Genome-wide SNP discovery and core marker sets for assessment of genetic variations in cultivated pumpkin(Cucurbita spp.)

Three pumpkin species Cucurbita maxima,C.moschata,and C.pepo are commonly cultivated worldwide.To identify genome-wide SNPs in these cultivated pumpkin species,we collected 48 F1 cultivars consisting of 40 intraspecific hybrids(15 C.maxima,18 C.moschata,and 7 C.pepo)and 8 interspecific hybrids(C.maxima x C.moschata).Genotyping by sequencing identified a total of 37,869 confident SNPs in this collection.These SNPs were filtered to generate a subset of 400 SNPs based on polymorphism and genome distribution.Of the 400 SNPs,288 were used to genotype an additional 188 accessions(94 F1 cultivars,50 breeding lines,and 44 landraces)with a SNP array-based platform.Reliable polymorphisms were observed in 224 SNPs(78.0%)and were used to assess genetic variations between and within the four predefined populations in 223 cultivated pumpkin accessions.Both principal component analysis and UPGMA clustering found four major clusters representing three pumpkin species and interspecific hybrids.This genetic differentiation was supported by pairwise Fst and Nei’s genetic distance.The interspecific hybrids showed a higher level of genetic diversity relative to the other three populations.Of the 224 SNPs,five subsets of 192,96,48,24,and 12 markers were evaluated for variety identification.The 192,96,and 48 marker sets identified 204(91.5%),190(85.2%),and 141(63.2%)of the 223 accessions,respectively,while other subsets showed<25%of variety identification rates.These SNP markers provide a molecular tool with many applications for genetics and breeding in cultivated pumpkin.

Impact of Piers on Tidal Marshes： Accumulation of Wood Preservative Metals in Water and Soils

Wood treated with chromated copper arsenate （CCA） is a common material for pier pilings. Research on CCA impacts in estuarine systems indicates that the magnitude of the biological effect is variable and dependent on sediment and water characteristics. To assist environmental agencies in assessing pier impacts a project was conducted in the U.S.A. to investigate the spatial distribution and magnitude of As, Cr, and Cu accumulation in waters and soils near old and new piers. For new piers, soluble metal levels were highest within 2.9 m of the piers. Total As and Cu levels approached background levels at distances of 2.9 m and 1.4 m, respectively. For old piers, total As and Cu approached background levels at a distance of 9.0 m. Total Cr never exceeded background levels. Threshold effects concentrations were exceeded by sedimented As and Cu within 3.6 m of old piers and 2.1 m of new piers. Apparent effects thresholds were never reached. The only water chemistry variable impacted by piers was As with new piers. It was concluded that leachates accumulate only close to piers and at levels below critical biological thresholds, and would be expected to have negligible ecological effects in reasonably flushed areas.

Genome-wide association study identifies QTL for eight fruit traits in cultivated tomato (Solanum lycopersicum L.)

Genome-wide association study(GWAS)is effective in identifying favorable alleles for traits of interest with high mapping resolution in crop species.In this study,we conducted GWAS to explore quantitative trait loci(QTL)for eight fruit traits using 162 tomato accessions with diverse genetic backgrounds.The eight traits included fruit weight,fruit width,fruit height,fruit shape index,pericarp thickness,locule number,fruit firmness,and brix.Phenotypic variations of these traits in the tomato collection were evaluated with three replicates in field trials over three years.We filtered 34,550 confident SNPs from the 51K Axiom®tomato array based on<10%of missing data and>5%of minor allele frequency for association analysis.The 162 tomato accessions were divided into seven clusters and their membership coefficients were used to account for population structure along with a kinship matrix.To identify marker-trait associations(MTAs),four phenotypic data sets representing each of three years and combined were independently analyzed in the multilocus mixed model(MLMM).A total of 30 significant MTAs was detected over data sets for eight fruit traits at P<0.0005.The number of MTA per trait ranged from one(brix)to seven(fruit weight and fruit width).Two SNP markers on chromosomes 1 and 2 were significantly associated with multiple traits,suggesting pleiotropic effects of QTL.Furthermore,16 of 30 MTAs suggest potential novel QTL for eight fruit traits.These results facilitate genetic dissection of tomato fruit traits and provide a useful resource to develop molecular tools for improving fruit traits via marker-assisted selection and genomic selection in tomato breeding programs.

Risk factors in street food practices in developing countries:A review

Street food trading solves major social and economic problems in developing countries through the provision of ready-made meals at relatively inexpensive prices and employment for teeming rural and urban populace along its value chain.However,due to informal nature of the enterprise,the activities of the practitioners are not regulated.This gives ample room for unwholesome practices.The results are the risks such activities pose to the health and safety of practitioners along the value chain.This review paper,a summary of literature reports on risk factors in street food trade in developing countries and recommended safety intervention,is written with the hope of providing global baseline for intervention to ensure safe food practices.Adoption of safety approaches that permeates the entire chain of street food business from good agricultural practices through hazard analysis critical control points strategy to good hygiene practices by farmers,vendors and consumers would significantly reduce risks in street food consumption.Above all,active collaboration of all stakeholders toward the strengthening and proper enforcement of public health policies to ensure safe practices and engender safer and healthier society is recommended.

Nucleus-Encoded Thylakoid Protein,OsY3IP1,Confers Enhanced Tolerance to Saline and Alkaline Stresses in Rice

Abiotic stress confers serious damage to the photosynthetic machinery,often resulting in plant growth inhibition.Hypothetical chloroplast open reading frame 3(Ycf3)-interacting protein 1(Y3IP1)is a nucleus-encoded thylakoid protein and plays an essential role in the assembly of photosystem I.The full-length cDNA over-expresser(FOX)gene-hunting system is an approach using systemically generated gain-of-function mutants.Among the FOX-rice lines,a line CE175 overexpressing rice Y3IP1gene(Os Y3IP1)displayed less inhibition of root growth under saline(NaCl)stress.The expression of Os Y3IP1 was up-regulated under saline and alkaline(Na2CO3)stresses in the rice variety Kitaake.After saline and alkaline treatments,transgenic Kitaake overexpressing OsY3IP1-GFP(OsY3IP1-GFPox/Kit)displayed higher levels of chlorophyll content compared to Kitaake.Under the stress conditions,the maximum quantum yield of photosystem II photochemistry levels was higher in OsY3IP1-GFPox/Kit than in Kitaake.The increased tolerance conferred by OsY3IP1 overexpression correlated with reduced reactive oxygen species accumulation.Our data provide new insights into the possible role of OsY3IP1 in the pathway suppressing photooxidative damage under stress conditions.These features can be further exploited to improve saline and alkaline tolerances of rice plants in future.

Water absorption characteristics of Canarium Schweinfurthii fruits

Water absorption characteristics of two varieties of Canarium Schweinfurthii engl.fruit(Canarium Schweinfurthii engl.long and short)essential for predicting their suitable absorption conditions was investigated at three different temperatures(35,50,65
C).Increase in moisture content of the fruits was measured at one-hour interval until constant values were obtained after five successive intervals of moisture measurements.Loss of soluble constituents,textural and nutritive qualities of the rehydrated products and their thermodynamic behavior were also measured and calculated.The results obtained revealed that saturation time for 35,50 and 65
C of long and short varieties are 14,18 and 40 h and 18,22 and 36 h respectively.Rate of absorption of the fruits differ significantly(p>0.05)with temperature and not with the variety.Water absorption rate of Canarium Schweinfurthii engl.long and short varieties are 2.71 and 2.25 kg/h respectively.The moisture bearing capacity,textural,and nutritive qualities of the reconstituted products showed no significant difference among varieties at different temperatures used.Fruits soaked at 35
C produced reusable residual water,retained their nutritive values and soluble constituent more than other soaking temperatures studied.However,the absorption reaction is endothermic with negative entropy and Gibbs energy values were above zero.Midilli model had the best quality for describing the absorption characteristics of both Canarium Schweifurthii engl.fruits.