New insights into the history of domesticated and wild apricots and its contribution to Plum pox virus resistance

Abstract

Studying domesticated species and their wild relatives allows understanding of the mechanisms of population divergence and adaptation, and identifying valuable genetic resources. Apricot is an important fruit in the Northern hemisphere, where it is threatened by the Plum pox virus (PPV), causing the sharka disease. The histories of apricot domestication and of its resistance to sharka are however still poorly understood. We used 18 microsatellite markers to genotype a collection of 230 wild trees from Central Asia and 142 cultivated apricots as representatives of the worldwide cultivated apricot germplasm; we also performed experimental PPV inoculation tests. The genetic markers revealed highest levels of diversity in Central Asian and Chinese wild and cultivated apricots, confirming an origin in this region. In cultivated apricots, Chinese accessions were differentiated from more Western accessions, while cultivated apricots were differentiated from wild apricots. An approximate Bayesian approach indicated that apricots likely underwent two independent domestication events, with bottlenecks, from the same wild population. Central Asian native apricots exhibited genetic subdivision and high frequency of resistance to sharka. Altogether, our results contribute to the understanding of the domestication history of cultivated apricot and point to valuable genetic diversity in the extant genetic resources of wild apricots.

The complex evolutionary history of apricots: Species divergence, gene flow and multiple domestication events

“…Morphological evidence supported the view that the cultivated apricot has been domesticated in Central Asia (Vavilov, , ), followed by subsequent diffusion toward the Caucasus (Kostina, ) and Europe (Bourguiba et al, ), along the trade routes. Genetic data combined with coalescent‐based simulations (approximate Bayesian computation) further supported this hypothesis and detected weak bottlenecks in cultivated apricots (Decroocq et al, ). Vavilov () also suggested a second origin for apricot domestication in China based on morphological observations.…”

“…As a consequence, many important traits, such as resistance to major crop pests or diseases, may be lacking in the cultivated germplasm while present in wild relatives. This is the case for the resistance to sharka in apricot, to mildew in grape or to apple scab in apple (Belfanti et al, ; Decroocq et al, ; Riaz et al, ). The potential contribution of wild relatives for crop improvement has long been recognized and today forms an important component of breeding and conservation programs for most cultivated species in the face of emerging diseases and climate changes (Kovach & McCouch, ; McCouch et al, ; Tanksley & McCouch, ; Zhang, Mittal, Leamy, Barazani, & Song, ).…”

“…Apricot, Prunus armeniaca L., is an emblematic fruit tree species that includes both the domesticated form, cultivated worldwide, and the wild form endemic to the Tian Shan Mountains in Central Asia (Decroocq et al, ). Apricot has recently become an attractive model species for studying fruit tree evolution because of the naturally occurring populations displaying substantial genetic and phenotypic diversities, especially regarding resistance to sharka disease (Decroocq et al, ).…”

“…Apricot, Prunus armeniaca L., is an emblematic fruit tree species that includes both the domesticated form, cultivated worldwide, and the wild form endemic to the Tian Shan Mountains in Central Asia (Decroocq et al, ). Apricot has recently become an attractive model species for studying fruit tree evolution because of the naturally occurring populations displaying substantial genetic and phenotypic diversities, especially regarding resistance to sharka disease (Decroocq et al, ). Morphological evidence supported the view that the cultivated apricot has been domesticated in Central Asia (Vavilov, , ), followed by subsequent diffusion toward the Caucasus (Kostina, ) and Europe (Bourguiba et al, ), along the trade routes.…”

Genetic Apricot Resources and their Utilisation in Breeding

“…The genetic markers confirmed highest levels of diversity in both wild and cultivated apricots in their original areas (Central Asia, China). Furthermore, high frequency of resistance to Sharka was detected in apricots native to Central Asia [36].…”