Submitted to: Allelopathy Journal
Publication Type: Peer reviewed journal
Publication Acceptance Date: 9/9/2005
Publication Date: 10/25/2005
Citation: Peterson, J.K., Harrison Jr, H.F., Snook, M.E., Jackson, D.M. 2005. Content of chlorogenic acid in sweetpotato germplasm and possible roles in disease and pest resistance. Allelopathy Journal. 16:239-250. Interpretive Summary: Sweetpotato breeders are trying to develop varieties that are more resistant to diseases and insects, but they need a faster way than field tests to identify breeding lines that are resistant. Because chlorgenic acid content in plants has been implicated in conferring resistance, we studied sweetpotato lines to see what levels of this chemical they contained. We also studied the effect of this chemical on growth of immature insects and plant pathogenic fungi. We found that sweetpotato lines vary in concentration of chlorogenic acid and that chlorogenic acid inhibits the growth of some fungi and immature insects. This information will help plant breeders develop more efficient ways of testing sweetpotato lines for resistance and thus help speed up the production of disease and insect resistant varieties.
Technical Abstract: Fourteen sweetpotato clones, covering a wide range of genetic diversity, were field grown under low stress conditions. The contents of chlorogenic acid were determined in periderm and cortex tissue of this germplasm collection. On a dry weight basis contents in periderm tissues ranged from 33 to 214 micrograms per gram tissue and in the cortex from 1416 to 4213 micrograms per gram tissue (181 to 1384 micrograms per gram FW). In vitro assays wee performed to assess the activity of chlorogenic acid with respect to germination of proso-millet, growth of four sweetpotato pathogenic fungi and growth and survival of diamondback larvae. The highest levels of chlorogenic acid occurring in sweetpotato cortex tissue exceeded the minimum inhibitory concentrations for larval growth and survival of diamondback larvae, and growth of three out of the four sweetpotato pathogenic fungi tested.