Genetic loci associated with field resistance to late blight in offspring of Solanum phureja and S.tuberosum grown under short-day conditions

Abstract

Field resistance to late blight -a fungal disease caused by Phytophthora infestans -has been genetically characterized by analyzing trait-marker association in a Solanum phureja (phu)×dihaploid Solanum tuberosum (dih-tbr) population. Trait data were developed at three locations over a 3-year period under natural infection pressure. RAPD (random amplified polymorphic DNA) and AFLP (amplified fragment length polymorphism) markers were used to develop anonymous genetic linkage groups subsequently anchored to potato chromosomes using mapped RFLP (restriction fragment length polymorphism), SSR (single sequence repeats) and AFLP markers. RFLP and SSR markers achieved the most-accurate anchoring. Two genetic maps were obtained, with 987.4 cM for phu and 773.7 cM for dih-tbr. Trait-marker association was revealed by single-marker and interval mapping analyses. Two important QTLs (quantitative trait loci) were detected on chromosomes VII and XII as a contribution from both parents, totalling up to 16% and 43%, respectively, of the phenotypic variation (PH). One additional QTL was detected on chromosome XI (up to 11% of the PH) as a contribution from the phu parent, and three others were detected on chromosome III (up to 13% of the PH), chromosome V (up to 11% of the PH) and chromosome VIII (up to 11% of the PH) as a contribution from the dih-tbr parent. Our results reveal new genetic loci of the potato genome that contribute to resistance to late blight. We postulate that some of these loci could be related to plant growth under short-day conditions.

Tagging QTLs for late blight resistance and plant maturity from diploid wild relatives in a cultivated potato (Solanum tuberosum) background

“…In previous studies (Leonards-Schippers et al 1994;Collins et al 1999;Oberhagemann et al 1999;Sandbrink et al 2000;Ghislain et al 2001;Visker et al 2003Visker et al , 2005Bormann et al 2004;Bradshaw et al 2004;Costanzo et al 2005) the most frequently detected QTL for foliage and whole tuber resistance is located on chromosome V, in the neighborhood of the R1 gene. In population 98-21, this region harboured the strongest QTL for length of vegetation period, which also inXuenced leaXet and whole tuber resistance to late blight.…”

Genetic linkage of QTLs for late blight resistance and foliage maturity type in six related potato progenies

“…Both QTLs for resistance were not associated with foliage maturity type, because QTLs for adjusted relative AUDPC were found on the same positions with comparable significances and effects. QTLs for resistance against P. infestans have been identified on similar regions of chromosome 3 (Leonards-Schippers et al, 1994;Collins et al, 1999;Oberhagemann et al, 1999;Ewing et al, 2000;Ghislain et al, 2001;Visker et al, 2003) and chromosome 10 (Sandbrink et al, 2000;Ghislain et al, 2001) in previous studies of other progenies. Expression of the QTL for resistance to late blight on chromosome 10 of parent CE and of the QTL for foliage maturity type on chromosome 3 of parent SH seems to be affected by environmental (year) influences.…”

Allele mining in Solanum: conserved homologues of Rpi-blb1 are identified in Solanum stoloniferum

“…Examples are S. pinnatisectum (Kuhl et al 2001) and S. bulbocastanum (Naess et al 2000;Song et al 2003; Van der Vossen et al 2003 andPark et al 2005) from Mexico and S. berthaultii (Rauscher et al 2006;Ewing et al 2000), S. microdontum (Sandbrink et al 2000), S. mochiquense (Smilde et al 2005) and S. paucissectum (Villamon et al 2005) from Andean countries. In addition, the cultivated diploid S. phureja has been described to contain valuable resistance (Ghislain et al 2001;Sliwka et al 2006). The presence of late blight Rgenes in the above-mentioned species indicates that wild and so-called primitive germplasm is a rich source for novel R-genes that may be exploited in breeding programs.…”