Haplotype-resolved chromosome-level genome assembly of Huyou (Citrus changshanensis).

Huyou (Citrus changshanensis) is a significant citrus species that originated in Zhejiang Province, China, where it is also primarily cultivated. It is valued for its distinctive flavor and notable health benefits, owing to its high content of bioactive compounds like naringin and limonin. However, the absence of a high quality reference genome has limited the exploration of these health-promoting compounds in Huyou and hindered research into the mechanisms behind its medicinal properties. In this study, we present a phased chromosome-level genome assembly of Huyou. By combining PacBio and Hi-C sequencing, we generated a primary genome assembly and two haplotypes, comprising nine pseudo-chromosomes, with sizes of 339.91 Mb, 323.51 Mb, and 311.89 Mb, respectively. By integrating transcriptome data and annotations of homologous species, we identified a total of 29,775 protein-coding genes in the genome of Huyou. Additionally, we detected lots of structural variants between the two haplotypes. This represents the first reference genome of Huyou, providing a valuable resource for future studies on its agricultural characteristics and medicinal applications.

Metabolite profile comparison of a graft chimera 'Hongrou Huyou' (Citrus changshan-huyou + Citrus unshiu) and its two donor plants.

BACKGROUND: Chimeras synthesized artificially by grafting are crucial to the breeding of perennial woody plants. 'Hongrou Huyou' (Citrus changshan-huyou + Citrus unshiu) is a new graft chimera originating from the junction where a Citrus changshan-huyou ("C") scion was top-grafted onto a stock Satsuma mandarin 'Owari' (C. unshiu, "O"). The chimera was named OCC because the cell layer constitutions were O for Layer 1(L1) and C for L2 and L3. In this study, profiles of primary metabolites, volatiles and carotenoids derived from different tissues in OCC and the two donors were investigated, with the aim of determining the relationship between the layer donors and metabolites. RESULTS: The comparison of the metabolite profiles showed that the amount and composition of metabolites were different between the peels and the juice sacs, as well as between OCC and each of the two donors. The absence or presence of specific metabolites (such as the carotenoids violaxanthin and ß-cryptoxanthin, the volatile hydrocarbon germacrene D, and the primary metabolites citric acid and sorbose) in each tissue was identified in the three phenotypes. According to principal component analysis (PCA), overall, the metabolites in the peel of the chimera were derived from donor C, whereas those in the juice sac of the chimera came from donor O. CONCLUSION: The profiles of primary metabolites, volatiles and carotenoids derived from the peels and juice sacs of OCC and the two donors were systematically compared. The content and composition of metabolites were different between the tissues and between OCC and the each of the two donors. A clear donor dominant pattern of metabolite inheritance was observed in the different tissues of OCC and was basically consistent with the layer origin; the peel of the chimera was derived from C, and the juice sacs of the chimera came from O. These profiles provide potential chemical markers for genotype differentiation, citrus breeding assessment, and donor selection during artificial chimera synthesis.

Study on power coupling of annular vortex beam propagating through a two-Cassegrain-telescope optical system in turbulent atmosphere.

As a new attractive application of the vortex beams, power coupling of annular vortex beam propagating through a two- Cassegrain-telescope optical system in turbulent atmosphere has been investigated. A typical model of annular vortex beam propagating through a two-Cassegrain-telescope optical system is established, the general analytical expression of vortex beams with limited apertures and the analytical formulas for the average intensity distribution at the receiver plane are derived. Under the H-V 5/7 turbulence model, the average intensity distribution at the receiver plane and power coupling efficiency of the optical system are numerically calculated, and the influences of the optical topological charge, the laser wavelength, the propagation path and the receiver apertures on the power coupling efficiency are analyzed. These studies reveal that the average intensity distribution at the receiver plane presents a central dark hollow profile, which is suitable for power coupling by the Cassegrain telescope receiver. In the optical system with optimized parameters, power coupling efficiency can keep in high values with the increase of the propagation distance. Under the atmospheric turbulent conditions, great advantages of vortex beam in power coupling of the two-Cassegrain-telescope optical system are shown in comparison with beam without vortex.

[Perinatal birth defects in 5 years in Changsha].

OBJECTIVE: To investigate and analyze the occurrence of 64,101 perinatal birth defects from 2000 to 2004, to determine the tendency of the incidence rate of birth defects and perinatal mortality, and to explore feasible and effective intervention strategy. METHODS: We investigated 64,101 perinatal infants who were born in 13 hospitals in Changsha from January 2000 to December 2004. The incidence rate of all birth defects, mortality of perinatal infants, the incidence rate of various kinds of birth defects, and the component rate of birth defects were analyzed. RESULTS: Altogether 1,050 neonate birth defects were found, with the incidence rate of 1.638%. The incidence rate of birth defects was increasing year-by-year in 2000 compared with that in 2002, 2003 and 2004, with significant differences (all P values<0.05): the incidence rate of birth defects in 2001 compared with that in 2002, 2003 and 2004, also with significant differences (P<0.05). Eight hundred seventy nine perinatal infants died, and the mortality was 1.371%. The mortality perinatal of infants increased in 2001 compared with that in 2002 and in 2003, with significant differences (P<0.05). The top 5 birth defects with the highest incidence were congenital heart disease, polydactly, auricle malformation, cheiloschisis, and palatoschisis, congenital hydrocephal in turn. The incidences of congenital heart disease and hydrocephal increased significantly. One hundred seventy seven fetuses were performed induced labor because of fetal defects from 2003. CONCLUSION: We must pay attention to the increasing tendency of birth defect incidence and perinatal mortality. Strengthening environmental protection and antenatal care can decrease the birth defect incidence. Performing antenatal examination and neonatal screening regularly can discover the birth defects in time. When severe birth defects occur, the induced labor should be performed.