Preliminary study of QTLs for susceptibility to blue mold in apple (Malus x domestica) identified with genome-wide association mapping

Purpose: Apple is one of the commercially most important fruits hosting a wide range of postharvest diseases that can threaten grower economy resulting in a yearly yield loss. Fungal diseases are the major problem in many countries, especially in organic culture as well as in countries with humid condition. Among the postharvest diseases, blue mold (caused by Penicillium expansum) is one of the most important. This disease is very destructive on apple, not only due to the economic damage but also because of mycotoxin patulin production. Research method: In the present study, we used wound inoculation and fruit trait data along with a large set of SNP data from the Axiom®Apple ۴۸۰ K array to explore possible QTLs associated with rate of lesion decay, ripening period, fruit firmness and softening. Findings: Due to the very large number of SNPs in the present study, the significance threshold (۵.۶۳) was higher than in most other Genome-Wide Association Studies. However, some close to significant associations involving lesion decay were found on linkage group ۳ (LG۳), spanning a distance of ۵۳۷ Kb (from ۳۰,۵۲۷,۰۷۷ to ۳۱,۰۶۴,۲۰۵). Interestingly, two SNPs associated with ripening period were also found on LG۳ at the same position (۳۰,۴۹۴,۵۲۳–۳۰,۸۸۵,۷۷۱). Research limitations: This study could be extended with inclusion of more cultivars from different locations in order to minimize the impact of environment and to enhance the study power. Originality/Value: Although the genetic mechanism of blue mold resistance seems to be controlled by several genes in apple, our results indicate a possible association on LG۳ which needs to be further investigated for candidate gene targeting. This finding may help to understand the genetic mechanism of blue mold disease in apple.

کلیدواژه ها:

Apple ، Blue mold ، QTL ، SNP marker ، Storage disease