Search Results (39)

Enzymatic browning, driven by polyphenol oxidase (PPO), remains a major postharvest challenge for potato (Solanum tuberosum L.), reducing product quality, shelf life, and consumer acceptance. To mitigate this trait in the elite tetraploid cultivar ‘Yagana-INIA’, we applied a geminivirus-derived CRISPR–Cas9 system to edit the StPPO genes most highly expressed in tubers, StPPO1 and particularly StPPO2. A paired-gRNA strategy generated a double-cut deletion in StPPO1, while StPPO2 editing required a complementary single-gRNA screening workflow. High-resolution fragment analysis and sequencing identified three StPPO2-edited lines, including one that lacked GFP, Cas9, and Rep/RepA sequences, confirming a transgene-free editing outcome. Edited tubers exhibited visibly reduced browning relative to wild type, and biochemical assays showed decreased PPO activity consistent with targeted disruption of StPPO2. Amplicon sequencing verified monoallelic editing at the gRNA2 site in the non-transgenic line. These results demonstrate the utility of a replicon-based CRISPR system for achieving targeted, transgene-free edits in tetraploid potato and identify a non-GM StPPO2-edited line with improved postharvest quality under Chile’s regulatory framework. Full article

The AGC kinase family is crucial for regulating plant disease resistance, integrating hormone signals, managing reactive oxygen species (ROS) metabolism, and maintaining redox balance. However, research on AGC kinases in Solanaceae plants is limited, and the functions of most AGC kinases remain unidentified. Using the tetraploid potato (Solanum tuberosum L.) cultivar ‘Tingsha No. 9’, we conducted a genome-wide identification of the AGC gene family and profiled transcript responses to late-blight (Phytophthora infestans) stress. Additionally, we examined the subcellular localization and characterized the phenotypic responses of overexpression lines of the late-blight–responsive kinase StD6PK under late-blight stress. A total of 141 AGC family members were identified in ‘Qingshu No. 9’, categorized into eight subfamilies. This classification includes one cultivar-specific subfamily that was previously unrecognized, as well as 50 AGC family members within subfamily 1. AGC family members had significant differences in physicochemical characteristics and most of which were located in the nucleus. AGC family members are distributed on 46 chromosomes, with the largest number of chromosome 11 and the least number of chromosome 7. Gene duplication is dominated by whole-genome duplication (WGD) and segmental duplication. Ka/Ks values of all collinear pairs are less than 1. Purification selection drives family evolution in a long evolutionary process. Its promoter is rich in light-responsive, hormone-responsive, and stress-responsive elements, and its expression varies significantly in tissues; and some genes are highly expressed in specific organs. RNA-seq analysis revealed that 78.1% of the members responded to late-blight stress, and the expression levels of the selected eight subfamily members all showed significant increases or decreases after inoculation with late blight. StD6PK (Soltu.Q9.Chr04_A40011450.g) was strongly induced at 48~72 h, and its expression level at 72 h was 5.7 times higher than that at 0 h. Stable transformation of potato demonstrated that overexpression of StD6PK could enhance the resistance of potato to late blight, with subcellular localization revealing its nuclear localization characteristic. This study was the first time to complete the identification of AGC family genome of tetraploid potato ‘Qingshu No. 9’, reveal its evolution and expression characteristics, clarify the response characteristics of StD6PK to late blight, and provide insights into the evolutionary and functional basis of the AGC kinase gene family in potato late blight resistance mechanisms, while supplying genetic resources to accelerate the development of late blight-resistant germplasm. Full article

Potato is an important crop in the world and is rich in various nutrients. Common tetraploid potato is not tolerant of low temperatures and frost. Low-temperature stress severely affects the growth above-ground and the yield underground in potato. The BBX genes play an important role in the plant response to low-temperature stress. However, the molecular mechanism underlying the potato StBBX genes involved in cold stress response remains unclear. In the present study, 30 StBBX genes were identified in potato and divided into five groups. A total of 10 motifs and 10 cis-acting elements were obtained in all BBX proteins. All StBBX genes contained light responsive elements in the promoter, of which nine StBBX genes harbored low-temperature responsive elements. In total, 15 pairs of StBBX genes were identified in duplicated genomic regions. The gene expression patterns of all StBBXs were assessed in different tissues by transcriptome data. The qRT-PCR analysis indicated that six StBBX genes were significantly induced in response to cold stress. Subcellular localization suggested that the StBBX17 protein was localized in the nucleus. Compared with wild type (WT), the cold tolerance in StBBX17 overexpression lines was dramatically increased. After cold treatment, the StBBX17 overexpression lines displayed a less injured area of leaves and lower electrolyte leakage compared with the WT plants, demonstrating StBBX17 positively regulated cold tolerances in potato. These results indicate that StBBX genes have important functions under cold stress, providing a theoretical reference for the breeding of cold-resistant potato. Full article

PYR/PYL (pyrroloquinoline quinone resistance/PYR1-like) are receptors for abscisic acid (ABA) in plants and play a crucial role in responses to abiotic stress. In this study, we identified 63 members of the StPYL gene family at the tetraploid whole-genome level in potatoes. We analyzed the physicochemical properties of these 63 StPYLs and constructed a phylogenetic tree using Arabidopsis thaliana and potato (Solanum tuberosum L.) cultivar ‘DM’ as the reference. By examining gene structure, conserved protein motifs, and collinearity, we found that StPYLs are highly conserved throughout evolution. The gene expression heat map under salt stress revealed that 57 StPYL genes are involved in the salt stress response. Among them, the expression level of StPYL9a-like changed significantly under salt stress. Through genetic transformation, we observed that overexpression of StPYL9a-like enhanced the growth and survival of potato plants under salt stress compared to the wild type. The contents of proline (Pro), superoxide dismutase (SOD), and chlorophyll in the leaves of overexpressing plants increased, while malondialdehyde (MDA) levels decreased. This suggests that StPYL9a-like positively regulates salt tolerance by affecting antioxidant enzyme activity and osmotic adjustment substances in potatoes. Subcellular localization demonstrated that StPYL9a-like is localized in the nucleus. This study provides a reference for the functional research of PYLs in potatoes, offers a basis for screening potato genes related to salt stress, and lays a foundation for developing salt-tolerant potato varieties. Full article

As the fourth-largest global food crop, the quality and functional characteristics of processed potato products are closely linked to endogenous sugar metabolism in tubers, with the trehalose–sucrose metabolism playing a key role in processing adaptability. This study analyzed 333 accessions from a tetraploid potato natural population. The trehalose and sucrose content of potato tubers at harvest was quantified using the high-performance liquid chromatography (HPLC) method. Combined with whole-genome resequencing, a genome-wide association study (GWAS) was conducted to map regulatory loci and identify candidate genes. The results showed that relative trehalose content in tubers was 20.38–24.78, while relative sucrose content was 10.32–19.50. Frequency histograms for both sugars exhibited normal distributions characteristic of quantitative traits, and a positive correlation was observed between them. GWAS for trehalose identified 111 significant SNP loci, mainly on chromosomes 10 and 12, leading to the identification of 88 candidate genes. Kyoto encyclopedia of genes and genomes analysis (KEGG) revealed that trehalose-related genes were primarily involved in pathways such as ABC transporters, tricarboxylic acid (TCA) cycle, and cysteine and methionine metabolism. Candidate genes potentially regulating tuber trehalose content included GH10, GH28, GH127, UXS, UGT, PMEI, and MYB108. For sucrose, GWAS identified 279 significant SNP loci, mainly on chromosomes 5, 6, and 12, resulting in 111 candidate genes. KEGG enrichment analysis showed that sucrose-related genes were enriched in pathways including starch and sucrose metabolism, cyanoamino acid metabolism, and phenylpropanoid biosynthesis. Candidate genes potentially regulating tuber sucrose content included GH17, GH31,GH47, GH9A4, SPP1, BGLU12, GSA1, TPS8, cwINV4, HXK, UST, MYB5, MYB14, and WRKY11. Therefore, this study provides marker loci for trehalose and sucrose metabolism research, aiming to clarify their regulatory mechanisms and support potato variety improvement and superior germplasm development. Full article

Potato (Solanum tuberosum L.) crop yields may be reduced by nitrogen deficiency stress tolerance. An evaluation of 144 tetraploid potato genotypes was carried out during two consecutive seasons (2019 and 2020), with the objective of characterizing their variability in key physiological and agronomic parameters. Physiological parameters included chlorophyll content and fluorescence, stomatal conductance, NDVI, leaf area, and perimeter, while agronomic characteristics such as yield, tuber fresh weight, tuber number, starch content, dry matter, and reducing sugars were evaluated. To genotype the population, the GGP V3 Potato array was used, generating 18,259 high-quality SNP markers. Marker–trait association analysis was conducted using the GWASpoly package in R, applying Q + K linear mixed models to enhance precision. This methodology enabled the identification of 18 SNP markers that exhibited statistically significant associations with the traits analyzed in both trials and periods, relating them to genes whose functional implication has already been described. Genetic loci associated with chlorophyll content and tuber number were detected across non-stress and stress treatments, while markers linked to leaf area and leaf perimeter were identified specifically under nitrogen deficiency stress. The genomic distribution of these markers revealed that genetic markers or single-nucleotide polymorphisms (SNPs) correlated with phenotypic traits under non-stress conditions were predominantly located on chromosome 11, whereas SNPs linked to stress responses were mainly identified on chromosomes 2 and 3. These findings contribute to understanding the genetic mechanisms underlying potato tolerance to nitrogen deficiency stress, offering valuable insights for the development of future marker-assisted selection programs aimed at improving nitrogen use efficiency and stress resilience in potato breeding. Full article

The aim of this study was to verify the influence of the dosage of the gene Ns (simplex or duplex), derived from S. tuberosum subsp. Andigena, on potato resistance to PVS and to evaluate changes in the response of potatoes depending on the method of inoculation used and different cultivation temperatures. The analyses carried out made it possible to distinguish 42 clones in duplex and 8 in simplex form. The analysis showed that the Ns gene, even in simplex form, confers full resistance to PVS. Our results also suggest that an increase in temperature may weaken the resistance response of host plants carrying the Ns gene. In our research, PVS overcame the resistance conferred by the Ns gene at higher temperatures in three tetraploid clones: Ns-II-3, Ns-II-4 and Ns-II-81. These clones were classified as ‘temperature-dependent’ (TD). For clones Ns-II-6, Ns-II-10, Ns-II-40 and Ns-II-43, the increase in temperature had no effect on the resistance response of host plants carrying the Ns gene. These clones were classified as ‘resistant’ (R). Full article

The color of tuber skin exhibits remarkable diversity in potato (Solanum tuberosum L.) and is intricately associated with variance in anthocyanin accumulation across different varieties. The regulatory mechanisms governing this phenomenon are poorly understood. In this study, we identified a natural, yellow-skinned variant (Z28M) from the red-skinned tetraploid variety, Zhongshu 28 (Z28W), using simple sequence repeat (SSR) molecular marker amplification and trait observation. The transcriptional regulatory mechanisms underlying tuber skin color variation were investigated by analyzing anthocyanin profiles and transcriptomic data at the developmental and maturation stages. Ultra-performance liquid chromatography (UPLC-QTOF-MS) analysis indicated markedly reduced levels of pelargonidin and peonidin in Z28M compared with those in Z28W. Transcriptome profiling identified 1858 differentially expressed genes between Z28W and Z28M, with significant enrichment in the flavonoid and phenylpropanoid biosynthetic pathways. Weighted gene co-expression network analysis indicated a red-skinned associated module, MEred, encompassing key anthocyanin biosynthetic genes co-expressed with the transcription factor, StMYB3, which exhibited substantially higher expression in Z28W than in Z28M. K-means clustering indicated coordinated expression patterns among StCHS, StDFR, and StMYB3, suggesting transcriptional co-regulation. Collectively, these results highlight StMYB3 as a pivotal regulator of anthocyanin biosynthesis and a contributor to the tuber skin color divergence observed between Z28W and Z28M. Full article

Senescence impacts plant growth and yields in tetraploid potatoes (Solanum tuberosum L.). Because of their homogenous tetraploid features, it is a major challenge to understand the genetic basis and molecular mechanisms of senescence. Here, we identified a novel central senescence regulator (Nicotinate-nucleotide pyrophosphorylase QPT/StNADC) through map-based cloning. Overexpression of StNADC^Z3 accelerated senescence in the late-senescence variety, with NAD content declining by around 40%. CRISPR/Cas9-induced StNADC mutant cr2–11 exhibited extremely early senescence, and the NAD content was reduced by 87% along with reduced chlorophyll content and photosynthesis. Moreover, the downstream products of the NAD synthesis pathway, such as NaMN, NAD, or niacin, can refresh the cr2–11 mutant to grow normally. Further, the transcriptomics and metabolomics data unveiled that the disrupting of StNADC impairs NAD metabolism, accelerating plant senescence through multiple biological levels. Our results show that StNADC is indispensable for NAD synthesis, and targeting the StNADC-mediated NAD synthesis pathway could be a useful strategy to regulate senescence in potato breeding preprograms. Full article

Potato is the most important non-cereal crop worldwide, and, yet, genetic gains in potato have been traditionally delayed by the crop’s biology, mostly the genetic heterozygosity of autotetraploid cultivars and the intricacies of the reproductive system. Novel site-directed genetic modification techniques provide opportunities for designing climate-smart cultivars, but they also pose new possibilities (and challenges) for breeding potato. As potato species show a remarkable reproductive diversity, and their ovules have a propensity to develop apomixis-like phenotypes, tinkering with reproductive genes in potato is opening new frontiers in potato breeding. Developing diploid varieties instead of tetraploid ones has been proposed as an alternative way to fill the gap in genetic gain, that is being achieved by using gene-edited self-compatible genotypes and inbred lines to exploit hybrid seed technology. In a similar way, modulating the formation of unreduced gametes and synthesizing apomixis in diploid or tetraploid potatoes may help to reinforce the transition to a diploid hybrid crop or enhance introgression schemes and fix highly heterozygous genotypes in tetraploid varieties. In any case, the induction of apomixis-like phenotypes will shorten the time and costs of developing new varieties by allowing the multi-generational propagation through true seeds. In this review, we summarize the current knowledge on potato reproductive phenotypes and underlying genes, discuss the advantages and disadvantages of using potato’s natural variability to modulate reproductive steps during seed formation, and consider strategies to synthesize apomixis. However, before we can fully modulate the reproductive phenotypes, we need to understand the genetic basis of such diversity. Finally, we visualize an active, central role for genebanks in this endeavor by phenotyping properly genotyped genebank accessions and new introductions to provide scientists and breeders with reliable data and resources for developing innovations to exploit market opportunities. Full article

The lipoxygenases (LOXs) are non-heme iron-containing dioxygenases that play an important role in plant growth and defense responses. There is scarce knowledge regarding the LOX gene family members and their involvement in biotic and abiotic stresses in potato. In this study, a total of 17 gene family members (StLOXs) in potato were identified and clustered into three subfamilies: 9-LOX type I, 13-LOX type I, and 13-LOX type II, with eleven, one, and five members in each subfamily based on phylogenetic analysis. By exploiting the RNA-seq data in the Potato Genome Sequencing Consortium (PGSC) database, the tissue-specific expressed and stress-responsive StLOX genes in double-monoploid (DM) potato were obtained. Furthermore, six candidate StLOX genes that might participate in drought and salt response were determined via qPCR analysis in tetraploid potato cultivars under NaCl and PEG treatment. Finally, the involvement in salt stress response of two StLOX genes, which were significantly up-regulated in both DM and tetraploid potato under NaCl and PEG treatment, was confirmed via heterologous expression in yeast under salt treatment. Our comprehensive analysis of the StLOX family provides a theoretical basis for the potential biological functions of StLOXs in the adaptation mechanisms of potato to stress conditions. Full article

Potato genetic improvement begins with crossing cultivars or breeding clones which often have complementary characteristics for producing heritable variation in segregating offspring, in which phenotypic selection is used thereafter across various vegetative generations (T_i). The aim of this research was to determine whether tetrasomic genomic best linear unbiased predictors (GBLUPs) may facilitate selecting for tuber yield across early T_i within and across breeding sites in inbred (S₁) and hybrid (F₁) tetraploid potato offspring. This research used 858 breeding clones for a T₁ trial at Umeå (Norrland, 63°49′30″ N 20°15′50″ E) in 2021, as well as 829 and 671 clones from the breeding population for T₂ trials during 2022 at Umeå and Helgegården (Skåne, 56°01′46″ N 14°09′24″ E), respectively, along with their parents (S₀) and check cultivars. The S₁ and F₁ were derived from selfing and crossing four S₀. The experimental layout was an augmented design of four-plant plots across testing sites, where breeding clones were non-replicated, and the parents and cultivars were placed in all blocks between the former. The genomic prediction abilities (r) for tuber weight per plant were 0.5944 and 0.6776 in T₂ at Helgegården and Umeå, respectively, when T₁ at Umeå was used as the training population. On average, r was larger in inbred than in hybrid offspring at both breeding sites. The r was also estimated using multi-environment data (involving at least one S₁ and one F₁) for T₂ performance at both breeding sites. The r was strongly influenced by the genotype in both S₁ and F₁ offspring irrespective of the breeding site. Full article

It has long been known that the phytohormone auxin plays a promoting role in tuber formation and stress tolerance in potatoes. Our study aimed to identify and characterize the complete sets of auxin-related genes that presumably constitute the entire auxin signaling system in potato (Solanum tuberosum L.). The corresponding genes were retrieved from sequenced genomes of the doubled monoploid S. tuberosum DM1-3-516-R44 (DM) of the Phureja group, the heterozygous diploid line RH89-039-16 (RH), and the autotetraploid cultivar Otava. Both canonical and noncanonical auxin signaling pathways were considered. Phylogenetic and domain analyses of deduced proteins were supplemented by expression profiling and 3D molecular modeling. The canonical and ABP1-mediated pathways of auxin signaling appeared to be well conserved. The total number of potato genes/proteins presumably involved in canonical auxin signaling is 46 and 108 in monoploid DM and tetraploid Otava, respectively. Among the studied potatoes, spectra of expressed genes obviously associated with auxin signaling were partly cultivar-specific and quite different from analogous spectrum in Arabidopsis. Most of the noncanonical pathways found in Arabidopsis appeared to have low probability in potato. This was equally true for all cultivars used irrespective of their ploidy. Thus, some important features of the (noncanonical) auxin signaling pathways may be variable and species-specific. Full article

Malnutrition is one of the global issues of public health concern, and iron and zinc deficiencies are at the top of the list. Iron deficiency affects more than 2 billion people in the world and is a major cause of anemia. Potato has the potential to be an important source of iron and zinc. This study assessed the nature and magnitude of genetic variability in Fe and Zn concentrations, tuber yield, and quality traits among biofortified tetraploid potato clones and their relationships through correlation and path analysis. A total of 45 potato genotypes, including the variety Gudanie, were grown in field trials in a 9 × 5 alpha lattice design with three replications. Significant differences in mineral, tuber quality, and yield traits were observed among the genotypes, and high broad-sense heritability was obtained for most traits, suggesting that progress through breeding can be achieved. However, negative correlations and direct effects on most of the traits with Fe and Zn contents are found both at genotypic and phenotypic levels. Therefore, attaining simultaneous genetic gain for yield and enhanced Fe and Zn concentrations will be challenging. Cluster analysis assembled them into five groups. Cluster II contained the most prominent genotypes, having better mean values compared to all other genotypes for micronutrient traits, viz., Fe (23.80 mg kg⁻¹) and Zn (17.07 mg kg⁻¹). The results of this study confirm the presence of sufficient genetic variation for iron and zinc mineral concentration and the possibility to make significant progress through breeding. Full article

Inbreeding depression (ID) is caused by increased homozygosity in the offspring after selfing. Although the self-compatible, highly heterozygous, tetrasomic polyploid potato (Solanum tuberosum L.) suffers from ID, some argue that the potential genetic gains from using inbred lines in a sexual propagation system of potato are too large to be ignored. The aim of this research was to assess the effects of inbreeding on potato offspring performance under a high latitude and the accuracy of the genomic prediction of breeding values (GEBVs) for further use in selection. Four inbred (S₁) and two hybrid (F₁) offspring and their parents (S₀) were used in the experiment, with a field layout of an augmented design with the four S₀ replicated in nine incomplete blocks comprising 100, four-plant plots at Umeå (63°49′30″ N 20°15′50″ E), Sweden. S₀ was significantly (p < 0.01) better than both S₁ and F₁ offspring for tuber weight (total and according to five grading sizes), tuber shape and size uniformity, tuber eye depth and reducing sugars in the tuber flesh, while F₁ was significantly (p < 0.01) better than S₁ for all tuber weight and uniformity traits. Some F₁ hybrid offspring (15–19%) had better total tuber yield than the best-performing parent. The GEBV accuracy ranged from −0.3928 to 0.4436. Overall, tuber shape uniformity had the highest GEBV accuracy, while tuber weight traits exhibited the lowest accuracy. The F₁ full sib’s GEBV accuracy was higher, on average, than that of S₁. Genomic prediction may facilitate eliminating undesired inbred or hybrid offspring for further use in the genetic betterment of potato. Full article