Prevalence, genomic characteristics, and pathogenicity of fowl adenovirus 2 in Southern China.

In recent years, the occurrence of fowl adenovirus 2 (FAdV-2) has been on the rise in China, posing a significant threat to the poultry industry. This study aimed to investigate the epidemiology, phylogenetic relationship, genomic characteristics, and pathogenicity of FAdV-2. The epidemiological analysis revealed the detection of multiple FAdV serotypes, including FAdV-1, FAdV-2, FAdV-3, FAdV-4, FAdV-8a, FAdV-8b, and FAdV-11 serotypes. Among them, FAdV-2 exhibited the highest proportion, accounting for 21.05% (8/38). The complete genomes of these 8 FAdV-2 strains were sequenced. Genetic evolution analysis indicated that these FAdV-2 strains formed a separate branch within the FAdV-D group, sharing 94.60 to 97.90% nucleotide similarity with the reference FAdV-2 and FAdV-11 strains. Notably, the recombination analysis revealed that 5 out of the 8 FAdV-2 strains, exhibited recombination events between FAdV-2 and FAdV-11. The recombination regions involved Hexon, Fiber, ORF19 genes and 3' end. Furthermore, pathogenicity experiments demonstrated that recombinant FAdV-2 XX strain is capable of inducing mortality rate of 66.70% and causing more severe hepatitis hydropericardium syndrome (HHS) in 6-wk-old specific-pathogen-free chickens. These findings contribute to our understanding of the prevalence, genomic characteristics, and the pathogenicity of FAdV-2, providing foundations for FAdV-2 vaccine development.

Antioxidant enzyme systems and the ascorbate-glutathione cycle as contributing factors to cadmium accumulation and tolerance in two oilseed rape cultivars (Brassica napus L.) under moderate cadmium stress.

Oilseed rape (Brassica napus L.) with high tolerance to cadmium (Cd) may be used in the phytoremediation of Cd-contaminated fields. However, the mechanisms responsible for Cd accumulation and tolerance in oilseed rape are still poorly understood. Here, we investigated the physiological and molecular processes involved in Cd tolerance of two oilseed rape cultivars with different Cd accumulation abilities. The total Cd accumulation in cultivar L351 was higher than cultivar L338, particularly with increasing concentrations of Cd exposure. L338 was a more pronounced Cd-sensitive cultivar than L351, while higher activities of antioxidant enzymes (CAT, APX, GR, DHAR) as well as higher contents of GSH and AsA were all observed in L351 under Cd treatments, especially at high levels. No differences were found in SOD activities between the two cultivars under the same Cd treatments, suggesting that SOD was not the key factor in relation to the differences of Cd tolerance and accumulation between them. Gene expression levels of BnFe-SOD, BnCAT, BnAPX, BcGR and BoDHAR in roots of L351 were relatively higher than that in L338 under Cd exposure as well as BnCAT and BcGR in leaves. It is concluded that antioxidant enzymes and the ascorbate-glutathione cycle play important roles in oilseed rape Cd accumulation and tolerance.