Genome-editing has revolutionized biology. When coupled with a recently streamlined regulatory process by the U.S. Department of Agriculture and the potential to generate transgene-free varieties, genome-editing provides a new avenue for crop improvement. For heterozygous, polyploid and vegetatively propagated crops such as cultivated potato, Solanum tuberosum Group Tuberosum L., genome-editing presents tremendous opportunities for trait improvement. In potato, traits such as improved resistance to cold-induced sweetening, processing efficiency, herbicide tolerance, modified starch quality and self-incompatibility have been targeted utilizing CRISPR/Cas9 and TALEN reagents in diploid and tetraploid clones. However, limited progress has been made in other such crops including sweetpotato, strawberry, grapes, citrus, banana etc., In this review we summarize the developments in genome-editing platforms, delivery mechanisms applicable to plants and then discuss the recent developments in regulation of genome-edited crops in the United States and The European Union. Next, we provide insight into the challenges of genome-editing in clonally propagated polyploid crops, their current status for trait improvement with future prospects focused on potato, a global food security crop.
The third most important food crop worldwide, potato (Solanum tuberosum L.) is a tetraploid outcrossing species propagated from tubers. Breeders have long been challenged by polyploidy, heterozygosity, and asexual reproduction. It has been assumed that tetraploidy is essential for high yield, that the creation of inbred potato is not feasible, and that propagation by seed tubers is ideal. In this paper, we question those assumptions and propose to convert potato into a diploid inbred line-based crop propagated by true seed. Although a conversion of this magnitude is unprecedented, the possible genetic gains from a breeding system based on inbred lines and the seed production benefits from a sexual propagation system are too large to ignore. We call on leaders of public and private organizations to come together to explore the feasibility of this radical and exciting new strategy in potato breeding. ; Public domain authored by a U.S. government employee
The genome of potato, a major global food crop, was recently sequenced. The work presented here details the integration of the potato reference genome (DM) with a new sequence-tagged site marker-based linkage map and other physical and genetic maps of potato and the closely related species tomato. Primary anchoring of the DM genome assembly was accomplished by the use of a diploid segregating population, which was genotyped with several types of molecular genetic markers to construct a new similar to 936 cM linkage map comprising 2469 marker loci. In silico anchoring approaches used genetic and physical maps from the diploid potato genotype RH89-039-16 (RH) and tomato. This combined approach has allowed 951 superscaffolds to be ordered into pseudomolecules corresponding to the 12 potato chromosomes. These pseudomolecules represent 674 Mb (similar to 93%) of the 723 Mb genome assembly and 37,482 (similar to 96%) of the 39,031 predicted genes. The superscaffold order and orientation within the pseudomolecules are closely collinear with independently constructed high density linkage maps. Comparisons between marker distribution and physical location reveal regions of greater and lesser recombination, as well as regions exhibiting significant segregation distortion. The work presented here has led to a greatly improved ordering of the potato reference genome superscaffolds into chromosomal pseudomolecules. ; Potato Genome Sequencing grant, UK; Scottish Government Rural and Environmental Science and Analytical Services Division (RESAS); Department for Environment, Food and Rural Affairs (DEFRA)Department for Environment, Food & Rural Affairs (DEFRA); Agriculture and Horticulture Development Board (AHDB)-Potato Council; Biotechnology and Biological Sciences Research Council (BBSRC)Biotechnology and Biological Sciences Research Council (BBSRC) [BB/F012640]; New Zealand Institute for Crop & Food Research Ltd Strategic Science Initiative; New Zealand Institute for Plant & Food Research Ltd Capability Fund, New Zealand; NMEA (Netherlands Ministry of Economic Affairs); CBSG (Centre for BioSystems Genomics); STW (Netherlands Technology Foundation), The Netherlands [07796]; Teagasc Core Funding; DAFF-Research Stimulus Fund, Ireland; International Potato Center (CIP-CGIAR)/CRP RTB, Peru; CONICYTComision Nacional de Investigacion Cientifica y Tecnologica (CONICYT) [Fondap 1509007, PBCT-PSD-03]; CONICYT (Basal CMM); CIRIC INRIA; INIA-Ministry of Agriculture of Chile, Chile; FEMCIDI OEA [PE/09/02 MINCyT-CONCyTEC]; Instituto Nacional de Tecnologia Agropecuaria (INTA-Core Funds); Ministerio de Ciencia y Tecnologia (MINCyT), Argentina; Proyecto FEMCIDI-OEA [SEDI/AE-305 /09]; Proyecto Bilateral Argentina, Per; FINCyT [099-FINCyT-EQUIP-2009) / (076-FINCyT-PIN-2008)]; Prestamo BID [1663/OC-PE]; Instituto Nacional de Innovacion Agraria, Ministry of Agriculture of Peru; Peruvian Ministry of Agriculture, Technical Secretariat of coordination; CGIAR; Consejo Nacional de Ciencia, Tecnologia e Innovacion Tecnologica, Peru (CONCYTEC); Special Multilateral Fund of the Inter-American Council for Integral Development (FEMCIDI-Peru); Biotechnology and Biological Sciences Research CouncilBiotechnology and Biological Sciences Research Council (BBSRC) [BB/F012640/1] ; We thank Andrzej Kilian (Diversity Arrays Technology, Australia) for DArT genotyping of the DMDD mapping population. We acknowledge Peter E. Hedley and Clare Booth (The James Hutton Institute, UK) for help with SNP genotyping. We thank S. B. Divito (Instituto Nacional de Tecnologia Agropecuaria, Balcarce, Argentina) for technical assistance. We are also grateful to Luke Ramsay and Peter E. Hedley (The James Hutton Institute, UK) for comments on the manuscript. AFLP and WGP are (registered) trademarks owned by KeyGene N.V. We acknowledge the funding made available by the Potato Genome Sequencing grant, UK [Scottish Government Rural and Environmental Science and Analytical Services Division (RESAS), Department for Environment, Food and Rural Affairs (DEFRA), Agriculture and Horticulture Development Board (AHDB)-Potato Council, Biotechnology and Biological Sciences Research Council (BBSRC, Grant BB/F012640)]; New Zealand Institute for Crop & Food Research Ltd Strategic Science Initiative and the New Zealand Institute for Plant & Food Research Ltd Capability Fund, New Zealand; NMEA (Netherlands Ministry of Economic Affairs), CBSG (Centre for BioSystems Genomics), STW (Netherlands Technology Foundation grant 07796), The Netherlands; Teagasc Core Funding, DAFF-Research Stimulus Fund, Ireland; International Potato Center (CIP-CGIAR)/CRP RTB, Peru; CONICYT (Fondap 1509007, Basal CMM, PBCT-PSD-03), CIRIC INRIA, INIA-Ministry of Agriculture of Chile, Chile; FEMCIDI OEA, PE/09/02 MINCyT-CONCyTEC, 2010-2011, Instituto Nacional de Tecnologia Agropecuaria (INTA-Core Funds) and Ministerio de Ciencia y Tecnologia (MINCyT), Argentina; Proyecto FEMCIDI-OEA SEDI/AE-305 /09 (2008-2012), Proyecto Bilateral Argentina, Per; FINCyT (099-FINCyT-EQUIP-2009) / (076-FINCyT-PIN-2008), Prestamo BID no. 1663/OC-PE, Instituto Nacional de Innovacion Agraria, Ministry of Agriculture of Peru, Peruvian Ministry of Agriculture, Technical Secretariat of coordination with the CGIAR, Consejo Nacional de Ciencia, Tecnologia e Innovacion Tecnologica, Peru (CONCYTEC), Special Multilateral Fund of the Inter-American Council for Integral Development (FEMCIDI-Peru).
