scholarly journals Influence of Rootstock on the Leaf Volatile Organic Compounds of Citrus Scion Is More Pronounced after the Infestation with Diaphorina citri

Plants ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 2422
Author(s):  
Shelley E. Jones ◽  
Nabil Killiny
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Fatty Acid Esters ◽  
Diaphorina Citri ◽  
Citrus Industry ◽  
Volatile Organic ◽  
Candidatus Liberibacter ◽  
Liberibacter Asiaticus ◽  
Citrus Leaves ◽  
Acid Esters

Nowadays, citrus greening or Huanglongbing is considered the most destructive disease in the citrus industry worldwide. In the Americas and Asia, the disease is caused by the putative pathogen, ‘Candidatus Liberibacter asiaticus’ and transmitted by the psyllid vector, Diaphorina citri. It has been shown that volatile organic compounds (VOC) that are released from citrus leaves attract the psyllid vector. Herein, we tested whether the rootstock influenced the stored VOC profile in the scion leaves and if these influences were altered after infestation with D. citri. The VOC profiles of the hexane-extracted leaves of the mandarin hybrid ‘Sugar Belle’ that were grafted on three different rootstocks (C-35, sour orange (SO), and US-897) with and without infestation with D. citri were studied. The GC-MS analysis showed that the scion VOC profiles of the non-infested control trees were similar to each other, and rootstock was not a strong influence. However, after one month of infestation with D. citri, clear differences in the scion VOC profiles appeared that were rootstock dependent. Although the total scion leaf VOC content did not differ between the three rootstocks, the infestation increased scion monoterpenes significantly on US-897 and C-35 rootstock, increased terpene alcohols on US-897 and SO rootstock, and increased sesquiterpenes on SO. Infestation with D. citri significantly reduced fatty acids and fatty acid esters across all of the rootstocks. Therefore, our results suggest that rootstock choice could influence scions with an inducible volatile defense by enhancing the amounts of VOCs that are available for repelling vectors or for signaling to their natural enemies or parasitoids. According to this study, US-897 may be the best choice among the three that were studied herein, due to its diverse and robust VOC defense response to infestation with D. citri.

scholarly journals Volatile Metabolism of Wine Grape Trincadeira: Impact of Infection with Botrytis cinerea

Plants ◽  
2022 ◽  
Vol 11 (1) ◽  
pp. 141
Author(s):  
Helena Santos ◽  
Catarina Augusto ◽  
Pedro Reis ◽  
Cecília Rego ◽  
Ana Cristina Figueiredo ◽  
...  
Keyword(s):  
Gas Chromatography ◽  
Fatty Acid ◽  
Volatile Organic Compounds ◽  
Botrytis Cinerea ◽  
Organic Compounds ◽  
Isoamyl Acetate ◽  
Fatty Acid Esters ◽  
Grape Quality ◽  
Volatile Organic ◽  
Acid Esters

The aroma of grapes is cultivar dependent and is influenced by terroir, vineyard practices, and abiotic and biotic stresses. Trincadeira is a non-aromatic variety associated with low phenolic content and high sugar and organic acid levels. This cultivar, widely used in Portuguese wines, presents high susceptibility to Botrytis cinerea. This work aimed to characterise the volatile profile of Trincadeira grapes and how it changes under infection with B. cinerea. Thirty-six volatile organic compounds were identified, from different functional groups, namely alcohols, ester acetates, fatty acid esters, fatty acids, aldehydes, and products of the lipoxygenase pathway. Both free and glycosidic volatile organic compounds were analysed by Gas Chromatography and Gas Chromatography coupled to Mass Spectrometry for component quantification and identification, respectively. A multivariance analysis showed a clear discrimination between healthy and infected grapes with 2-trans-hexenal and isoamyl-acetate among the compounds identified as negative and positive markers of infection, respectively. Ester acetates such as 2-phenylethyl acetate, isoamyl acetate, and 2-methylbutyl acetate were present in higher contents in infected samples, whereas the contents of several fatty acid esters, such as ethyl decanoate and ethyl dodecanoate, decreased. These data were integrated with quantitative PCR data regarding genes involved in volatile metabolism and showed up-regulation of a gene coding for Hydroperoxide Lyase 2 in infected grapes. Altogether, these changes in volatile metabolism indicate an impact on the grape quality and may be related to defence against B. cinerea. The presence/absence of specific compounds might be used as infection biomarkers in the assessment of Trincadeira grapes’ quality.

scholarly journals Tracing Penicillin Movement in Citrus Plants Using Fluorescence-Labeled Penicillin

Antibiotics ◽  
2019 ◽  
Vol 8 (4) ◽  
pp. 262
Author(s):  
Nabil Killiny ◽  
Pedro Gonzalez-Blanco ◽  
Yulica Santos-Ortega ◽  
Fuad Al-Rimawi ◽  
Amit Levy ◽  
...  
Keyword(s):  
Vascular Tissue ◽  
Vascular System ◽  
Citrus Greening ◽  
Application Site ◽  
Asian Citrus Psyllid ◽  
Diaphorina Citri ◽  
Candidatus Liberibacter Asiaticus ◽  
Citrus Industry ◽  
Candidatus Liberibacter ◽  
Liberibacter Asiaticus

Huánglóngbìng (HLB), citrus greening, is one of the most destructive diseases of citrus plants worldwide. In North America, HLB is caused by the phloem-limited bacterium Candidatus Liberibacter asiaticus and is transmitted by the Asian citrus psyllid, Diaphorina citri. No cure exists at present, and the use of antibiotics for the control of HLB has gained interest due to the significant losses to the citrus industry. Because of unsatisfactory results when using foliar applications of antibiotics, concerns were raised regarding the uptake and translocation of these materials within trees. We, therefore, investigated a method that allows us to study the movement of antibiotic materials in citrus plants. Herein, we utilized a fluorescence-labeled penicillin, BOCILLIN™ FL-Penicillin (FL-penicillin), to study the uptake and translocation of penicillin in citrus plants. FL-penicillin was applied by puncture to the stem of young citrus seedlings and was traced by using fluorescence microscopy. After application, we detected FL-penicillin in the leaves and in the stem xylem and phloem tissues above and below the application site in both intact and partially bark-girdled citrus seedlings, indicating that it is easily taken up and transported through the plant vascular system. In addition, we detected FL-penicillin in the gut of D. citri, which were allowed to feed on the treated plants, suggesting translocation of this molecule into the vascular tissue. We propose that the use of fluorescent-labeled molecules could be an effective tool for understanding the uptake and translocation of antibiotics and other macromolecules in plants and insects.

scholarly journals Metabolic Profiling of Hybrids Generated from Pummelo and Citrus latipes in Relation to Their Attraction to Diaphorina citri, the Vector of Huanglongbing

Metabolites ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 477
Author(s):  
Nabil Killiny ◽  
Shelley E. Jones ◽  
Faraj Hijaz ◽  
Abdelaziz Kishk ◽  
Yulica Santos-Ortega ◽  
...  
Keyword(s):  
Leaf Morphology ◽  
Bacterial Pathogen ◽  
Gas Chromatography Mass Spectrometry ◽  
Insect Vector ◽  
Diaphorina Citri ◽  
Metabolomic Analysis ◽  
Citrus Industry ◽  
Candidatus Liberibacter ◽  
Citrus Maxima ◽  
Liberibacter Asiaticus

The citrus industry at present is severely affected by huanglongbing disease (HLB). HLB is caused by the supposed bacterial pathogen “Candidatus Liberibacter asiaticus” and is transmitted by the insect vector, the Asian citrus psyllid, Diaphorina citri Kuwayama. Developing new citrus hybrids to improve HLB management is much needed. In this study, we investigated the metabolomic profiles of three new hybrids produced from the cross of C2-5-12 Pummelo (Citrus maxima (L.) Osbeck) × pollen from Citrus latipes. The hybrids were selected based on leaf morphology and seedling vigor. The selected hybrids exhibited compact and upright tree architecture as seen in C. latipes. Hybrids were verified by simple sequence repeat markers, and were subjected to metabolomic analysis using gas chromatography-mass spectrometry. The volatile organic compounds (VOCs) and polar metabolites profiling also showed that the new hybrids were different from their parents. Interestingly, the levels of stored VOCs in hybrid II were higher than those observed in its parents and other hybrids. The level of most VOCs released by hybrid II was also higher than that released from its parents. Additionally, the preference assay showed that hybrid II was more attractive to D. citri than its parents and other hybrids. The leaf morphology, compact and upright architecture of hybrid II, and its attraction to D. citri suggest that it could be used as a windbreak and trap tree for D. citri (double duty), once its tolerance to HLB disease is confirmed. Our results showed that metabolomic analysis could be successfully used to understand the biochemical mechanisms controlling the interaction of D. citri with its host plants.

scholarly journals Improvement in the Excised Citrus Leaf Assay to Investigate Inoculation of ‘Candidatus Liberibacter asiaticus’ by the Asian Citrus Psyllid Diaphorina citri

Plant Disease ◽  
2017 ◽  
Vol 101 (3) ◽  
pp. 409-413 ◽  
Author(s):  
Laudecir L. Raiol-Junior ◽  
Ana D. B. Baia ◽  
Fernanda Q. B. F. Luiz ◽  
Camila G. Fassini ◽  
Viviani V. Marques ◽  
...  
Keyword(s):  
Quantitative Polymerase Chain Reaction ◽  
Leaf Age ◽  
Infection Process ◽  
Diaphorina Citri ◽  
Candidatus Liberibacter Asiaticus ◽  
Leaf Petiole ◽  
Candidatus Liberibacter ◽  
Liberibacter Asiaticus ◽  
Citrus Leaves ◽  
Time Required

Huanglongbing (HLB) is a difficult-to-control and highly destructive citrus disease that, in Brazil, is associated mainly with the bacterium ‘Candidatus Liberibacter asiaticus’ transmitted by the psyllid Diaphorina citri. The aim of this study was to improve our understanding of the ‘Ca. L. asiaticus’ infection process by exposing excised, fully expanded, immature citrus leaves in 50-ml Falcon tubes to one, four, or eight adults from a ‘Ca. L. asiaticus’-exposed colony for 1-, 3-, 7-, or 15-day periods for access to inoculation (IAP). The leaves were incubated at 26°C for 1, 3, 7, 15, and 21 days (incubation period [IP]). Infection frequencies and ‘Ca. L. asiaticus’ titers were assessed by quantitative polymerase chain reaction (qPCR). ‘Ca. L. asiaticus’ infection was a function of leaf age, number of insects, IAP, and IP. In general, higher infection rates were observed on younger leaves inoculated with higher numbers of insects and after longer IAP and IP. The immature excised leaf method allowed determination of 3 to 7 days as the range of time required by ‘Ca. L. asiaticus’ to reach qPCR detectable levels. Even though leaf survival could be prolonged by the maintenance of a branch segment at the base of the leaf petiole, leaf degradation, visible after about 15 days IP, did not allow observation of the entire infection process which, in the intact plant, culminates with the appearance of the blotch mottling symptom on leaf blades.

scholarly journals Silencing of Aquaporin Homologue Accumulates Uric Acid and Decreases the Lifespan of the Asian Citrus Psyllid, Diaphorina citri (Hemiptera: Liviidae)

Insects ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 931
Author(s):  
Yulica Santos-Ortega ◽  
Nabil Killiny
Keyword(s):  
Uric Acid ◽  
Target Genes ◽  
Elevated Temperatures ◽  
Lipid Membrane ◽  
Asian Citrus Psyllid ◽  
Diaphorina Citri ◽  
Citrus Industry ◽  
Good Target ◽  
Candidatus Liberibacter ◽  
Liberibacter Asiaticus

The Asian citrus psyllid, Diaphorina citri Kuwayama is devastating the citrus industry worldwide. It transmits ‘Candidatus Liberibacter asiaticus’, the pathogen of Huanglongbing in citrus. RNA interference is an excellent tool for functional genomics and for screening target genes for pest control. Herein, we silenced the aquaporin (AQP) gene (DcAQP) homologue in D. citri to study its functionality and whether it could be a good target for a control strategy. AQP is an integral membrane channel protein that aids in the rapid flux of water and other small solutes that move across the lipid membrane. In Hemiptera, it is well established that AQP plays important roles in adjusting to physiological challenges including (1) regulating osmotic stress between the gut lumen and hemolymph after imbibing large quantities of a low nitrogen, sugar-rich liquid diet; (2) avoiding or preventing dehydration and desiccation; and (3) surviving at elevated temperatures. The dsRNA-DcAQP was applied twice to nymphs of the 4th and 5th instars through a soaking technique. Silencing AQP caused a significant increase in nymph mortality. Emerged adults showed malformations and a shorter lifespan. Silencing DcAQP provoked alterations in some metabolites and increased the uric acid content in emerged adults. DcAQP could be a useful target to control D. citri.

scholarly journals Uptake, Translocation, and Stability of Oxytetracycline and Streptomycin in Citrus Plants

Antibiotics ◽  
2019 ◽  
Vol 8 (4) ◽  
pp. 196 ◽  
Author(s):  
Fuad Al-Rimawi ◽  
Faraj Hijaz ◽  
Yasser Nehela ◽  
Ozgur Batuman ◽  
Nabil Killiny
Keyword(s):  
Enzyme Linked Immunosorbent Assay ◽  
Asian Citrus Psyllid ◽  
Diaphorina Citri ◽  
Candidatus Liberibacter Asiaticus ◽  
In Planta ◽  
Citrus Industry ◽  
Candidatus Liberibacter ◽  
Effective Program ◽  
Liberibacter Asiaticus ◽  
Root Tissues

Huanglongbing (HLB), or citrus greening, is the most destructive disease to the citrus industry. In Florida, it is caused by the bacterium, Candidatus Liberibacter asiaticus (CLas) and is transmitted by the Asian citrus psyllid, Diaphorina citri. Recent studies suggested that antibiotics could inhibit the growth of the CLas pathogen in planta. In the current study, we investigated the uptake and translocation of oxytetracycline and streptomycin in citrus seedlings. Oxytetracycline and streptomycin were delivered via root and stem and their level in various tissues was monitored using enzyme-linked immunosorbent assay (ELISA). Oxytetracycline and streptomycin were detected in the leaves, xylem, phloem, and root after root drench and stem delivery. High levels of antibiotics were detected in the roots after root drench, whereas high levels of antibiotics were detected in the canopy after stem delivery. The level of oxytetracycline detected in the phloem, xylem, and leaves after root drench was higher than that of streptomycin. Whereas the level of streptomycin in root was higher than that of oxytetracycline, indicating that streptomycin was bound to the xylem tissues. Oxytetracycline and streptomycin were detected in the phloem, xylem, leaves, and root tissues thirty-five days after the root incubation in 200 µg·mL−1 solution. These results demonstrated that oxytetracycline and streptomycin were relatively stable and could inhibit CLas growth for a couple of months in citrus trees. Observations reported in this study regarding the distribution and stability of oxytetracycline and streptomycin in citrus plants could be useful for designing an effective program for the control of HLB disease using antibiotics.

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