Summary: Potato (Solanum tuberosum L.) originated in the Andes and evolved its vegetative propagation strategy through short day‐dependent tuber development. Herein, we present a high‐quality, chromosome‐scale reference genome sequence of a tetraploid potato cultivar. The total length of this genome assembly was 2.67 Gb, with scaffold N50 and contig N50 sizes of 46.24 and 2.19 Mb, respectively. In total, 1.69 Gb repetitive sequences were obtained through de novo annotation, and long terminal repeats were the main transposable elements. A total of 126 070 protein‐coding genes were annotated, of which 125 077 (99.21%) were located on chromosomes. The 48 chromosomes were classified into four haplotypes. We annotated 31 506 homologous genes, including 5913 (18.77%) genes with four homologues, 11 103 (35.24%) with three homologues, 12 177 (38.65%) with two homologues and 2313 (7.34%) with one homologue. MLH3, MSH6/7 and RFC3, which are the genes involved in the mismatch repair pathway, were found to be significantly expanded in the tetraploid potato genome relative to the diploid potato genome. Genome‐wide association analysis revealed that cytochrome P450, flavonoid synthesis, chalcone enzyme, glycosyl hydrolase and glycosyl transferase genes were significantly correlated with the flesh colours of potato tuber in 150 tetraploid potatoes. This study provides valuable insights into the highly heterozygous autotetraploid potato genome and may facilitate the development of tools for potato cultivar breeding and further studies on autotetraploid crops.
Steroidal glycoalkaloids (SGAs) existing in most potato tissues are toxic to humans when the fresh weight is over 200 mg kg−1, and high SGAs content would also damage the quality of potato tubers. Sterol side chain reductase 2 (StSSR2) is a key enzyme in the biosynthetic of SGAs in potatoes. To reduce the concentration of SGAs in tetraploid cultivated potato (Solanum tuberosum L.), the gene StSSR2 was edited by the CRISPR/Cas9 system. A total number of 64 mutant lines were generated, and the mutation efficiency was 46%. The percentage of insertion was 6.25%, and the percentage of deletion was 93.75%. Compared to the wild-type (WT), the content of SGAs reduced significantly in the mutated potatoes. The lowest SGAs concentration was 54% of the WT level, which was recorded in the peels of line #360. In the tuber fleshes, the lowest SGAs were 66% of WT level, which was found in line #378. In the leaves, the lowest SGAs concentration was 44% of the WT level as found in lines #204 and #378. In a word, our results showed that the StSSR2 gene of tetraploid cultivated potato could be successfully edited by the CRISPR/Cas9 system to reduce toxic SGAs.
7 January 2019 in American Journal of Potato Research
Background: Nitrogen (N) is a major element and fundamental constituent of grain yield. N fertilizer plays an essential role in the roots, shoots, and leaves of crop plants. Here, we obtained two N-sensitive potato cultivars. Results: The plants were cultivated in the pots using N-deficient and N-sufficient conditions. Crop height, leaf chlorophyll content, dry matter, and N-accumulation significantly decreased under N-deficient conditions. Furthermore, we performed a comprehensive analysis of the phenotype and transcriptome, GO terms, and KEGG pathways. We used WGCNA of co-expressed genes, and 116 differentially expressed hub genes involved in photosynthesis, nitrogen metabolism, and secondary metabolites to generate 23 modules. Among those modules, six NRT gene families, four pigment genes, two auxin-related genes, and two energy-related genes were selected for qRT-PCR validation. Conclusions: Overall, our study demonstrates the co-expressed genes and potential pathways associated with N transport and accumulation in potato cultivars’ roots, shoots, and leaves under N-deficient conditions. Therefore, this study provides new ideas to conduct further research on improving nitrogen use efficiency in potatoes.
With the intensifying global warming trend, extreme heat and drought are becoming more frequent, seriously impacting potato yield and quality. To maintain sustainable potato production, it is necessary to breed new potato varieties that are adaptable to environmental changes and tolerant to adversity. Despite its importance, there is a significant gap in research focused on the potential mechanisms of potato resistance to abiotic stresses like drought and high temperatures. This article provides a comprehensive review of the recent research available in academic databases according to subject keywords about potato drought tolerance and high temperature tolerance with a view to providing an important theoretical basis for the study of potato stress mechanism and the selection and breeding of potato varieties with drought and high-temperature resistance. The suitable relative soil moisture content for potato growth and development is 55% to 85%, and the suitable temperature is 15 °C to 25 °C. The growth and development of potato plants under drought and high-temperature stress conditions are inhibited, and plant morphology is altered, which affects the process of potato stolon formation, tuberization and expansion, ultimately leading to a significant reduction in potato tuber yields and a remarkable degradation of the market grade of tubers, the specific gravity of tubers, and the processing quality of tubers. In addition, stress also adversely affects potato physiological and biochemical characteristics, such as reduction in root diameter and leaf area, decrease in net photosynthetic rate of leaves, production of reactive oxygen species (ROS), and increase in membrane lipid peroxidation. In addition, various types of genes and transcription factors are involved in the response to drought and heat at the molecular level in potato. This paper illustrates the effects of stress on potato growth and development and the molecular mechanisms of potato response to adversity in detail, which is intended to reduce the damage caused by drought and high temperature to potato in the context of global warming and frequent occurrence of extreme weather to ensure potato yield and quality and to further safeguard food security.
Spatial metabolomics, as a frontier technology, is capable of conducting the comprehensive characterization of metabolites within organisms in terms of qualitative, quantitative and positional dimensions, so as to facilitate the visual analysis of biological processes. This paper summarizes the birth and development of spatial metabolomics, explains its differences and advantages from traditional metabolomics and summarizes its application in plant research. In addition, the limitations of spatial metabolomics are summarized and discussed, along with the technological improvement and application innovation of spatial metabolomics, in order to provide reference for the development strategy of spatial metabolomics and its application in plant research.