De novo Genome Assembly of Sweet Chestnut (Castanea sativa Mill.) Insights into the Molecular Basis of its Nutritional Properties

Abstract

The Sweet Chestnut (Castanea sativa Mill.) is a tree species that holds significant economic importance and naturally spreads throughout central-southern Europe and Asia Minor. Its highly nutritious nuts have a unique composition that sets them apart from other nuts, being rich in vitamins, including vitamin C, and B vitamins such as thiamine, niacin, and folate. Over the last few decades, breeding efforts have prioritized the development of sweet chestnut cultivars that are resistant to blight and produce better nuts. However, despite these efforts, molecular genetic studies of the sweet chestnut have been insufficient. To bridge this knowledge gap, we set out to create the first reference genome of the sweet chestnut using whole-genome shotgun paired-end sequencing. Our study involved genome-wide analyses to identify and functionally annotate genes in sweet chestnut, and develop and confirm SSR-SNP markers. Additionally, we have identified and characterized specific genomic loci that enhance the nutritional value of sweet chestnuts. To the best of our knowledge, this is the first study to investigate the genetic loci responsible for determining the nutritional value of chestnuts. We anticipate that our findings will significantly contribute to the development of sweet chestnut cultivars with higher levels of bioactive compounds, minerals, and digestibility, ultimately enhancing the nutritional value of chestnuts.