RESUMEN
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.
Asunto(s)
Actinidia , Genoma de Planta , Tetraploidía , Actinidia/genética , Evolución Molecular , Adaptación Fisiológica/genética , Evolución BiológicaRESUMEN
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.
