Isolation and genetic characteristics of Novel H4N1 Avian Influenza viruses in ChongQing, China.

BACKGROUND: Avian influenza viruses (AIVs) constitute significant zoonotic pathogens encompassing a broad spectrum of subtypes. Notably, the H4 subtype of AIVs has a pronounced ability to shift hosts. The escalating prevalence of the H4 subtype heightens the concern for its zoonotic potential, signaling an urgent need for vigilance. METHODS: During the period from December 2021 to November 2023, we collected AIV-related environmental samples and assessed them using a comprehensive protocol that included nucleic acid testing, gene sequencing, isolation culture, and resequencing. RESULTS: In this study, a total of 934 environmental samples were assessed, revealing a remarkably high detection rate (43.66%, 289/662) of AIV in the live poultry market. Notably, the H4N1 subtype AIV (cs2301) was isolated from the live poultry market and its complete genome sequence was successfully determined. Subsequent analysis revealed that cs2301, resulting from a reassortment event between wild and domesticated waterfowl, exhibits multiple mutations and demonstrates potential for host transfer. CONCLUSIONS: Our research once again demonstrates the significant role of wild and domesticated waterfowl in the reassortment process of avian influenza virus, enriching the research on the H4 subtype of AIV, and emphasizing the importance of proactive monitoring the environment related to avian influenza virus.

Genome assembly of autotetraploid Actinidia arguta highlights adaptive evolution and enables dissection of important economic traits.

Actinidia arguta, the most widely distributed Actinidia species and the second cultivated species in the genus, can be distinguished from the currently cultivated Actinidia chinensis on the basis of its small and smooth fruit, rapid softening, and excellent cold tolerance. Adaptive evolution of tetraploid Actinidia species and the genetic basis of their important agronomic traits are still unclear. Here, we generated a chromosome-scale genome assembly of an autotetraploid male A. arguta accession. The genome assembly was 2.77 Gb in length with a contig N50 of 9.97 Mb and was anchored onto 116 pseudo-chromosomes. Resequencing and clustering of 101 geographically representative accessions showed that they could be divided into two geographic groups, Southern and Northern, which first diverged 12.9 million years ago. A. arguta underwent two prominent expansions and one demographic bottleneck from the mid-Pleistocene climate transition to the late Pleistocene. Population genomics studies using paleoclimate data enabled us to discern the evolution of the species' adaptation to different historical environments. Three genes (AaCEL1, AaPME1, and AaDOF1) related to flesh softening were identified by multi-omics analysis, and their ability to accelerate flesh softening was verified through transient expression assays. A set of genes that characteristically regulate sexual dimorphism located on the sex chromosome (Chr3) or autosomal chromosomes showed biased expression during stamen or carpel development. This chromosome-level assembly of the autotetraploid A. arguta genome and the genes related to important agronomic traits will facilitate future functional genomics research and improvement of A. arguta.

[Photosynthetic physiological characteristics of Angelica dahurica var.formosana from Sichuan province in different growth years].

In this study,the leaves of autumn-sown Angelica dahurica var. formosana from Sichuan province in different growth years was used to explore the fitting model of photosynthetic response curve and the different photosynthetic physiological characteristics between annual and biennial A. dahurica var. formosana from Sichuan province. The results showed that the fitting model of the optimum light response curve of the leaves of A. dahurica var. formosana from Sichuan province with different growth years was all rectangular hyperbolic correction model. The light saturation points were 1 600,1 700 µmol·m-2·s-1,the light compensation points were17. 98,52. 23 µmol·m-2·s-1 in the leaves of annual and biennial plant,respectively. The diurnal variation curves of net photosynthetic rate,transpiration rate and stomatal conductance in the leaves all acted as a single peak value wave. The daily mean values of net photosynthetic rate and transpiration rate in the leaves of biennial plant were significantly higher than that of annual plant. There was no significant difference in daily mean stomatal conductance. The net photosynthetic rate was significantly positively correlated with stomatal conductance in both of the different growth years. The net photosynthetic rate of annual and biennial A. dahurica var. formosana from Sichuan province had extremely significant and significantly negative correlation with the intercellular CO2 respectively. The transpiration rate of annual plant was positively correlated with the effective photosynthetic radiation intensity and air temperature,but had significantly negative correlation with the intercellular CO2 concentration. The transpiration rate of biennial plant had extremely positive correlation with the effective photosynthetic radiation intensity,and negatively correlated with the intercellular CO2 concentration. In conclusion,the photosynthetic efficiency of the leaves in biennial plant of A. dahurica var. formosana from Sichuan province was higher than that in annual plant,but the ability to utilize weak light was lower than that of annual plant. It should be planted in the sunny field.