Recent Advances in Molecular Improvement for Potato Tuber Traits

Abstract

Potato is an important crop due to its nutritional value and high yield potential. Improving the quality and quantity of tubers remains one of the most important breeding objectives. Genetic mapping helps to identify suitable markers for use in the molecular breeding, and combined with transgenic approaches provides an efficient way for gaining desirable traits. The advanced plant breeding tools and molecular techniques, e.g., TALENS, CRISPR-Cas9, RNAi, and cisgenesis, have been successfully used to improve the yield and nutritional value of potatoes in an increasing world population scenario. The emerging methods like genome editing tools can avoid incorporating transgene to keep the food more secure. Multiple success cases have been documented in genome editing literature. Recent advances in potato breeding and transgenic approaches to improve tuber quality and quantity have been summarized in this review.

Keywords: CRISPR; QTL mapping; RNAi; genome selection; plant breeding tools.

Figure 1

A schematic flow diagram of genome-assisted breeding. ① A core collection of S. tuberosum germplasm exhibits the trait of interest and wide genetic diversity. ②/③ After genetic resource selection, a trait-based phenotyping assessment is performed, followed by genotyping of selected populations. ④ Genotype-phenotype linkage is detected through various techniques. ⑤ The breeding program results in the development of improved potato varieties.

Figure 2

An overview of agrobacterium-mediated gene transformation in plants. ① Ti-Plasmid isolation from parent cell (Agrobacterium tumefaciens). ② Digestion of the plasmid with specific endonucleases enzymes. ③ Ligation of foreign DNA into the plasmid. ④ Insertion of recombinant-plasmid into the bacterium and its incorporation into plant’s cell nuclear DNA after infection. ⑤ Growth of transgenic plant tissues artificially. ⑥ Development of transgenic potato grown in a field.

Figure 3

Overview of CRISPR-Cas9 mediated gene editing. ① A complex of CRISPR-Cas9 genetic scissors and artificially constructed single guide RNA (sgRNA) scans DNA and traces code where a cut has to be made. ② Formation of non-homologous end-joining (NHEJ) and homology direct repair (HDR) strands after DNA double-strand break (DSB). ③ Ligation of the DNA DSB by nucleotides addition on the right and deletion on the left result in gene disruption. ④ Repairing the DSB in HDR by employing an externally provided homologous DNA template for copying. The donor template’s DNA sequence is duplicated at the targeted site, which results in a guided repair.