Submitted to: Genetic Resources and Crop Evolution
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/17/1999
Publication Date: N/A
Citation: N/A Interpretive Summary: The Colorado potato beetle is a serious pest of the cultivated potato. Natural resistance has been found in a few related wild species, including Solanum chacoense, in which the resistance is attributed to the presence of compounds called leptines. This trait could be useful in a breeding program to introduce resistance to the beetle into the cultivated potato. However, even within S. chacoense, plants which produce high levels of leptines are presumed to be rare. In this manuscript, we report on the results of a survey of S. chacoense plants collected from various locations within Argentina and surrounding areas (the natural range of the species) in an effort to determine the frequency of leptine-producing plants, and to see if a specific location could be found where such plants grow. We found no high leptine producers, but low to mid levels of leptine were detected in some plants along a north-south region in northwest Argentina. We also detected nine unidentified compounds in some plants. This information will be useful to scientists in identifying sources of plant material which contain leptines, and the unidentified compounds may also be useful as sources of insect or pest resistance.
Technical Abstract: The Colorado potato beetle is a serious pest of the cultivated potato. Natural resistance has been found in a few wild species, including Solanum chacoense Bitter, in which the resistance is attributed to the presence of leptine glycoalkaloids. Production and accumulation of these compounds within S. chacoense vary widely and appear to be inherited in a quantitative fashion, but high leptine producing clones occur rarely. In this study, 15 different accessions from various locations and altitudes of origination were analyzed for foliar glycoalkaloid content in order to determine the frequency and distribution of genes for leptine production/accumulation, and to see if we could find a center, or core, of leptine production. Leptines were detected in 8 of the 15 accessions, and the amounts within each accession varied widely, but none of the individuals produced high amounts of leptine (defined as # 62% of total glycoalkaloids). All leptine-containing accessions originated from western Argentina. There was no relationship between elevational level and leptine, but there was a negative trend with total glycoalkaloids (TGA) and elevation; this was due to levels of solanine and chaconine decreasing with increasing elevation.