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ARS Home » Southeast Area » Fort Pierce, Florida » U.S. Horticultural Research Laboratory » Subtropical Insects and Horticulture Research » Research » Publications at this Location » Publication #351416
Research Project: IPM Methods for Insect Pests of Orchard Crops

Location: Subtropical Insects and Horticulture Research

Title: Salivary sheaths of the Asian citrus psyllid show signs of degradation 3-4 weeks following their deposition into citrus leaves by the feeding psyllids

Author
item AMMAR, ELDESOUKY - Oak Ridge Institute For Science And Education (ORISE)
item Hall, David
item Shatters, Robert

Submitted to: Journal of Microscopy and Ultrastructure
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/30/2018
Publication Date: 7/1/2018
Citation: Ammar, E., Hall, D.G., Shatters, R.G. Salivary sheaths of the Asian citrus psyllid show signs of degradation 3-4 weeks following their deposition into citrus leaves by the feeding psyllids. Journal of Microscopy and Ultrastructure. 6(3):129-133. 2018. https://doi.org/10.4103/jmau.jmau_13_18.
DOI: https://doi.org/10.4103/jmau.jmau_13_18

Interpretive Summary: An earlier report suggested that the salivary sheaths of the Asian citrus psyllid (ACP), vector of the huanglongbing (citrus greening) disease bacterium, start to dissipate one week after their deposition in citrus leaves. Here, using epifluorescence microscopy we found that ACP salivary sheaths show signs of disintegration in 3-4 weeks, and become mostly disintegrated by 6 weeks, following their deposition by the psyllids in citrus tissues. The disintegrated parts of the salivary sheaths are not associated with fungi or bacteria. We speculate that disintegration of the salivary sheaths may be due to enzymatic activities in the host plant tissues.

Technical Abstract: Salivary sheaths, also known as stylet sheaths or stylet tracks, are essential features of the ‘piercing-sucking’ feeding mechanism of all plant-feeding hemipteran insects, many of which are vectors of economically important plant viral and bacterial pathogens. However, in most cases, it is not known how long these salivary sheaths may last after their deposition into host plants by these insects during feeding or probing. An earlier report suggested that the salivary sheaths of the Asian citrus psyllid, Diaphorina citri (Hemiptera, Liviidae), vector of the huanglongbing (citrus greening) disease bacterium, start to dissipate one week after their deposition in citrus leaves. Here, using epifluorescence microscopy of cross sections of in citron leaves, we found that Diaphornia citri salivary sheaths show signs of disintegration in 3-4 weeks, and become mostly disintegrated by 6 weeks, following their deposition by the psyllids in citrus tissues. Disintegration of the salivary sheath starts at or near the ‘flange’ area close to the leaf surface and continues gradually inward through the intercellular part of the sheath, within the mesophyll tissue, but apparently does not extend to the deeper or intracellular parts of the sheath in or near the phloem. Staining citron leaf sections with the fluorescent stain Calcofluor White, which stains fungi, or propidium iodide (DNA/Ribonucleic acid stain) suggested that the disintegrated parts of the older salivary sheaths are not associated with fungi or bacteria. We speculate that disintegration of the salivary sheaths may be due to enzymatic activities in the host plant tissues.