Genetic dissection of rice appearance quality and cooked rice elongation by genome-wide association study

Appearance and cooked rice elongation are key quality traits of rice. Although some QTL for these traits have been identified, understanding of the genetic relationship between them remains limited. In the present study, large phenotypic variation was observed in 760 accessions from the 3 K Rice Genomes Project for both appearance quality and cooked rice elongation. Most component traits of appearance quality and cooked rice elongation showed significant pairwise correlations, but a low correlation was found between appearance quality and cooked rice elongation. A genome-wide association study identified 74 QTL distributed on all 12 chromosomes for grain length, grain width, length to width ratio, degree of endosperm with chalkiness, rice elongation difference, and elongation index. Thirteen regions containing QTL stably expressed in multiple environments and/or exerting pleiotropic effects on multiple traits were detected. By gene-based association analysis and haplotype analysis, 46 candidate genes, including five cloned genes, and 49 favorable alleles were identified for these 13 QTL. The effect of the candidate gene Wx on rice elongation difference was validated by a transgenic strategy. These results shed light on the genetic bases of appearance quality and cooked rice elongation and provide gene resources for improving rice quality by molecular breeding.

The Sources of Bacillus cereus Contamination and their Association with Cereulide Production in Dairy and Cooked Rice Processing Lines

Bacillus cereus,a spore-forming bacterium and frequent cause of food poisoning,poses a safety threat to dairy and rice industries due to its high contamination rates and ability to produce toxins such as cereulide.Because of widespread presence and thermal resistance of the spores,B.cereus cannot be eliminated from the environment and may survive in processing plants.Surviving spores can develop into vegetative cells,leading to a heightened risk of cereulide production in the processing environment.Both spores and vegetative cells have the ability to adhere to the surfaces of dairy plants and form biofilms,serving as the site for cereulide production and accumulation.Therefore,it is crucial for the food industry to address potential sources and pathways of B.cereus contamination and their connections to cereulide production in processing lines.In this review,sources of contamination of B.cereus,including spores,vegetative cells,and biofilms and their potential role in cereulide production at each stage of dairy and cooked rice processing were analyzed.In addition,control methods to prevent B.cereus contamination and cereulide production in processing lines were proposed,offering valuable insights for improving microbial risk management in the food industry.