The in vivo glycaemic response of different rice varieties in Sri Lanka

Introduction: Diabetes poses a heavy economic burden in Sri Lanka. High glycaemic index (GI) diets are known to promote a higher risk of diabetes. This study was aimed to determine the GI values of nine improved and three traditional rice varieties of Sri Lanka including Bg406, H.H.Z.36, Ld368, Bw367, Bg94-1, At405, At362, Bg300, Bg352, Sudu heenati, Madathawalu, and Pachchaperumal. Furthermore, comparisons of GI values between improved and traditional varieties, as well as the effect of subject gender and colour of pericarp on GI were described. Methods: Fourteen healthy subjects consisting of seven males and seven females were fed with a reference food and cooked rice varieties containing 50 g available carbohydrate; GI were calculated. Results: The GI of 12 rice varieties varied from 40-69. All traditional varieties including Sudu heenati, Madathawalu and Pachchaperumal were in the low GI category presenting GI values of 51, 54, and 41, respectively. Rice with red pericarp obtained significantly lower GI compared to those with white pericarp. Yet, GI values obtained in males were significantly higher than females. Conclusion: The result of this study suggested that all traditional varieties and improved rice H.H.Z 36, Ld368, and Bg406 could have beneficial effects on lowering the glycaemic response in healthy subjects. Glycaemic index can be predicted from the colour of the rice grain. Gender should be considered in the determination of GI.

Transposon-induced inversions activate gene expression in the maize pericarp

Chromosomal inversions can have considerable biological and agronomic impacts including disrupted gene function, change in gene expression and inhibited recombination. Here we describe the molecular structure and functional impact of six inversions caused by Alternative Transpositions between p1 and p2 genes responsible for floral pigmentation in maize. In maize line p1-wwB54, the p1 gene is null and the p2 gene is expressed in anther and silk but not in pericarp, making the kernels white. By screening for kernels with red pericarp, we identified inversions in this region caused by transposition of Ac and fractured Ac (fAc) transposable elements. We hypothesize that these inversions place the p2 gene promoter near a p1 gene enhancer, thereby activating p2 expression in kernel pericarp. To our knowledge, this is the first report of multiple recurrent inversions that change the position of a gene promoter relative to an enhancer to induce ectopic expression in a eukaryote.

Application of Oxalic Acid and 1-Methylcyclopropane (1-Mcp) with Low and High-Density Polyethylene on Post-Harvest Storage of Litchi Fruit

The present study investigates the effects of oxalic acid and 1-methylcyclopropane (1-MCP) treatments in combination with low-density polyethylene (LDPE) and high-density polyethylene (HDPE) on the post-harvest storage of litchi fruits. The physicochemical properties, bioactive compounds, antioxidant activities, and dismutase enzyme activity (SOD) of treated and untreated litchi fruits were examined during 30 days of storage at 4 ℃. The most effective combination was 1-MCP and HDPE packaging, which lowered the weight loss and preserved the red pericarp. Fruits treated with 1-MCP and HDPE also exhibited higher content of ascorbic acid (74.73–34.95 mg/100 g), total phenol (55.70–28.83 mg/100 g), and total flavonoid content (82.46–48.54 mg/100 g), whereas anthocyanin content (0.24–0.39 mg/100 g) was lowered during the entire storage period. In addition, higher levels of DPPH activity, reducing power, and SOD activity were observed in 1-MCP and HDPE-treated fruits. While antioxidants, SOD activities, and acidity were positively associated with total phenol and flavonoid content, these were negatively associated with anthocyanin content. Thus, the combined treatment of 1-MCP and HDPE are proposed as a sustainable strategy to preserve red pericarp, improve quality, and increase fruit shelf life of litchi.

Genetic analysis and molecular mapping of Rp, a mutant gene encoding red pericarp in rice (Oryza sativa L.)

Coloured rice has pigments deposited in the grain pericarp; red rice is the most common type of coloured rice. Red rice is rich in essential nutrients and has been grown and consumed in China for a long time. In this study, we report the genetic characterisation and preliminary molecular mapping of a mutant gene encoding red pericarp in rice (Oryza sativa L.). To analyse the genetic basis of the red pericarp mutant, a reciprocal cross between GER-3 (red pericarp, indica cv.) and 898 (white pericarp, indica cv.) was made. The genetic analysis results confirmed that there was only one dominant gene, temporarily designated Rp (Red pericarp) controlling the segregation of the red pericarp in the F₂ population. For the molecular mapping of Rp, an F₂ population derived from an inter-subspecific cross between Gene Engineering Rice-3 (GER-3) and C418 (japonica cv., white pericarp) was constructed. The genotype of the pericarp colour of the F₂ individuals in the mapping population was validated by progeny testing of the F_2:3 families. Simple sequence repeat (SSR) markers and the bulked segregation analysis (BSA) method were used; Rp was mapped to the short arm of chromosome 7 between the SSR markers RM21182 and RM21268, with a genetic distance of 3.5 and 12.0 cM, respectively. In this paper, the potential origin of the red pericarp mutant gene Rp was also discussed.

How Can Weedy Rice Stand against Abiotic Stresses? A Review

Weedy rice is one of the most common weeds in rice cultivation in many rice areas throughout the world and it is able to cause significant yield reductions. Weedy rice is characterized by a high biological diversity that permits different populations to be identified on the basis of their morphological and physiological traits. This variability contributes to its success in different environments and allows different abiotic stresses, which are intensified by climate change, to be faced. Taller plants, enhanced tillering, seed shattering and the presence of red pericarp, variable hull coloration and awn morphology, linked to a deeper seed dormancy, are some of the traits that help weedy rice to spread in changing environments. The higher phenotypic plasticity and genetic variability of weedy rice make it more able to cope with temperature variations, intermittent water availability, soil salinity, drought conditions and increased CO2 concentrations than cultivated rice. As these abiotic stresses will become more frequent in the future, weedy rice competitiveness may be higher, with a spread of infestations. Thus, the control of weedy rice should be based on an integration of different preventive and agronomic techniques, a sensible use of herbicides and the use of suitable rice varieties.

Anticancer Potential and Capsianosides Identification in Lipophilic Fraction of Sweet Pepper (Capsicum annuum L.)

This study aimed to determine the health-promoting properties of sweet pepper by comparing the activity of fractions with variable lipophilicity. Fractions from red pericarp: aqueous (F1), 40% MeOH (F2), and 70% MeOH (F3) were analyzed for antiradical activity (with DPPH• and ABTS+•), and the contents of total phenolic compounds (TP), flavonoids (TF), and dihydroxycinnamic acids (TDHCA). The anticancer potential of the fractions was evaluated in vitro using different cancer cell lines: human colorectal carcinoma (HCT116) and PC-3 (prostate cancer cell). Fibroblast-like cells of L929 obtained from subcutaneous adipose tissue of mouse were used as normal cells. The highest content of TP, TF, and TDHCA along with the strongest antiradical activity was observed for fraction F2, while the strongest anticancer properties against PC-3 were observed in fraction F3. Fraction F3 primarily contained capsianoside derivatives, which had been isolated through chromatographic methods and identified by spectral methods. These analyses helped in identifying 8 compounds, including 3 new compounds.

Assessment of the Genetic Diversity of Rice Germplasms Characterized by Black-Purple and Red Pericarp Color Using Simple Sequence Repeat Markers

The assessment of the genetic diversity within germplasm collections can be accomplished using simple sequence repeat (SSR) markers and association mapping techniques. The present study was conducted to evaluate the genetic diversity of a colored rice germplasm collection containing 376 black-purple rice samples and 172 red pericarp samples, conserved by Dong-A University. There were 600 pairs of SSR primers screened against 11 rice varieties. Sixteen informative primer pairs were selected, having high polymorphism information content (PIC) values, which were then used to assess the genetic diversity within the collection. A total of 409 polymorphic amplified fragments were obtained using the 16 SSR markers. The number of alleles per locus ranged from 11 to 47, with an average of 25.6. The average PIC value was 0.913, ranging from 0.855 to 0.964. Four hundred and nine SSR loci were used to calculate Jaccard’s distance coefficients, using the unweighted pair-group method with arithmetic mean cluster analysis. These accessions were separated into several distinctive groups corresponding to their morphology. The results provided valuable information for the colored rice breeding program and showed the importance of protecting germplasm resources and the molecular markers that can be derived from them.

Euscaphis japonica var. wupingensis, a new variety with yellow pericarp from Fujian, China

Euscaphis japonica (Thunberg) Kanitz var. wupingensis B. P. Cai et Z. R. Chen, a new variety is described and illustrated here. The new variety with yellow pericarp is apt to be distinguished from E. japonica var. japonica (Thunb.) Kanitz with red pericarp. The new taxa also can be distinguished from E. japonica var. japonica by their buds, twigs, inflorescences, fruits and seeds.