Differential DNA methylation in the Vinv promoter region controls Cold Induced Sweetening in potato
Control of potato sprouting is important to ensure constant supply of high-quality potato to the industry. Efficient control of sprouting can be achieved by chemical treatment or cold temperature. Recent bans on anti-sprouting molecules are prompting the use of cold storage in the potato value chain. Unfortunately, storage of potato at low temperatures is associated with cold induced sweetening (CIS) due to the induction of the vacuolar invertase gene under low temperatures. Because CIS is associated with the production of the potentially carcinogenic acrylamide in processed potatoes, concise knowledge on the regulatory mechanisms controlling the CIS-phenotype in potatoes is expected to help pave the way for the production of CIS-resistant potato varieties. Here, we dissect the promoters of the Vacuolar invertase (Vinv) genes from CIS-susceptible and CIS-resistant varieties to investigate their implication in CIS-phenotype determination. Using bisulfite sequencing and CRISPR-dCas9-DRM2-mediated de novo DNA methylation, we show that the CIS-resistant phenotype of Verdi, is in part due to hypermethylation of its Vinv promoter, more specifically in the 1.0-1.7kb region. Those findings open new perspectives to engineer CIS-resistant potatoes by genome and epigenome modifications.