Search Results (9)

Enzymatic browning and cold-induced sweetening (CIS) affect the post-harvest quality of potato tubers. Browning is caused by polyphenol oxidase 2 (PPO2), which is activated by mechanical damage during harvest and storage. CIS occurs when vacuolar invertase converts sucrose into reducing sugars, which react with amino acids during frying, forming brown pigments and acrylamide. While cold storage prevents sprouting and disease, it also increases vacuolar invertase expression, leading to quality loss. Using CRISPR/Cas9, we developed gene-edited potato lines with improved resistance to browning and CIS. Line 6A (cv. Atlantic) and E03-3 (cv. Spunta) exhibited complete vacuolar invertase (InvVac) knockout, maintaining chip quality for at least 60 days at 4 °C. Line 6A, renamed PIRU INTA, was tested in field trials and preserved frying quality for up to 90 days under cold storage. PIRU INTA is currently undergoing registration as a new variety. Additionally, lines E04-5B and E03-3 (cv. Spunta) showed partial PPO2 gene edits, reducing enzymatic browning by 80% and 40%, respectively. This study demonstrates the potential of CRISPR/Cas9 to develop non-transgenic, gene-edited potatoes with enhanced storage quality, benefiting both growers and the food industry. Full article

The production of chips is an increasing part of the potato market. While the potato tubers are stored at low temperatures to minimize storage problems, they tend to accumulate reducing sugars, which negatively impact the quality and color of fried products. The goal of this study was to analyze the impact of cytoplasm type on chip color after harvest and after cold storage at 4 °C, as well as on proline content in cold-stressed potato tubers in a diploid potato population obtained from reciprocal crossing of parents with T- and D-type cytoplasm. Using 224 F1 progeny clones genotyped with Diversity Array Technology (DArTseq™), we mapped the Quantitative Trait Loci (QTL), treating cytoplasm type as a covariate. We detected five QTLs for chip color after harvest and six after cold storage, with the strongest QTL for both traits overlapping on chromosome III. Five QTL for proline content were detected on chromosomes V, X and XII, with the most significant one located on chromosome X. Although the progeny clones with T-type cytoplasm produced significantly lighter chips after cold storage, the cytoplasm type used as a covariate caused only minor modifications to the obtained QTL landscapes for chip color and proline content. Full article

Cold temperature storage (lower than 10 °C) has been used as a management strategy to extend marketability and reduce potato storage losses. However, cold temperatures may result in dark-colored chips through a process known as cold-induced sweetening (CIS). ‘Dakota Crisp’ and ‘Dakota Diamond’ are two North Dakota State University potato breeding program cultivar releases selected for cold-chipping ability with high tuber yield potential. Two-year storage trials were conducted to examine sugar development and tuber processing quality of four cultivars grown at three nitrogen rates under irrigated and non-irrigated field conditions. The two-way interaction between storage period and storage temperature was significant for sucrose content, glucose content, visual chip color, and Agtron values, indicating a difference in sugar development for each storage temperature profile. Among the four cultivars evaluated under both irrigated and non-irrigated production conditions, ‘Dakota Pearl’ accumulated significantly less sucrose and glucose compared to other cultivars under the same storage conditions. ‘Dakota Crisp’ produced acceptable chip color from 8.9 °C after long term storage, while ‘Dakota Diamond’ produced acceptable chip color from 8.9 °C for up to 6 months of storage. These results emphasize the importance of developing cultivar-specific management profiles including storage and the informational need for producers and processors in determining the best practices for individual cultivars. Full article

Chestnuts become sweetened with better tastes for fried products after cold storage, but the possible mechanism is not clear. The dynamics of sugar components and related physiological responses, as well as the possible molecular mechanism in chestnuts during cold storage, were investigated. Sucrose accumulation and starch degradation contributed to taste improvement. Sucrose content reached the peak after two months of cold storage, along with the accumulation of reducing sugars of maltose, fructose and glucose to a much lesser extent. Meanwhile, alpha-amylase and beta-amylase maintained high levels, and the activities of acid invertase and sucrose synthase increased. Transcriptome data demonstrated that differentially expressed genes (DEGs) were significantly enriched in the process of starch and sucrose metabolism pathway, revealing the conversion promotion of starch to sucrose. Furthermore, DEGs involved in multiple phytohormone biosynthesis and signal transduction, as well as the transcription regulators, indicated that sucrose accumulation might be interconnected with the dormancy release of chestnuts, with over 90% germinated after two months of cold storage. Altogether, the results indicated that cold storage improved the taste of chestnuts mainly due to sucrose accumulation induced by DEGs of starch and sucrose metabolism pathway in this period, and the sweetening process was interconnected with dormancy release. Full article

Colored potatoes have been of interest because of their nutritional and health-promoting properties. However, their aptitude for processing regarding acrylamide formation levels is highly variable and for the most part unknown. In this work, the effect of cultivation season (summer and winter), and postharvest cold storage (1, 2, and 5 months at 5 °C ± 1 °C) on the Maillard reaction precursors (reducing sugars, sucrose, and asparagine), phenolic compounds (anthocyanins, phenolic acids and other flavonoids), and acrylamide after frying (GC-MS) were assessed on the “Michuñe negra” potato cultivar from the southern region of Chile grown under fertigation. Acrylamide levels were surveyed on six samples of commercial colored potato chips for comparison purposes. Cultivation season and cold storage showed an effect on both main primary and secondary metabolites. The amount of reducing sugars such as fructose increased with cold storage. Anthocyanin and phenolic contents were higher in the winter season and increased with cold storage. Acrylamide levels were high, surpassing the EFSA benchmark value (750 µg kg⁻¹) in all cases, notably in chips made after one month of cold storage (2125% higher). Additional measures in both agronomical and processing stages of the purple-fleshed potato need to be implemented to lower the acrylamide levels down to acceptable values. Full article

Stevia rebaudiana Bertoni is an economically important source of natural low-calorie sweeteners, steviol glycosides (SGs), with stevioside (Stev) and rebaudioside A (RebA) being the most abundant. Pre-sowing seed treatment with cold plasma (CP) was shown to stimulate SGs biosynthesis/accumulation up to several fold. This study aimed to evaluate the possibility to predict CP-induced biochemical changes in plants from morphometric parameters. Principle component analysis (PCA) was applied to two different sets of data: morphometric parameters versus SGs concentrations and ratio, and morphometric parameters versus other secondary metabolites (total phenolic content (TPC), total flavonoid content (TFC)) and antioxidant activity (AA). Seeds were treated for 2, 5 and 7 min with CP (CP2, CP5 and CP7 groups) before sowing. CP treatment stimulated SGs production. CP5 induced the highest increase of RebA, Stev and RebA+Stev concentrations (2.5-, 1.6-, and 1.8-fold, respectively). CP did not affect TPC, TFC or AA and had a duration-dependent tendency to decrease leaf dry mass and plant height. The correlation analysis of individual plant traits revealed that at least one morphometric parameter negatively correlates with Stev orRebA+Stev concentration after CP treatment. Full article

Maximal oxygen consumption ($\dot{\mathrm{V}}$O_2max) is a major determinant of 5-km running time-trial (TT) performance. Glycerol-induced hyperhydration (GIH) could improve $\dot{\mathrm{V}}$O_2max in recreationally active persons through an optimal increase in plasma volume. Moreover, ingestion of a large bolus of cold fluid before exercise could decrease thermal stress during exercise, potentially contributing to improved performance. We determined the effect of GIH on 5-km running TT performance in 10 recreationally active individuals (age: 24 ± 4 years; $\dot{\mathrm{V}}$O_2max: 48 ± 3 mL/kg/min). Using a randomized and counterbalanced protocol, participants underwent two, 120-min hydration protocols where they ingested a 1) 30 mL/kg fat-free mass (FFM) of cold water (~4 °C) with an artificial sweetener + 1.4 g glycerol/kg FFM over the first 60 min (GIH) or 2) 7.5 mL/kg FFM of cold water with an artificial sweetener over the first 20 min (EUH). Following GIH and EUH, participants underwent a 5-km running TT at 30 °C and 50% relative humidity. After 120 min, GIH was associated with significantly greater fluid retention (846 ± 415 mL) and plasma volume changes (10.1 ± 8.4%) than EUH, but gastrointestinal (GI) temperature did not differ. During exercise, 5-km running TT performance (GIH: 22.95 ± 2.62; EUH: 22.52 ± 2.74 min), as well as heart rate, GI temperature and perceived exertion did not significantly differ between conditions. This study demonstrates that the additional body water and plasma volume gains provided by GIH do not improve 5-km running TT performance in the heat in recreationally active individuals. Full article

In potato (Solanum tuberosum L.), protoplast techniques are limited to a few genotypes; thus, the use of regular regeneration procedures of multicellular explants causes us to face complexities associated to CRISPR/Cas9 gene editing efficiency and final identification of individuals. Geminivirus-based replicons contained in T-DNAs could provide an improvement to these procedures considering their cargo capability. We built a Bean yellow dwarf virus-derived replicon vector, pGEF-U, that expresses all the editing reagents under a multi-guide RNA condition, and the Green Fluorescent Protein (GFP) marker gene. Agrobacterium-mediated gene transfer experiments were carried out on ‘Yagana-INIA’, a relevant local variety with no previous regeneration protocol. Assays showed that pGEF-U had GFP transient expression for up to 10 days post-infiltration when leaf explants were used. A dedicated potato genome analysis tool allowed for the design of guide RNA pairs to induce double cuts of genes associated to enzymatic browning (StPPO1 and 2) and to cold-induced sweetening (StvacINV1 and StBAM1). Monitoring GFP at 7 days post-infiltration, explants led to vector validation as well as to selection for regeneration (34.3% of starting explants). Plant sets were evaluated for the targeted deletion, showing individuals edited for StPPO1 and StBAM1 genes (1 and 4 lines, respectively), although with a transgenic condition. While no targeted deletion was seen in StvacINV1 and StPPO2 plant sets, stable GFP-expressing calli were chosen for analysis; we observed different repair alternatives, ranging from the expected loss of large gene fragments to those showing punctual insertions/deletions at both cut sites or incomplete repairs along the target region. Results validate pGEF-U for gene editing coupled to regular regeneration protocols, and both targeted deletion and single site editings encourage further characterization of the set of plants already generated. Full article

Potato tubers (Solanum tuberosum L.) are usually stored at low temperature, which can suppress sprouting and control the occurrence of diseases. However, low temperatures lead potatoes to easily suffer from cold-induced sweetening (CIS), which has a negative effect on food processing. The aim of this research was to investigate potential treatments on controlling CIS in potatoes during postharvest storage. “Atlantic” potatoes were treated with gibberellin and (S)-carvone, respectively, and stored at 4 °C for 90 days. The results showed that gibberellin can significantly accelerate sprouting and sugar accumulation by regulating expressions of ADP-glucose pyrophosphorylase (AGPase), granule-bound starch synthase (GBSS), β-amylase (BAM1/2), UDP-glucose pyrophosphorylase (UGPase) and invertase inhibitor (INH1/2) genes. The opposite effects were found in the (S)-carvone treatment group, where CIS was inhibited by modulation of the expressions of GBSS and INH1/2 genes. In summary, gibberellin treatment can promote sugar accumulation while (S)-carvone treatment has some effects on alleviating sugar accumulation. Thus, (S)-carvone can be considered as a potential inhibitor of some of the sugars which are vital in controlling CIS in potatoes. However, the chemical concentration, treatment time, and also the treatment method needs to be optimized before industrial application. Full article