelosbisi responseofcitrusgermplasmseedlingstocandidatusliberibacterasiaticusinfectionundercontrolledgreenhouseconditions AT utealbrecht responseofcitrusgermplasmseedlingstocandidatusliberibacterasiaticusinfectionundercontrolledgreenhouseconditions AT kimdbowman responseofcitrusgermplasmseedlingstocandidatusliberibacterasiaticusinfectionundercontrolledgreenhouseconditions |