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United States Department of Agriculture

Agricultural Research Service

Title: MICRO-INJECTION OF LYGUS SALIVARY GLAND PROTEINS TO SIMULATE FEEDING DAMAGE IN ALFALFA AND COTTON FLOWERS

Authors
item Shackel, K - UNIV OF CA-DAVIS
item Celorio-Mancera, M - UNIV OF CA-DAVIS
item Ahmadi, H - UNIV OF CA-DAVIS
item Greve, L - UNIV OF CA-DAVIS
item Tauber, L - UNIV OF CA-DAVIS
item Backus, Elaine
item Labavitch, J - UNIV OF CA-DAVIS

Submitted to: Archives of Insect Biochemistry and Physiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 12, 2004
Publication Date: January 20, 2005
Citation: Shackel, K.A., Celorio-Mancera, M.P., Ahmadi, H., Greve, L.C., Tauber, L.B., Backus, E.A., Labavitch, J.M. 2005. Micro-injection of lygus salivary gland proteins to simulate feeding damage in alfalfa and cotton flowers. Archives of Insect Biochemistry and Physiology. 58: 69-83

Interpretive Summary: Alfalfa and cotton flowers were pierced with small glass capillary tubes, of the same size and shape as Lygus stylets, and injected with small quantities (75 to 400 nL) of solutions that contained Lygus salivary enzymes. Crude and partially purified protein solutions from Lygus heads and isolated salivary glands showed substantial polygalacturonase (PG) activity, as has been previously reported. Following injection with both crude and partially purified protein solutions, as well as with pure fungal and bacterial PGs, flowers of both alfalfa and cotton exhibited damage similar to that caused by Lygus feeding. Injection with the same volume of a buffer control as well as a buffer control containing BSA at a comparable protein concentration (approximately 6ug/mL), showed no symptons. These results suggest that the extensive tissue damage caused by Lygus feeding is primarily due to the action of the PG enzyme on the host tissue, rather than to mechanical damage cause by the insect stylet. Substantial genotypic variation for a PG inhibiting protein (PGIP) exists in alfalfa and cotton. We therefore suggest that breeding and selection for increased native PG levels, or transformation with genes encoding PG from other plant species, may be of value in obtaining alfalfa and cotton varieties that are more resistant to Lygus feeding damage.

Technical Abstract: Alfalfa and cotton flowers were pierced with small glass capillaries, of an overall size and shape similar to that of Lygus stylets, and injected with small quantities (75 to 400nL) of soloutions that contained Lygus salivary enzymes. Crude and partially purified protein solutions from Lygus heads and isolated salivary glands showed substantial polygalacturonase(PG)activity, as has been previously reported. Following injection with both crude and partially purified protein solutions, as well as with pure fungal and bacterial PGs, flowers of both alfalfa and cotton exhibited damage similar to that caused by Lygus feeding. Injection with the same volume of a buffer control as well as a buffer control containing BSA at a comparable protein concentration (approximately 6ug/mL), showed no symptoms. These results are consistent with a previously suggested hypothesis that the extensive tissue damage caused by Lygus feeding is primarily due to the action of the PG enzyme on the host tissue, rather than to mechanical damage cause by the insect stylet. Substantial genotypic variation for a PG inhibiting protein (PGIP) exists in alfalfa and cotton. We therefore suggest that breeding and selection for increased native PG levels, or transformation with genes encoding PG from other plant species, may be of value in obtaining alfalfa and cotton varieties that are more resistant to Lygus feeding damage.

Last Modified: 10/31/2014
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