RAPD and SCAR Markers Linked to an Introgressed Gene Conditioning Resistance to Peronospora tabacina D.B. Adam. in Tobacco

Abstract

mentally sustainable method for controlling blue mold. Naturally occurring resistance within N. tabacum is gen-Blue mold, caused by the fungal pathogen Peronospora tabacina erally very low, however (Rufty, 1989). Resistance can D.B. Adam, is one of the most important foliar diseases of tobacco (Nicotiana tabacum L.). Identification of molecular markers linked be found within several Nicotiana species of Australian to genetic factors controlling resistance would facilitate development origin where blue mold is endemic and has reportedly of resistant cultivars. Bulked segregant analysis was used to screen been introgressed into cultivated tobacco from N. deb-1216 random amplified polymorphic DNA (RAPD) primers for theirneyi Lea, 1963), N. ability to reveal polymorphism between DNA bulks from susceptible goodspeedii Wheeler (Wark, 1963(Wark, , 1970, and N. veludoubled haploid (DH) lines and resistant DH lines possessing resistina Wheeler (Wark, 1963(Wark, , 1970. Resistance induced tance derived from cultivar Ovens 62. Fifteen RAPD markers were by treatment of flue-cured cultivar Virginia Gold with tentatively identified as being linked to a major gene conditioning the mutagen triethylene iminotrazine has also been reresistance to blue mold. These 15 markers (12 in coupling phase ported (Marani et al., 1972). Few resistant cultivars are linkage with resistance and three in repulsion phase) were found to available to growers worldwide, however (Shoemaker,

Genetic Dissection of Disease Resistance to the Blue Mold Pathogen, Peronospora tabacina, in Tobacco

“…Taking advantage of the tobacco genetic map constructed by Bindler et al [15], we mapped RBM1 against polymorphic SSR markers on LG7 and generated a genetic map ( Figure 2). As can be seen from this map, the RBM1 locus is flanked by the two dominant SCAR marker loci developed by Milla et al [9]. After sequencing these two SCAR markers (Supplementary Materials Table S1), we performed BLAST searches, but no high-quality hit was found in any of the sequenced Nicotiana genomes.…”

“…Unfortunately, natural resistance to P. tabacina is very low in N. tabacum, and most commercial varieties are highly susceptible to blue mold disease [7]. A high level of functional resistance to P. tabacina infection was identified in both N. debneyi and N. goodspeedii and was transferred into cultivated tobacco by crossing [8][9][10][11]. Resistant tobacco varieties were first released beginning in the 1960s.…”

“…Molecular markers closely linked to the blue mold resistance locus (RBM1 hereafter) derived from N. debneyi have been developed and used for marker-assisted selection [9,14]. Utilization of these markers greatly facilitates tobacco breeding for blue mold resistance.…”

“…Consequently, selection solely based on disease phenotype can be misleading. Three sequence characterized amplified region (SCAR) markers, two of which were converted from flanking random amplified polymorphic DNA (RAPD) markers [9] and one that was derived from an amplified fragment length polymorphism (AFLP) marker [14], have become valuable assets to breeding programs worldwide for the improvement of blue mold resistance in tobacco. However, these SCAR markers are dominant, precluding differentiation of plants that are homozygous from those that are heterozygous at the resistance locus, and their genetic locations are unknown.…”

Production and characterization of amphihaploid hybrids between Nicotiana wuttkei Clarkson et Symon and N. tabacum L

“…The blue mold pathogen is notorious for mutations and the ability to develop new races (Masiak 1982;Zipper et al 2009) and, according to the recent molecular studies (Milla et al 2005), all important resistant cultivars probably derive their resistance from a single source (N. debneyi) even if previously reported otherwise. The hybridization of N. wuttkei with N. tabacum may also be important for basic studies in plant biology, gaining increased understanding of phylogenetic relationships among species, and for investigating aspects of evolution of the genus Nicotiana.…”