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Glutathione peroxidase-like enzyme is an important enzymatic antioxidant in plants. It is involved in scavenging reactive oxygen species, which can effectively prevent oxidative damage and improve resistance. GPXL has been studied in many plants but has not been reported in potatoes, the world's fourth-largest food crop. This study identified eight StGPXL genes in potatoes for the first time through genome-wide bioinformatics analysis and further studied the expression patterns of these genes using qRT-PCR. The results showed that the expression of StGPXL1 was significantly upregulated under high-temperature stress, indicating its involvement in potato defense against high-temperature stress, while the expression levels of StGPXL4 and StGPXL5 were significantly downregulated. The expression of StGPXL1, StGPXL2, StGPXL3, and StGPXL6 was significantly upregulated under drought stress, indicating their involvement in potato defense against drought stress. After MeJA hormone treatment, the expression level of StGPXL6 was significantly upregulated, indicating its involvement in the chemical defense mechanism of potatoes. The expression of all StGPXL genes is inhibited under biotic stress, which indicates that GPXL is a multifunctional gene family, which may endow plants with resistance to various stresses. This study will help deepen the understanding of the function of the potato GPXL gene family, provide comprehensive information for the further analysis of the molecular function of the potato GPXL gene family as well as a theoretical basis for potato molecular breeding.

MicroRNAs are small, non-coding RNAs that are responsible for regulation of gene expression during plant growth and development. Although there are many studies on miRNAs in other plants, little work has been done to understand the role of miRNAs in abiotic stress tolerance in potatoes. This study investigates changes in miRNA profiles of two different potato cultivars (tolerant, Unica and susceptible, Russet Burbank) in response to heat, drought and their combination. Transcriptomic studies revealed that miRNA profiles depend on the susceptibility and tolerance of the cultivar and also the stress conditions. Large number of miRNAs were expressed in Unica, whereas Russet Burbank indicated lesser number of changes in miRNA expression. Physiological and transcriptional results clearly supported that Unica cultivar is tolerant to combined drought and heat stress compared to Russet Burbank. Moreover, psRNATarget analysis predicted that major miRNAs identified were targeting genes playing important roles in response to drought and heat stress and their important roles in genetic and post-transcriptional regulation, root development, auxin responses and embryogenesis were also observed. This study focused on eight miRNAs (Novel_8, Novel_9, Novel_105, miR156d-3p, miR160a-5p, miR162a-3p, miR172b-3p and miR398a-5p) and their putative targets where results indicate that they may play a vital role at different post-transcriptional levels against drought and heat stresses. We suggest that miRNA overexpression in plants can lead to increased tolerance against abiotic stresses; furthermore, there should be more emphasis on the studies to investigate the role of miRNAs in combined abiotic stress in plants., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Fifty potato genotypes from twenty-four different countries of origin, four different flesh colours (yellow, purple, red and marble) and different cultivation types (Andean accessions, landraces, breeder lines and cultivated varieties) were studied in terms of their nutritional and physicochemical characteristics. In general, cultivated varieties and breeder lines showed the highest similarity (slight differences only in some particular fatty acids distributions: C10:0, C12:0 and C22:0) concerning the physicochemical parameters assayed in this work, independently of the geographical origin or tuber flesh colour of these genotypes. Nonetheless, some of the studied landraces and Andean accessions proved to be similar enough to be considered as genotypes with good potential for commercial cultivation. These results can contribute to the supply of new potato genotypes into sustainable farming systems, supporting the protection of potato biodiversity, particularly Andean accessions, landraces and coloured genotypes (red or purple flesh) which are not widely cultivated so far., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Certain changes in phenolics and sugars can occur during the storage of potatoes, where particularly amounts of sugars represent the critical factor as they are involved in potentially harmful acrylamide (AA) formation during frying. This research investigates the impact of cultivars (Birgit and Lady Claire), tuber's age (1, 5, and 9 months), and storage duration (1, 5, and 8 days at 10 °C) on the content of phenolics and sugars in raw, boiled, and fried fresh-cut potato (FCP). The influence of these factors on the formation of AA in fried FCP was also assessed. Significant differences in phenolics and sugars were observed between cultivars (cv. Birgit contained 5.77 mg of phenolics 100 g -1 of dry weight (DW) and 1.75 g of sugars 100 g -1 DW, while cv. Lady Claire contained 10.13 mg of phenolics 100 g -1 DW and 0.65 g of sugars 100 g -1 DW). The content of phenolics significantly decreased, while sugars increased during tubers' aging. FCP storage time had no significant influence on the content of phenolics and sugars. The phenolics and sugars were the highest in the raw samples and the lowest in the boiled ones. Although the AA level in fried samples was significantly influenced by cultivar (Birgit > Lady Claire) and it increased with FCP storage time, it was below European Food Safety Authority (EFSA) regulation's approved maximum value (750 µg kg -1 FW) in both cultivars. Therefore, cvs. Birgit and Lady Claire could be considered as promising FCP cultivars and for frying purposes. PRACTICAL APPLICATION: The results of this research reveal that quantitative changes of chemical constituents occurring during storage and cooking of fresh-cut slices of potato cultivars Birgit and Lady Claire are not a concern. This is of particular importance to fresh-cut producers and customers. Phenolics were reduced during storage, but they were still present in all cooked samples independently of the cooking method. The analysis of sugars showed that tubers as old as 9 months could be used for fresh-cut potato processing, providing safe frying without critical levels of acrylamide., (© 2021 Institute of Food Technologists®.)

Potato starch is one of the most important renewable sources for industrial manufacturing of organic compounds. Currently, it is produced from mixed potato varieties that often are harvested from different fields. Meanwhile, tuber starches of various potato breeds differ in their crystallinity, granule morphology, and other physical and chemical parameters. We studied the reactions of raw potato starches of different origins to chemical and biochemical reactions typically used for industrial starch modification. The results clearly demonstrate that there is a significant difference in the reactivity of the starches of different potato genotypes. While the main products of the transformations are the same, their preparative yields differ significantly. Thus, tuber starch of certain potato varieties may be more suitable for specific industrial purposes. Starch reactivity may potentially be a phenotypical trait for potato breeding to obtain potato starches for various industrial applications.

The basic region-leucine zipper (bZIP) transcription factors (TFs) form homodimers and heterodimers via the coil-coil region. The bZIP dimerization network influences gene expression across plant development and in response to a range of environmental stresses. The recent release of the most comprehensive potato reference genome was used to identify 80 StbZIP genes and to characterize their gene structure, phylogenetic relationships, and gene expression profiles. The StbZIP genes have undergone 22 segmental and one tandem duplication events. Ka/Ks analysis suggested that most duplications experienced purifying selection. Amino acid sequence alignments and phylogenetic comparisons made with the Arabidopsis bZIP family were used to assign the StbZIP genes to functional groups based on the Arabidopsis orthologs. The patterns of introns and exons were conserved within the assigned functional groups which are supportive of the phylogeny and evidence of a common progenitor. Inspection of the leucine repeat heptads within the bZIP domains identified a pattern of attractive pairs favoring homodimerization, and repulsive pairs favoring heterodimerization. These patterns of attractive and repulsive heptads were similar within each functional group for Arabidopsis and S. tuberosum orthologs. High-throughput RNA-seq data indicated the most highly expressed and repressed genes that might play significant roles in tissue growth and development, abiotic stress response, and response to pathogens including Potato virus X . These data provide useful information for further functional analysis of the StbZIP gene family and their potential applications in crop improvement.

Basic leucine zipper (bZIP) transcription factors play important roles in numerous growth and developmental processes. Potato (Solanum tuberosum L.) is a worldwide important vegetable crop; nevertheless, no systematic identification or functional analysis of the potato bZIP gene family has been reported. In this research, 65 potato bZIPs distributed on 12 potato chromosomes were identified. According to the topology of Arabidopsis and potato bZIP phylogenetic tree, the bZIPs were classified into thirteen groups, designated as A-K, M, and S, with no potato bZIPs included in groups J and M. The bZIPs from the same group shared a conserved exon-intron structure, intron phase, and motif composition. Eighteen potato bZIPs were involved in segmental duplications, and the duplicated gene pairs were under purifying selection. No tandemly duplicated potato bZIP was found. Each potato bZIP promoter contained at least one kind of stress-responsive or stress-related hormone-responsive element. RNA-seq and qRT-PCR analyses revealed different expression patterns of potato bZIPs under abiotic stresses. The overexpression of StbZIP-65 in Arabidopsis enhanced salt tolerance. The StbZIP-65 protein localized in the nucleus. β-Glucuronidase staining showed that promoter activity of StbZIP-65 was induced by exogenous methyl jasmonate. These results may aid in further functional studies of potato bZIP transcription factors., Competing Interests: Declaration of competing interest The authors declare that they have no conflict of interest., (Copyright © 2020. Published by Elsevier B.V.)

The chloroplasts are a crucial part of photosynthesizing plant cells and are extensively utilized in phylogenetic studies mainly due to their maternal inheritance. Characterization and analysis of complete plastome sequences is necessary to understand their diversity and evolutionary relationships. Here, a panel of thirteen plastomes from various potato taxa are presented. Though they are highly similar with respect to gene order and content, there is also a great extent of SNPs and InDels between them, with one of the Solanum bukasovii plastomes (BUK2) having the highest number of SNPs and InDels. Five different potato plastome types (C, S, A, W, W2) are present in the panel. Interestingly, the S. tuberosum subsp. tuberosum (TBR) accession has a W-type plastome, which is not commonly found in this species. The S-type plastome has a conserved 48 bp deletion not found in other types, which is responsible for the divergence of the S-type from the C-type plastome. Finally, a phylogenetic analysis shows that these plastomes cluster according to their types. Congruence between the nuclear genome and the plastome phylogeny of these accessions was seen, however with considerable differences, supporting the hypothesis of introgression and hybridization between potato species., Competing Interests: The authors have declared that no competing interests exist.

Understanding plant disease resistance is important in the integrated management of Phytophthora infestans, causal agent of potato late blight. Advanced field-based methods of disease detection that can identify infection before the onset of visual symptoms would improve management by greatly reducing disease potential and spread as well as improve both the financial and environmental sustainability of potato farms. In-vivo foliar spectroscopy offers the capacity to rapidly and non-destructively characterize plant physiological status, which can be used to detect the effects of necrotizing pathogens on plant condition prior to the appearance of visual symptoms. Here, we tested differences in spectral response of four potato cultivars, including two cultivars with a shared genotypic background except for a single copy of a resistance gene, to inoculation with Phytophthora infestans clonal lineage US-23 using three statistical approaches: random forest discrimination (RF), partial least squares discrimination analysis (PLS-DA), and normalized difference spectral index (NDSI). We find that cultivar, or plant genotype, has a significant impact on spectral reflectance of plants undergoing P. infestans infection. The spectral response of four potato cultivars to infection by Phytophthora infestans clonal lineage US-23 was highly variable, yet with important shared characteristics that facilitated discrimination. Early disease physiology was found to be variable across cultivars as well using non-destructively derived PLS-regression trait models. This work lays the foundation to better understand host-pathogen interactions across a variety of genotypic backgrounds, and establishes that host genotype has a significant impact on spectral reflectance, and hence on biochemical and physiological traits, of plants undergoing pathogen infection., Competing Interests: Declaration of Competing Interest The authors declare no competing interests., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Background: Polysaccharides have been expected to have a suppressive effect on starch digestibility by blending. The objective of this study was to investigate the effects of anionic (xanthan gum), neutral (guar gum), and cationic (chitosan) polysaccharides on the in vitro digestibility of raw and gelatinized starch using six potato cultivars differing in phosphorus content., Results: By comparing the starch digestibility between potato cultivars, a significant difference was observed for the raw starches, and 'Benimaru', which is a potato cultivar containing a higher proportion of short-chain amylopectin and the lowest phosphorus content in starch, showed a distinctly faster rate of starch hydrolysis. The added polysaccharides decreased the extent of digestion of both raw and gelatinized starches. No significant correlation between phosphorus content and the extent of starch digestion was observed in mixed systems, whereas significant correlations were noted between the extent of starch digestion and Rapid Visco Analyser parameters. The extent of raw and gelatinized starch digestion negatively correlated with pasting temperature, initial viscosity before heating, and peak viscosity (P < 0.01)., Conclusion: The added polysaccharides were observed to decrease the starch digestibility, and their suppressive effects were mainly dependent on the increase of viscosity rather than chemical interactions. A combination of potato cultivar and type of polysaccharide was proved to be important for nutritional value of potato starch. © 2020 Society of Chemical Industry., (© 2020 Society of Chemical Industry.)

A conversion of amyloplasts into chloroplasts in the potato tuber after light exposure is known as tuber greening and is one of the major causes of tuber loss. We report here the first mapping of the factors affecting tuber greening in potato. We used an F1 mapping population of diploid potatoes and DArTseq™ markers to construct a genetic map. The individuals of the mapping population, parents and standards were phenotyped for two tuber greening parameters: external tuber greening and internal greening depth on 0-5 scales in three years 2015, 2016 and 2018. The results were used for the analysis of Quantitative Trait Loci (QTLs) by an interval QTL mapping. Two most important QTLs were covering large regions of chromosomes VII and X and had the strongest effect on both greening parameters in data sets obtained in particular years and in the mean data set. Variance observed in the mean tuber greening could be ascribed in 16.9% to the QTL on chromosome VII and in 23.4% to the QTL on chromosome X. The QTL on chromosome VII explained 13.1%, while the QTL on chromosome X explained up to 17.7% of the variance in the mean tuber greening depth. Additional, minor QTLs were year- and/or trait-specific. The QTLs on chromosomes VII and X determine big parts of the observed tuber greening variation and should be investigated further in order to identify the genes underlying their effects but also should be taken into account when selecting non-greening potato lines in the breeding process.

This study investigated the influence of factors that could affect the levels of 3-MCPD esters in French fries, including the cultivar, the type of frying oil, and the use of pre-treatments such as blanching and application of edible coatings. Under the selected experimental conditions of frying, the cultivar Agata, which presented the highest dry matter content, showed the lowest oil uptake and 3-MCPD esters concentrations. In relation to the frying medium, the use of oils containing higher levels of 3-MCPD esters resulted in a higher contamination of French fries. Blanching treatment of potatoes before frying increased up to 33% the concentrations of 3-MCPD esters. On the other hand, the levels of the contaminants decreased by 19% with the application of a pectin solution. It could be observed that factors affecting oil uptake in French fries may also affect the contamination by 3-MCPD esters and should be considered as possible mitigation strategies to minimize human exposure to these chemical contaminants., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

As an important nongrain crop, the growth and yield of potato ( Solanum tuberosum L.) is often affected by an unfavorable external environment in the process of cultivation. The MYB family is one of the largest and most important gene families, participating in the regulation of plant growth and development and response to abiotic stresses. Several MYB genes in potato that regulate anthocyanin synthesis and participate in abiotic stress responses have been identified. To identify all Solanum tuberosum L. MYB ( StMYB ) genes involved in hormone or stress responses to potentially regulate potato growth and development, we identified the MYB gene family at the genome-wide level. In this work, 158 StMYB genes were found in the potato genome. According to the amino acid sequence of the MYB domain and gene structure, the StMYB genes were divided into R2R3-MYB and R1R2R3-MYB families, and the R2R3-MYB family was divided into 20 subgroups (SGs). The expression of 21 StMYB genes from different SGs in roots, stems, leaves, flowers, shoots, stolons, young tubers, and mature tubers was determined by quantitative real-time polymerase chain reaction (qRT-PCR). The expression patterns of StMYB genes in potatoes treated with abscisic acid (ABA), indole-3-acetic acid (IAA), gibberellin acid 3 (GA3), NaCl, mannitol, and heat were also measured. We have identified several potential candidate genes that regulate the synthesis of potato flavonoids or participate in hormone or stress responses. This work provides a comprehensive understanding of the MYB family in potato and will lay a foundation for the future investigation of the potential functions of StMYB genes in the growth and development of potato.

One hundred eighty-two authentic potato samples ( Solanum tuberosum) of known variety were collected from various German regions in 2016 and 2017. Samples were extracted with a liquid-liquid-extraction protocol that included isopropanol, methanol, and water in order to focus on lipophilic metabolites. The analysis of nonpolar extracts was performed using an UPLC-IMS-QToF-MS system; data sets obtained were evaluated via multivariate data analysis. A selection of 14 key metabolites with a significant difference in their abundance profiles was identified. This set of markers contained four hydroxylated glucocerebrosides, two phosphoinositols, one phosphocholine, and seven acylated sterol glucosides based on stigmasterol and β-sitosterol, which primarily enable the varietal discrimination. Fragments and neutral losses commonly appearing within one class or subclass of lipids were summarized within a new database that included ion mobility data. The performance of the approach was verified with twenty-nine commercial potato samples.

Solanum tuberosum, commonly known as the potato, is a worldwide food staple. During harvest, storage, and distribution the crop is at risk of mechanical damage. Wounding of the tuber skin can also become a point of entry for bacterial and fungal pathogens, resulting in substantial agricultural losses. Building on the proposal that potato tubers produce metabolites to defend against microbial infection during early stages of wound healing before protective suberized periderm tissues have developed, we assessed extracts of wound tissues from four potato cultivars with differing skin morphologies (Norkotah Russet, Atlantic, Chipeta, and Yukon Gold). These assays were conducted at 0, 1, 2, 3 and 7 days post wounding against the plant pathogen Erwinia carotovora and a non-pathogenic Escherichia coli strain that served as a control. For each of the potato cultivars, only polar wound tissue extracts demonstrated antibacterial activity. The polar extracts from earlier wound-healing time points (days 0, 1 and 2) displayed notably higher antibacterial activity against both strains than the later wound-healing stages (days 3 and 7). These results support a burst of antibacterial activity at early time points. Parallel metabolite profiling of the extracts revealed differences in chemical composition at different wound-healing time points and allowed for identification of potential marker compounds according to healing stage for each of the cultivars. It was possible to monitor the transformations in the metabolite profiles that could account for the phenomenon of temporal resistance by looking at the relative quantities of various metabolite classes as a function of time., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Auxin response factors (ARFs) play central roles in conferring auxin-mediated responses through selection of target genes in plants. Despite their physiological importance, systematic analysis of ARF genes in potato have not been investigated yet. Our genome-wide analysis identified 20 StARF (Solanum tuberosum ARF) genes from potato and found that they are unevenly distributed in all the potato chromosomes except chromosome X. Sequence alignment and conserved motif analysis suggested the presence of all typical domains in all but StARF18c that lacks B3 DNA-binding domain. Phylogenetic analysis indicated that potato ARF could be clustered into 3 distinct subgroups, a result supported by exon-intron structure, consensus motifs, and domain architecture. In silico expression analysis and quantitative real-time PCR experiments revealed that several StARFs were expressed in tissue-specific, biotic/abiotic stress-responsive or hormone-inducible manners, which reflected their potential roles in plant growth, development or under various stress adaptions. Strikingly, most StARFs were identified as highly abiotic stress responsive, indicating that auxin signaling might be implicated in mediating environmental stress-adaptation responses. Taken together, this analysis provides molecular insights into StARF gene family, which paves the way to functional analysis of StARF members and will facilitate potato breeding programs.

Patatin is the major tuber storage protein constituted by multiple isoforms highly variable across potato ( S. tuberosum) varieties. Here, we report a first association study of the variability of patatin isoforms between cultivars with their differences in tuber quality traits. Patatin-based proteomic distances were assessed between 15 table and/or processing potato cultivars from profiles of patatin obtained by two-dimensional electrophoresis. The content of ash, dry matter, reducing sugars, starch, total protein, and amino acid composition was also evaluated in tubers of each cultivar. Results showed that proteomic distances were significantly ( P < 0.05) associated with differences in the content of ash, dry matter, and essential amino acids. Proteomic distances were also able to identify outlier cultivars regarding the content of dry matter, content of protein, and protein quality. In conclusion, patatin-based proteomic distances can shorten the screening and selection processes of potato cultivars with advantageous characteristics in molecular breeding.

Introduction: The native potatoes (Solanum tuberosum ssp. tuberosum L.) cultivated on Chiloé Island in southern Chile have great variability in terms of tuber shape, size, color and flavor. These traits have been preserved throughout generations due to the geographical position of Chiloé, as well as the different uses given by local farmers., Objectives: The present study aimed to investigate the diversity of metabolites in skin and pulp tissues of eleven native accessions of potatoes from Chile, and evaluate the metabolite associations between tuber tissues., Methods: For a deeper characterization of these accessions, we performed a comprehensive metabolic study in skin and pulp tissues of tubers, 3 months after harvesting. Specific targeted quantification of metabolites using 96 well microplates, and high-performance liquid chromatography combined with non-targeted metabolite profiling by gas chromatography time-of-flight mass spectrometry were used in this study., Results: We observed differential levels of antioxidant activity and phenolic compounds between skin and pulp compared to a common commercial cultivar (Desireé). In addition, we uncovered considerable metabolite variability between different tuber tissues and between native potatoes. Network correlation analysis revealed different metabolite associations among tuber tissues that indicate distinct associations between primary metabolite and anthocyanin levels, and antioxidant activity in skin and pulp tissues. Moreover, multivariate analysis lead to the grouping of native and commercial cultivars based on metabolites from both skin and pulp tissues., Conclusions: As well as providing important information to potato producers and breeding programs on the levels of health relevant phytochemicals and other abundant metabolites such as starch, proteins and amino acids, this study highlights the associations of different metabolites in tuber skins and pulp, indicating the need for distinct strategies for metabolic engineering in these tissues. Furthermore, this study shows that native Chilean potato accessions have great potential as a natural source of phytochemicals.

Breeders rely on genetic integrity of material from genebanks; however, admixture, mislabeling, and errors in original data can occur and be detrimental. Two hundred and fifty accessions, representing paired samples consisting of original mother plants and their in vitro counterparts from the cultivated potato collection at the International Potato Center (CIP) were fingerprinted using the Infinium 12K V2 Potato Array to confirm genetic identity of the accessions and evaluate genetic diversity of the potato collection. Diploid, triploid, and tetraploid accessions were included, representing seven cultivated potato taxa (based on Hawkes, 1990). Fingerprints between voucher mother plants maintained in the field and in vitro clones of the same accession were used to evaluate identity, relatedness, and ancestry using hierarchal clustering and model-based Bayesian admixture analyses. Generally, in vitro and field clones of the same accession grouped together; however, 11 (4.4%) accessions were mismatches genetically, and in some cases the SNP data revealed the identity of the mixed accession. SNP genotypes were used to assess genetic diversity and to evaluate inter- and intraspecific relationships along with determining population structure and hybrid origins. Phylogenetic analyses suggest that the triploids included in this study are genetically similar. Further, some genetic redundancies among individual accessions were also identified along with some putative misclassified accessions. Accessions generally clustered together based on taxonomic classification and ploidy level with some deviations. STRUCTURE analysis identified six populations with significant gene flow among the populations, as well as revealed hybrid taxa and accessions. Overall, the Infinium 12K V2 Potato Array proved useful in confirming identity and highlighting the diversity in this subset of the CIP collection, providing new insights into the accessions evaluated. This study provides a model for genetic identity of plant genetic resources collections as mistakes in conservation of these collections and in genebanks is a reality. For breeders and other users of these collections, confirmed identity is critical, as well as for quality management programs and to provide insights into the accessions evaluated.

Tobacco rattle virus (TRV) causes the economically important corky ring spot disease in potato. Chemical control is difficult due to the soilborne nature of the TRV-transmitting nematode vector, and identifying natural host resistance against TRV is considered to be the optimal control measure. The present study investigated the sensitivity of 63 cultivars representing all market types (evaluated at North Dakota and Washington over 2 years) for the incidence of TRV-induced tuber necrosis and severity. This article also investigates the cultivar-location interaction (using a mixed-effects model) for TRV-induced necrosis. TRV-induced tuber necrosis (P < 0.0001) and severity (P < 0.0001) were significantly different among cultivars evaluated separately in North Dakota and Washington trials. Mixed-effects model results of pooled data (North Dakota and Washington) demonstrated that the interaction of cultivar and location had a significant effect (P = 0.03) on TRV-induced necrosis. Based on the virus-induced tuber necrosis data from both years and locations, cultivars were categorized into sensitive, moderately sensitive, insensitive, and moderately insensitive groups. Based on data from North Dakota, 10 cultivars, including Bintje, Centennial Russet, Ciklamen, Gala, Lelah, Oneida Gold, POR06V12-3, Rio Colorado, Russian Banana, and Superior, were rated as insensitive to TRV-induced tuber necrosis. Similar trials assessing TRV sensitivity among cultivars conducted in Washington resulted in a number of differences in sensitivity rankings compared with North Dakota trials. A substantial shift in sensitivity of some potato cultivars to TRV-induced tuber necrosis was observed between the two locations. Four cultivars (Centennial Russet, Oneida Gold, Russian Banana, and Superior) ranked as insensitive for North Dakota trials were ranked as sensitive for Washington trials. These results can assist the potato industry in making cultivar choices to reduce the economic impact of TRV-induced tuber necrosis.

Glycoside Hydrolase 3 (GH3) is a phytohormone-responsive family of proteins found in many plant species. These proteins contribute to the biological activity of indolacetic acid (IAA), jasmonic acid (JA), and salicylic acid (SA). They also affect plant growth and developmental processes as well as some types of stress. In this study, GH3 genes were identified in 48 plant species, including algae, mosses, ferns, gymnosperms, and angiosperms. No GH3 representative protein was found in algae, but we identified 4 genes in mosses, 19 in ferns, 7 in gymnosperms, and several in angiosperms. The results showed that GH3 proteins are mainly present in seed plants. Phylogenetic analysis of all GH3 proteins showed three separate clades. Group I was related to JA adenylation, group II was related to IAA adenylation, and group III was separated from group II, but its function was not clear. The structure of the GH3 proteins indicated highly conserved sequences in the plant kingdom. The analysis of JA adenylation in relation to gene expression of GH3 in potato ( Solanum tuberosum ) showed that StGH3.12 greatly responded to methyl jasmonate (MeJA) treatment. The expression levels of StGH3.1 , StGH3.11 , and StGH3.12 were higher in the potato flowers, and StGH3.11 expression was also higher in the stolon. Our research revealed the evolution of the GH3 family, which is useful for studying the precise function of GH3 proteins related to JA adenylation in S. tuberosum when the plants are developing and under biotic stress.

The reported narrow genetic base of cultivated potato (Solanum tuberosum) can be expanded by the introgression of many related species with large genetic diversity. The analysis of the genetic structure of a potato population is important to broaden the genetic base of breeding programs by the identification of different genetic pools. A panel composed by 231 diverse genotypes was characterized using single nucleotide polymorphism (SNP) markers of the Illumina Infinium Potato SNP Array V2 to identify population structure and assess genetic diversity using discriminant analysis of principal components (DAPC) and pedigree analysis. Results revealed the presence of five clusters within the populations differentiated principally by ploidy, taxonomy, origin and breeding program. The information obtained in this work could be readily used as a guide for parental introduction in new breeding programs that want to maximize variability by combination of contrasting variability sources such as those presented here.

Potato leaf roll virus (PLRV) can reduce tuber yield and quality in potato. Green peach aphid (Myzus persicae [Sulzer]) and potato aphid (Macrosiphum euphorbiae [Thomas]) are the two most important potato-colonizing PLRV vectors in the Pacific Northwest. We compared My. persicae and Ma. euphorbiae densities and PLRV incidences among potato varieties in the field to clarify the relationships between aphid abundance and PLRV incidence in plants. Aphids were sampled weekly over three years in the potato varieties Russet Burbank, Ranger Russet, and Russet Norkotah in a replicated field trial. In all years, My. persicae was more abundant than Ma. euphorbiae, representing at least 97% of samples. My. persicae densities did not differ among potato varieties across years; very low numbers of Ma. euphorbiae precluded such statistical comparisons for this species. PLRV infection did not differ significantly among potato varieties, although the percent of PLRV-infected plants differed among years when all varieties were combined (46% in 2013, 29% in 2011, 13% in 2012). For Ranger Russet and Russet Norkotah, PLRV incidence was positively correlated with aphid abundance as well as proportion of PLRV-positive aphids. In Russet Burbank, only aphid abundance was positively correlated with PLRV infection. Our results suggest that the three most commonly grown potato varieties in our region do not differ in their susceptibility to PLRV infection, and that aphid density was a consistent indicator of the risk of infection by this virus across varieties. Both of these findings can be used to hone PLRV monitoring and modeling efforts.

The potato (Solanum tuberosum L.) ranks third in worldwide consumption among food crops. Whereas disposal of potato peels poses significant challenges for the food industry, secondary metabolites in these tissues are also bioactive and essential to crop development. The diverse primary and secondary metabolites reported in whole tubers and wound-healing tissues prompted a comprehensive profiling study of native periderms from four cultivars with distinctive skin morphologies and commercial food uses. Polar and nonpolar soluble metabolites were extracted concurrently, analyzed chromatographically, and characterized with mass spectrometry; the corresponding solid interfacial polymeric residue was examined by solid-state 13 C NMR. In total, 112 secondary metabolites were found in the phellem tissues; multivariate analysis identified 10 polar and 30 nonpolar potential biomarkers that distinguish a single cultivar among Norkotah Russet, Atlantic, Chipeta, and Yukon Gold cultivars which have contrasting russeting features. Compositional trends are interpreted in the context of periderm protective function.

The potato (Solanum tuberosum L.) is the fourth most important crop food in the world and Colombia has one of the most important collections of potato germplasm in the world (the Colombian Central Collection-CCC). Little is known about its potential as a source of genetic diversity for molecular breeding programs. In this study, we analyzed 809 Andigenum group accessions from the CCC using 5968 SNPs to determine: 1) the genetic diversity and population structure of the Andigenum germplasm and 2) the usefulness of this collection to map qualitative traits across the potato genome. The genetic structure analysis based on principal components, cluster analyses, and Bayesian inference revealed that the CCC can be subdivided into two main groups associated with their ploidy level: Phureja (diploid) and Andigena (tetraploid). The Andigena population was more genetically diverse but less genetically substructured than the Phureja population (three vs. five subpopulations, respectively). The association mapping analysis of qualitative morphological data using 4666 SNPs showed 23 markers significantly associated with nine morphological traits. The present study showed that the CCC is a highly diverse germplasm collection genetically and phenotypically, useful to implement association mapping in order to identify genes related to traits of interest and to assist future potato genetic breeding programs.

Reported content and process stability of phenolics in potato products is inconsistent. Changes in phenolic content of select varieties through fresh and industrial preparation/reconstitution were assessed. Total chlorogenic acids (CQAs) ranged from 43 to 953mg/100g dw and were more concentrated in pigmented compared to white/yellow-fleshed potatoes. Anthocyanin (ANC) content ranged from 18.6 to 22.9mg/100g dw and were mainly present in the flesh of pigmented potatoes. Retention of phenolics through commercial processing ranged from 49 to 85% for pigmented varieties and 32-55% for white/yellow. CQA levels were reduced through processing but to a greater extent in white relative to pigmented potatoes. ANCs were well retained through industrial processing of pigmented potatoes (79-129%). Levels of CQA were significantly (p<0.05) lower in some industrially versus freshly processed products but not for all products. While some differences exist, overall, industrially processed potato products compare favorably to fresh preparation in levels and recovery of phenolics., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

A major bottleneck to introgressive hybridization is the lack of genome collinearity between the donor (alien) genome and the recipient crop genome. Structural differences between the homeologs may create unbalanced segregation of chromosomes or cause linkage drag. To assess large-scale collinearity between potato and two of its wild relatives (Solanum commersonii and Solanum chacoense), we used BAC-FISH mapping of sequences with known positions on the RH potato map. BAC probes could successfully be hybridized to the S. commersonii and S. chachoense pachytene chromosomes, confirming their correspondence with linkage groups in RH potato. Our study shows that the order of BAC signals is conserved. Distances between BAC signals were quantified and compared; some differences found suggest either small-scale rearrangements or reduction/amplification of repeats. We conclude that S. commersonii and S. chacoense are collinear with cultivated Solanum tuberosum on the whole chromosome scale, making these amenable species for efficient introgressive hybridization breeding.

Genomic analyses have shown that most genes in eukaryotic lineages belong to families. Gene families vary in terms of number of members, nucleotide similarity, gene integrity, expression, and function. Often, the members of gene families are arranged in clusters, which contribute to maintaining similarity among gene copies and also to generate duplicates through replication errors. Gene families offer us an opportunity to examine the forces involved in the evolution of the genomes and to study recombination events and genomic rearrangements. In this work, we focused on the evolution of two plant resistance gene families, Sw5 and Mi-1, and analyzed the completely sequenced nuclear genomes of potato and tomato. We first noticed that the potato genome carries larger resistance gene families than tomato, but all gene copies are pseudogenes. Second, phylogenetic analyses indicated that Sw5 and Mi-1 gene families had dissimilar evolutionary histories. In contrast to Sw5, Mi-1 homologues suffered repeated gene conversion events among the gene copies, particularly in the tomato genome.

Background: The isolation of unknown DNA sequences flanked by known sequences is an important task in the event-specific detection of GMOs. None of event-specific detection method was developed based on the junction sequence of an exogenous integrant in the transgenic potato AV43-6-G7., Results: The flanking sequence between the exogenous fragment and recombinant chromosome of this potato was successfully acquired through exogenous gene 5'-RACE. The event-specific primers and Taqman probe were designed to amplify fragments spanning the exogenous DNA and potato genomic DNA. The specific real-time PCR and digital PCR detection methods for AV43-6-G7 potato were established based on primers designed according to the flanking sequences. The detection limit of the qualitative PCR assay was 0.01 % for AV43-6-G7 potato in 100 ng of potato genomic DNA, corresponding to approximately 11.6 copies of the potato haploid genome. The ddPCR assays for Potato AV43-6-G7 achieved a limit of quantification of approximately 58 target copies, with RSD ≤ 25 %. The aLOQ of this system was approximately 1.2 copies., Conclusions: These results indicated that these event-specific methods would be useful for the identification of potato AV43-6-G7.

Resistant starch (RS) has unique digestive and absorptive properties which may provide health benefits. We conducted a study to determine the contributions of cultivar, cooking method and service temperature on the RS contents of potatoes (Solanum tuberosum L.). We hypothesized that the RS content would vary by variety, cooking method and service temperature. Potatoes of three common commercial varieties (Yukon Gold, Dark Red Norland, and Russet Burbank) were subjected to two methods of cooking (baking or boiling) and three service temperatures: hot (65°C), chilled (4°C) and reheated (4°C for 6d; reheated to 65°C) and analyzed the starch content by modification of a commercially available assay. Results showed that RS content (g/100g) varied by cooking method and service temperature but not variety. Baked potatoes had higher RS contents than boiled; chilled potatoes had more RS than either hot or reheated. These results may assist in dietary choices for reducing chronic disease risk., (Published by Elsevier Ltd.)

Furan, a typical food contaminant formed by heating process, is classified as a possible carcinogen to humans. Many factors lead to the formation of furan in food processing. In our present study, 3 potato varieties, white potato, sweet potato, and purple potato were selected to investigate the effect of thermal processing temperature and time on furan formation. The results showed that the formation of furan was highly correlated with frying temperature and time. Among the 3 potato varieties, sweet potato resulted in the highest furan concentration when fried at 200 °C for 5 min. In addition, the frying temperature and time also influenced the water activity and the color of the 3 kinds of potato slices, which had significant correlation with the formation of furan. Furan concentration decreased along with the increasing of water activity in the 3 potato varieties and the changes presented regression relationships. Meanwhile, there was an inverse correlation between furan content and color changes in the 3 potato varieties. The level of furan decreased as total color changes (ΔE) increased and the changes also presented regression relationships. These results could be used to estimate the possibility of furan formation in the 3 varieties of potato slices systems., (© 2016 Institute of Food Technologists®)

Invertase activity and processing attributes of three potato cultivars were studied to find the reason for deterioration of processing quality during their prolonged storage in commercial cold stores (4°C) as compared to elevated temperature storage (12 ± 0.5°C), with CIPC {Isopropyl-N-(3-Cholorophenyl) carbamate}. Lower storage temperature (4°C) tended to be more effective in increasing invertase activity of potato tubers than elevated temperature. Non-processing cultivar viz., Kufri Pukhraj resulted in accumulation of more invertase activity than relatively two processing cultivars. Kufri Chipsona-1 and Kufri Chipsona-3 at 12 ± 0.5°C possessed basal invertase activity ranging from 39.3 to 79.8 and 54.1 to 93.8 (pmoles hexose h⁻¹ g⁻¹ f.wt.) respectively, during two years. Total invertase activity at 4°C increased abruptly and remained high from 30 to 60 days of storage. The activity progressively reached 90.6 to 106.6 and 81.4 to 101.3 during both the years respectively, after 60 days of storage to that observed initially. Reducing sugar content increased from 23.3 to 105.7 and 389.0 to 1138.2 (mg 100g⁻¹ f.wt.) after 90 days of storage at 12 ± 0.5°C and 4°C, respectively. Studies concluded that basal and total invertase, were responsible for cold-induced sweetening and resulted in deterioration of processing quality of potatoes during storage at 4°C. Since this activity is low at 12 ± 0.5°C, the processing traits remained acceptable to industry and consumers.

Background: The commercial potato cultivars are diverse not only in their physical characteristics but also in their nutritional compositions and their content of functional compounds (resistant starch, total phenolic content and antioxidant activity), but there is little information about these differences. The aim of this study was to characterise the nutritional value (focusing on carbohydrates and functional compounds) and instrumental parameters of eight potato cultivars consumed in Spain and to determine whether these parameters are useful for classifying the cultivars., Results: Significant Pearson's correlations were found due to the common and complex interactions between the constituents of potatoes and their properties (P < 0.05). Principal component analysis revealed the correlations among the physicochemical properties, and the first two principal components explained 56.84% of the variance among the cultivars studied., Conclusion: The eight cultivars could be classified into three groups: (1) Red Pontiac, Caesar, Kennebec, Agria and Cherie cultivars, (2) Agata and Monalisa cultivars and (3) Spirit cultivar. The results demonstrated that certain nutritional and functional parameters indicated the potential efficacy of different cultivars to satisfy the nutritional needs of consumers, improving the knowledge on the biochemical basis of potato processing to obtain higher-quality products., (© 2015 Society of Chemical Industry.)

Potato late blight, caused by the oomycete phytopathogen Phytophthora infestans, is a devastating disease found in potato-growing regions worldwide. Long-term management strategies to control late blight include the incorporation of host resistance to predominant strains. However, due to rapid genetic changes within pathogen populations, rapid and recurring identification and integration of novel host resistance traits is necessary. Wild relatives of potato offer a rich source of desirable traits, including late blight resistance, but screening methods can be time intensive. We tested the ability of taxonomy, ploidy, crossing group, breeding system, and geography to predict the presence of foliar and tuber late blight resistance in wild Solanum spp. Significant variation for resistance to both tuber and foliar late blight was found within and among species but there was no discernable predictive power based on taxonomic series, clade, ploidy, breeding system, elevation, or geographic location. We observed a moderate but significant correlation between tuber and foliar resistance within species. Although previously uncharacterized sources of both foliar and tuber resistance were identified, our study does not support an assumption that taxonomic or geographic data can be used to predict sources of late blight resistance in wild Solanum spp.

The cultivation, storage, and distribution of potato tubers are compromised by mechanical damage and suboptimal healing. To investigate wound-healing progress in cultivars with contrasting russeting patterns, metabolite profiles reported previously for polar tissue extracts were complemented by GC/MS measurements for nonpolar extracts and quantitative (13)C NMR of interfacial solid suspensions. Potential marker compounds that distinguish cultivar type and wound-healing time point included fatty acids, fatty alcohols, alkanes, glyceryl esters, α,ω-fatty diacids, and hydroxyfatty acids. The abundant long-chain fatty acids in nonpolar extracts and solids from the smooth-skinned Yukon Gold cultivar suggested extensive suberin biopolymer formation; this hypothesis was supported by high proportions of arenes, alkenes, and carbonyl groups in the solid and among the polar markers. The absence of many potential marker classes in nonpolar Atlantic extracts and interfacial solids suggested a limited extent of suberization. Modest scavenging activities of all nonpolar extracts indicate that the majority of antioxidants produced in response to wounding are polar.

The aim of the current study was to characterize the anthocyanin content and composition of a purple potato landrace cultivar (Solanum tuberosum 'Synkeä Sakari') and to compare the postprandial effects of purple-fleshed potatoes, yellow-fleshed potatoes and bilberries in potato starch on postprandial glycemia and insulinemia in healthy males. The purple potato meal caused smaller insulinemia than the yellow potato meal (iAUC 120 min 1347 and 2226, respectively, p = 0.012 and iAUC 240 min 1448 and 2403, p = 0.007) or the bilberry meal (iAUC 120 min 1920, p = 0.027). The purple potato meal caused a smaller plasma glucose at 40 min postprandially compared with the yellow potato meal (p = 0.044). The results of this study suggest that anthocyanin-containing purple-fleshed potatoes influence the postprandial insulinemia positively. Since potatoes are the world's largest non-grain commodity, replacing yellow-fleshed potatoes with purple-fleshed potatoes as staple food could have large potential in maintaining public health.

Late embryogenesis abundant (LEA) proteins were first described as accumulating late in plant seed development. They were also shown to be involved in plant responses to environmental stress and as well as in bacteria, yeast and invertebrates. They are known to play crucial roles in dehydration tolerance. This study describes a genome-wide analysis of LEA proteins and the corresponding genes in Solanum tuberosum. Twenty-nine LEA family members encoding genes in the Solanum genome were identified. Phylogenetic analyses allowed the classification of the potato LEA proteins into nine distinct groups. Some of them were identified as putative orthologs of Arabidopsis and rice LEA genes. In silico analyses confirmed the hydrophilicity of most of the StLEA proteins, whereas some of them can be folded. The in silico expression analyses showed that the identified genes displayed tissue-specific, stress and hormone-responsive expression profiles. Five StLEA classified as dehydrins were selected for expression analyses under salt and drought stresses. The data revealed that they were induced by both stresses. The analyses indicate that several factors such us developmental stages, hormones, and dehydration, can regulate the expression and activities of LEA protein. This report can be helpful for the further functional diversity studies and analyses of LEA proteins in potato. These genes can be overexpressed to improve potato abiotic stress response.

Here, we report the draft genome sequence of Solanum commersonii, which consists of ∼830 megabases with an N50 of 44,303 bp anchored to 12 chromosomes, using the potato (Solanum tuberosum) genome sequence as a reference. Compared with potato, S. commersonii shows a striking reduction in heterozygosity (1.5% versus 53 to 59%), and differences in genome sizes were mainly due to variations in intergenic sequence length. Gene annotation by ab initio prediction supported by RNA-seq data produced a catalog of 1703 predicted microRNAs, 18,882 long noncoding RNAs of which 20% are shown to target cold-responsive genes, and 39,290 protein-coding genes with a significant repertoire of nonredundant nucleotide binding site-encoding genes and 126 cold-related genes that are lacking in S. tuberosum. Phylogenetic analyses indicate that domesticated potato and S. commersonii lineages diverged ∼2.3 million years ago. Three duplication periods corresponding to genome enrichment for particular gene families related to response to salt stress, water transport, growth, and defense response were discovered. The draft genome sequence of S. commersonii substantially increases our understanding of the domesticated germplasm, facilitating translation of acquired knowledge into advances in crop stability in light of global climate and environmental changes., (© 2015 American Society of Plant Biologists. All rights reserved.)

Potatoes are a popular source of dietary carbohydrate worldwide and are generally considered to be a high glycemic index (GI) food. Potato starch characteristics play a key role in determining their rate of digestion and resulting glycemic response. Starches isolated from seven potato cultivars with different GI values, including a low GI cultivar (Carisma), were examined for relative crystallinity, granule size distribution, amylopectin chain length, and thermal and pasting properties. Starch from the Carisma cultivar was more thermally stable and more resistant to gelatinization, with significantly higher (p < 0.05) pasting temperature and differential scanning calorimetry (DSC) gelatinization onset, peak and conclusion temperatures, compared to the other cultivars. Differences between the potatoes in the other properties measured did not align with the GI ranking. Thermal analysis and starch pasting properties may be useful indicators for preliminary identification of potato cultivars that are digested slowly and have a lower GI.

Andean potatoes are gaining popularity not only for their appealing colors and culinary uses but also for their potential higher content of polyphenolic compounds. The objective of this study was to identify potato varieties with increased phenolic content. This was achieved through characterization and quantitation of the phenolic composition in 20 varieties of native Andean potatoes from 4 different Solanum species with different colors. Major quantitative and qualitative differences among evaluated samples were more dependent on the coloration of the extracted sample rather than on the species. The most predominant anthocyanidins were petunidin-3-coumaroylrutinoside-5-glucoside and pelargonidin-3-coumaroylrutinoside-5-glucoside in purple and red potato extracts, respectively, while chlorogenic acid and its isomers were the main phenolic compund (43% of the total phenolic content). Our study suggested that the appropriate selection of native potatoes could provide new sources of polyphenolics with health promoting properties and natural pigments with increased stability for food applications.

Potato is one of the most important food in the world. Rapid and noninvasive identification of potato cultivars plays a important role in the better use of varieties. In this study, The identification ability of optical spectroscopy techniques, including near-infrared (NIR) Raman spectroscopy and NIR fluorescence spectroscopy, for invasive detection of potato cultivars was evaluated. A rapid NIR Raman spectroscopy system was applied to measure the composite Raman and NIR fluorescence spectroscopy of 3 different species of potatoes (98 samples in total) under 785 nm laser light excitation. Then pure Raman and NIR fluorescence spectroscopy were abstracted from the composite spectroscopy, respectively. At last, the partial least squares-discriminant analysis (PLS-DA) was utilized to analyze and classify Raman spectra of 3 different types of potatoes. All the samples were divided into two sets at random: the calibration set (74samples) and prediction set (24 samples), the model was validated using a leave-one-out, cross-validation method. The results showed that both the NIR-excited fluorescence spectra and pure Raman spectra could be used to identify three cultivars of potatoes. The fluorescence spectrum could distinguish the Favorita variety well (sensitivity: 1, specificity: 0.86 and accuracy: 0.92), but the result for Diamant (sensitivity: 0.75, specificity: 0.75 and accuracy: 0. 75) and Granola (sensitivity: 0.16, specificity: 0.89 and accuracy: 0.71) cultivars identification were a bit poorer. We demonstrated that Raman spectroscopy uncovered the main biochemical compositions contained in potato species, and provided a better classification sensitivity, specificity and accuracy (sensitivity: 1, specificity: 1 and accuracy: 1 for all 3 potato cultivars identification) among the three types of potatoes as compared to fluorescence spectroscopy.

Potatoes are usually a high-glycaemic index (GI) food. Finding a low-GI potato and developing a screening method for finding low-GI cultivars are both health and agricultural priorities. The aims of the present study were to screen the commonly used and newly introduced cultivars of potatoes, in a bid to discover a low-GI potato, and to describe the relationship between in vitro starch digestibility of cooked potatoes and their in vivo glycaemic response. According to International Standard Organisation (ISO) guidelines, seven different potato cultivars were tested for their GI. In vitro enzymatic starch hydrolysis and chemical analyses, including amylose content analysis, were carried out for each potato cultivar, and correlations with the respective GI values were sought. The potato cultivars had a wide range of GI values (53-103). The Carisma cultivar was classified as low GI and the Nicola cultivar (GI = 69) as medium GI and the other five cultivars were classified as high GI according to ISO guidelines. The GI values were strongly and positively correlated with the percentage of in vitro enzymatic hydrolysis of starch in the cooked potatoes, particularly with the hydrolysis percentage at 120 min (r 0·91 and P <0·01). Amylose, dietary fibre and total starch content was not correlated with either in vitro starch digestibility or GI. The findings suggest that low-GI potato cultivars can be identified by screening using a high-throughput in vitro digestion procedure, while chemical composition, including amylose and fibre content, is not indicative.

Cytoplasm types of the potato somatic hybrids from Solanum tuberosum × Solanum etuberosum were analysed using chloroplast (cp) and mitochondrial (mt) organelle genomes-specific markers. Of the 29 markers (15 cpDNA and 14 mtDNA) amplified in the 26 genotypes, 5 cpDNA (H3, NTCP4, NTCP8, NTCP9, and ALC1/ALC3) and 13 mtDNA markers showed polymorphism. The cluster analysis based on the mtDNA markers detected higher diversity compared with the cpDNA markers. Presence of new mtDNA fragments of the markers, namely, T11-2, Nsm1, pumD, Nsm3, and Nsm4, were observed, while monomorphic loci revealed highly conserved genomic regions in the somatic hybrids. The study revealed that the somatic hybrids had diverse cytoplasm types consisting predominantly of T-, W-, and C-, with a few A- and S-type cp genomes; and α-, β-, and γ-type mt genomes. Somatic hybridization has unique potential to widen the cytoplasm types of the cultivated gene pools from wild species through introgression by breeding methods.

In recent time the interest of industry increases particularly in processing and use of potato high amylopectin (AMP) starches. Therefore the plant breeders effort to obtain "waxy" potato cultivars with low amylose (AMS) content. In this four-year study sixteen potato cultivars grown on five experimental locations were evaluated on the percentage of AMS/AMP by enzymatic method, starch content by the underwater weight method, phosphorus (P) content in starch digests spectrophotometrically, and starch granule size determined by laser diffraction method. Between enzymatic and iodine-potassium iodide method good correlation has been revealed (r=0.71). The correlation analysis between AMS and P levels showed a clear negative correlation. For all measured parameters (starch, AMS, P, starch granule size) significant impact of cultivar has been determined. Location and year have lower, but significant impact. No statistically significant effect of year on AMS has been found. The cultivar Amado distinguished with the highest AMP and P contents and the cultivar Westamyl showed all positive values interesting for growers and processors., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

The carotenoid profile of sixty potato cultivars (commercial, bred, old and native cultivars) has been characterised in order to provide information to be used in selective breeding programs directed to improve the nutritional value of this important staple food. Cultivars were segregated into three groups according to the major pigment in the carotenoid profile: violaxanthin (37 cultivars; especially those with higher carotenoid content), lutein (16 cultivars), and neoxanthin (7 cultivars). Other minor carotenoids were antheraxanthin, β-cryptoxanthin and β-carotene, while zeaxanthin was absent in all sample. The total carotenoid content ranged from 50.0 to 1552.0 μg/100 g dry wt, with an average value of about 435.3 μg/100 g dry wt. Sipancachi, Poluya and Chaucha native cultivars showed the highest carotenoid content (1020.0, 1478.2 and 1551.2 μg/100 g dry wt, respectively). Xanthophyll esters were present in most cultivars, mainly as diesterified forms, being observed a direct correlation between the carotenoid content and the esterified fraction, suggesting that the esterification process facilitates the accumulation of these lipophilic compounds within the plastids. Therefore, the presence of xanthophyll esters should be a phenotypic character to be included in the breeding studies, and more efforts should be dedicated to the understanding of the biochemical process leading to this structural modification of carotenoids in plants., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

The common potato, Solanum tuberosum ssp. tuberosum (tbr, 2n = 4x = 48; 4EBN), has many closely related wild tuber-bearing species. Around 28 to 35 of them spontaneously grow in Argentina overlapping, in some areas, with the crop and/or experimental transgenic potatoes. Although it is well proven that hybridization barriers in potatoes can be incomplete, information on gene flow between cultivated and wild germplasm is scarce. Thus, a gene flow field experiment with a circular array was set up in Balcarce, Argentina, in 2009, and evaluated over two seasons. The tetraploid tbr cultivar Huinkul MAG and one compatible cloned genotype of the related wild potato S. chacoense Bitter (chc, 2n = 2x = 24; 2EBN), which produced 2n eggs, were used, respectively, as pollen donor and receptor. Berries with hybrid seeds - as revealed by ploidy and RAPD profiles - were obtained in one season, at 30 m from the pollen donor. These results reinforce others previously obtained with the same pollen donor and a male sterile tbr cultivar in a similar array, pointing out to the need of increasing isolation distances in areas of overlap between cultivated and wild potato germplasm to prevent or minimize undesirable pollen-mediated gene flow., (© 2013 The Authors.)

Yellow fleshed potatoes contain significant amounts of lutein and zeaxanthin but the bioaccessibility of potato carotenoids has not yet been investigated. The purpose of this study was to estimate the in vitro bioaccessibility of carotenoids provided by potato. Lutein and zeaxanthin concentrations of boiled, freeze dried and milled samples of seven yellow fleshed potato accessions were determined by HPLC before and after different steps (gastric, duodenal and micellar phase) of in vitro digestion. The gastric and duodenal digestive stability of lutein and zeaxanthin in boiled tubers of the different accessions ranged from 70 to 95 % while the efficiency of micellarization ranged from 33 to 71 % for lutein and from 51 to 71 % for zeaxanthin. For all accessions, amounts of lutein and zeaxanthin after micellarization were significantly lower than the original amount found in the boiled samples. The accession 701862 showed the highest bioaccessible lutein concentration (280 μg/100 g, FW) and the accessions 703566 and 704218 showed the highest bioaccessible zeaxanthin concentration (above 600 μg/100 g, FW). Considering the mean potato intake in the Andes (500 g per day), the accession 701862 provides 14 % of the lutein intake suggested for health benefits and the accessions 703566 and 704218 provide 50 % more than the suggested zeaxanthin intake.

Background: Potatoes contain a diverse range of phytochemicals which have been suggested to have health benefits. Metabolite profiling and quantification were conducted on plant extracts made from a white potato cultivar and 'Urenika', a purple potato cultivar traditionally consumed by New Zealand Maori. There is limited published information regarding the metabolite profile of Solanum tuberosum cultivar 'Urenika'., Results: Using ultra-high- performance liquid chromatography-mass spectrometry (UHPLC-MS), a total of 31 compounds were identified and quantified in the potato extracts. The majority of the compounds were identified for the first time in 'Urenika'. These compounds include several types of anthocyanins, hydroxycinnamic acid (HCA) derivatives, and hydroxycinnamic amides (HCAA). Six classes of compounds, namely organic acids, amino acids, HCA, HCAA, flavonols and glycoalkaloids, were present in both extracts but quantities varied between the two extracts., Conclusions: The unknown plant metabolites in both potato extracts were assigned with molecular formulae and identified with high confidence. Quantification of the metabolites was achieved using a number of appropriate standards. High-resolution mass spectrometry data critical for accurate identification of unknown phytochemicals were achieved and could be added to potato or plant metabolomic database., (© 2013 Society of Chemical Industry.)

Potatoes of purple varieties and red flesh colour were estimated as the important food product containing valuable protein. Amino acids concentration and protein nutritive value of coloured potatoes were analysed and compared with traditional yellow-fleshed varieties. Studies comprised potatoes of 13 varieties: 7 of purple-fleshed, four of red-fleshed and two of yellow-fleshed. There were observed differences between studied potatoes with respect to dry matter, starch and protein content as well as to amino acids concentration and protein quality independently on flesh colour. Potatoes of low as well of high content of total protein, independently on flesh colour, characterised similar protein quality, like for example varieties of Blaue Anneliese and Highland B. Red or Blue Congo and Salad Blue. Leucine limited the quality of majority of coloured fleshed potato varieties used for the experiment. The best amino acid profiles and protein quality confirmed by chemical scores and EAA index values characterised purple fleshed Vitelotte and Blaue Anneliese, yellow fleshed Verdi as well as red fleshed Herbie 26, Highland B. Red and Rosemarie., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Much remains unknown about how transcription factors and sugars regulate phenylpropanoid metabolism in tuber crops like potato (Solanum tuberosum). Based on phylogeny and protein similarity to known regulators of phenylpropanoid metabolism, 15 transcription factors were selected and their expression was compared in white, yellow, red, and purple genotypes with contrasting phenolic and anthocyanin profiles. Red and purple genotypes had increased phenylalanine ammonia lyase (PAL) enzyme activity, markedly higher levels of phenylpropanoids, and elevated expression of most phenylpropanoid structural genes, including a novel anthocyanin O-methyltransferase. The transcription factors Anthocyanin1 (StAN1), basic Helix Loop Helix1 (StbHLH1), and StWD40 were more strongly expressed in red and purple potatoes. Expression of 12 other transcription factors was not associated with phenylpropanoid content, except for StMYB12B, which showed a negative relationship. Increased expression of AN1, bHLH1, and WD40 was also associated with environmentally mediated increases in tuber phenylpropanoids. Treatment of potato plantlets with sucrose induced hydroxycinnamic acids, flavonols, anthocyanins, structural genes, AN1, bHLH1, WD40, and genes encoding the sucrose-hydrolysing enzymes SUSY1, SUSY4, and INV2. Transient expression of StAN1 in tobacco leaves induced bHLH1, structural genes, SUSY1, SUSY4, and INV1, and increased phenylpropanoid amounts. StAN1 infiltration into tobacco leaves decreased sucrose and glucose concentrations. In silico promoter analysis revealed the presence of MYB and bHLH regulatory elements on sucrolytic gene promoters and sucrose-responsive elements on the AN1 promoter. These findings reveal an interesting dynamic between AN1, sucrose, and sucrose metabolic genes in modulating potato phenylpropanoids.