scholarly journals Host plant preference of Trioza erytreae on lemon and bitter orange plants

2021 ◽  
Author(s):  
Jacinto Benhadi-Marín ◽  
Elisa Garzo ◽  
Aránzazu Moreno ◽  
José Alberto Pereira ◽  
Alberto Fereres
Keyword(s):  
Feeding Behaviour ◽  
Host Preference ◽  
Bitter Orange ◽  
Citrus Greening Disease ◽  
Feeding Experiments ◽  
Trioza Erytreae ◽  
Management Measures ◽  
Choice Pattern ◽  
Liberibacter Asiaticus ◽  
Settlement Experiment

AbstractTrioza erytreae, the African citrus psyllid, is a vector of Candidatus Liberibacter spp., the causal agent of the citrus greening disease or Huanglongbing (HLB). The spread of the vector throughout the Iberian Peninsula has been continuous since its introduction in mainland Spain in 2014. The patterns of host preference and feeding behaviour largely depend on olfactory cues. Understanding these patterns is crucial to prevent further dispersion and develop management measures against the pest. In this work, a series of settlement, olfactometric, probing, and feeding experiments were conducted to assess the host preference of T. erytreae for lemon or bitter orange plants. The settlement experiment provided evidence on the preference of both sexes of T. erytreae for lemon plants, whereas males did not show any significant choice pattern in the case of the olfactometric assays. Forty EPG variables were analysed to describe and compare the probing and feeding behaviour of T. erytreae on lemon and bitter orange plants. The EPG variables indicated that T. erytreae has some difficulties in accepting the phloem of bitter orange plants. This suggests that lemon plants would be a better source for the acquisition of Candidatus Liberibacter asiaticus (CLas) by T. erytreae since the psyllid spends much longer periods feeding from the phloem on lemon than on bitter orange.

scholarly journals Viability of ‘Candidatus Liberibacter asiaticus’ Prolonged by Addition of Citrus Juice to Culture Medium

2014 ◽  
Vol 104 (1) ◽  
pp. 15-26 ◽  
Author(s):  
Jennifer K. Parker ◽  
Sarah R. Wisotsky ◽  
Evan G. Johnson ◽  
Faraj M. Hijaz ◽  
Nabil Killiny ◽  
...  
Keyword(s):  
Grapefruit Juice ◽  
Culture Medium ◽  
Quantitative Polymerase Chain Reaction ◽  
Chemical Characterization ◽  
Candidatus Liberibacter Asiaticus ◽  
Citrus Greening Disease ◽  
Candidatus Liberibacter ◽  
The Media ◽  
Liberibacter Asiaticus

Huanglongbing, or citrus greening disease, is associated with infection by the phloem-limited bacterium ‘Candidatus Liberibacter asiaticus’. Infection with ‘Ca. L. asiaticus’ is incurable; therefore, knowledge regarding ‘Ca. L. asiaticus’ biology and pathogenesis is essential to develop a treatment. However, ‘Ca. L. asiaticus’ cannot currently be successfully cultured, limiting its study. To gain insight into the conditions conducive for growth of ‘Ca. L. asiaticus’ in vitro, ‘Ca. L. asiaticus’ inoculum obtained from seed of fruit from infected pomelo trees (Citrus maxima ‘Mato Buntan’) was added to different media, and cell viability was monitored for up to 2 months using quantitative polymerase chain reaction in conjunction with ethidium monoazide. Media tested included one-third King's B (K), K with 50% juice from the infected fruit, K with 50% commercially available grapefruit juice, and 100% commercially available grapefruit juice. Results show that juice-containing media dramatically prolong viability compared with K in experiments reproduced during 2 years using different juice sources. Furthermore, biofilm formed at the air–liquid interface of juice cultures contained ‘Ca. L. asiaticus’ cells, though next-generation sequencing indicated that other bacterial genera were predominant. Chemical characterization of the media was conducted to discuss possible factors sustaining ‘Ca. L. asiaticus’ viability in vitro, which will contribute to future development of a culture medium for ‘Ca. L. asiaticus’.

Feeding behaviour of Merino wethers under conditions similar to lot-feeding before live export

1990 ◽  
Vol 30 (3) ◽  
pp. 343 ◽  
Author(s):  
CL McDonald ◽  
RT Norris ◽  
EJ Speijers ◽  
H Ridings
Keyword(s):  
Western Australia ◽  
Feed Intake ◽  
Feeding Behaviour ◽  
Reliable Indicator ◽  
Central Location ◽  
Feeding Experiments ◽  
Linear Relationships ◽  
Diet Type ◽  
Live Export ◽  
As If

Sheep from different farms (lines) in Western Australia were mixed in 3 experiments and lot-fed for 6-7 days as if for export. A marking method to identify sheep which eat from troughs was tested and used to examine the effects of feeding treatments on the proportion of sheep which eat during lot-feeding. Paint soaked sponges attached to troughs were used to monitor whether sheep ate. Positive linear relationships between liveweight change and paint marking score (R = 0.93, 0.93 and 0.94, in the 3 experiments) suggested that the technique was a reliable indicator of feed intake. Feeding treatments imposed were period of fasting before lot feeding (experiments 2 and 3); and diet type (hay pellets, hay/pellet mix) and trough location in the feedlot (experiment 3). There were large differences between lines in the percentage of sheep not marked. Values � s.e. ranged from 1 � 1 to 79 � 3% for the 8 lines used in 3 experiments. In experiment 2, fasting for 48 h before lot-feeding resulted in more sheep (P<0.05) not marked (18 � 7 3%) than did fasting for <12 h (9 � 3%) and <24 h (8 � 2%). In experiment 3, fasting for 96 h compared with 48 h resulted in fewer sheep marked daily when fed a hay-pellet mixture (75 � 2 v. 93 � 1%; P<0.001). When fed only pellets in experiment 3, the percentages of marked sheep increased with time (days). Feeding pellets only compared with a hay-pellet mixture resulted in fewer sheep marked daily (60 � 2 v. 79 � 2%; P<0.001) and more sheep not marked (11 � 3 v. 3 � 2%; P<0.05). If troughs were located in the centre of yards instead of on the fenceline, it took 2 rather than 7 days for the daily percentage of animals marked on the pellets only diet to exceed 80%. The central location also resulted in a mean of 78 � 2% of sheep marked daily compared with 67 � 2% for fenceline troughs (P<0.001) and a mean intake higher (P<0.01) by 0.13 � 0.04 kg/wether.day. It was concluded that line of sheep, fasting, diet and trough location all had significant effects on feeding behaviour during lot feeding. Of these treatments, the greatest variation in feeding behaviour was associated with the line of sheep.

scholarly journals Asian citrus psyllid adults inoculate huanglongbing bacterium more efficiently than nymphs when this bacterium is acquired by early instar nymphs

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
El-Desouky Ammar ◽  
Justin George ◽  
Kasie Sturgeon ◽  
Lukasz L. Stelinski ◽  
Robert G. Shatters
Keyword(s):  
Latent Period ◽  
Salivary Glands ◽  
Emerging Adults ◽  
Citrus Greening ◽  
Asian Citrus Psyllid ◽  
Diaphorina Citri ◽  
Citrus Greening Disease ◽  
Early Instar ◽  
Liberibacter Asiaticus ◽  
Greening Disease

Abstract The Asian citrus psyllid (Diaphorina citri) transmits the bacterium ‘Candidatus Liberibacter asiaticus’ (CLas), which causes huanglongbing (citrus greening) disease, in a circulative-propagative manner. We compared CLas inoculation efficiency of D. citri nymphs and adults into healthy (uninfected) citron leaves when both vector stages were reared from eggs on infected plants. The proportion of CLas-positive leaves was 2.5% for nymphs and 36.3% for adults. CLas acquisition by early instar nymphs followed by dissections of adults and 4th instar nymphs revealed that CLas bacterium had moved into the head-thorax section (containing the salivary glands) in 26.7–30.0% of nymphs and 37–45% of adults. Mean Ct values in these sections were 31.6–32.9 and 26.8–27.0 for nymphs and adults, respectively. Therefore, CLas incidence and titer were higher in the head-thorax of adults than in nymphs. Our results suggest that following acquisition of CLas by early instar D. citri nymphs, emerging adults inoculate the bacteria into citrus more efficiently than nymphs because adults are afforded a longer latent period necessary for multiplication and/or translocation of CLas into the salivary glands of the vector. We propose that CLas uses D. citri nymphs mainly for pathogen acquisition and multiplication, and their adults mainly for pathogen inoculation and spread.

Phototactic response of Trioza erytreae (Del Guercio) (Hemiptera: Triozidae) to yellow-coloured surfaces, and an attempt at commercial suppression using yellow barriers and trap trees

1987 ◽  
Vol 77 (1) ◽  
pp. 91-98 ◽  
Author(s):  
M. J. Samways
Keyword(s):  
Adhesive Tape ◽  
Mass Trapping ◽  
Mature Trees ◽  
Significant Drop ◽  
Citrus Greening Disease ◽  
Trioza Erytreae ◽  
Phototactic Response ◽  
Greening Disease ◽  
One Year ◽  
Monitoring Trap

AbstractTrioza erytreae (Del Guercio), the vector of the serious citrus greening disease, was found to be highly attracted to yellow surfaces, particularly fluorescent yellow-green (about 530 nm). The phototactic response was used to develop a monitoring trap using 3M Saturn Yellow self-adhesive tape adhering to a glass or Perspex sheet. Transparent PVC foils smeared with a thin layer of clear polybutene were clipped in position over the Saturn Yellow surface and acted as the sticky catchment surface. A spectroradiometric comparison of new and weathered traps indicated only a 10% decrease in reflectance after one year. The traps were a sensitive indicator of psylla abundance. Valencia orchards in the Transvaal, South Africa, supported higher population levels than did navel orchards. A mass-trapping experiment was also done, and involved a cordon of yellow sticky polyethylene strips (Gundle Flexipipe smeared with polybutene) placed around an orchard. This perimeter barrier was combined with aldicarb-treated trap trees within the orchard in an attempt to reduce further the already low psylla numbers. Inside the experimental area there was no statistically significant drop in psylla numbers compared with the control trees outside. These poor economic results making use of the flight response of T. erytreae suggest that carefully integrated biological and chemical suppression of the psylla vector is at present the most practical entomological method for containing greening disease on mature trees.

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 ‘Candidatus Liberibacter asiaticus’ Multimeric LotP Mediates Citrus sinensis Defense Response Activation

2021 ◽  
Vol 12 ◽  
Author(s):  
Marcelo L. Merli ◽  
Kaylie A. Padgett-Pagliai ◽  
Alexandra E. Cuaycal ◽  
Lucila Garcia ◽  
Maria Rosa Marano ◽  
...  
Keyword(s):  
Protein Interactions ◽  
Plant Tissue ◽  
Substrate Binding ◽  
Lon Protease ◽  
Plant Proteins ◽  
Protein Protein Interactions ◽  
Citrus Plant ◽  
Protein Protein Interaction ◽  
Citrus Greening Disease ◽  
Liberibacter Asiaticus

‘Candidatus Liberibacter asiaticus’ is known as the most pathogenic organism associated with citrus greening disease. Since its publicized emergence in Florida in 2005, ‘Ca. L. asiaticus’ remains unculturable. Currently, a limited number of potential disease effectors have been identified through in silico analysis. Therefore, these potential effectors remain poorly characterized and do not fully explain the complexity of symptoms observed in citrus trees infected with ‘Ca. L. asiaticus.’ LotP has been identified as a potential effector and have been partially characterized. This protein retains structural homology to the substrate binding domain of the Lon protease. LotP interacts with chaperones like GroEL, Hsp40, DnaJ, and ClpX and may exercise its biological role through interactions with different proteins involved in proteostasis networks. Here, we evaluate the interactome of LotP—revealing a new protein–protein interaction target (Lon-serine protease) and its effect on citrus plant tissue integrity. We found that via protein–protein interactions, LotP can enhance Lon protease activity, increasing the degradation rate of its specific targets. Infiltration of purified LotP strained citrus plant tissue causing photoinhibition and chlorosis after several days. Proteomics analysis of LotP tissues recovering after the infiltration revealed a large abundance of plant proteins associated with the stabilization and processing of mRNA transcripts, a subset of important transcription factors; and pathways associated with innate plant defense were highly expressed. Furthermore, interactions and substrate binding module of LotP suggest potential interactions with plant proteins, most likely proteases.

scholarly journals Mitochondrial genetic variation reveals phylogeographic structure and cryptic diversity in Trioza erytreae

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Inusa Ajene ◽  
Fathiya M. Khamis ◽  
Gerhard Pietersen ◽  
Barbara van Asch
Keyword(s):  
South Africa ◽  
Citrus Greening ◽  
Phylogeographic Structure ◽  
Citrus Greening Disease ◽  
Trioza Erytreae ◽  
Baseline Information ◽  
Candidatus Liberibacter ◽  
Mitochondrial Sequences ◽  
Greening Disease ◽  
Genetic Clustering

AbstractTrioza erytreae is the main vector for ‘Candidatus Liberibacter africanus’, the causative agent of African Citrus Greening disease. The insect is widespread in Africa, and has recently disseminated to Southwestern Europe. This study aimed at generating reference mitogenome sequences for T. erytreae, as a background for future genetic diversity surveys. Complete mitochondrial sequences of three specimens collected in Ethiopia, Uganda and South Africa were recovered using Ion Torrent technology. The mitogenomes of T. erytreae from Uganda and Ethiopia were highly similar, and distinct from that found in South Africa. The phylogeographic structure of T. erytreae was assessed using genetic clustering and pairwise distances, based on a dataset of public COI sequences recorded as T. erytreae. The dataset revealed ten haplotypes with strong phylogeographic structure in Africa and Europe. Three haplotypes found in Kenya on Clausena anisata belonged to pairs separated by distances as high as 11.2%, and were basal to all other sequences. These results indicate that not all sequences identified as T. erytreae belong to the same species, and that some degree of specificity with different plant hosts is likely to exist. This study provides new baseline information on the diversity of T. erytreae, with potential implications for the epidemiology of African Citrus Greening disease.

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