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Magnolia sinostellata is one of the endangered species in China and largely suffers light deficiency stress in the understory of forest. However, the weak light response molecular mechanism remains unclear. More importantly, hub genes in the molecular network have not been pinpointed. To explore potential regulators in the mechanism, weighted gene co-expression network analysis (WGCNA) was performed to analysis the trancriptome data of M. sinostellata leaves subjected to weak light with different time points. Gene co-expression analysis illustrated that module 1, 2 and 3 were closely associated with light deficiency treatment, which. Gene ontology and KEGG analyses showed that genes in module 1 mainly participated in amino and nucleotide metabolism, module 2 mostly involved in carbon fixation and module 3 mostly regulated photosynthesis related pathways, among which 6, 7 and 8 hub genes were identified, respectively. Hub genes isoform_107196 in module 1 and isoform_55976 in module 2 were unique to M. sinostellata. This study found that light deficiency inhibited photosynthesis and stress tolerance, while improved carbon metabolism and flowering related pathways in M. sinostellata, which can impact its accumulation reserves of growth and reproduction in the next season. In addition, key shade response regulators identified in this study have laid a firm foundation for further investigation of shade response molecular mechanism and protection of other shade sensitive plants. [ABSTRACT FROM AUTHOR]

Camptotheac acuminata Decne is a unique tree species in China with an important secondary metabolite, camptothecin (CPT), used in the treatment of cancer. Nitrogen (N) is an important element that affects plant growth and the accumulation of CPT. Reports on the effect of N on CPT synthesis from a genetic perspective are scarce. To explore the effects of different N sources and levels on CPT synthesis in C. acuminata, two-year-old seedlings were fertilized with different concentrations of pure ammonium sulphate, source of ammonium N (NH4+–N), and potassium nitrate for nitrate N (NO3−–N). Concentrations of 2.5, 5, 7.5, and 10 g pot−1 NH4+–N and NO3−–N were used. The results showed that 7.5 g NH4+–N and NO3−–N treatments were best for growth and fresh weight of leaves. Compared with the other treatments, the CPT content, tryptophan synthase and tryptophan decarboxylase activities, and expression of the CaTSB and CaTDC1 genes under the 2.5 g NH4+–N and NO3−–N treatments peaked significantly at 30 days. However, the expression of CaTDC2 surpassed that of the other two genes at 60 days. Therefore, compared with NH4+–N source, the NO3−–N source was more beneficial for growth, and NO3−–N was better for CPT yield. Consequently, leaves of C. acuminata treated with 2.5 g NO3−–N could be harvested after 30 days to obtain maximum CPT content. CaTDC1 is more closely linked to CPT synthesis. The results of this study improved the production of CPT in C. acuminata via fertilization. [ABSTRACT FROM AUTHOR]

Key message: In Magnolia sinostellata plants grown under shading and waterlogging conditions, solar noon PFD level of 1050 ± 30 µmol·m− 2·s− 1 and running water combined treatment (L1W2) triggers changes in chlorophyll metabolism and photosynthesis, which benefits growth of this endangered species.Abstract: Magnolias are widely used as ornamental plants in cities, but they are facing extinction in the wild. It has been hypothesized that shading from trees in the upper canopy and stress from waterlogging conditions reduce their survival rates. To test this hypothesis, we grew 2-year-old Magnolia sinostellata seedlings either under natural light level (solar noon PFD of 1400 ± 28 µmol·m− 2·s− 1) and normal watering conditions (watered every 3 days) (control, CK) or reduced light levels (L1 1050 ± 30 µmol·m− 2·s− 1; L2 700 ± 27 µmol·m− 2·s− 1 and L3 490 ± 25 µmol·m− 2·s− 1) in combination with two types of waterlogging scenarios: still water treatment (W1, water level kept at 2 cm above soil surface) or running water treatment (W2, constantly irrigated via drip-irrigation). Measurements of chlorophyll content, gas exchange, and relative expression of genes involved in chlorophyll synthesis revealed that chlorophyll content, net photosynthetic rate, stomatal conductance, and transpiration rate were significantly higher in L1W2 treatment than the control or any of the other treatment examined, whereas the intercellular CO2 concentration was lower under the L1W2 treatment. The expression levels of genes involved in chlorophyll biosynthesis were higher under L1W2 than CK conditions, but lower under L1W1, L2W1, L2W2, L3W1, and L3W2 treatment. These results suggest that L1W2 condition is most suitable for chlorophyll synthesis and photosynthesis of M. sinostellata. This study provides new insights into the physiology and development of endangered plants and useful guidance for conservation efforts aimed at protecting wild magnolia species. [ABSTRACT FROM AUTHOR]

Magnolia sinostellata is an endemic species of Magnoliaceae that is narrowly distributed in the south of Zhejiang Province, China. To explore the genetic diversity and population structure of this endangered species, this study developed sequence tag-simple sequence repeat (EST-SSR) markers based on transcriptome data of M. sinostellata. In total, 25472 SSRs were identified among 110644 unique assembled sequences with a total of 90.83 Mb and an average frequency of 23.02%. The mononucleotide (33.53%) and dinucleotide (42.08%) motifs appeared to be the most abundant. In total, 150 potential loci were randomly selected to validate the quality of the developed SSR markers; an effective PCR rate of 32.00% and a polymorphism rate of 15.33% were obtained for these loci. After performing sequencing and cloning for validation, 23 pairs of SSR primers were retained and used to characterize the genetic diversity and population structure of M. sinostellata. Overall, 204 alleles were amplified. The results of Shannon's information index (I), heterozygosity (Ho), heterozygosity (He) and Nei's expected heterozygosity (H) indicated rich genetic diversity in M. sinostellata. However, the high inbreeding coefficient and differential coefficient suggest that serious genetic drift occurred within populations, and genetic differentiation is apparent among the populations. Consequently, although M. sinostellata has high genetic diversity among populations, it is still in a serious and dangerous condition. Habitat destruction caused by human activities is the main threat to this species, and enhancing the species abundance by adopting some conservation measures should be favourable for saving the species. [ABSTRACT FROM AUTHOR]

Haemolytic disease is a condition characterized by anaemia and jaundice, and the course may be more complicated in twins. We investigated the demographic and laboratory characteristics of twins with haemolytic disease of the newborn (HDN) and compared these characteristics between groups categorized according to multiple birth status (twins vs. singletons) and conception method (assisted reproductive technology (ART) vs. spontaneous conception). Fifty-five twins with HDN and 253 singletons with HDN who were born during the same period (controls) were included in the study, and we performed comparisons between them. The results showed that twin infants were more likely to be premature, have a low birth weight and be conceived via ART than their singleton counterparts. Moreover, a variety of comorbidities were identified more frequently in twins with HDN than singletons with HDN. The minimum haemoglobin and the initial and maximum total bilirubin, albumin and complement 3 (C3) were all significantly lower in twins than in singletons; however, these two groups were not found to differ significantly by direct antiglobulin test (DAT) status. Twins conceived via ART had a lower minimum haemoglobin and initial bilirubin than twins conceived spontaneously. The results of this study suggested that neonatal comorbidities were more common in twins with HDN than singletons with HDN; however, DAT positivity did not appear to play a major role in the higher rates of comorbidities and lower concentration of haemoglobin observed in twins. Among twins with HDN, conception via ART may serve as a risk factor for increased disease severity. [ABSTRACT FROM AUTHOR]