scholarly journals Ground Application of Overdoses of Manganese Have a Therapeutic Effect on Sweet Orange Trees Infected with Candidatus Liberibacter asiaticus

HortScience ◽  
2019 ◽  
Vol 54 (6) ◽  
pp. 1077-1086 ◽  
Author(s):  
Flavia T. Zambon ◽  
Davie M. Kadyampakeni ◽  
Jude W. Grosser
Keyword(s):  
Therapeutic Effect ◽  
Sweet Orange ◽  
Quantitative Polymerase Chain Reaction ◽  
Therapeutic Effects ◽  
Tree Health ◽  
Rough Lemon ◽  
Canopy Volume ◽  
Liberibacter Asiaticus ◽  
Root Health ◽  
Orange Trees

There is accumulating evidence that root system collapse is a primary symptom associated with Huanglongbing (HLB)-induced tree decline, especially for commercial sweet orange and grapefruit trees on Swingle and Carrizo rootstocks. Maintaining root health is imperative to keep trees productive in an HLB-endemic environment. Preliminary greenhouse and field studies have shown that HLB-impacted trees had secondary and micronutrient deficiencies that were much greater in the roots than in the leaves, and that treatments containing three-times the recommended dose of manganese (Mn) improved tree health and growth and increased feeder root density in greenhouse trees. These results suggested that trees in an HLB-endemic environment have higher specific micronutrient requirements than those currently recommended. To test this hypothesis, established Vernia sweet orange grafted onto rough lemon rootstock trees were divided into eight supplemental CRF nutrition treatments (including two-times and four-times the recommended doses of Mn and boron) using a randomized complete block design in a commercial grove in St. Cloud, FL. The following supplemental nutrition treatments were used: no extra nutrition (control); Harrell’s–St. Helena mix 0.9 kg per tree; Harrell’s with 32 g of Florikan polycoated sodium borate (PSB) per tree; Harrell’s with 90 g of TigerSul® Mn sulfate (MS) per tree; Harrell’s with 32 g of PSB and 90 g of MS per tree; 180 g of MS per tree; 64 g of PSB per tree; and 180 g of MS plus 64 g of PSB per tree applied every 6 months since Fall 2015. Leaf and soil nutritional analyses were performed in Mar. 2017, Sept. 2017, and May 2018; a quantitative polymerase chain reaction was performed for Candidatus Liberibacter asiaticus (CLas) titer estimation in Nov. 2017. Significantly higher cycle threshold (Ct) values indicating reduced CLas bacterial populations were observed in trees that received the higher doses of Mn, especially those receiving four-times the recommended dosage of Mn (180 g Mn). Many trees exhibited Ct values of 32 or more, indicating a nonactive infection. Fruit yields of these trees were also increased. No significant differences in juice characteristics, canopy volume, and trunk section area were found between control plants and plants treated with 180 g Mn. Soil and leaf nutrients B, K, Mn, and Zn were significantly different among treatments at various times during the study. Our results strongly suggest that overdoses of Mn can suppress CLas bacterial titers in sweet orange trees on rough lemon rootstock, thus providing a therapeutic effect that can help restore tree health and fruit yields. This response was not observed when Mn and B were combined in the overdose, suggesting an antagonistic effect from B on Mn metabolism. When an overdose of Mn is used, biological functions and tree tolerance lost due to nutritional imbalances caused by HLB might be restored. Further studies are needed to elucidate which metabolic pathways are altered by comparing overdosed and conventionally fertilized HLB-impacted trees and to determine if the observed therapeutic effects can be achieved in trees grafted to other important commercial rootstocks.

scholarly journals Canopy health, but not Candidatus Liberibacter asiaticus Ct values, are correlated with fruit yield in Huanglongbing affected sweet orange trees

2021 ◽  
Author(s):  
Amit Levy ◽  
Taylor Livingston ◽  
Chunxia Wang ◽  
Diann Achor ◽  
Tripti Vashisth
Keyword(s):  
Sweet Orange ◽  
Field Trials ◽  
Fruit Yield ◽  
Ct Value ◽  
Independent Field ◽  
Canopy Volume ◽  
Candidatus Liberibacter ◽  
Liberibacter Asiaticus ◽  
Almost All ◽  
Orange Trees

AbstractIn Florida, almost all citrus trees are infected with Huanglongbing (HLB), caused by the gram-negative, intracellular phloem limited bacteria Candidatus liberibacter asiaticus (CLas). Distinguishing between the severely and mildly sick trees is important for managing the groves and testing new HLB therapies. A mildly sick tree is one that produces higher fruit yield, compared to a severely sick tree, but measuring yields is laborious and time consuming. Here we characterized HLB affected sweet orange trees in the field in order to identify the specific traits that are correlated with the yields. We found that canopy volume, fruit detachment force (FDF) and the percentage of photosynthetically active radiation interception in the canopy (%INT) were positively correlated with fruit yields. Specifically, %INT measurements accurately distinguished between mild and severe trees in independent field trials. We could not find a difference in the Ct value between high and low producing HLB trees. Moreover, Ct values did not always agree with the number of CLas in the phloem that were visualized by transmission electron microscopy. Overall, our work identified an efficient way to distinguish between severe and mild HLB trees in Florida by measuring %INT and suggests that health of the canopy is more important for yields than the Ct value.

scholarly journals First record of a Hop stunt viroid variant on Nagpur mandarin and Mosambi sweet orange trees on rough lemon and Rangpur lime rootstocks

2005 ◽  
Vol 54 (4) ◽  
pp. 571-571 ◽  
Author(s):  
P. Ramachandran ◽  
J. Agarwal ◽  
A. Roy ◽  
D. K. Ghosh ◽  
D. R. Das ◽  
...  
Keyword(s):  
Sweet Orange ◽  
First Record ◽  
Rangpur Lime ◽  
Stunt Viroid ◽  
Rough Lemon ◽  
Hop Stunt Viroid ◽  
Orange Trees

Growth, yield and fruit composition of Washington Navel and Late Valencia orange trees, as affected by rootstock and root temperature

1977 ◽  
Vol 17 (85) ◽  
pp. 336
Author(s):  
PR Cary ◽  
PGJ Weerts
Keyword(s):  
Sweet Orange ◽  
Growth Yield ◽  
Poncirus Trifoliata ◽  
The Other ◽  
Root Temperature ◽  
Rough Lemon ◽  
Washington Navel ◽  
C 30 ◽  
Increasing Temperature ◽  
Orange Trees

Wahington Navel and Late Valencia scions were budded onto three clonal rootstocks (rough lemon, sweet orange and Poncirus trifoliata) mist propagated and grown in sand. The six scion/rootstock combinations were grown in containers in a glasshouse with three root temperature treatments (19�C, 25�C, 30�C). Juvenile characteristics, evident for 5-6 years when scions are budded onto seedling rootstocks, were less marked when clonal rootstocks were used. Highest yield of fruit was produced by Late Valencia/sweet orange. This yield was 30 per cent better than previously obtained with Late Valencia grown from rooted cuttings under similar conditions. The yield from Washington Navel/sweet orange was about 30 per cent less than from Late Valencia/sweet orange; and the yields from the other scion/rootstock combinations were about 50 per cent of that from Washington Navel/ sweet orange. For most combinations more total dry matter was produced at a root temperature of 25�C than at 19�C, but there was little benefit from increasing temperature to 30�C. With either scion on rough lemon, fruit abscission was marked if root temperature treatments were imposed early (in late August). The effect was particularly severe at 25� and 30�C. Root temperature treatments for the other rootstocks were not imposed until mid-October when fruitlets were about 15 mm in diameter; under these conditions there was negligible fruit drop.

scholarly journals Ultrastructural Changes and Putative Phage Particles Observed in Sweet Orange Leaves Infected with ‘Candidatus Liberibacter asiaticus’

Plant Disease ◽  
2015 ◽  
Vol 99 (3) ◽  
pp. 320-324 ◽  
Author(s):  
S. M. Fu ◽  
John Hartung ◽  
C. Y. Zhou ◽  
H. N. Su ◽  
J. Tan ◽  
...  
Keyword(s):  
Sweet Orange ◽  
Light And Electron Microscopy ◽  
Ultrastructural Changes ◽  
Candidatus Liberibacter Asiaticus ◽  
Candidatus Liberibacter ◽  
Liberibacter Asiaticus ◽  
Orange Trees ◽  
First Time ◽  
Citrus Disease ◽  
Putative Phage

Huanglongbing (HLB), also known as citrus greening, is currently the most destructive citrus disease. Anatomical analyses of HLB-affected sweet orange were carried out by light and electron microscopy. As compared with healthy citrus, the phloem plasmodesmata were plugged with callose, and in some samples the phloem was collapsed. Chloroplast structures were deformed. Prophage sequences occupy a significant portion of the genome of ‘Candidatus Liberibacter asiaticus’ and have been used to distinguish strains from Yunnan and Guangdong provinces in China and Florida. Interestingly, a large number of possible putative phage particles were observed attached on the surface of ‘Ca. L. asiaticus’ cells in plants inoculated with strain FJ3 from Fujian Province, China. Phage particles have been observed previously only in periwinkle plants artificially inoculated in Florida with ‘Ca. L. asiaticus’ that carried the SC1-type prophage. PCR assays verified the presence of the SC1-type prophage sequences previously described from this bacterium in Florida in the FJ3 isolate. This is the first time that suspected phage particles have been observed in sweet orange trees infected with ‘Ca. L. asiaticus.’

scholarly journals Seasonal Variation of ‘Candidatus Liberibacter asiaticus’ Titers in New Shoots of Citrus in Distinct Environments

Plant Disease ◽  
2017 ◽  
Vol 101 (4) ◽  
pp. 583-590 ◽  
Author(s):  
Silvio A. Lopes ◽  
Fernanda Q. B. F. Luiz ◽  
Hermes T. Oliveira ◽  
Juan C. Cifuentes-Arenas ◽  
Laudecir L. Raiol-Junior
Keyword(s):  
Sweet Orange ◽  
Quantitative Polymerase Chain Reaction ◽  
Diaphorina Citri ◽  
Candidatus Liberibacter Asiaticus ◽  
Cumulative Rainfall ◽  
Data Loggers ◽  
Minas Gerais State ◽  
Candidatus Liberibacter ◽  
Liberibacter Asiaticus ◽  
Polymerase Chain

The major citrus area of Brazil occupies near 450,000 ha between the Triângulo Mineiro (TM) region of Minas Gerais State and the south of São Paulo State (SPS). Significant climatic variation occurs between regions which could affect huanglongbing (HLB) progress, which is lower in TM. To investigate this possibility, young sweet orange shoots were sampled periodically over 2 years to determine ‘Candidatus Liberibacter asiaticus’ titers in naturally infected trees in orchards in Analândia, central SPS, and Frutal and Comendador Gomes, within TM. Data-loggers recorded local temperature and relative humidity hourly. In the laboratory, five ‘Ca. L. asiaticus’-free Diaphorina citri adults were placed on each sampled shoot for 48 h to feed and acquire the pathogen. Shoots and insects were individually analyzed by quantitative polymerase chain reaction to determine ‘Ca. L. asiaticus’ titers. The incidence of ‘Ca. L. asiaticus’-positive shoots, ‘Ca. L. asiaticus’ titers, and acquisition rates were lower for shoots from Comendador Gomes than those from Frutal or Analândia. Stronger association was observed between ‘Ca. L. asiaticus’ titers and the number of hours below 15°C (h < 15°C) or above 30°C (h > 30°C), and cumulative rainfall registered during the 15 days prior to sampling of shoots on each occasion. ‘Ca. L. asiaticus’ titers associated positively with h < 15°C and rainfall and negatively with h > 30°C. The slower spread and lower incidence of HLB in TM may be related to lower incidences of ‘Ca. L. asiaticus’-positive young shoots and lower titers of ‘Ca. L. asiaticus’ in the same shoots as a consequence of the warmer and drier conditions.

scholarly journals Performance of the pineapple sweet orange on different rootstocks

2020 ◽  
Vol 36 (2) ◽  
Author(s):  
Carlos Roberto Martins ◽  
Hélio Wilson Lemos de Carvalho ◽  
Adenir Vieira Teodoro ◽  
Inácio de Barros ◽  
Luciana Marques de Carvalho ◽  
...  
Keyword(s):  
Sweet Orange ◽  
Chemical Quality ◽  
Santa Cruz ◽  
Rangpur Lime ◽  
Rough Lemon ◽  
Physico Chemical ◽  
High Regularity ◽  
Orange Trees ◽  
Swingle Citrumelo

This study aimed at evaluating the agronomical performance of ‘Pineapple’ sweet orange grafted on ten rootstocks, in 2011-2017 harvests, so as to recommend the best combinations to be commercially explored in citrus growing regions in Bahia and Sergipe states, Brazil. An experiment was installed to test ten rootstock for 'pineapple' sweet orange: 'Santa Cruz' Rangpur lime, 'Red Rough' Lemon, 'Orlando' Tangelo, 'Sunki Tropical' Mandarin, 'Swingle' citrumelo, the citrandarins 'Indio' and 'Riverside' and the hybrids HTR-051, LVKxLCR-010 and TSKxCTTR-002. The trial was installed in 2008 in the municipality of Umbauba in Sergipe. The experimental design was complete randomized blocks with four replications and two plants per plot. Plant spacing was 6 x 4 m which corresponds to 416 plants per hectare and the orchard was rainfed and followed conventional management. The following agronomical parameters were evaluated: vegetative growth, drought tolerance, yield and physico-chemical quality of fruits as well as the abundance of phytophagous mites. Both hybrids LVK x LCR – 010 and TSKC x CTTR-002 and the ‘Santa Cruz’ rangpur lime bestowed higher tolerance to the dry period on the ‘Pineapple’ orange tree, by comparison with higher water deficit susceptibility conferred by the ‘Orlando’ tangelo and the ‘Swingle’ citrumelo. Rootstocks HTR-051, ‘Riverside’ citrandarin, ‘Swingle’ citrumelo and TSKC x CTTR-02 induced plants to remain small and, thus, showed aptitude for culture densification. Cumulative yield of the ‘Pineapple’ orange was higher on rootstocks ‘Red Rough’ lemon and ‘Santa Cruz’ Rangpur lime, the hybrid LVK x LCR-010 and ‘Sunki Tropical’. Yield efficiency was not influenced by the rootstocks. Physico-chemical quality of fruits of ‘Pineapple’ orange is affected by the rootstocks and meets the requirements of juice industries. Regarding plant resistance, the rootstocks did not influence the population density of mites P. oleivora, E. banksi and T. mexicanus on ‘Pineapple’ oranges. Results show that both rootstocks ‘Red Rough’ lemon and ‘Santa Cruz’ rangpur lime conferred high regularity to ‘Pineapple’ orange trees in citrus growing regions in Bahia and Sergipe states.

scholarly journals Comparative Transcriptional and Anatomical Analyses of Tolerant Rough Lemon and Susceptible Sweet Orange in Response to ‘Candidatus Liberibacter asiaticus’ Infection

2012 ◽  
Vol 25 (11) ◽  
pp. 1396-1407 ◽  
Author(s):  
Jing Fan ◽  
Chunxian Chen ◽  
Qibin Yu ◽  
Abeer Khalaf ◽  
Diann S. Achor ◽  
...  
Keyword(s):  
Sweet Orange ◽  
Phloem Transport ◽  
Differential Sensitivity ◽  
Transcriptional Analysis ◽  
Candidatus Liberibacter Asiaticus ◽  
Transport Activity ◽  
Phloem Cell ◽  
Rough Lemon ◽  
Candidatus Liberibacter ◽  
Liberibacter Asiaticus

Although there are no known sources of genetic resistance, some Citrus spp. are reportedly tolerant to huanglongbing (HLB), presumably caused by ‘Candidatus Liberibacter asiaticus’. Time-course transcriptional analysis of tolerant rough lemon (Citrus jambhiri) and susceptible sweet orange (C. sinensis) in response to ‘Ca. L. asiaticus’ infection showed more genes differentially expressed in HLB-affected rough lemon than sweet orange at early stages but substantially fewer at late time points, possibly a critical factor underlying differences in sensitivity to ‘Ca. L. asiaticus’. Pathway analysis revealed that stress responses were distinctively modulated in rough lemon and sweet orange. Although microscopic changes (e.g., callose deposition in sieve elements and phloem cell collapse) were found in both infected species, remarkably, phloem transport activity in midribs of source leaves in rough lemon was much less affected by HLB than in sweet orange. The difference in phloem cell transport activities is also implicated in the differential sensitivity to HLB between the two species. The results potentially lead to identification of key genes and the genetic mechanism in rough lemon to restrain disease development and maintain (or recover) phloem transport activity. These potential candidate genes may be used for improving citrus tolerance (or even resistance) to HLB by genetic engineering.

scholarly journals Citrus Viroids: Symptom Expression and Performance of Washington Navel Sweet Orange Trees Grafted on Carrizo Citrange

Plant Disease ◽  
2015 ◽  
Vol 99 (1) ◽  
pp. 125-136 ◽  
Author(s):  
N. Murcia ◽  
S. M. Bani Hashemian ◽  
P. Serra ◽  
J. A. Pina ◽  
N. Duran-Vila
Keyword(s):  
Sweet Orange ◽  
Fruit Production ◽  
Symptom Expression ◽  
Trifoliate Orange ◽  
Carrizo Citrange ◽  
Hop Stunt Viroid ◽  
Washington Navel ◽  
Canopy Volume ◽  
Viroid Infection ◽  
Orange Trees

Citrus are natural hosts of several viroid species. Citrus exocortis viroid (CEVd) and Hop stunt viroid (HSVd) are the causal agents of two well-known diseases of citrus, exocortis and cachexia. Other viroids have been found to induce specific symptoms and different degrees of stunting in trees grafted on trifoliate orange and trifoliate orange hybrids. A field assay was initiated in 1989 to establish the effect of CEVd, HSVd, Citrus bent leaf viroid (CBLVd), Citrus dwarfing viroid (CDVd), and Citrus bark cracking viroid (CBCVd) on Washington navel sweet orange trees grafted on Carrizo citrange rootstock. Here we report the effect of viroid infection on symptom expression, tree size, fruit production and quality evaluated from 2004 to 2007. Vegetative growth was affected by viroid infection with height and canopy volume being reduced. No bark scaling symptoms were observed in CEVd-infected trees albeit they presented lesions and blisters in the roots. Bark cracking symptoms were consistently observed in CBCVd-infected trees that were smaller with enhanced productivity and fruit size. No major effects were found as a result of infection with CBLVd, HSVd, or CDVd. The quality of the fruits was not affected by viroid infection, except for the low diameter of the fruits harvested from HSVd-infected trees. An interesting effect was identified in terms of tree productivity increase (yield/canopy volume) as a result of infection with CEVd, CDVd, and especially CBCVd.

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