A recent study led by Salomé Prat, a CSIC researcher at the Centre for Research in Agricultural Genomics (CRAG) in Barcelona, Spain, revealed groundbreaking findings on the role of the StCDF1 gene in nitrogen use efficiency in potatoes. The study was published in New Phytologist.
The study, conducted in collaboration with Christian Bachem’s group at the University of Wageningen (WUR), broadens the understanding of the StCDF1 gene, which was previously known primarily as a key regulator of day-length-dependent tuberization, according to a press release. Tuber formation is an adaptive strategy of potato plants for winter survival and is triggered by shorter day lengths and cooler temperatures perceived by the plant as the approach of winter.
In wild potatoes, tuber formation is strictly regulated by short days. However, modern cultivars possess mutations in a locus known as “earliness,” which allows them to bypass this strict control. This adaptation occurred after potatoes were introduced to Europe, leading to the development of early-maturing varieties that carry one or more copies of these alleles. These naturally occurring mutations enhance the stability of the StCDF1 factor, a key regulator in the day-length pathway that modulates the expression of SP6A, a member of the FLOWERING LOCUS T family and a primary signal for tuberization.
The study found that the StCDF1 gene not only regulates tuberization but also controls the expression of genes involved in nitrogen assimilation and transport in potatoes. Researchers discovered that StCDF1 binds to the promoter region of Nitrate Reductase (StNR), an enzyme crucial for nitrate reduction. Potatoes have a single copy of the StNR gene, which contributes to their efficient nitrate utilization. Silencing StCDF1 in potato plants led to improved nitrogen use, as the repression of StNR was lifted, allowing for greater expression of the enzyme. The study also identified genetic variations in the StNR regulatory region, suggesting early potato cultivars evolved to adapt to StCDF1 stabilization, enhancing nitrogen assimilation.
Prat highlighted the significance of these findings, stating, “The novelty of our research lies in uncovering StCDF1’s dual role in regulating both tuberization and the nitrogen assimilation pathways. This insight reveals new genetic and molecular targets for enhancing nitrogen utilization in potatoes.”
The releases notes that “the implications of this research are profound, contributing to the broader goal of sustainable agriculture. The study provides molecular targets that can be used for breeding climate-smart potato varieties requiring less nitrate inputs for high tuber production. Breeders could leverage this knowledge to develop potato varieties less dependent on chemical fertilizers.”
