Mineral nutrient variability of potato (Solanum tuberosum L.) tubers with different colors grown in Niksar, Kazova and Artova locations of Tokat Province, Turkey

Potato is one of the most commonly consumed non-grain staple food crops in the world therefore, the mineral nutrient content of the potato is extremely important for human nutrition. The lack of mineral nutrients causes significant health problems, thus, many of these nutrients are often taken as supplements. This study was carried out to investigate the effects of potato flesh color and location on different mineral nutrient contents under Niksar, Kazova and Artova locations in Tokat Province, Turkey, during 2013 and 2014 potato growing seasons. The experimental design in each location was randomized blocks with three replications. In this study, a total of 67 clones (including varieties and advanced breeding selections) with nine white, 10 cream, 30 light yellow, and 18 dark yellow flesh colors were used. Potatoes with cream flesh colors had the highest K (23.81 g kg^-1), P (0.31 g kg^-1), Mg (1.20 g kg^-1), Zn (27.26 mg kg^-1), Cu (8.28 mg kg^-1) and Mn (7.21 mg kg^-1) contents, and the lowest Ca (45.6 mg kg^-1) content. The mineral contents (except K and Cu) of potatoes grown in Artova were higher compared to the other two locations. The results clearly suggested that Artova is the most suitable location to produce potatoes with a high mineral composition, and Kazova is suitable to cultivate potatoes with high K and Cu contents. In addition, the knowledge of nutrient rich potato accessions is valuable for developing biofortified potato genotypes.

Genotyping of polyploid plants using quantitative PCR: application in the breeding of white-fleshed triploid loquats (Eriobotrya japonica)

BACKGROUND

Ploidy manipulation is effective in seedless loquat breeding, in which flesh color is a key agronomic and economic trait. Few techniques are currently available for detecting the genotypes of polyploids in plants, but this ability is essential for most genetic research and molecular breeding.

RESULTS

We developed a system for genotyping by quantitative PCR (qPCR) that allowed flesh color genotyping in multiple tetraploid and triploid loquat varieties (lines). The analysis of 13 different ratios of DNA mixtures between two homozygous diploids (AA and aa) showed that the proportion of allele A has a high correlation (R² = 0.9992) with parameter b [b = a₁/(a₁ + a₂)], which is derived from the two normalized allele signals (a₁ and a₂) provided by qPCR. Cluster analysis and variance analysis from simulating triploid and tetraploid hybrids provided completely correct allelic configurations. Four genotypes (AAA, AAa, Aaa, aaa) were found in triploid loquats, and four (AAAA, AAAa, AAaa, Aaaa; absence of aaaa homozygotes) were found in tetraploid loquats. DNA markers analysis showed that the segregation of flesh color in all F₁ hybrids conformed to Mendel's law. When tetraploid B431 was the female parent, more white-fleshed triploids occurred among the progeny.

CONCLUSIONS

qPCR can detect the flesh color genotypes of loquat polyploids and provides an alternative method for analyzing polyploid genotype and breeding, dose effects and allele-specific expression.

Transcriptome regulation of carotenoids in five flesh-colored watermelons (Citrullus lanatus)

BACKGROUND

Fruit flesh color in watermelon (Citrullus lanatus) is a great index for evaluating the appearance quality and a key contributor influencing consumers' preferences. But the molecular mechanism of this intricate trait remains largely unknown. Here, the carotenoids and transcriptome dynamics during the fruit development of cultivated watermelon with five different flesh colors were analyzed.

RESULTS

A total of 13 carotenoids and 16,781 differentially expressed genes (DEGs), including 1295 transcription factors (TFs), were detected in five watermelon genotypes during the fruit development. The comprehensive accumulation patterns of carotenoids were closely related to flesh color. A number of potential structural genes and transcription factors were found to be associated with the carotenoid biosynthesis pathway using comparative transcriptome analysis. The differentially expressed genes were divided into six subclusters and distributed in different GO terms and metabolic pathways. Furthermore, we performed weighted gene co-expression network analysis and predicted the hub genes in six main modules determining carotenoid contents. Cla018406 (a chaperone protein dnaJ-like protein) may be a candidate gene for β-carotene accumulation and highly expressed in orange flesh-colored fruit. Cla007686 (a zinc finger CCCH domain-containing protein) was highly expressed in the red flesh-colored watermelon, maybe a key regulator of lycopene accumulation. Cla003760 (membrane protein) and Cla021635 (photosystem I reaction center subunit II) were predicted to be the hub genes and may play an essential role in yellow flesh formation.

CONCLUSIONS

The composition and contents of carotenoids in five watermelon genotypes vary greatly. A series of candidate genes were revealed through combined analysis of metabolites and transcriptome. These results provide an important data resource for dissecting candidate genes and molecular basis governing flesh color formation in watermelon fruit.

Atlantic Salmon (Salmo salar L., 1758) Gut Microbiota Profile Correlates with Flesh Pigmentation: Cause or Effect?

In Tasmania (Australia), during the marine phase, it has been observed that flesh pigmentation significantly drops in summer, possibly due to high water temperatures (> 20 °C). Although this deleterious effect of summer temperatures has been ascertained, there is a lack of knowledge of the actual mechanisms behind the impaired uptake and/or loss of pigments in Atlantic salmon in a challenging environment. Since the microbial community in the fish intestine significantly changes in relation to the variations of water temperature, this study was conducted to assess how the gut microbiota profile also correlates with the flesh color during temperature fluctuation. We sampled 68 fish at three time points covering the end of summer to winter at a marine farm in Tasmania, Australia. Flesh color was examined in two ways: the average color throughout and the evenness of the color between different areas of the fillet. Using 16S rRNA sequencing of the v3-v4 region, we determined that water temperature corresponded to changes in the gut microbiome both with alpha diversity (Kruskal-Wallis tests P = 0.05) and beta diversity indices (PERMANOVA P = 0.001). Also, there was a significant correlation between the microbiota and the color of the fillet (PERMANOVA P = 0.016). There was a high abundance of Pseudoalteromonadaceae, Enterobacteriaceae, Microbacteriaceae, and Vibrionaceae in the pale individuals. Conversely, carotenoid-synthesizing bacteria families (Bacillaceae, Mycoplasmataceae, Pseudomonas, Phyllobacteriaceae, and Comamonadaceae) were found in higher abundance in individuals with darker flesh color.