Tea is the world's oldest and most popular caffeine-containing beverage with immense economic, medicinal, and cultural importance. Here, we present the first high-quality nucleotide sequence of the repeat-rich (80.9%), 3.02-Gb genome of the cultivated tea tree Camellia sinensis. We show that an extraordinarily large genome size of tea tree is resulted from the slow, steady, and long-term amplification of a few LTR retrotransposon families. In addition to a recent whole-genome duplication event, lineage-specific expansions of genes associated with flavonoid metabolic biosynthesis were discovered, which enhance catechin production, terpene enzyme activation, and stress tolerance, important features for tea flavor and adaptation. We demonstrate an independent and rapid evolution of the tea caffeine synthesis pathway relative to cacao and coffee. A comparative study among 25 Camellia species revealed that higher expression levels of most flavonoid- and caffeine- but not theanine-related genes contribute to the increased production of catechins and caffeine and thus enhance tea-processing suitability and tea quality. These novel findings pave the way for further metabolomic and functional genomic refinement of characteristic biosynthesis pathways and will help develop a more diversified set of tea flavors that would eventually satisfy and attract more tea drinkers worldwide.

To understand the potential genetic basis of highland adaptation of fungal pathogenicity, we present here the ~116 Mb de novo assembled high-quality genome of Ophiocordyceps sinensis endemic to the Qinghai-Tibetan Plateau. Compared with other plain-dwelling fungi, we find about 3.4-fold inflation of the O. sinensis genome due to a rapid amplification of long terminal repeat retrotransposons that occurred ~38 million years ago in concert with the uplift of the plateau. We also observe massive removal of thousands of genes related to the transport process and energy metabolism. O. sinensis displays considerable lineage-specific expansion of gene families functionally enriched in the adaptability of low-temperature of cold tolerance, fungal pathogenicity and specialized host infection. We detect signals of positive selection for genes involved in peroxidase and hypoxia to enable its highland adaptation. Resequencing and analyzing 31 whole genomes of O. sinensis, representing nearly all of its geographic range, exhibits latitude-based population divergence and nature selection for population inhabitation towards higher altitudes on the Qinghai-Tibetan Plateau.

Background Moral injury among physicians and other health professionals has attracted attention in the mainstream literature, this study aim to assess the psychometric properties of the 10-item Moral Injury Symptoms Scale-Health Professional (MISS-HP) among healthcare professionals in China. Methods A total of 583 nurses and 2423 physicians were recruited from across mainland China. An online survey was conducted from March 27 to April 26, 2020 (during the middle of the COVID-19 pandemic) using the Chinese version of the MISS-HP. Reliability was assessed by internal consistency reliability and test-retest reliability. Exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) were performed to determine scale structure. Results Cronbach’s α of the scale for both samples was acceptable (0.71 for nurses and 0.70 for physicians), as was test-retest reliability (ICCs for the individual items ranged from 0.41 to 0.74, with 0.77 for the overall scale in physicians). EFA suggested three factors, and the CFA indicated good fit to the data. Convergent validity was demonstrated with the 4-item Expressions of Moral Injury Scale (r = 0.45 for physicians, r = 0.43 for nurses). Discriminant validity was demonstrated by correlations with burnout and well-being (r = 0.34–0.47), and concurrent validity was suggested by correlations with depression and anxiety symptoms (r = 0.37–0.45). Known groups validity was indicated by a higher score in those exposed to workplace violence (B = 4.16, 95%CI: 3.21–5.10, p < 0.001). Conclusions The MISS-HP demonstrated acceptable reliability and validity in a large sample of physicians and nurses in mainland China, supporting its use as a screening measure for moral injury symptoms among increasingly stressed health professionals in this country during the COVID-19 pandemic.

The rubber tree, Hevea brasiliensis, produces natural rubber that serves as an essential industrial raw material. Here, we present a high-quality reference genome for a rubber tree cultivar GT1 using single-molecule real-time sequencing (SMRT) and Hi-C technologies to anchor the $1.47-Gb genome assembly into 18 pseudochromosomes. The chromosome-based genome analysis enabled us to establish a model of spurge chromosome evolution, since the common paleopolyploid event occurred before the split of Hevea and Manihot. We show recent and rapid bursts of the three Hevea-specific LTR-retrotransposon families during the last 10 million years, leading to the massive expansion by $65.88% ($970 Mbp) of the whole rubber tree genome since the divergence from Manihot. We identify large-scale expansion of genes associated with whole rubber biosynthesis processes, such as basal metabolic processes, ethylene biosynthesis, and the activation of polysaccharide and glycoprotein lectin, which are important properties for latex production. A map of genomic variation between the cultivated and wild rubber trees was obtained, which contains $15.7 million high-quality single-nucleotide polymorphisms. We identified hundreds of candidate domestication genes with drastically lowered genomic diversity in the cultivated but not wild rubber trees despite a relatively short domestication history of rubber tree, some of which are involved in rubber biosynthesis. This genome assembly represents key resources for future rubber tree research and breeding, providing novel targets for improving plant biotic and abiotic tolerance and rubber production.

Objective: Caring for patients during the COVID-19 pandemic has placed considerable stress on health care professionals (HCPs), increasing their risk of moral injury (MI) and clinician burnout. The present study sought to examine the prevalence and correlates of MI among physicians and nurses in mainland China during the pandemic. Method: A cross-sectional study was performed via an online survey conducted from March 27, 2020 to April 26, 2020. The 10-item Moral Injury Symptoms Scale-Health Professional version (MISS-HP) was administered along with measures of clinician mental health and burnout. A total of 3,006 physicians and nurses who completed the questionnaire were included in the final analysis. Unconditional logistic regression modeling was performed to determine the associations, including that between COVID-19 patient exposure and the risk of moral injury. Results: MISS-HP scores strongly and positively correlated with depression, anxiety, low well-being, and burnout symptoms. The estimated prevalence of MI in the total sample was 41.3%, 95% confidence interval (CI) [39.3%, 43.0%]. HCPs providing medical care to COVID-19 patients experienced a 28% greater risk of MI than those providing medical care to patients without the coronavirus (odds ratio = 1.28, 95% CI [1.05, 1.56], p = .01). Conclusions: A significant proportion of HCPs in mainland China are at risk for significant MI symptoms as well as mental health problems and burnout during the COVID-19 pandemic. MI symptoms are strongly correlated with higher clinician burnout, greater psychological distress, and lower level of subjective well-being. Effective strategies are needed to address MI and other mental health problems in frontline health care workers treating those with and without COVID-19 disease. Clinical Impact StatementMoral injury (MI) symptoms are correlated with higher clinician burnout, greater psychological distress, and lower level of subjective well-being. Strategies shown to be effective for MI in former military personnel might be used to address burnout and mental health problems in frontline health care workers tasked with treating those with and without COVID-19 disease. Our findings provide a profile of HCPs who are at risk for MI symptoms and may help to identify those at risk of downstream effects in terms of psychological health and patient safety.

BackgroundThe genus Camellia, belonging to the family Theaceae, is economically important group in flowering plants. Frequent interspecific hybridization together with polyploidization has made them become taxonomically “difficult taxa”. The DNA content is often used to measure genome size variation and has largely advanced our understanding of plant evolution and genome variation. The goals of this study were to investigate patterns of interspecific and intraspecific variation of DNA contents and further explore genome size evolution in a phylogenetic context of the genus.Methodology/Principal FindingsThe DNA amount in the genus was determined by using propidium iodide flow cytometry analysis for a total of 139 individual plants representing almost all sections of the two subgenera, Camellia and Thea. An improved WPB buffer was proven to be suitable for the Camellia species, which was able to counteract the negative effects of secondary metabolite and generated high-quality results with low coefficient of variation values (CV) <5%. Our results showed trivial effects on different tissues of flowers, leaves and buds as well as cytosolic compounds on the estimation of DNA amount. The DNA content of C. sinensis var. assamica was estimated to be 1C = 3.01 pg by flow cytometric analysis, which is equal to a genome size of about 2940 Mb.ConclusionIntraspecific and interspecific variations were observed in the genus Camellia, and as expected, the latter was larger than the former. Our study suggests a directional trend of increasing genome size in the genus Camellia probably owing to the frequent polyploidization events.

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Panax notoginseng (Burk) F.H. Chen, belonging to the genus Panax (Araliaceae), is one of the most highly valued medicinal plants in the world. The dried root of this plant, known as ''Sanchi'', is one of the most commonly used traditional Chinese medicines and has been used as a top-class tonic for more than 2000 years. Approximately 60 triterpene saponins that are considered to be the principal bioactive components responsible for the pharmacological features have been isolated from P. notoginseng (Wan et al., 2007). Triterpene saponins are synthesized via the mevalonic acid (MVA) and the 2-C-methyl-D-erythritol 4-phosphate (MEP)-dependent pathways (Zhao et al., 2014). Although several genes likely to be involved in the triterpene saponin biosynthesis have been identified (Luo et al., 2011;Liu et al., 2015), we still lack the overall knowledge of genetic basis of the ginsenoside biosynthetic pathway in P. notoginseng.