Tannins are plant defense compounds that exhibit antibiotic (e.g. toxic) and antixenotic (e.g. repellent) effects against an array of plant pests. They are broadly divided into two major groups, hydrolysable tannins (gallotannins and ellagitannins) and proanthocyanidins, each with an undetermined number of compounds. We investigated constitutive levels of hydrolysable tannins and proanthocyanidins in the leaves and stems of American (Castanea dentata Marshall) (Fagales: Fagaceae) and Chinese (C. mollissima Blume) chestnut. American chestnut contained more proanthocyanidins in leaves and stems than Chinese chestnut, but Chinese chestnut contained more foliar hydrolysable tannins. Regardless of these differences, gypsy moth (Lymantria dispar L, Lepidoptera: Lymantriidae) performance did not differ when fed American and Chinese chestnuts. We also investigated the effects of jasmonic acid (JA) treatment on differential tannin induction in American and Chinese chestnut leaves and stems. JA treatment increased proanthocyanidins in American chestnut stems and hydrolysable tannins in both tissue types of American chestnut, but did not influence tannin concentrations in Chinese chestnut leaves or stems. HPLC-ESI-MS analysis of pooled samples suggested that hydrolysable tannins in each tissue were qualitatively comprised primarily of ellagitannins, and JA generally increased the number of hydrolysable tannins that could be detected by ESI-MS. Third, we investigated the performance of gypsy moths on JA treated and untreated American and Chinese chestnut. Caterpillar relative growth was not influenced by JA treatment on Chinese chestnut, but decreased in response to JA application on American chestnut. Our results indicate that JA-dependent defenses differ between these chestnut species. This study improves our understanding of ecologically important differences in tannin induction and herbivore susceptibility in Castanea, and has important implications in efforts for American chestnut restoration and commercial chestnut production.
|Number of pages||7|
|State||Published - Jun 2008|
Bibliographical noteFunding Information:
We thank Fred Hebard (The American Chestnut Foundation) for chestnut seed and Ann E. Hagerman (University of Miami OH) for technical advice. John May (University of Kentucky, Environmental Research Training Laboratory) gave technical advice and assistance with LC/MS/MS analysis. Melanie Antonik and Tom Coleman provided technical assistance. We also thank anonymous reviewers for comments on a previous version of this manuscript. This research was funded by the American Chestnut Foundation, the Northern Nut Growers Association, and McIntire Stennis fund s from the Kentucky Agricultural Experimental Station, and is published as Experiment Station Project 07-08-026.
- Chestnut blight
- Jasmonic acid
ASJC Scopus subject areas
- Ecology, Evolution, Behavior and Systematics