Search Results (7)

Sweet potato (Ipomoea batatas) is an important food crop that plays a pivotal role in preserving worldwide food security. Due to its polyploid genome, high heterogeneity, and phenotypic plasticity, sweet potato genetic characterization and breeding is challenging. Genome-wide association studies (GWASs) can provide important resources for breeders to improve breeding efficiency and effectiveness. GWASpoly was used to identify 28 single nucleotide polymorphisms (SNPs), comprising 21 unique genetic loci, associated with sweet potato storage root traits including dry matter (4 loci), subjective flesh color (5 loci), flesh hue angle (3 loci), and subjective skin color and skin hue angle (9 loci), in 384 accessions from the USDA sweet potato germplasm collection. The I. batatas ‘Beauregard’ and I. trifida reference genomes were utilized to identify candidate genes located within 100 kb from the SNPs that may affect the storage traits of dry matter, flesh color, and skin color. These candidate genes include transcription factors (especially Myb, bHLH, and WRKY family members), metabolite transporters, and metabolic enzymes and associated proteins involved in starch, carotenoid, and anthocyanin synthesis. A greater understanding of the genetic loci underlying sweet potato storage root traits will enable marker-assisted breeding of new varieties with desired traits. This study not only reinforces previous research findings on genes associated with dry matter and β-carotene content but also introduces novel genetic loci linked to these traits as well as other root characteristics. Full article

In this study, single-layer coating using chitosan (Ch) and sodium alginate (SA) solutions and their gel coating (ChCSA) formed by layer-by-layer (LbL) electrostatic deposition using calcium chloride (C) as a cross linking agent were prepared to improve storage qualities and shelf-life of fresh-cut purple-flesh sweet potatoes (PFSP). The preservative effects of single-layer coating in comparison with LbL on the quality parameters of fresh-cut PFSP, including color change, weight loss, firmness, microbial analysis, CO₂ production, pH, solid content, total anthocyanin content (TAC), and total phenolic content (TPC) were evaluated during 16 days of storage at 5 °C. Uncoated samples were applicable as a control. The result established the effectiveness of coating in reducing microbial proliferation (~2 times), color changes (~3 times), and weight loss (~4 times) with negligible firmness losses after the storage period. In addition, TAC and TPC were better retained in the coated samples than in the uncoated samples. In contrast, quality deterioration was observed in the uncoated fresh cuts, which progressed with storage time. Relatively, gel-coating ChCSA showed superior effects in preserving the quality of fresh-cut PFSP and could be suggested as a commercial method for preserving fresh-cut purple-flesh sweet potato and other similar roots. Full article

Carotenoids are important compounds of quality and coloration within sweet potato storage roots, but the mechanisms that govern the accumulation of these carotenoids remain poorly understood. In this study, metabolomic and transcriptomic analyses of carotenoids were performed using young storage roots (S2) and old storage roots (S4) from white-fleshed (variety S19) and yellow-fleshed (variety BS) sweet potato types. S19 storage roots exhibited significantly lower total carotenoid levels relative to BS storage roots, and different numbers of carotenoid types were detected in the BS-S2, BS-S4, S19-S2, and S19-S4 samples. β-cryptoxanthin was identified as a potential key driver of differences in root coloration between the S19 and BS types. Combined transcriptomic and metabolomic analyses revealed significant co-annotation of the carotenoid and abscisic acid (ABA) metabolic pathways, PSY (phytoene synthase), CHYB (β-carotene 3-hydroxylase), ZEP (zeaxanthin epoxidase), NCED3 (9-cis-epoxycarotenoid dioxygenase 3), ABA2 (xanthoxin dehydrogenase), and CYP707A (abscisic acid 8’-hydroxylase) genes were found to be closely associated with carotenoid and ABA content in these sweet potato storage roots. The expression patterns of the transcription factors OFP and FAR1 were associated with the ABA content in these two sweet potato types. Together, these results provide a valuable foundation for understanding the mechanisms governing carotenoid biosynthesis in storage roots, and offer a theoretical basis for sweet potato breeding and management. Full article

Sweet potato is a hexaploid heterozygote with a complex genetic background, self-pollination infertility, and cross incompatibility, which makes genetic linkage analysis quite difficult. Genome-wide association studies (GWAS) provide a new strategy for gene mapping and cloning in sweet potato. Storage root flesh color (SRFC) is an important sensory evaluation, which correlates with storage root flesh composition, such as starch, anthocyanin, and carotenoid. We performed GWAS using SRFC data of 300 accessions and 567,828 single nucleotide polymorphism (SNP) markers. Furthermore, we analyzed transcriptome data of different SRFC varieties, and conducted real-time quantitative PCR (qRT-PCR) to measure the expression level of the candidate gene in purple and non-purple fleshed sweet potato genotypes. The results showed that five unique SNPs were significantly (−log₁₀P > 7) associated with SRFC. Based on these trait-associated SNPs, four candidate genes, g55964 (IbF3′H), g17506 (IbBAG2-like), g25206 (IbUGT-73D1-like), and g58377 (IbVQ25-isoform X2) were identified. Expression profiles derived from transcriptome data and qRT-PCR analyses showed that the expression of g55964 in purple-fleshed sweet potato was significantly (p < 0.01) higher than that of non-purple fleshed sweet potato. By combining the GWAS, transcriptomic analysis and qRT-PCR, we inferred that g55964 is the key gene related to purple formation of storage root in sweet potato. Our results lay the foundation for accelerating sweet potato genetic improvement of anthocyanin through marker-assisted selection. Full article

Cassava is the most widely cultivated and consumed crop in Ghana. Malnutrition is endemic in cassava-producing regions of Africa, partly due to the low micronutrient content of this crop. The aim of this study was to generate genetic information on characteristics such as total carotenoid content, dry matter content, root weight and number, and cassava mosaic disease (CMD), and their possible combination in cassava clones, using a North Carolina II breeding scheme. Five genetically diverse yellow-fleshed clones at advanced selection stages, with CMD resistance, were used as females and two high dry matter content white-fleshed clones, selected from farmers’ fields in Ghana, were used as males. Ten F₁ families were generated, and evaluated at two locations in Ghana. General combining ability (GCA) mean squares were larger than specific combining ability (SCA) mean squares for harvest index, CMD, and carotenoid content, indicating additive genetic effects. The positive significant correlations that were observed between pulp color and carotenoid content; carotenoid content and CMD; pulp color and CMD; and pulp color and cortex color, make the screening of large numbers of progenies possible in the cassava breeding program. This could allow breeders to combine carotenoid content and CMD at the early breeding stages through visual assessment of pulp color and CMD symptoms. Large numbers of genotypes can be evaluated and a few can be selected to be quantified for carotenoid content at later stages of the breeding program, to save costs. One of the parents (P6), showed positive GCA effects for carotenoid content, dry matter content, CMD and storage root weight, hence could be used as a parent to generate clones that combine carotenoid content and dry matter content. Full article

Background: Quality and safety of potato is both cultivar and postharvest management dependent. The precise assessment of freshness and cultivar are complex tasks requiring time-consuming, expensive, and destructive techniques. Method: Potatoes from three commercial cultivars were stored for 5 months at 5 °C. Color and chlorophyll fluorescence were recorded, Red-Green-Blue (R-G-B), Red-Green-Near infrared (R-G-NIR) and Red-Blue-Near infrared (R-B-NIR) digital images, as well as hyperspectral images were acquired both on the external periderm of the tuber and in the inner flesh part. Partial least square regression (PLSR) and discriminant analysis, combined with feature selection techniques were implemented, in order to assess the potato freshness and to classify them into the respective genotypes. Results: The PLSR analysis of visible/near infrared (Vis/NIR) spectra reflectance most reliably predicted potato freshness, with a cross-validated regression coefficient equal to 0.981 and 0.947, as determined by external or internal measurements, respectively. Variance inflation factor, variable importance scores, and genetic algorithms identified specific wavelength regions that mostly affected the accuracy of the model in terms of strongest regression and lowest collinearity and root mean cross validation error. Conclusions: Vis/NIR spectra reflectance data from the skin of the potato tubers may be reliably used in the assessment of postharvest storage life, as well as in the cultivar discrimination process. Full article

Sweet potatoes (SPs) are considered by the FAO as a primary crop for “traditional agriculture” in the tropics, but in Europe, its consumption is not widespread. However, consumer demand has grown exponentially over the past five years. This study has evaluated the quality and nutrient contents of storage roots of 29 SPs accessions to characterize their role in improving the human diet. Roots were analyzed for nutraceuticals, sugars, and minerals. Results underlined a considerable variability of nutrient content related to color among SPs accessions. The deep-orange-fleshed SPs showed a higher content of β-carotene compared to the light orange- and cream-fleshed ones; 100 g of edible product of HON86 can supply 32.3% of the daily value contribution of vitamin A, followed by the pale orange-fleshed BRA32 and BRA54. The total phenolic content of the purple ecotypes was about two to five times higher than the other genotypes. The calcium content was generally low, whereas, in many accessions, magnesium and phosphorus content reached 20%, or higher of the contribution to the daily value. Such a high variability suggests different use of the different accessions according to their strengths, but might also be used for breeding to improve quality traits of the commercial varieties. Full article