scholarly journals The insect vector Cacopsylla picta vertically transmits the bacterium ‘Candidatus Phytoplasma mali’ to its progeny

2017 ◽  
Vol 66 (6) ◽  
pp. 1015-1021 ◽  
Author(s):  
C. Mittelberger ◽  
L. Obkircher ◽  
S. Oettl ◽  
T. Oppedisano ◽  
F. Pedrazzoli ◽  
...  
Keyword(s):  
Insect Vector ◽  
Cacopsylla Picta ◽  
Candidatus Phytoplasma Mali

scholarly journals Temporal Dynamics of ‘Ca. Phytoplasma mali’ Load in the Insect Vector Cacopsylla melanoneura

Insects ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 592
Author(s):  
Valentina Candian ◽  
Monia Monti ◽  
Rosemarie Tedeschi
Keyword(s):  
Host Plants ◽  
Developmental Stages ◽  
Temporal Dynamics ◽  
Control Strategies ◽  
Vector Competence ◽  
Insect Vector ◽  
Life Stages ◽  
Candidatus Phytoplasma Mali ◽  
High Infection ◽  
Cacopsylla Melanoneura

The transmission of phytoplasmas is the result of an intricate interplay involving pathogens, insect vectors and host plants. Knowledge of the vector’s competence during its lifespan allows us to define more sustainable well-timed control strategies targeted towards the most worrisome life stages. We investigated the temporal dynamics of ‘Candidatus Phytoplasma mali’ load in Cacopsylla melanoneura in the different developmental stages in Northwest Italy. The phytoplasma load in the vector was evaluated in overwintering adults, nymphs and newly emerged adults after different acquisition access periods. Moreover, we followed the multiplication of the phytoplasma during the aestivation and the overwintering period on conifers. Our results confirmed the ability of remigrants to retain the phytoplasma until the end of winter. We also highlighted the high acquisition efficiency and vector competence, based on phytoplasma load, of nymphs and newly emerged adults. Therefore, particular attention should be paid to the management of overwintered C. melanoneura as soon as they return to the orchards, but also to newly emerged adults, particularly in orchards with a high infection rate and when the migration to conifers is delayed.

scholarly journals Identification of Plant DNA in Adults of the Phytoplasma Vector Cacopsylla picta Helps Understanding Its Feeding Behavior

Insects ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 835
Author(s):  
Dana Barthel ◽  
Hannes Schuler ◽  
Jonas Galli ◽  
Luigimaria Borruso ◽  
Jacob Geier ◽  
...  
Keyword(s):  
Feeding Behavior ◽  
Whole Body ◽  
Herbaceous Plant ◽  
Plant Dna ◽  
Cacopsylla Picta ◽  
Candidatus Phytoplasma Mali ◽  
Deep Sequencing Technology ◽  
Phytoplasma Vector ◽  
Plant Families ◽  
Phloem Feeding

Apple proliferation is an economically important disease and a threat for commercial apple cultivation. The causative pathogen, the bacterium ‘Candidatus Phytoplasma mali’, is mainly transmitted by Cacopsylla picta, a phloem-feeding insect that develops on the apple tree (Malus spp.). To investigate the feeding behavior of adults of the phytoplasma vector Cacopsylla picta in more detail, we used deep sequencing technology to identify plant-specific DNA ingested by the insect. Adult psyllids were collected in different apple orchards in the Trentino-South Tyrol region of northern Italy. DNA from the whole body of the insect was extracted and analyzed for the presence of plant DNA by performing PCR with two plant-specific primers that target the chloroplast regions trnH-psbA and rbcLa. DNA from 23 plant genera (trnH) and four plant families (rbcLa) of woody and herbaceous plant taxa was detected. Up to six and three plant genera and families, respectively, could be determined in single specimens. The results of this study contribute to a better understanding of the feeding behavior of adult Cacopsylla picta.

scholarly journals Effect of Daytime and Tree Canopy Height on Sampling of Cacopsylla melanoneura, a ‘Candidatus Phytoplasma mali’ Vector

Plants ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 1168 ◽  
Author(s):  
Dana Barthel ◽  
Christine Kerschbamer ◽  
Bernd Panassiti ◽  
Igor Malenovský ◽  
Katrin Janik
Keyword(s):  
Apple Tree ◽  
Tree Canopy ◽  
Temperature Threshold ◽  
Insect Vector ◽  
Apple Proliferation ◽  
Candidatus Phytoplasma Mali ◽  
Cacopsylla Melanoneura ◽  
Cacopsylla Pruni ◽  
Vector Behavior ◽  
Practical Impact

The psyllids Cacopsylla melanoneura and Cacopsylla picta reproduce on apple (Malus × domestica) and transmit the bacterium ‘Candidatus Phytoplasma mali’, the causative agent of apple proliferation. Adult psyllids were collected by the beating-tray method from lower and upper parts of the apple tree canopy in the morning and in the afternoon. There was a trend of catching more emigrant adults of C.melanoneura in the morning and in the lower part of the canopy. For C.melanoneura remigrants, no differences were observed. The findings regarding the distribution of adults were reflected by the number of nymphs collected by wash-down sampling. The density of C.picta was too low for a statistical analysis. The vector monitoring and how it is commonly performed, is suitable for estimating densities of C.melanoneura. Nevertheless, above a certain temperature threshold, prediction of C.melanoneura density might be skewed. No evidence was found that other relatively abundant psyllid species in the orchard, viz. Baeopelma colorata, Cacopsylla breviantennata, Cacopsylla brunneipennis, Cacopsylla pruni and Trioza urticae, were involved in ‘Candidatus Phytoplasma mali’ transmission. The results of our study contribute to an advanced understanding of insect vector behavior and thus have a practical impact for an improved field monitoring.

scholarly journals An Immunodominant Membrane Protein (Imp) of ‘Candidatus Phytoplasma mali’ Binds to Plant Actin

2012 ◽  
Vol 25 (7) ◽  
pp. 889-895 ◽  
Author(s):  
K. Boonrod ◽  
B. Munteanu ◽  
B. Jarausch ◽  
W. Jarausch ◽  
G. Krczal
Keyword(s):  
Membrane Proteins ◽  
Fluorescent Protein ◽  
Transmembrane Domain ◽  
The Body ◽  
Actin Binding ◽  
Wild Type Plant ◽  
Insect Vector ◽  
Rabbit Muscle ◽  
Remarkable Change ◽  
Candidatus Phytoplasma Mali

The phytopathogenic, cell-wall-less phytoplasmas exhibit a dual life cycle: they multiply in the phloem of their host plant and in the body of their insect vector. Their membrane proteins are in direct contact with both hosts and are supposed to play a crucial role in the phytoplasma spread within the plant as well as by the insect vector. Three types of nonhomologous but highly abundant and immunodominant membrane proteins (IDP) have been identified within the phytoplasmas: Amp, IdpA, and Imp. Although recent results indicate that Amp is involved in vector specificity interacting with insect proteins such as actin, little is known about the interaction of IDP with the plant. We could demonstrate that transiently expressed Imp of ‘Candidatus Phytoplasma mali’ as well as the Imp without transmembrane domain (Imp▴Tm) bind with plant actins in vivo. Moreover, in vitro co-sediment and binding assays showed that Escherichia coli-expressed recombinant Imp▴Tm-His binds to both G- and F-actins isolated from rabbit muscle. Transgenic plants expressing Imp- or Imp▴Tm-green fluorescent protein did not exhibit any remarkable change of phenotype compared with the wild-type plant. These results indicate that Imp specifically binds to plant actin and a role of Imp-actin binding in phytoplasma motility is hypothesized.

scholarly journals The phytopathogen ‘Candidatus Phytoplasma mali’ alters apple tree phloem composition and affects oviposition behavior of its vector Cacopsylla picta

Chemoecology ◽  
2020 ◽  
Author(s):  
Louisa Maria Görg ◽  
Jannicke Gallinger ◽  
Jürgen Gross
Keyword(s):  
Host Plant ◽  
Morphological Changes ◽  
Oviposition Behavior ◽  
Sugar Content ◽  
Soluble Sugar ◽  
Amino Acid Content ◽  
Cacopsylla Picta ◽  
Mediated Effects ◽  
Candidatus Phytoplasma Mali ◽  
Induced Changes

Abstract Apple proliferation disease is caused by the phloem-dwelling bacterium ‘Candidatus Phytoplasma mali’, inducing morphological changes in its host plant apple, such as witches’ broom formation. Furthermore, it triggers physiological alterations like emission of volatile organic compounds or phytohormone levels in the plant. In our study, we assessed phytoplasma-induced changes in the phloem by sampling phloem sap from infected and non-infected apple plants. In infected plants, the soluble sugar content increased and the composition of phloem metabolites differed significantly between non-infected and infected plants. Sugar and sugar alcohol levels increased in diseased plants, while organic and amino acid content remained constant. As ‘Ca. P. mali’ is vectored by the phloem-feeding insect Cacopsylla picta (Foerster, 1848), we assessed whether the insect–plant interaction was affected by ‘Ca. P. mali’ infection of the common host plant Malus domestica Borkh. Binary-choice oviposition bioassays between infected and non-infected apple leaves revealed C. picta’s preference for non-infected leaves. It is assumed and discussed that the changes in vector behavior are attributable to plant-mediated effects of the phytoplasma infection.

scholarly journals A Novel Effector Protein of Apple Proliferation Phytoplasma Disrupts Cell Integrity of Nicotiana spp. Protoplasts

2019 ◽  
Vol 20 (18) ◽  
pp. 4613 ◽  
Author(s):  
Cecilia Mittelberger ◽  
Hagen Stellmach ◽  
Bettina Hause ◽  
Christine Kerschbamer ◽  
Katja Schlink ◽  
...  
Keyword(s):  
Plant Pathogens ◽  
Effector Proteins ◽  
Plant Diseases ◽  
Effector Protein ◽  
Insect Vector ◽  
Cell Integrity ◽  
Apple Proliferation ◽  
Disease Manifestation ◽  
Candidatus Phytoplasma Mali ◽  
Exact Function

Effector proteins play an important role in the virulence of plant pathogens such as phytoplasma, which are the causative agents of hundreds of different plant diseases. The plant hosts comprise economically relevant crops such as apples (Malus × domestica), which can be infected by ‘Candidatus Phytoplasma mali’ (P. mali), a highly genetically dynamic plant pathogen. As the result of the genetic and functional analyses in this study, a new putative P. mali effector protein was revealed. The so-called “Protein in Malus Expressed 2” (PME2), which is expressed in apples during P. mali infection but not in the insect vector, shows regional genetic differences. In a heterologous expression assay using Nicotiana benthamiana and Nicotiana occidentalis mesophyll protoplasts, translocation of both PME2 variants in the cell nucleus was observed. Overexpression of the effector protein affected cell integrity in Nicotiana spp. protoplasts, indicating a potential role of this protein in pathogenic virulence. Interestingly, the two genetic variants of PME2 differ regarding their potential to manipulate cell integrity. However, the exact function of PME2 during disease manifestation and symptom development remains to be further elucidated. Aside from the first description of the function of a novel effector of P. mali, the results of this study underline the necessity for a more comprehensive description and understanding of the genetic diversity of P. mali as an indispensable basis for a functional understanding of apple proliferation disease.

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