In vitro anther culture and Agrobacterium-mediated transformation of the AP1 gene from Salix integra Linn. in haploid poplar(Populus simonii × P. nigra)

A reliable,efficient anther culture system,the dominant technique for generating haploid plants in breeding programs,that can be used for generating transgenic poplar plants has been needed.In the present study,therefore,an anther culture system was developed using isolated mid-and late-uninucleate anthers of poplar(Populus simonii x P.nigra).From a combination of SSR and ploidy analyses,six double haploid and two haploid lines were characterized from 86 plants grown from 16 regenerated anther cultured lines.After 48 months of development,two plant lines from the regenerated plants maintained their haploid level in vitro for over 2 years.A number of haploid plants from the different lines weretransferred to soil.The leaves of these transplants were then used as explants for transformation with the APETALA1(AP1) gene using Agrobacterium tumefaciens.Overexpression of AP1 in haploid poplar induced early flowering with obvious petals when ectopically expressed.To our knowledge,this is the first report on changes in flowering time in AP1-trangenic poplar,which is important for elucidating the regulatory mechanism of tree flower development.

Over expression of TaFer gene from Tamarix androssowii improves iron and drought tolerance in transgenic Populus tomentosa

Ferritin, a universal intracellular protein, can store large amounts of iron and improve plant resistance to abiotic and biotic stress. In this study, a ferritin gene(TaFer) from Tamarix androssowii Litv. was transferred into Populus tomentosa Carr. cv 'BJR01' via Agrobacterium. Six independent transgenic lines were obtained with a tolerance to kanamycin and three were randomly selected for further analysis. The PCR and RT-PCR results indicate that the TaFer gene had been integrated into the poplar genome. The effect of the gene on abiotic stress tolerance was tested, and the results show that transgenic plants improve growth, had higher chlorophyll and lower MDA contents, and higher relative electrical conductivity,fewer changes of SOD and POD activities, higher iron content, higher root ferric reductase activity and lower levels of ROS accumulation and cell death in response to drought, Fe-insufficient or Fe-excess tolerance. These results indicate that the TaFer gene can improve abiotic stress tolerance in transgenic Populus tomentosa.

Somatic embryogenesis and plant regeneration in Betula platyphalla

Betula platyphylla is a native tree species in northern China that has high economic and medicinal value.We developed an efficient protocol for the induction of somatic embryogenesis in B.platyphalla from immature zygotic embryos and assessed the effects of explant type,genotype,and plant growth regulators(PGRs)on embryogenic callus induction.Among the various explants evaluated,embryogenic callus was only produced from mature and immature zygotic embryos on medium with added 2,4-dichlorophenoxyacetic acid(2,4-D).Supplementation of 2,4-D-containing medium with cytokinins increased the frequency of embryogenic callus induction.On the 20 days after pollination,immature zygotic embryos that had been collected in mid-May yielded embryogenic tissue at the highest frequency(16.8%)when cultured on half-strength MS medium supplemented with 2.0 mg L^(-1)2,4-D and 0.2 mg L^(-1)6-benzylaminopurine(6-BA).The process of proliferation of embryogenic callus,somatic embryo formation,and subsequent plantlet conversion occurred under optimal culture conditions.When regenerated plants weretransplanted to soil,95%of them developed normally and grew vigorously.This somatic embryogenesis system required 3–4 months for the regeneration of B.platyphalla plantlets from immature zygotic embryos.

Sex-specific and dose-response relationships of urinary cobalt and molybdenum levels with glucose levels and insulin resistance in U.S. adults

Growing studies have linked metal exposure to diabetes risk.However,these studies had inconsistent results.We used a multiple linear regression model to investigate the sexspecific and dose-response associations between urinary metals(cobalt(Co)and molybdenum(Mo))and diabetes-related indicators(fasting plasma glucose(FPG),hemoglobin A1c(HbA1c),homeostasis model assessment for insulin resistance(HOMA-IR),and insulin)in a cross-sectional study based on the United States National Health and Nutrition Examination Survey.The urinary metal concentrations of 1423 eligible individuals were stratified on the basis of the quartile distribution.Our results showed that the urinary Co level in males at the fourth quartile(Q4)was strongly correlated with increased FPG(β=0.61,95%CI:0.17–1.04),HbA1c(β=0.31,95%CI:0.09–0.54),insulin(β=8.18,95%CI:2.84–13.52),and HOMA–IR(β=3.42,95%CI:1.40–5.44)when compared with first quartile(Q1).High urinary Mo levels(Q4 vs.Q1)were associated with elevated FPG(β=0.46,95%CI:0.17–0.75)and HbA1c(β=0.27,95%CI:0.11–0.42)in the overall population.Positive linear dose-response associations were observed between urinary Co and insulin(Pnonlinear=0.513)and HOMA–IR(Pnonlinear=0.736)in males,as well as a positive linear dose-response relationship between urinary Mo and FPG(Pnonlinear=0.826)and HbA1c(Pnonlinear=0.376)in the overall population.Significant sex-specific and dose-response relationships were observed between urinary metals(Co and Mo)and diabetes-related indicators,and the potential mechanisms should be further investigated.

PuHox52 promotes coordinated uptake of nitrate,phosphate, and iron under nitrogen deficiency in Populus ussuriensis

It is of great importance to better understand how trees regulate nitrogen(N) uptake under N deficiency conditions which severely challenge afforestation practices, yet the underlying molecular mechanisms have not been well elucidated. Here,we functionally characterized PuHox52, a Populus ussuriensis HD-ZIP transcription factor, whose overexpression greatly enhanced nutrient uptake and plant growth under N deficiency. We first conducted an RNA sequencing experiment to obtain root transcriptome using PuHox52-overexpression lines of P. ussuriensis under low N treatment. We then performed multiple genetic and phenotypic analyses to identify key target genes of PuHox52 and validated how they acted against N deficiency under PuHox52 regulation.PuHox52 was specifically induced in roots by N deficiency, and overexpression of PuHox52promoted N uptake, plant growth, and root development. We demonstrated that several nitrate-responsive genes(PuNRT1.1, PuNRT2.4,PuCLC-b, PuNIA2, PuNIR1, and PuNLP1),phosphate-responsive genes(PuPHL1A and PuPHL1B), and an iron transporter gene(PuIRT1) were substantiated to be direct targets of PuHox52. Among them, PuNRT1.1, PuPHL1A/B, and PuIRT1 were upregulated to relatively higher levels during PuHox52-mediated responses against N deficiency in PuHox52-overexpression lines compared to WT. Our study revealed a novel regulatory mechanism underlying root adaption to N deficiency where PuHox52 modulated a coordinated uptake of nitrate, phosphate, and iron through 'PuHox52-PuNRT1.1', 'PuHox52-PuPHL1A/PuPHL1B', and'PuHox52-PuIRT1' regulatory relationships in poplar roots.

Epidemic Features of COVID-19 and Potential Impact of Hospital Strain During the Omicron Wave—Australia,2022

Summary What is already known about this topic?Hospitals have experienced a surge in admissions due to the increasing number of Omicron cases.Understanding the epidemiological features of coronavirus disease 2019(COVID-19)and the strain it places on hospitals will provide scientific evidence to help policymakers better prepare for and respond to future outbreaks.What is added by this report?The case fatality rate of COVID-19 was 1.4 per 1,000 persons during the Omicron wave.

Comparative Analysis of Vaccine Inequity and COVID-19 Transmission Amid the Omicron Variant Among Countries--Six Countries,Asia-Pacific Region,2022

What is already known about this topic?The coronavirus disease 2019(COVID-19)persists as a significant global public health crisis.The predominant strain,severe acute respiratory syndrome coronavirus 2(SARS-CoV-2),notably the Omicron variant,continues to undergo mutations.While vaccination is heralded as the paramount solution to cease the pandemic,challenges persist in providing equitable access to COVID-19 vaccines.What is added by this report?The distribution of vaccine coverage exhibited disparities between high-income and middle-income countries,with middle-income countries evidencing lower levels of vaccination.The data further suggested that countries with lesser vaccination levels tended to display a higher case fatality rate.Findings indicated that an increase in population-wide vaccination was effective in mitigating COVID-19 related mortalities.What are the implications for public health practice?The findings of this research underscore the pressing necessity for equitable access to vaccines to effectively mitigate the COVID-19 pandemic within the Asia-Pacific region.

维生素E生物合成的相关进展

维生素E是具有抗氧化活性的脂溶性化合物,是维持机体代谢的必需维生素,被广泛应用于食品、医药及化妆品等多个领域,市场需求量极大.市场上的维生素E主要来自化学合成和从植物油馏出物中提取.传统的化学合成方式因不能合成特定的立体构型而受到限制.植物提取的方法也受制于有限的植物资源和高的时间成本.利用微生物合成特定构型的复杂天然化合物是一种经济、清洁的方法.本综述首先总结了维生素E生物合成的代谢途径及其研究进展,其次对维生素E生物合成的关键中间体尿黑酸和牻牛儿基牻牛儿基焦磷酸的代谢途径在模式微生物中的代谢工程改造进行了总结,最后对于利用微生物来生物合成维生素E的现状进行了概述,并对其前景进行了展望.