OsFK1 encodes C-14 sterol reductase,which is involved in sterol biosynthesis and affects premature aging of leaves in rice

The enzyme C-14 sterol reductase is involved in biosynthesis of brassinosteroids(BR)and sterols,as well as plant development.OsFK1,a member of the sterol biosynthesis pathway located in the endoplasmic reticulum(ER),encodes C-14 sterol reductase.However,there is little research on the function of C-14 sterol reductase in rice.Compared with the wild type,an osfk1 mutant showed dwarf phenotype and premature aging in the second leaf during the trefoil stage,and abnormal development of leaf veins during the tillering stage.The osfk1 mutant showed signs of aberrant PCD,as evidenced by TUNEL staining.This suggested that high ROS buildup caused DNA damage and ROS-mediated cell death in the mutant.The osfk1 mutant also showed decreased chlorophyll content and aberrant chloroplast structure.Sequencing of the osfk1 mutant allele revealed a non-synonymous G to A mutation in the final intron,leading to early termination.Here,we identified the OsFK1 allele,cloned it by Mutmap sequencing,and verified it by complementation.HPLC-MS/MS assays demonstrated that the osfk1 mutation caused lower phytosterol levels.These findings showed that the OsFK1 allele encoding C-14 sterol reductase is involved in phytosterol biosynthesis and mediates normal development of rice plants.

Chlorophyll Content and Photosynthetic Characteristics of Pepper Inbred Lines

This study aimed to investigate chlorophyll content and photosynthetic characteristics of 17 pepper inbred lines which were selected independently. The results showed that chlorophyll contents significantly varied among different inbred lines. To be specific, chlorophyll content of No. 68 inbred line was significantly higher than that of other 14 inbred lines ; chlorophyll content of No. 55 inbred line was signifieandy lower than that of other 15 inbred lines. The chlorophyll content of various inbred lines showed a decreasing order of No. 68 〉 No. 47 〉 No. 66 〉 No. 62 〉 No. 63 〉 No. 60 〉 No. 61 〉 No. 64 〉 No. 56 〉 No. 67 〉 No. 65 〉 No. 48 〉 No. 59 〉 No. 58 〉 No. 57 〉 No. 69 〉 No. 55 ; the photosynthetic rate of various inbred lines showed a decreasing order of No. 68 〉 No. 57 〉 No. 60 〉 No. 48 〉 No. 58 〉 No. 47 〉 No. 62 〉 No. 63 〉 No. 64 〉 No. 65 ; the maximum photesynthetie rate of No. 65 inbred line was significantly lower than other seven inbred lines, while no signifi- cant difference was observed among other nine inbred lines.

COVID-19 Outbreak Caused by Contaminated Packaging of Imported Cold-Chain Products—Liaoning Province,China,July 2020

Summary What is known about this topic?Few major outbreaks of coronavirus disease 2019(COVID-19)have occurred in China after major nonpharmaceutical interventions and vaccines have been deployed and implemented.However,sporadic outbreaks that had high possibility to be linked to cold chain products were reported in several cities of China..What is added by this report?In July 2020,a COVID-19 outbreak occurred in Dalian,China.The investigations of this outbreak strongly suggested that the infection source was from COVID-19 virus-contaminated packaging of frozen seafood during inbound unloading personnel contact.What are the implications for public health practice?Virus contaminated paper surfaces could maintain infectivity for at least 17–24 days at-25℃.Exposure to COVID-19 virus-contaminated surfaces is a potential route for introducing the virus to a susceptible population.Countries with no domestic transmission of COVID-19 should consider introducing prevention strategies for both inbound travellers and imported goods.Several measures to prevent the introduction of the virus via cold-chain goods can be implemented.