In vitro culture and plant regeneration derived from ray florets of Chrysanthemum morifolium

Nine cultivars of Chrysanthemum morifolium were screened using the ray floret explants to determine the capability for plant regeneration on four media protocols and subsequently to find out the best genotype source linked with the optimum medium conditions for the high potentiality of shoot formation. The results indicated that all in vitro culture traits were highly significantly influenced by the differences in genotypes, medium protocols and their interaction. The percentage of explants whichdeveloped calli ranged from 73.83% “Ping Pong” to 25.67% “Palisade White” among the cultivars across the four medium protocols with an average of 48.28%. The highest percentage of embryogenic callus, shoot formation and mean value of shoot length was produced by cultivar "Delistar White" when calli were differentiated on medium protocol B. The medium protocol B showed the greatest potential for shoot length across the cultivars and it was significantly superior to all other medium protocolsexcept the medium protocol A. The present study indicated that the medium protocol “B” and then "A" appear to be the best protocols for plant regeneration. The cultivar "Delistar White" with the medium protocols B and then A, could be successfully utilized for further in vitro mutagenesis investigations

COVID-19 Host Genetics Initiative. A first update on mapping the human genetic architecture of COVID-19

The COVID-19 pandemic continues to pose a major public health threat, especially in countries with low vaccination rates. To better understand the biological underpinnings of SARS-CoV-2 infection and COVID-19 severity, we formed the COVID-19 Host Genetics Initiative1. Here we present a genome-wide association study meta-analysis of up to 125,584 cases and over 2.5 million control individuals across 60 studies from 25 countries, adding 11 genome-wide significant loci compared with those previously identified2. Genes at new loci, including SFTPD, MUC5B and ACE2, reveal compelling insights regarding disease susceptibility and severity.</p