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Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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Record number 403606
Title New structure in cell puncture activities by aphid stylets: a dual-mode EPG study
Author(s) Tjallingii, W.F.; Garzo, E.; Fereres, A.
Source Entomologia Experimentalis et Applicata 135 (2010)2. - ISSN 0013-8703 - p. 193 - 207.
Department(s) Laboratory of Entomology
Publication type Refereed Article in a scientific journal
Publication year 2010
Keyword(s) nonpersistent virus transmission - intracellular punctures - salivation - penetration - signals - inoculation - acquisition - ingestion - behavior - system
Abstract Intracellular punctures by aphid stylets appear as potential drop (pd) waveforms in DC electrical penetration graph (EPG) recordings. We used a dual-EPG device that recorded in one channel the ‘full EPG’ with R-plus emf-components (i.e., the usual DC EPG) and concurrently in a second channel the ‘R-EPG’ with R-components only. The circuit of the latter channel was an optimised amplitude modulation (AM) version derived from early (before 1990) AC systems. We also made some ‘emf-EPG’ recordings using a separate high input resistance ‘emf-amplifier’ sensitive to emf-components only. The intracellular pd waveforms have previously been divided into three subphases, and we aimed to distinguish and separate these subphases more accurately by the dual-EPG recordings than with the normal full EPG only. In this study, we temporarily distinguished five subphases (a–e), but unequivocal distinction of only a few of these appeared possible, in spite of the information coming from the two signals. The lack of clearly separable features in R-EPG signals often provided serious difficulties in pd recognition without the concurrent full EPG, but once located, only subphase II-2 features were clear and supported the II-2 data from the full EPG. Consequently, we could not distinguish subphases of complete pd waveforms better with additional R-EPG information during cell punctures by Aphis gossypii Glover (Hemiptera: Aphididae). In Brevicoryne brassicae (L.) (Hemiptera: Aphididae), however, distinguishing II-2 subphases in the full EPG was sometimes a problem. Our detailed dual-EPG observations showed some waveform continuity from halfway into the II-1 subphase (start of the newly recognised subphase ß) until the end of the pd, with a strong but variable emf origin. This waveform tended to overrule other subphase waveforms in B. brassicae more than in A. gossypii and Myzus persicae (Sulzer) (Hemiptera: Aphididae). Subphase waveforms in full EPGs were especially difficult to recognise when pd periods had been interrupted in a virus inoculation experiment and additional R-EPG information could then be useful. This inoculation experiment showed again that only the first subphase (II-1) contributes to virus (Cucumber mosaic virus) inoculation by A. gossypii. In B. brassicae, the benefit of concurrent R-EPG information in such virus experiments is presently under further investigation. Apart from this special application to virus experiments, we do not recommend the routine use of the dual-EPG device. Furthermore, we do not advocate the distinction of more than the previously recognised three intracellular pd subphases as a feasible option in future studies. Analysis of EPGs with concurrent R-EPGs requires substantially more analysis work without yielding consistently useful additional insights. This confirms earlier dual-EPG results from thrips
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