ABSTRACT
Common carp are among the oldest domesticated fish in the world. As such, there are many food and ornamental carp strains with abundant phenotypic variations due to natural and artificial selection. Hebao red carp (HB, Cyprinus carpio wuyuanensis), an indigenous strain in China, is renowned for its unique body morphology and reddish skin. To reveal the genetic basis underlying the distinct skin color of HB, we constructed an improved high-fidelity (HiFi) HB genome with good contiguity, completeness, and correctness. Genome structure comparison was conducted between HB and a representative wild strain, Yellow River carp (YR, C. carpio haematopterus), to identify structural variants and genes under positive selection. Signatures of artificial selection during domestication were identified in HB and YR populations, while phenotype mapping was performed in a segregating population generated by HB×YR crosses. Body color in HB was associated with regions with fixed mutations. The simultaneous mutation and superposition of a pair of homologous genes ( mitfa) in chromosomes A06 and B06 conferred the reddish color in domesticated HB. Transcriptome analysis of common carp with different alleles of the mitfa mutation confirmed that gene duplication can buffer the deleterious effects of mutation in allotetraploids. This study provides new insights into genotype-phenotype associations in allotetraploid species and lays a foundation for future breeding of common carp.
Subject(s)
Carps , Animals , Carps/genetics , Skin Pigmentation/genetics , Genome , Skin , MutationABSTRACT
In order to determine how the diameter class length distribution (DCLD) of fine roots of Chinese fir (Cunninghamia lanceolata) would be affected by soil warming, nitrogen addition and their interaction, a factorial experiment of soil warming (ambient, +5 â) and nitrogen addition (ambient, +4 and +8 g N·m-2·a-1) was carried out in the Chenda State-owned Forest Farm in Sanming, Fujian Province. An expanded extreme value model fitted the DCLD of roots of all the six treatments very well (R2=0.97). The model parameters showed that soil warming reduced the total root length, but its effect on root diameter was not significant. Nitrogen addition decreased both total root length and root diameter. The interaction of soil warming and nitrogen addition had significant effects on total root length, but had no significant effects on root diameter. DCLD of fine roots under the six treatments could be fitted well by the extreme value function (R2>0.98). The correlation analysis showed that specific root length for roots of 0-1 mm diameter was significantly negatively correlated with the parameter c, and the actual total root length was significantly positively correlated with the parameter b. It was concluded that the root morphology of Chinese fir seedlings would respond to both soil warming, nitrogen addition and their interaction, and these responses could be reflected by the changes in parameters of the extreme value model.
Subject(s)
Cunninghamia/growth & development , Nitrogen/chemistry , Soil , Temperature , Biomass , China , Forests , Plant Roots/growth & development , Seedlings/growth & developmentABSTRACT
A precipitation exclusion experiment was set up in Cunninghamia lanceolata seedling plots in Chenda State-Owned Forest Farm, Sanming, Fujian Province, which included 50% precipi-tation reduction and ambient precipitation (control). Using soil coring and in-growth core me-thods, changes in fine-root functional traits of C. lanceolata seedlings, including fine-root biomass, morphology, stoichiometry, specific root respiration, and nonstructural carbohydrates, were exa-mined after 1 year's precipitation exclusion. The results showed that precipitation exclusion significantly decreased biomass of 0-1 mm diameter roots but had no effect on 1-2 mm diameter roots. However, adaptive morphological changes occurred in the precipitation exclusion treatment. The specific root length (SRL) of the 0-1 and 1-2 mm diameter roots increased by 21.1% and 30.5%, respectively, and root tissue density (RTD) significantly decreased and specific root surface area (SRA) significantly increased in the 0-1 mm diameter roots. Precipitation exclusion led to increase in nitrogen concentration in fine roots, but the absorption capacity for phosphorus was impeded, resulting in increased root N:P, which implied a nutritional imbalance in fine roots. Precipitation exclusion did not significantly change fine root specific respiration rate and nonstructural carbohydrate (NSC) content. However, the soluble sugar content and the ratio of soluble sugar to starch were significantly decreased, and the starch content was increased by 33.3% in the 1-2 mm diameter roots, indicating an adaptation response of C. lanceolata seedlings to reduced precipitation by increasing the storage of nonstructural carbohydrate in fine roots.
