scholarly journals Improving Suppression of Hemipteran Vectors and Bacterial Pathogens of Citrus and Solanaceous Plants: Advances in Antisense Oligonucleotides (FANA)

2021 ◽  
Vol 3 ◽  
Author(s):  
Wayne Brian Hunter ◽  
William Rodney Cooper ◽  
Andres F. Sandoval-Mojica ◽  
Greg McCollum ◽  
Veenu Aishwarya ◽  
...  
Keyword(s):  
Bacterial Pathogens ◽  
Bactericera Cockerelli ◽  
Citrus Greening Disease ◽  
Potato Plants ◽  
Efficient Delivery ◽  
Detached Leaves ◽  
Citrus Production ◽  
Development Evaluation ◽  
Reducing Costs ◽  
Citrus Trees

We report on the development, evaluation, and efficient delivery of antisense oligonucleotide FANA (2′-deoxy-2′-fluoro-arabinonucleotide) RNA-targeting technology into citrus trees and potato plants for management of bacterial pathogens and arthropod pests. The FANA ASO technology is a single nucleotide strand of 20–24 nt in length that incorporates 2′F- chemically modifications of nucleotides, along with a phosphorothioate backbone and modified flanking nucleotides, in their structure called “gapmers,” produced by AUM LifeTech., Inc. These unique modified structures of FANA “triggers” enables gymnotic activity that self-delivers into cells, moving systemically in treated plants and insects, with significant suppression of their RNA targets. Reported is the FANA suppression of two plant-infecting bacterium Candidatus Liberibacter asiaticus, CLas (in citrus trees), and C. Liberibacter solanacearum, CLso (in potato and tomato). The CLas pathogen is associated with huanglongbing (a.k.a. Citrus Greening Disease), which causes severe loss of citrus trees, threatening global citrus production. The CLas bacterium is transmitted during feeding by the Asian citrus psyllid, Diaphorina citri (Hemiptera: Liviidae). CLso causes Zebra-Chip disease in potato and is transmitted by the potato psyllid, Bactericera cockerelli (Hemiptera: Triozidae). Infected citrus trees or potato plants were treated with aqueous FANA solutions applied as a soil drench, root-infusion, topical spray, tree trunk injection or by absorption into cuttings, detached leaves, and leaf disks. Plants showed significant reduction of each pathogen or symptom development in response to FANA treatments. Similarly, ingestion of FANA solutions designed specifically to CLas by insects via artificial diets produced significant titer reductions in infected citrus psyllid adults that resulted in reduction of CLas transmission. The unique properties of FANA ASO solves many of the problems of stability, cell entry, and binding affinity that plagues exogenous RNAi strategies. Breakthroughs in production methods are reducing costs enabling these ASO to expand beyond medical applications into agricultural treatments. Thus, FANA ASO may provide viable treatments in the response to crop pandemics, like huanglongbing in citrus that threatens global food production.

scholarly journals Mortality of Potato Psyllid (Hemiptera: Triozidae) on Host Clippings Inoculated With Ergot Alkaloids

2020 ◽  
Vol 113 (5) ◽  
pp. 2079-2085
Author(s):  
Navneet Kaur ◽  
W Rodney Cooper ◽  
Jennifer M Duringer ◽  
Arash Rashed ◽  
Ismael E Badillo-Vargas ◽  
...  
Keyword(s):  
Ergot Alkaloids ◽  
Morning Glory ◽  
Potato Psyllid ◽  
Bactericera Cockerelli ◽  
Artificial Diets ◽  
Synthetic Compounds ◽  
Potato Plants ◽  
Ipomoea Tricolor ◽  
Crude Extracts ◽  
Host Tissues

Abstract Our previous study provided correlative evidence that morning glory species harboring endophytic fungi (Periglandula) are resistant to potato psyllid [Bactericera cockerelli (Šulc)], whereas species free of fungi often allowed psyllid development. In this study, we manipulated levels of ergot alkaloids in host tissues by inoculating clippings from potato plants with extracts from morning glories that harbor Periglandula [Ipomoea leptophylla Torrey, Ipomoea imperati (Vahl) Grisebach, Ipomoea tricolor Cavanilles, Ipomoea pandurata (L.) G. F. Meyer, and Turbina corymbosa (L.)] and one species (Ipomoea alba L.) that does not harbor the endophyte. Ergot alkaloids (clavines, lysergic acid amides, and ergopeptines) were detected in potato clippings, thus confirming that leaves had taken up compounds from solutions of crude extracts. Psyllid mortality rates on inoculated clippings ranged between 53 and 93% in treatments producing biochemically detectable levels of alkaloids, when compared with 15% mortality in water controls or the alkaloid-free I. alba. We then tested synthetic analogs from each of the three alkaloid classes that had been detected in the crude extracts. Each compound was assayed by inoculating clippings of two host species (potato and tomato) at increasing concentrations (0, 1, 10, and 100 µg/ml in solution). Psyllids exhibited a large and significant increase in mortality rate beginning at the lowest two concentrations, indicating that even very small quantities of these chemicals led to mortality. Feeding by nymphs on artificial diets containing synthetic compounds resulted in 100% mortality within 48 h, irrespective of compound. Further testing of ergot alkaloids to characterize the mode of action that leads to psyllid mortality is warranted.

scholarly journals Identification and Characterization of the Huanglongbing Bacterium in Pummelo from Multiple Locations in Guangdong, P. R. China

Plant Disease ◽  
2008 ◽  
Vol 92 (4) ◽  
pp. 513-518 ◽  
Author(s):  
X. Deng ◽  
J. Chen ◽  
Z. Feng ◽  
Z. Shan ◽  
H. Guo ◽  
...  
Keyword(s):  
Sweet Orange ◽  
Nucleotide Polymorphisms ◽  
Sequence Comparisons ◽  
Research Attention ◽  
Republic Of China ◽  
Citrus Greening Disease ◽  
Citrus Production ◽  
History Of ◽  
Candidatus Liberibacter ◽  
Liberibacter Asiaticus

Huanglongbing (HLB, yellow shoot disease, ex. citrus greening disease), caused by Candidatus Liberibacter spp., is highly destructive to citrus production in Asia, Africa, and South America. Although primarily affecting sweet orange and mandarin, HLB has long been observed in pummelo in Guangdong Province, People's Republic of China; however, the disease in pummelo has received little research attention. Accordingly, it remains unclear how closely related the strains of Ca. Liberibacter in pummelo are to those in other citrus species. In this study, the loci of 16S rDNA, rplAJ (β-operon of ribosomal protein), and an outer membrane protein (omp) gene were analyzed and characterized among strains of Ca. Liberibacter in pummelo samples from six different locations in Guangdong. Sequence comparisons indicated that ‘Candidatus Liberibacter asiaticus’, but not ‘Ca. Liberibacter africanus’ or ‘Ca. Liberibacter americanus’, was exclusively associated with HLB symptoms in pummelo. The pummelo strains of ‘Ca. Liberibacter asiaticus’ from Guangdong were highly homogeneous. Analyses of single-nucleotide polymorphisms in the omp locus showed that the Guangdong pummelo strains grouped with ‘Ca. Liberibacter asiaticus’ strains from Thailand, Nepal, and an unspecified location in China but differed from the Philippine and China-Behai strains. Based on the sequence homogeneity at the omp locus, the history of pummelo culture and the means by which HLB is known to be spread, we believe that, likely, the pummelo strain of ‘Ca. Liberibacter asiaticus’ recently was spread to pummelo in the study areas from infected sweet orange or mandarin trees by insect vectors or by propagation of pummelo infected elsewhere.

scholarly journals Magnesium (Mg) for Citrus Trees

EDIS ◽  
2013 ◽  
Vol 2013 (6) ◽  
Author(s):  
Mongi Zekri ◽  
Tom Obreza
Keyword(s):  
Magnesium Deficiency ◽  
Mg Deficiency ◽  
Fact Sheet ◽  
Deficiency Symptoms ◽  
Mature Leaves ◽  
Citrus Production ◽  
Water Science ◽  
Soil And Water ◽  
Leaf Symptoms ◽  
Citrus Trees

Magnesium deficiency has been a major problem in citrus production. In Florida, Mg deficiency is commonly referred to as “bronzing.” Trees with inadequate Mg may have no symptoms in the spring growth flush, but leaf symptoms develop as the leaves age and the fruit expand and mature in the summer and fall. Magnesium deficiency symptoms occur on mature leaves following the removal of Mg to satisfy fruit requirements. This 4-page fact sheet was written by Mongi Zekri and Tom Obreza and published by the UF Department of Soil and Water Science, July 2013. http://edis.ifas.ufl.edu/ss582

scholarly journals Annotation of glycolysis, gluconeogenesis, and trehaloneogenesis pathways provide insight into carbohydrate metabolism in the Asian citrus psyllid

2021 ◽  
Author(s):  
Blessy Tamayo ◽  
Kyle Kercher ◽  
Chad Vosburg ◽  
Crissy Massimino ◽  
Margaryta R Jernigan ◽  
...  
Keyword(s):  
Metabolic Pathways ◽  
Economic Losses ◽  
Asian Citrus Psyllid ◽  
Citrus Greening Disease ◽  
Copy Numbers ◽  
Glycolysis Pathway ◽  
Citrus Production ◽  
Rnai Therapeutics ◽  
Candidatus Liberibacter ◽  
Gene Models

Citrus greening disease is caused by the pathogen Candidatus Liberibacter asiaticus, which is transmitted by the Asian citrus psyllid, Diaphorina citri. There is no curative treatment or significant prevention mechanism for this detrimental disease that causes continued economic losses from reduced citrus production. A high quality genome of D. citri is being manually annotated to provide accurate gene models required to identify novel control targets and increase understanding of this pest. Here, we annotated genes involved in glycolysis, gluconeogenesis, and trehaloneogenesis in the D. citri genome, as these are core metabolic pathways and suppression could reduce this pest. Specifically, twenty-five genes were identified and annotated in the glycolysis and gluconeogenesis pathways and seven genes for the trehaloneogenesis pathway. Comparative analysis showed that the glycolysis genes in D. citri are highly conserved compared to orthologs in other insect systems, but copy numbers vary in D. citri. Expression levels of the annotated gene models were analyzed and several enzymes in the glycolysis pathway showed high expression in the thorax. This is consistent with the primary use of glucose by flight muscles located in the thorax. A few of the genes annotated in D. citri have been targeted for gene knockdown as a proof of concept, for RNAi therapeutics. Thus, manual annotation of these core metabolic pathways provides accurate genomic foundations for developing gene-targeting therapeutics to reduce D. citri.

scholarly journals Neocosmospora spp. associated with dry root rot of citrus in South Africa

2021 ◽  
Vol 60 (1) ◽  
pp. 79-100
Author(s):  
Vladimiro GUARNACCIA ◽  
Jan VAN NIEKERK ◽  
Pedro CROUS ◽  
Marcelo SANDOVAL-DENIS
Keyword(s):  
South Africa ◽  
Rna Polymerase ◽  
Root Rot ◽  
Large Subunit ◽  
Elongation Factor ◽  
Common Disease ◽  
Atp Citrate Lyase ◽  
Internal Transcribed Spacer Region ◽  
Citrus Production ◽  
Citrus Trees

Citrus is one of the most important fruit crops cultivated in South Africa. Internationally, citrus dry root rot is a common disease in major citrus production areas. Several abiotic and biotic factors are involved in disease development, in which Neocosmospora species are important biotic agents. The diversity of Neocosmospora species associated with dry root rot symptoms of Citrus trees cultivated in South Africa was evaluated using morphological and molecular analyses. Multi-locus analysis was conducted, based on fragments of seven loci including: ATP citrate lyase (acl1), calmodulin (cal), internal transcribed spacer region of the rRNA (ITS), large subunit of the rRNA (LSU), RNA polymerase largest subunit (rpb1), RNA polymerase second largest subunit (rpb2), and translation elongation factor 1-alpha (tef1). A total of 62 strains representing 11 Neocosmospora species were isolated from crowns, trunks and roots of citrus trees affected by dry root rot, as well as from soils sampled in affected citrus orchards. The most commonly isolated taxa were N. citricola, N. ferruginea and N. solani, while rarely encountered taxa included N. brevis, N. crassa, N. hypothenemi and N. noneumartii. Furthermore, four Neocosmospora species are also newly described, namely N. addoensis, N. citricola, N. gamtoosensis and N. lerouxii.

2021–2022 Florida Citrus Production Guide: Nutrition Management for Citrus Trees

EDIS ◽  
2021 ◽  
Author(s):  
Kelly T. Morgan ◽  
Davie Kadyampakeni ◽  
Mongi Zekri ◽  
Arnold W. Schumann ◽  
Tripti Vashisth ◽  
...  
Keyword(s):  
Nutrition Management ◽  
Citrus Production ◽  
Florida Citrus ◽  
Citrus Trees

FERTIGATION FOR CITRUS TREES

EDIS ◽  
2017 ◽  
Vol 2017 (5) ◽  
Author(s):  
Mongi Zekri ◽  
Arnold Schumann ◽  
Tripti Vashisth ◽  
Davie Kadyampakeni ◽  
Kelly T. Morgan ◽  
...  
Keyword(s):  
Water Conservation ◽  
Production Systems ◽  
Sprinkler Irrigation ◽  
Fertilizer Management ◽  
Irrigation Methods ◽  
Management Efficiency ◽  
Citrus Production ◽  
Freeze Protection ◽  
Irrigation Research ◽  
Citrus Trees

Microirrigation is an important component of citrus production systems in Florida. For citrus trees, microirrigation is more desirable than other irrigation methods for several reasons: water conservation, fertilizer management efficiency, and freeze protection. Research has shown that when microirrigation systems are properly managed, water savings can amount to as much as 80% compared with subirrigation and 50% compared with overhead sprinkler irrigation. Research has also shown the important advantage of microsprinklers for freeze protection of citrus. This 4-page fact sheet discusses fertilizer solubility and some common fertigation materials. It also offers a fertigation summary. Written by Mongi Zekri, Arnold Schumann, Tripti Vashisth, Davie Kadyampakeni, Kelly Morgan, Brian Boman, and Tom Obreza, and published by the UF Horticultural Sciences Department, September 2017.

2020–2021 Florida Citrus Production Guide: Irrigation Management of Citrus Trees

EDIS ◽  
2020 ◽  
Author(s):  
Davie Kadyampakeni ◽  
Kelly T. Morgan ◽  
Mongi Zekri ◽  
Rhuanito S. Ferrarezi ◽  
Arnold W. Schumann ◽  
...  
Keyword(s):  
Irrigation Management ◽  
Citrus Production ◽  
Florida Citrus ◽  
Citrus Trees

2021–2022 Florida Citrus Production Guide: Irrigation Management of Citrus Trees

EDIS ◽  
2021 ◽  
Author(s):  
Davie Kadyampakeni ◽  
Kelly T. Morgan ◽  
Mongi Zekri ◽  
Rhuanito S. Ferrarezi ◽  
Arnold W. Schumann ◽  
...  
Keyword(s):  
Irrigation Management ◽  
Citrus Production ◽  
Florida Citrus ◽  
Citrus Trees

Spatially Explicit Changes in Potato Psyllid (Hemiptera: Triozidae) Populations in Three South Texas Potato Fields

2019 ◽  
Vol 113 (2) ◽  
pp. 988-1000 ◽  
Author(s):  
Don C Henne ◽  
Jenita Thinakaran
Keyword(s):  
Population Structure ◽  
Goodness Of Fit ◽  
Negative Binomial ◽  
Information Criterion ◽  
Potato Psyllid ◽  
Bactericera Cockerelli ◽  
Spatial And Temporal Patterns ◽  
Chi Square ◽  
Frequency Distributions ◽  
Potato Plants

Abstract Insect abundance is commonly recorded in the form of discrete counts taken from plants. Analyses of these counts provide information about spatial distributions and population structure. A study was conducted in the Lower Rio Grande Valley of Texas during April and May 2014 to determine how populations of potato psyllids [Bactericera cockerelli (Šulc)] within three potato fields change over time. It was found that potato psyllid populations in these potato fields frequently changed both spatially and temporally. Chi-square goodness of fit tests and Akaike’s Information Criterion indicated that the frequency distributions of potato psyllid counts conformed to a negative binomial distribution, implying an aggregated spatial pattern. Variance–mean ratios were always much larger than one, also implying spatially clumped populations. However, with a few exceptions, a Spatial Analysis by Distance IndicEs analysis showed that potato psyllid counts were mostly random in space, the clumping generally occurring on individual potato plants and rarely involving groups of potato plants in close proximity. Trends in proportions of plants infested by at least one potato psyllid and the clumping parameter k were similar for all three potato fields. Potato psyllid spatial population structure is a dynamic process that involves continuous adult movements leading to substantial redistribution of potato psyllids over limited time spans of 2 to 3 d. By capturing elements of their spatial and temporal patterns of redistribution, the study reported here is a step towards a better understanding of the population dynamics and movement of potato psyllids.

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