Requirements for human embryonic stem cells

‘Requirements for Human Embryonic Stem Cells’ is the first set of guidelines on human embryonic stem cells in China, jointly drafted and agreed upon by experts from the Chinese Society for Stem Cell Research. This standard specifies the technical requirements, test methods, test regulations, instructions for use, labelling requirements, packaging requirements, storage requirements and transportation requirements for human embryonic stem cells, which is applicable to the quality control for human embryonic stem cells. It was originally released by the China Society for Cell Biology on 26 February 2019 and was further revised on 30 April 2020. We hope that publication of these guidelines will promote institutional establishment, acceptance and execution of proper protocols, and accelerate the international standardization of human embryonic stem cells for applications.     

Functional divergence of two duplicated Fertilization Independent Endosperm genes in rice with respect to seed development

Fertilization Independent Endosperm (FIE) is an essential member of Polycomb Repressive Complex 2 (PRC2) that plays important roles in the developmental regulation of plants. OsFIE1 and OsFIE2 are two FIE homologs in the rice genome. Here, we showed that OsFIE1 probably duplicated from OsFIE2 after the origin of the tribe Oryzeae, but has a specific expression pattern and methylation landscape. During evolution, OsFIE1 underwent a less intensive purifying selection than did OsFIE2. The mutant osfie1 produced smaller seeds and displayed reduced dormancy, indicating that OsFIE1 predominantly functions in late seed development. Ectopic expression of OsFIE1, but not OsFIE2, was deleterious to vegetative growth in a dose‐dependent manner. The newly evolved N‐terminal tail of OsFIE1 was probably not the cause of the adverse effects on vegetative growth. The CRISPR/Cas9‐derived mutant osfie2 exhibited impaired cellularization of the endosperm, which suggested that OsFIE2 is indispensable for early seed development as a positive regulator of cellularization. Autonomous endosperm was observed in both OsFIE2^+? and osfie1/OsFIE2^+? but at a very low frequency. Although OsFIE1‐PRC2 exhibited H3K27me3 methyltransferase ability in plants, OsFIE1‐PRC2 is likely to be less important for development in rice than is OsFIE2‐PRC2. Our findings revealed the functional divergence of OsFIE1 and OsFIE2 and shed light on their distinct evolution following duplication.     

Uncovering the evolutionary origin of blue anthocyanins in cereal grains

Functional divergence after gene duplication plays a central role in plant evolution. Among cereals, only Hordeum vulgare (barley), Triticum aestivum (wheat) and Secale cereale (rye) accumulate delphinidin‐derived (blue) anthocyanins in the aleurone layer of grains, whereas Oryza sativa (rice), Zea mays (maize) and Sorghum bicolor (sorghum) do not. The underlying genetic basis for this natural occurrence remains elusive. Here, we mapped the barley Blx1 locus involved in blue aleurone to an approximately 1.13 Mb genetic interval on chromosome 4HL, thus identifying a trigenic cluster named MbHF35 (containing HvMYB4H, HvMYC4H and HvF35H). Sequence and expression data supported the role of these genes in conferring blue‐coloured (blue aleurone) grains. Synteny analyses across monocot species showed that MbHF35 has only evolved within distinct Triticeae lineages, as a result of dispersed gene duplication. Phylogeny analyses revealed a shared evolution pattern for MbHF35 in Triticeae, suggesting that these genes have co‐evolved together. We also identified a Pooideae‐specific flavonoid 3′,5′‐hydroxylase (F3′5′H) lineage, termed here Mo_F35H2, which has a higher amino acid similarity with eudicot F3′5′Hs, demonstrating a scenario of convergent evolution. Indeed, selection tests identified 13 amino acid residues in Mo_F35H2 that underwent positive selection, possibly driven by protein thermostablility selection. Furthermore, through the interrogation of barley germplasm there is evidence that HvMYB4H and HvMYC4H have undergone human selection. Collectively, our study favours blue aleurone as a recently evolved trait resulting from environmental adaptation. Our findings provide an evolutionary explanation for the absence of blue anthocyanins in other cereals and highlight the importance of gene functional divergence for plant diversity and environmental adaptation.     

秦岭蕨类植物新记录科——肠蕨科

报道了秦岭蕨类植物新记录科——肠蕨科,其新记录种为川黔肠蕨,该科也是陕西省新记录。文中提供了形态描述和野外照片及植株局部照片,并对其生境特点进行了简要分析。凭证标本藏于陕西理工大学植物标本馆。     

圈养林麝麝香分泌时间节律及影响因素

在2016年和2017年的5—8月,我们对川西马尔康麝场圈养林麝（Moschus berezovskii）的麝香分泌进行了行为与生理监测,对麝香分泌的各阶段进行了准确判定,记录了泌香启动、泌香盛期开始、泌香盛期终止及泌香结束的时间阶段及持续时间长,分析了林麝麝香分泌的时间阶段与体重和年龄等因素的关系。结果表明,马尔康麝场的雄性林麝平均泌香启动日在6月16日[（167.06±7.75）d,n=141],于6月17日进入泌香盛期[（168.52±7.67）d,n=141],6月21日[（172.17±7.26）d, n=138]泌香活动减弱,至6月25日[（176.27±8.11）d, n=131]泌香结束;雄麝体重与其泌香启动、泌香盛期停止及泌香结束时间呈显著负相关（r_PS = -0.234,P_PS =0.028;r _VSF = -0.215,P_VSF = 0.047;r _SE = -0.229,P_SE = 0.043）,即雄麝的体重越大,其泌香越早;各年龄组间的平均泌香时长差异显著（F _{17, 113} = 3.482, P = 0.003）,其中2岁雄麝平均泌香时长最长[（13.07±2.08）d, n=20],显著高于3岁[（9.38±0.76）d, n=12, P = 0.042]和4岁[（7.80±1.60）d, n=5, P = 0.013]个体;马尔康林麝平均泌香量为（11.85g±0.96）g, （n=114）,随泌香时长延长有增加趋势,但不显著（P = 0.854）。基于上述林麝雄体的泌香时间、泌香量与年龄和体重等因素间的关联,可对圈养的林麝个体间的泌香力、泌香量等进行区分和预判,作为圈养林麝驯养生产力优化的依据,并可为圈养林麝优质品系的选育提供参考。     

以青砖茶为原料的果茶饮料制备

以青砖茶、新鲜苹果汁、西瓜汁和菠萝汁为主要原料进行果茶饮料的研制,采用单因素试验及正交分析试验对果茶饮料的配方进行工艺优化,以感官评价和吸光值为评定指标,确定果茶饮料的最佳配方。结果表明,体积比分别为8∶2的茶汤与苹果汁的混合汁、5∶5的茶汤与西瓜汁的混合汁和3∶7的茶汤与菠萝汁的混合汁混匀调配出的茶饮料的口感最佳,色泽清透,且香气较佳。本研究为黑茶果茶饮料的研 制提供了理论依据。     

基于焦磷酸测序技术建立基因编辑水稻检测方法

基因编辑技术发展迅速,但对应的检测方法较少。为寻找创建基因编辑作物适用的检测方法,以 PL3 基因编辑水稻编辑位点为靶标,有效设计了焦磷酸测序的扩增引物及测序引物,并进行有效性检测,分别利用Sequence to Analyze等程序以及SNP和AQ两种模式完成了对PL3 基因的定性和定量检测试验,建立了 PL3 基因编辑水稻编辑位点焦磷酸测序检测方法。结果表明,基于焦磷酸测序技术可以通过检测编辑位点从而将基因编辑型水稻与野生型水稻进行区分。与常规的转基因检测方法相比,该检测方法具有较好的准确性、高效性及高灵敏度等优点,在基因编辑型水稻编辑位点定性和定量检测分析方面具有很好的应用前景。