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ARS Home » Southeast Area » Tifton, Georgia » Crop Genetics and Breeding Research » Research » Publications at this Location » Publication #236898
Title: Changes of oxidase and hydrolase activities in pecan leaves elicited by black pecan aphid (Hemiptera: Aphididae) feeding

Author
item CHEN, YIGEN - UNIV OF GA/MICHIGAN STATE
item Ni, Xinzhi
item Cottrell, Ted
item Wood, Bruce
item BUNTIN, G. DAVID - UNIV OF GA

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/23/2009
Publication Date: 6/1/2009
Citation: Chen, Y., Ni, X., Cottrell, T.E., Wood, B.W., Buntin, G. 2009. Changes of oxidase and hydrolase activities in pecan leaves elicited by black pecan aphid (Hemiptera: Aphididae) feeding. Journal of Economic Entomology 102:1262-1269.

Interpretive Summary: The black pecan aphid is a foliar feeder of pecan tree, which removes tree sap and causes chlorosis of leaflet lamina, physiological damage to foliage and trees, and commonly reduction of crop yield and quality. However, key aspects of this host-pest interaction are poorly understood. We report here the effects of black pecan aphid feeding on the foliar biochemical changes in relation to the degree of aphid resistance among pecan varieties. Two years of examinations showed that black pecan aphid infested foliage exhibited elevated peroxidase activity only in susceptible (‘Desirable’, ‘Sumner’ and ‘Schley’), but not in resistant (‘Cape Fear’, ‘Gloria Grande’ and ‘Money Maker’) genotypes. Susceptible genotypes also exhibited more leaf chlorosis in response to black pecan aphid feeding than resistant genotypes; however, the aphid feeding did not influence either catalase or esterase activity. Black pecan aphid feeding also influences activity of two lipoxygenase isozymes, with lipoxygenase-3 (LOX3) being more frequently induced than lipoxygenase-1 (LOX1). Foliar LOX3 activity in the moderately resistant ‘Oconee’ and in aphid-resistant ‘Money Maker’ and ‘Cape Fear’ was more frequently induced by the aphid feeding than in more susceptible genotypes. Therefore, elevation of peroxidase and LOX3 activities in susceptible varieties is likely to be associated with severe leaf chlorosis. These findings contribute to our understanding how the black pecan aphid injures pecan foliage, and may also be used to develop enzyme markers for identifying aphid resistance and/or susceptibility in pecan germplasm.

Technical Abstract: The black pecan aphid, Melanocallis caryaefoliae (Davis) (Hemiptera: Aphididae), is a foliar feeder of pecan, Carya illinoinensis (Wangenh.) K. Koch (Juglandaceae). The pest causes chlorosis of leaflet lamina, physiological damage to foliage and trees, and commonly limits the profitability of commercial pecan orchard enterprises. However, key aspects of this host-pest interaction are poorly understood. We report here the effects of M. caryaefoliae feeding on the foliar activity of oxidative (i.e., catalase, lipoxygenase 1 and 3, and peroxidase) and hydrolytic (i.e., esterase) enzymes in relation to the degree of aphid resistance among pecan varieties. The two-year study showed that M. caryaefoliae infested foliage exhibited elevated peroxidase activity only in susceptible (‘Desirable’, ‘Sumner’ and ‘Schley’), but not in resistant (‘Cape Fear’, ‘Gloria Grande’ and ‘Money Maker’) genotypes. Susceptible genotypes also exhibited more leaf chlorosis in response to M. caryaefoliae feeding than the resistant genotypes; however, the aphid feeding did not influence catalase or esterase activity. Melanocallis caryaefoliae feeding also influences activity of two lipoxygenase isozymes, with lipoxygenase-3 (LOX3) being more frequently induced than lipoxygenase-1 (LOX1). Foliar LOX3 activity in the moderately resistant ‘Oconee’ and highly resistant Money Maker and Cape Fear was more frequently induced by M. caryaefoliae feeding than in the susceptible genotypes. Therefore, elevation of peroxidase and LOX3 activities in susceptible varieties is likely to be associated with severe leaf chlorosis. These findings contribute to our understanding of the etiology of M. caryaefoliae-elicited leaf chlorosis on pecan foliage. Such information may also be used to develop enzyme markers for identifying black pecan aphid resistance and/or susceptibility in pecan germplasm.