Search Results (30)

Background: Di19 (drought-induced 19)proteins belong to the C2H2-type zinc-finger family and play a crucial role in regulating plant growth, developmental processes, hormone signal transduction, and abiotic stress adaptation. However, research on the Di19 gene family in sweet potato and its diploid relatives remains relatively limited. Methods: At the whole-genome level, members of the Di19 gene family in sweet potato (Ipomoea batatas, 2n = 6x = 90) and its two diploid relatives, Ipomoea trifida (2n = 2x = 30) and Ipomoea triloba (2n = 2x = 30) were systematically identified, and multi-dimensional bioinformatics analyses were carried out. Results: Seven Di19 genes were identified per species, with the family’s overall evolutionary characteristics conserved. Some IbDi19s showed species-specific structural variations, mainly manifested as an increase in the number of exons, loss or substitution of conserved motifs. The expression patterns of Di19s of two diploid relatives are highly conserved. IbDi19s are mainly expressed in leaves and roots. Most members respond significantly to JA treatment, but hardly respond to IAA. The expression of IbDi19-1 was significantly up-regulated by 336-fold and 68-fold under GA3 and cold treatments, respectively. Based on bioinformatics and expression data, a hypothesis was proposed that IbDi19-1 may be involved in the regulation of low-temperature response and gibberellin signaling pathways. Conclusions: This study provides candidate genes and a theoretical basis for evolutionary analysis, stress-resistant molecular breeding of the Di19 gene family in sweet potato and its two diploid relatives. Full article

Embryo spots on potato seed enhance the efficiency of doubled haploid screening by facilitating selection. While the spots are known to involve anthocyanin accumulation, their genetic regulation remains unclear. Here, loci and genes regulating spot formation were investigated. An F₁ population was generated by crossing the haploid inducer IVP101 (embryo-spotted male parent) with the diploid inbred line Y8 (non-spotted female parent). Subsequent BSA-seq of the extreme F₁ pools mapped a locus to chromosome 10 (49.96–54.31 Mb). QTL mapping via a high-density genetic map of the F₂ segregating population (derived from F₁ selfing) identified four QTLs (on chromosomes 2, 5, 10, 11). These included the QTLs qSP10-1 (explaining 23.85% of phenotypic variance) and qSP11-1 (18.23%). qSP11-1 overlapped with the reported P locus encoding flavonoid 3′,5′-hydroxylase (F3′5′H), whereas qSP10-1 confirmed the BSA-seq results. Integration of the BSA-seq and QTL mapping results narrowed the target gene locus to a 384.6 kb interval at the end of chromosome 10. Transcriptome sequencing of spotted vs. non-spotted F₁ seed, together with gene expression profiling in the qSP10-1 interval, identified five differentially expressed candidate genes. These findings clarify the genetic basis of potato embryo spot formation and provide a reference for breeding and further research. Full article

Potato is globally recognized as the fourth most crucial staple food crop, trailing behind wheat, rice, and maize. Cadmium (Cd), a predominant heavy-metal pollutant in agricultural soils, demonstrates high biological toxicity and mobility. Therefore, exploring the genetic and molecular mechanisms underpinning cadmium tolerance in potato is of substantial theoretical and practical significance. In this research, an F₂ population composed of 170 families was established through the cross-breeding of homozygous diploid potato lines HD-5 (highly cadmium-tolerant) and M9 (cadmium-sensitive). Employing hydroponic cultivation, six traits, namely plant height (PH), root length (RL), shoot fresh weight (SFW), root fresh weight (RFW), chlorophyll content (SPAD), and nitrogen content (LNC), were measured in potato seedlings following a 9-day treatment with 40 mg·L⁻¹ CdCl₂. By utilizing the high-density genetic map of this population for QTL mapping, a total of 35 genetic loci associated with cadmium tolerance in potato seedlings were identified. Notably, loci21 and loci22 on chromosome 9, loci29 on chromosome 10, and loci31 and loci33 on chromosome 12 were consistently detected across multiple environmental conditions. This reproducibility across environments suggests the phenotypic stability of these five loci, which are thus considered reliable and robust genetic determinants. In addition, transcriptome sequencing analysis of roots from parental lines HD-5 and M9 after cadmium treatment revealed that significantly differentially expressed genes between the two parents were associated with glutathione metabolism and photosynthesis. By integrating QTL mapping, transcriptome analysis, and gene annotation, we screened four candidate genes involved in cadmium tolerance regulation: DM8C09G01000 (GST), DM8C09G01060 (GST), DM8C09G02130 (OXP1), and DM8C06G22960 (PsaH). These findings provide molecular targets and a genetic basis for molecular breeding of cadmium-tolerant potato varieties. Full article

The cultivated potato (Solanum tuberosum L.) is a globally important crop with a narrow genetic pool, making it vulnerable to biotic and abiotic stresses. The present study analyzed the relative content of the nuclear, mitochondrial, and plastid genomes and their contributions to agronomic traits in 30 diploid interspecific potato hybrids with diverse cytoplasmic types and pedigrees. The nuclear genome size (2C-value) was estimated using flow cytometry, while the organelle DNA content and cytoplasm types were determined by quantitative polymerase chain reaction (qPCR) and multiplex PCR, respectively. The genome size of individual diploid genotypes remained stable across cultivation conditions, such as in vitro or greenhouse environments. Significant variation was observed in genome size, organelle content, and cytoplasmic types, which were associated with differences in pollen fertility and starch content. Kendall’s correlation analysis revealed a strong positive correlation between the content of plastid and mitochondrial DNA, and between starch content and chip colour after cold storage. Principal component analysis (PCA) demonstrated that variation in plastid and mitochondrial DNA content explained differences among genotypes, with nuclear DNA content contributing independently. Notably, cytoplasmic male sterility was observed in some T-type cytoplasm genotypes, thus highlighting the role of nuclear–cytoplasmic interactions. The results obtained demonstrate that organelle genome composition exerts a significant influence on agronomic traits and offer valuable insights into the potential for the enhancement of potato breeding programmes through the analysis of cytoplasm and nuclear genomes. Full article

Sweetpotato (Ipomoea batatas L. Lam) production is threatened by complex viral diseases, notably sweet potato virus disease (SPVD) worldwide, which results from co-infection by sweet potato feathery mottle virus (SPFMV) and sweet potato chlorotic stunt virus (SPCSV). This study provides virus-specific transcriptomic insights into the immune responses of three sweetpotato cultivars, ‘Beauregard’, ‘Tanzania’, and ‘New Kawogo’, to SPFMV, SPCSV, and SPVD. Using RNA-seq profiling across three timepoints post-infection at 3, 6, and 12 weeks, we identified distinct virus- and genotype-specific gene expression responses. ‘New Kawogo’ activated early and sustained immune pathways involving redox regulation, transcriptional control, and hormonal signaling in response to both SPCSV and SPFMV, while showing minimal transcriptional disruption under SPVD, reflecting robust tolerance. ‘Beauregard’ exhibited early suppression of immune and metabolic genes, with delayed and disorganized recovery efforts, particularly under SPVD. Defense-related pathways including NBS-LRR signaling, RNA silencing, and hormonal regulation were consistently upregulated in ‘New Kawogo’ and to a lesser extent in ‘Tanzania’, but remained inactive in ‘Beauregard’. This study highlights candidate resistance and susceptibility genes for each virus, providing a molecular basis for developing virus-resilient sweetpotato cultivars through functional genomics and marker-assisted breeding. These findings elucidate the molecular basis of virus resistance in sweetpotato and identify candidate genes for marker-assisted breeding, despite limitations arising from the use of a diploid reference genome and discrete sampling intervals. Full article

Potato (Solanum tuberosum L.) is a globally important food crop, but its tetrasomic inheritance and diploid self-incompatibility have limited the discovery of potato genes and progress in breeding. Here, we developed an F₂ segregating population consisting of 174 lines by crossing a self-compatible genome-homozygous diploid line (Y8, female parent) with a heterozygous diploid line (IVP101, male parent), followed by selfing. Using whole-genome resequencing, we constructed a high-density genetic map containing 4464 recombinant bin markers with an average physical distance of 165.51 Kb. Phenotypic evaluation of 8 traits related to yield, tuber shape, and tuber eye number across three environments revealed significant parental differences and wide phenotypic variation within the F₂ population. QTL (Quantitative trait loci) mapping using this genetic map and multi-environment phenotypic data identified 89 QTLs, including 7 previously reported QTLs/genes. In addition, 10 QTLs were stably detected across multiple seasons (stable QTLs). Further genetic effect analysis showed that favorable alleles of these stable QTLs significantly enhanced phenotypic values. Notably, two pleiotropic QTLs were identified on chromosomes 5 and 12; the major-effect QTL on chromosome 12 (qTY-12-6, qTS-12-3, and qTE-12-4) exhibited high phenotypic variance explained (PVE). Its favorable allele from Y8 significantly increased mean tuber weight, tuber number per plant, and promoted rounder tuber shape while reducing eye number, simultaneously improving yield and quality. Collectively, this study provides a reference for genetic mapping using homozygous and heterozygous diploid parents, and the identified QTLs offer valuable genetic resources for potato breeding and molecular mechanism research, enhancing our understanding of the genetic regulation of yield, tuber shape, and eye number in potato. Full article

The Bcl-2 associated athanogene (BAG) family is a multifunctional group of proteins that perform diverse functions, ranging from apoptosis to tumorigenesis. In plants, BAGs play a key role in growth, autophagy, and stress response. However, the BAG family has not been explored in sweet potato. In this study, we identified 15, 14, and 14 BAGs in cultivated hexaploid sweet potato (I. batatas, 2n = B₁B₁B₂B₂B₂B₂ = 6x = 90) and its two diploid relatives I. trifida (2n = 2x = 30) and I. triloba (2n = 2x = 30) by sequence alignment, genome structure analysis, and phylogenetic characterization. Based on their phylogenetic relationships with Arabidopsis, we divided these BAGs into three subfamilies. Protein physicochemical properties, chromosome localization, collinearity and Ka/Ks analysis, phylogenetic relationships, gene structures, promoter cis-elements, protein interaction networks, and expression patterns were systematically investigated to explore the possible functions of these 43 BAGs in the development and abiotic and biotic stress response of sweet potato. The results suggested that homologous BAGs have differentiated functions and play various vital roles in plant growth, tuberous root development, and abiotic and biotic stress response in sweet potato and its two diploid relatives. This work provides a comprehensive comparison and understanding of the BAG genes in sweet potato and its two diploid relatives, supplying a theoretical foundation for their functional study and further facilitating the molecular breeding of sweet potato. Full article

Dickeya solani causes soft rot in potato (Solanum tuberosum L.) tubers. We used bulk RNA-seq to compare the early transcriptional responses of the diploid F₁ genotypes from the mapping population that varied in tuber resistance to D. solani. RNA was collected from wounded tubers inoculated with D. solani (B), wounded tubers treated with sterile water (W), and non-treated tubers (NT) at 8, 24, and 48 hours post-inoculation (hpi). The largest transcriptional divergence between resistant (R) and susceptible (S) genotypes occurred at 8 hpi, with R tubers showing stronger induction of phenylpropanoid biosynthesis, phenylalanine and tyrosine metabolism, amino sugar and nucleotide sugar metabolism, isoquinoline alkaloid biosynthesis, and glutathione metabolism. Phenylpropanoid biosynthesis was dominant in R tubers, in 17 differentially expressed genes (DEGs), consistent with rapid suberin and lignin deposition as a physical barrier. RT-qPCR of nine defence-related genes corroborated the RNA-seq trends. The suberisation-associated anionic peroxidase POPA was located within a QTL for D. solani resistance on chromosome II, supporting its role as a candidate for future functional studies. This is the first transcriptome-based comparison of R and S potato genotypes challenged with D. solani, providing candidate pathways and genes that may guide future molecular breeding once their roles are validated. Full article

Potato common scab is one of the major diseases posing a threat to potato production on a global scale. No chemical agents have been found to effectively control the occurrence of this disease, and research on the identification of resistance genes and the development of molecular markers remains relatively limited. In this study, a diploid potato variety H535, which exhibits resistance to the predominant pathogen Streptomyces scabies, was utilized as the male parent, whereas the susceptible diploid potato variety H012 served as the female parent. Building upon the resistance QTL intervals pinpointed through a genome-wide association study, two potential resistance loci were localized on chromosome 2 of the potato genome, spanning the regions between 38–38.6 Mb and 41.3–42.7 Mb. These intervals accounted for 18.03% of the total phenotypic variance and are presumed to be the primary QTLs underlying scab resistance. Building upon this foundation, we expanded the hybrid progeny population, conducted resistance assessments, selected individuals with extreme phenotypes, developed molecular markers, and conducted fine mapping of the resistance gene. A phenotypic evaluation of scab resistance was carried out using a pot-based inoculation test on 175 potato hybrid progenies to characterize the F1 generation population. Twenty lines exhibiting high resistance and thirty lines displaying high susceptibility were selected for investigations. Within the preliminary mapping interval on potato chromosome 2 (spanning 38–43 Mb), a total of 214 SSR (Simple Sequence Repeat) and 133 InDel (Insertion/Deletion) primer pairs were designed. Initial screening with parental lines identified 18 polymorphic markers (8 SSR and 10 InDel) that demonstrated stable segregation patterns. Validation using bulked segregant analysis revealed that 3 SSR markers (with 70–90% linkage) and 6 InDel markers (with 70–90% linkage) exhibited significant co-segregation with the resistance trait. A high-density genetic linkage map spanning 104.59 cm was constructed using 18 polymorphic markers, with an average marker spacing of 5.81 cm. Through linkage analysis, the resistance locus was precisely mapped to a 767 kb interval (41.33–42.09 Mb) on potato chromosome 2, flanked by SSR-2-9 and InDel-3-9. Within this refined interval, four candidate disease resistance genes were identified: RHC02H2G2507, RHC02H2G2515, PGSC0003DMG400030643, and PGSC0003DMG400030661. This study offers novel insights into the genetic architecture underlying scab resistance in potato. The high-resolution mapping results and characterized markers will facilitate marker-assisted selection (MAS) in disease resistance breeding programs, providing an efficient strategy for developing cultivars with enhanced resistance to Streptomyces scabies. Full article

DNA methylation is a conserved and vital epigenetic modification that plays essential roles in plant growth, development, and responses to environmental stress. Cytosine-5 DNA methyltransferases (C5-MTases) and DNA demethylases (dMTases) are key regulators of DNA methylation dynamics. However, a comprehensive characterization of these gene families in sweet potato has remained elusive. In this study, we systematically identified and analyzed eight C5-MTase and five dMTase genes in the genomes of diploid (Ipomoea trifida, 2n = 2x = 30) and autohexaploid (Ipomoea batatas, 2n = 6x = 90) sweet potato. Phylogenetic, structural, and synteny analyses revealed a high degree of conservation among these genes, suggesting their essential roles during evolution. Promoter analysis uncovered multiple cis-acting elements, particularly those responsive to light and hormones. In addition, we examined the expression profiling of IbC5-MTases and IbdMTases genes during storage root development, revealing that several were highly expressed during the early and rapid expansion stages. These findings suggest that C5-MTases and dMTases may contribute to the regulation of storage root formation in sweet potato through epigenetic mechanisms, offering valuable insights for future functional studies and epigenetic breeding efforts. Full article

Most cultivated potato (Solanum tuberosum) varieties are highly susceptible to common scab (Streptomyces scabei). The disease is widespread in all major potato production areas and leads to high economic losses and food waste. Varietal resistance is seen as the most viable and sustainable long-term management strategy. However, resistant potato varieties are scarce, and their genetic architecture and resistance mechanisms are poorly understood. Moreover, diploid potato relatives to commercial potatoes remain to be fully explored. In the current study, a panel of 384 ethyl methane sulfonate (EMS)-mutagenized diploid potato clones were evaluated for common scab coverage, severity, and incidence traits under field conditions, and genome-wide association studies (GWASs) were conducted to dissect the genetic architecture of their traits. Using the GAPIT-MLM and RTM-GWAS statistical models, and Mann–Whitney non-parametric U-tests, we show that 58 QTNs/QTLs distributed on all 12 potato chromosomes were associated with common scab resistance, 52 of which had significant allelic effects on the three traits. In total, 38 of the 52 favorable QTNs/QTLs were found to be pleiotropic on at least two of the traits, while 14 were unique to a single trait and were found distributed over 3 chromosomes. The identified QTNs/QTLs showed low to high effects, highlighting the quantitative and multigenic inheritance of common scab resistance. The QTLs/QTNs associated with the three common scab traits were found to be co-located in genomic regions carrying 79 candidate genes playing roles in plant defense, cell wall component biosynthesis and modification, plant–pathogen interactions, and hormone signaling. A total of 61 potato clones were found to be tolerant or resistant to common scab. Taken together, the data show that the studied germplasm panel, the identified QTNs/QTLs, and the candidate genes are prime genetic resources for breeders and biologists in breeding and targeted gene editing. Full article

Potato (Solanum tuberosum L.) is sensitive to drought, which severely impacts tuber yield and quality. In this study, we characterized a XERICO gene, encoding a RING-H2 type E3 ubiquitin ligase, StXERICO1, from a diploid potato, investigated its role in enhancing drought resistance and ABA accumulation, and identified its interaction with the miRNA novel-miR1730-3p, as well as its protein interactions with StUBC and StTLP. StXERICO1, with a complete Open Reading Frame (ORF) of 459 bp encoding 152 amino acids, was highly responsive to drought, ABA treatment, and abiotic stresses in potato plants. Overexpression of the StXERICO1 significantly enhanced drought resistance and ABA accumulation in transgenic potato and tobacco plants and exhibited greater sensitivity to ABA treatment, which was associated with the upregulation of expression of ABA biosynthetic genes NCED and CYP707A. Furthermore, our results revealed that StXERICO1 and its encoding protein interacted with miRNAs and other proteins. 5′ RLM-RACE (cDNA terminal rapid amplification) experiment showed that the miRNA novel-miR1730-3p targets 5′ UTR region of the StXERICO1 gene. Dual luciferase assay and virus-based miRNA silencing experiment showed that the novel-miR1730-3p negatively regulates StXERICO1 expression. Moreover, yeast two-hybrid assay indicated that StXERICO1 interacts with StUBC (an E2 ubiquitin ligase) and StTLP (a Tubby-like protein), suggesting that StXERICO1 might function on ABA homeostasis at the post-translational level. These findings elucidate the molecular mechanisms by which StXERICO1, a RING-H2 type E3 ubiquitin ligase, enhances drought resistance through increased ABA accumulation, how its expression is regulated by miRNA, and how it exerts its function through interactions with other proteins. The results also provide a potential candidate gene for subsequent precision molecular breeding aimed at improving crop drought resistance. Full article

Recent advances in diploid F₁ hybrid potato breeding rely on the production of inbred lines using the S-locus inhibitor (Sli) gene. As a result of this method, female parent lines are self-fertile and require emasculation before hybrid seed production. The resulting F₁ hybrids are self-fertile as well and produce many undesirable berries in the field. Utilization of cytoplasmic male sterility would eliminate the need for emasculation, resulting in more efficient hybrid seed production and male sterile F₁ hybrids. We observed plants that completely lacked anthers in an F₂ population derived from an interspecific cross between diploid S. tuberosum and S. microdontum. We studied the antherless trait to determine its suitability for use in hybrid potato breeding. We mapped the causal locus to the short arm of Chromosome 6, developed KASP markers for the antherless (al) locus and introduced it into lines with T and A cytoplasm. We found that antherless type male sterility is not expressed in T and A cytoplasm, proving that it is a form of CMS. We hybridized male sterile al/al plants with P cytoplasm with pollen from al/al plants with T and A cytoplasm and we show that the resulting hybrids set significantly fewer berries in the field. Here, we show that the antherless CMS system can be readily deployed in diploid F₁ hybrid potato breeding to improve hybridization efficiency and reduce berry set in the field. 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

Potato is an important crop, used not only for food production but also for various industrial applications. With the introduction of the potato as a staple food strategy, the potato industry in China has grown rapidly. However, issues related to bacterial wilt, exacerbated by factors such as seed potato transportation and continuous cropping, have become increasingly severe in the primary potato cultivation regions of China, leading to significant economic losses. The extensive genetic diversity of Ralstonia solanacearum (R. solanacearum), which is the pathogen of bacterial wilt, has led to a lack of highly resistant potato genetic resources. There is a need to identify and cultivate potato varieties with enhanced resistance to reduce the adverse impact of this disease on the industry. We screened 55 accessions of nine different wild potato species against the bacterial wilt pathogen R. solanacearum PO2-1, which was isolated from native potato plants and belongs to phylotype II. Three accessions of two species (ACL24-2, PNT880-3, and PNT204-23) were identified with high resistance phenotypes to the tested strains. We found these accessions also showed high resistance to different phylotype strains. Among them, only PNT880-3 was capable of flowering and possessed viable pollen, and it was diploid. Consistent with the high resistance, decreased growth of R. solanacearum was detected in PNT880-3. All these findings in our study reveal that the wild potato PNT880-3 was a valuable resistance source to bacterial wilt with breeding potential. Full article