Chemical basis for resistance in sweetpotato Ipomoea batatas to the sweetpotato weevil Cylas puncticollis
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Date
2009
Journal Title
Journal ISSN
Volume Title
Publisher
Pure and Applied Chemistry
Abstract
The aim of this work was to determine the basis of resistance in a sub-Saharan
sweetpotato variety, New Kawogo, to the African sweetpotato weevil Cylas puncticollis. This
insect feeds on the roots, reducing quality and yield, and is the most important production
constraint of sweetpotato in Africa. Laboratory bioassays were designed to determine how
the performance of weevils differed on susceptible and resistant roots. Subsequently, liquid
chromatography-mass spectrometry (LC-MS) analysis of the root surface and root latex identified
quantitative and qualitative differences in the chemical profiles with higher levels of
octadecyl and hexadecyl esters of hydroxycinnamic acids reported in the resistant variety.
The compounds were synthesized to confirm their identity and incorporated into artificial
diets for bioassays on C. puncticollis. High levels of mortality and developmental inhibition
were recorded for larvae feeding on treated diets, and the effect was dose-dependent. Thus,
in contrast to previous work on resistant African sweetpotato cultivars, resistance in New
Kawogo is not only active, but is quantifiable and manageable for breeding. Work is underway
to determine what effect these compounds have on the weevils at a molecular level. The
inheritance of the root latex esters will be studied in new crosses and mapped in new populations
using quantitative trait loci (QTLs) that are currently being developed.
Description
Keywords
Hexadecyl esters, Octadecyl esters, Hydroxycinnamic acid, Caffeic acid ester, Coumaric, Root latex, Ipomoea batatas, Cylas brunneus, Resistance
Citation
Stevenson, PC, Muyinza, H., Hall, DR, Porter, EA, Farman, DI, Talwana, H., & Mwanga, RO (2009). Chemical basis for resistance in sweetpotato Ipomoea batatas to the sweetpotato weevil Cylas puncticollis. Pure and Applied Chemistry , 81 (1), 141-151. 10.1351/PAC-CON-08-02-10