|Van Den Berg, Jan|
Submitted to: Euphytica
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/5/2007
Publication Date: 6/30/2008
Citation: Simko, I., Van Den Berg, J.H., Vreugdenhil, D., Ewing, E.E. 2008. Mapping loci for chlorosis associated with chlorophyll b deficiency in potato. Euphytica Vol 162, Pages 99-107, 2008. Interpretive Summary: Chlorosis is a condition in which plant produces insufficient level of chlorophyll leading to pale green, yellow, or yellow-white leaves. In some cases chlorosis can be accompanied with leaf deformation. Chlorotic plants have decreased ability to manufacture carbohydrates and severe chlorosis leads to plant death. In the present work we have investigated chlorosis observed in a potato mapping population that originates from a cross between Solanum tuberosum and S. berthaultii. Testing with molecular markers revealed that a single recessive gene located on chromosome 1 controls the trait. The effect of this gene appeared to be accentuated by a second gene, located on chromosome 12. Chlorotic plants showed a 50% decrease in chlorophyll b level in the affected parts of leaves. The proposed symbol for this potato gene that confers phenotype with chlorotic and malformed leaves is cml (chlorotic and malformed leaves). Information about chlorosis will be useful to potato breeders and physiologists.
Technical Abstract: About thirty percent of the potato plants from a (Solanum tuberosum × S. berthaultii) × S. tuberosum backcross population had chlorotic, malformed leaves; but a gradation in symptom severity suggested regulation by more than one gene. The study was undertaken to determine whether this was the case, whether any genes previously reported to control chlorosis in potato were involved, and to see how symptoms were related to effects on chlorophyll. Testing for quantitative trait loci indicated major control by a single recessive gene on chromosome 1, close to one or more loci that have been reported to produce chlorosis in tomato, but distinct from similar genes previously identified in potato. The proposed symbol for the potato gene that confers phenotype with chlorotic and malformed leaves is cml (chlorotic and malformed leaves). The effects of this gene appeared to be accentuated by a second gene, located on chromosome 12. Chlorotic plants showed a 50% decrease in chlorophyll b level in the affected parts of leaves. It is concluded that cml is different from previously reported genes for chlorosis in potato, that at least one other gene modifies the intensity of symptom expression, and that the observed chlorosis is produced through effects on chlorophyll b level.