花生重组近交系(RIL)根部性状的遗传分析

利用花生R IL群体,分析了主根长、侧根数、根基粗(1 cm和3 cm处)、根体积、主根鲜重、干重、侧根鲜重和干重、主侧根瘤数等11个花生根部性状的遗传力,估算基因对数及性状间的相互关系,根据偏度系数(g1)和峰度系数(g2)的估算控制性状基因互作情况。结果表明:在11个研究性状中,有6个性状在2个亲本间差异显著或极显著。但不论性状在亲本间的差异显著与否,在R IL群体中基因型间的性状差异均表现为连续变异和明显的超亲分离。同时主根粗(1 cm)和主根长的变异系数较小,分别为11.27%和11.218%。11个花生根部性状都是受多基因控制的数量性状,如影响侧根根瘤数、侧根鲜重和侧根干重的基因均在10对左右;而其它性状的基因估计在5~7对左右,尤其是控制侧根数的基因最少为5对左右。而在R IL群体中,除侧根干重的遗传力最高,达0.569,其次是侧根根瘤和侧根数分别达0.545和0.542外,其它性状的遗传力均较低。同时控制主根长和主根粗(1 cm)的基因间存在重叠作用;而控制侧根根瘤、侧根鲜重和侧根干重基因间存在互作,表现为互补作用;控制其它性状的基因间互补或重叠作用不明显或者不存在。主根干重和侧根干重与根体积、主根粗(1 cm)和主根粗(3 cm)显著相关,根体积与主根粗(3 cm)极显著相关,主根鲜重和侧根鲜重与根体积的相关表现不一致。     

转拟南芥P5CS1基因增强羽衣甘蓝的耐旱性

为提高羽衣甘蓝的耐旱性,本文将拟南芥Δ1-吡咯啉-5-羧酸合成酶（P5CS1）基因经农杆菌介导转入羽衣甘蓝植株中,检测转基因株系与野生型植株在干旱胁迫下P5CS1 mRNA表达量、幼苗脯氨酸含量、株系根系性状、整株干重、鲜重和整株存活率。结果表明,在15%PEG6000渗透胁迫下,转基因植株的P5CS1基因mRNA表达量明显增加,转基因植株脯氨酸含量是野生型的2.4倍;主根长、最长侧根长、侧根数目、整株干重和鲜重均高于野生型,干重/鲜重则低于野生型,转基因植株的平均存活率为78%,极显著高于野生型。数据显示,AtP5CS1基因在羽衣甘蓝中的表达明显改善了转基因植株的耐旱性。     

水稻籼粳交DH群体花器性状的遗传分析

水稻花器性状是影响杂交稻制种异交结实率的重要因素之一。利用一个水稻籼粳交(窄叶青8号/京系17)来源的DH群体对水稻柱头外露率、花柱长、柱头长、柱头宽、花药长、花药宽、颖花长、颖花宽和颖花长宽比9个花器性状和穗抽出度进行遗传分析。不论性状在2个亲本间的差异显著与否,在DH群体中10个研究性状在基因型间的差异均达到极显著水平(P<0.01),并表现为连续变异和明显的超亲分离。除花药宽的遗传力较低(50%)、且估计的基因数多达13个之外,其余9个研究性状的遗传力均较高,为68%～93%,控制这些性状的基因数估计为7～10个。这些结果表明,10个研究性状均为受多基因控制的数量性状,其增效和减效基因在2个亲本中均有分布,通过基因重组可产生正向和负向两个方向的超亲基因型。除了柱头长、柱头宽和穗伸出度3个性状未发现有基因间的上位性互作外,其余7个性状均检测到显著的互补性互作。性状相关和通径分析的结果显示,与柱头外露率关系最密切的花器性状为柱头长、柱头宽和颖花长宽比,颖花长和颖花宽主要通过影响颖花长宽比来对柱头外露率产生影响。其次,与柱头外露率关系较密切的为花柱长。柱头外露率高的基因型通常表现为长柱头、长粒型和长花柱。花药长、花药宽与上述花器性状间的相关性较弱。在DH群体中,穗伸     

红豆树优树种子和幼苗性状的变异分析及优良家系的初选

以不同产地(包括江西资溪,浙江的龙泉和庆元,福建的泰宁、南平和柘荣及四川内江)的76株红豆树(Ormosia hosiei Hemsl.et E.H.Wilson)优树的种子为供试材料,采用随机区组设计进行大田育苗,对其种子性状以及各家系幼苗的生长性状、叶片性状、根系性状和苗高生长节律进行测量和计算,并进行了方差分析、遗传力估算和相关性分析;此外,对供试红豆树优树中的优良家系进行了初选。结果表明:红豆树优树间的种子性状和家系间的幼苗性状均存在显著(P0.05)或极显著(P0.01)差异。红豆树幼苗生长性状、叶片性状和根系性状的家系遗传力为0.479~0.854,显示家系遗传控制程度中等或较强。相关性分析结果显示:红豆树幼苗的苗高和地径与种厚、百粒质量均呈极显著正相关;地径与叶片性状和根系性状的表型相关系数和遗传相关系数均达到显著或极显著水平,而苗高仅与主根长和单株长度大于5 cm的一级侧根数呈显著或极显著正相关;苗高与其线性生长始期、最大线性生长速率、线性生长速率和线性生长总量总体上呈极显著正相关,而与其线型生长末期和线性生长期呈不显著相关。根据家系遗传力,选择苗高作为主要性状,同时兼顾地径,从76个优树家系中初选出19个优良家系,其中,63.2%的优良家系来自浙江龙泉,26.3%的优良家系来自福建柘荣,浙江龙泉12家系的苗高和地径均为最大,浙江龙泉11家系的苗高和浙江龙泉19家系的地径次之。此外,最大叶片的长度和宽度的家系遗传力较高,且与地径呈显著或极显著正相关,可作为红豆树优良家系初选的辅助指标。研究结果显示:苗高、地径和叶片大小可用于初步筛选红豆树优良家系,且初选的优良家系可作为红豆树育种和无性繁殖材料。     

水稻分蘖角度的QTL定位和主效基因的遗传分析

利用水稻籼粳亚种间组合Asominori×IR24重组自交系(RIL)群体71个株系和相应的全基因组染色体片段置换系(Chromosomesegmentsubstitutionline,CSSL)群体65个株系,在2种环境下对分蘖角度性状进行了数量性状基因座(QTL)定位和上位性效应的遗传分析。在两种群体中都出现了分蘖角度的超亲分离。在RIL群体中发现了5个主效QTLs和3对上位性双位点互作标记基因座,控制水稻分蘖角度。其中在第9染色体上位于XNpb108~C506RFLP分子标记区间的qTA-9基因座在2种环境中同时出现,其贡献率平均为28·6%,增加分蘖角度的等位基因来自籼稻品种IR24。利用CSSL群体图示基因型分析,证实在第9染色体上含有RFLP标记C609和C506约15cM的染色体区段,存在增加分蘖角度的基因,来源于染色体片段供体亲本IR24,在Asominori的遗传背景中能增加分蘖角度约15°,该基因的位置与RIL群体在第9染色体上定位的QTL相同,证实了qTA-9的存在。F1表型测定及F2代遗传分析表明,来自IR24的等位基因是一个不完全显性基因。除一对上位性位点存在显著的环境互作效应外,未发现其他位点存在与环境的互作效应。不同基因的加性效应和双位点的上位性效应的共同作用可能是造成水稻分蘖角度超亲分离的主要原因。     

花生种质资源的根系性状研究及AFLP分析

对22份花生种质资源进行根系性状和AFLP分析研究.结果表明,珍珠豆型花生种质资源具有根干重小、根基粗小和主侧根干重比小等特点;龙生型花生种质资源具有根干重大、根基粗大和主侧根干重比大等特点.用根系性状和AFLP标记都能将22份花生品种分为两大组,但是AFLP标记聚类结果比根系性状的聚类结果更能反映花生品种亲源关系和地域生态上的差异.     

应用RAPD标记检测与水稻株高和抽穗期有关的QTLs

以生产上广泛应用的杂交稻组合汕优１０号的保持系珍汕９７Ｂ和恢复系密阳４６构建Ｆ２群体。应用ＲＡＰＤ标记检测,分析了与株高和抽穗期有关的ＱＴＬｓ,并探讨了基因的互作方式。在Ｆ２群体中性状表型分离明显,基本符合正态分布。单因子方差分析检测到与抽穗期和株高相关的标记数９个,并计算了单个ＱＴＬ对相关性状的贡献率。双因子方差分析发现上述检测到的ＱＴＬｓ之间大多不存在互作,但发现了一些有显著互作的新的ＱＴＬｓ,其互作贡献率远大于单因子方差分析检测到的ＱＴＬｓ,说明该群体中株高和抽穗期主要由不同座位间的互作控制,进一步的分析表明互作方式以重叠基因为主。     

云杉属7个种针叶性状种间和种内变异分析

以沙坝国家云杉/落叶松良种基地苗圃的云杉属7个种(2007年移栽的欧洲云杉、西加云杉、红皮云杉、黑云杉、蓝云杉、白云杉和恩氏云杉)实生苗1 a针叶为对象,研究种间和种内针叶性状的遗传差异,为云杉苗期识别和进行适应性评价提供依据。结果表明:(1)云杉种间针叶长、宽、长/宽、鲜重、干重、冬季含水率差异达显著水平,且云杉针叶性状种间和种内都存在着丰富的遗传变异。(2)7个云杉种间针叶性状的变异系数从大到小依次为鲜重(47.65%)＞干重(40.94%)＞宽(24.98%)＞长(22.39%)＞长/宽(21.32%)＞冬季含水率(12.75%),鲜重的变异系数最大,冬季含水率是最稳定的性状。(3)种内白云杉的鲜重、干重的变异系数最大,分别为50.85%和38.01%,蓝云杉针叶冬季含水率变异系数最小,为2.11%。(4)针叶性状间除长/宽与鲜重、干重、冬季含水率不相关外,其余性状间呈极显著相关关系;除针叶长/宽与苗高、当年高生长量不相关外,其余针叶性状与树高、当年高生长量呈显著或极显著正相关关系。(5)种间针叶干重与针叶长、宽回归方程的决定系数在0.793～0.993间,根据针叶长指标将7个云杉种划分为3类,并可根据云杉针叶长、宽、长/宽、鲜重、干重、颜色和气孔带等性状进行苗期识别和选择。     

檫木叶片性状沿海拔梯度的响应特征

植物叶片性状是植物与环境长期互作的结果,对环境变化具有敏锐的捕捉力,而且植物叶片性状影响植物的"投资-收益"关系。本文以天目山不同海拔的檫木叶片为材料,分析檫木叶面积、叶长宽比、叶片干重和比叶面积等叶片形态性状以及叶绿素含量和叶氮含量(N_(area))等叶片生理性状对海拔的响应。结果表明,不同海拔亚群体间叶面积具有显著差异,比叶面积、叶长宽比和叶片干重存在极显著差异;叶长宽比和叶片干重在亚群体内的变异系数小于叶面积和比叶面积,说明檫木叶片形态性状在亚群体间存在着不同程度的变异。比叶面积与叶面积和叶长宽比具有显著正相关,与叶片干重呈显著负相关;叶绿素含量与N_(area)呈显著正相关;通过檫木叶片性状与温度的线性回归表明,叶面积、比叶面积、叶绿素含量和N_(area)随着温度下降而下降,与之相反,叶片干重和叶长宽比则逐渐增加。     

籼型杂交稻光合特性的配合力分析

以6个籼型杂交稻三系不育系和5个恢复系按不完全双列杂交设计配制的30个杂交稻组合及其亲本品种为材料,对其光合性状进行了测定和分析,结果表明:(1)杂交稻组合的光合特性存在显著或极显著的组合间遗传差异,光合特性的遗传变异主要来自基因的非加性效应;(2)胞间CO2浓度、蒸腾速率、叶绿素a、叶绿素b和类胡萝卜素含量受不育系的影响大于恢复系,而气孔导度、叶绿素a+b含量受恢复系的影响大于不育系;(3)杂交稻光合性状的广义遗传力均大于狭义遗传力,各性状主要受基因互作及环境的影响。狭义遗传力的大小依次为叶绿素b、叶绿素a+b、叶绿素a、气孔导度、胞间CO2浓度、类胡萝卜素和蒸腾速率,这些性状具有中等遗传力;(4)9个光合性状杂交稻F1表型值与父母本一般配合力效应值之和的相关系数均达极显著水平。因此,可以根据父母本一般配合力效应值之和来预测杂交稻组合光合性状的表现,有利于高效选育高光效杂交稻组合。     

A Unique Protease Cleavage Site Predicted in the Spike Protein of the Novel Pneumonia Coronavirus (2019-nCoV) Potentially Related to Viral Transmissibility

正Dear Editor,In December 2019, a novel human coronavirus caused an epidemic of severe pneumonia(Coronavirus Disease 2019,COVID-19) in Wuhan, Hubei, China(Wu et al. 2020; Zhu et al. 2020). So far, this virus has spread to all areas of China and even to other countries. The epidemic has caused 67,102 confirmed infections with 1526 fatal cases     

Curcuminoids as inhibitors of thioredoxin reductase: A receptor based pharmacophore study with distance mapping of the active site

Curcumin is the yellow pigment of turmeric that interacts irreversibly forming an adduct with thioredoxin reductase (TrxR), an enzyme responsible for redox control of cell and defence against oxidative stress. Docking at both the active sites of TrxR was performed to compare the potency of three naturally occurring curcuminoids, namely curcumin, demethoxy curcumin and bis-demethoxy curcumin. Results show that active sites of TrxR occur at the junction of E and F chains. Volume and area of both cavities is predicted. It has been concluded by distance mapping of the most active conformations that Se atom of catalytic residue SeCYS498, is at a distance of 3.56 from C13 of demethoxy curcumin at the E chain active site, whereas C13 carbon atom forms adduct with Se atom of SeCys 498. We report that at least one methoxy group in curcuminoids is necessary for interation with catalytic residues of thioredoxin. Pharmacophore of both active sites of the TrxR receptor for curcumin and demethoxy curcumin molecules has been drawn and proposed for design and synthesis of most probable potent antiproliferative synthetic drugs.     

Comparative morphology of the carpel in the Liliaceae: Hewardieae, Petrosavieae, and Tricyrteae

The young pistils in the melanthioid tribes, Hewardieae, Petrosavieae and Tricyrteae, are uniformly tricarpellate and syncarpous. They lack raphide idioblasts. All are multiovulate, with bitegmic ovules. The Petrosavieae are marked by the presence of septal glands and incomplete syncarpy. Tepals and stamens adhere to the ovary in the Hewardieae and the Petrosavieae but not in the Tricyrteae. Two vascular bundles occur in the stamens of the Hewartlieae and Tricyrtis latifolia. Ventral bundles in the upper part of the ovary of the Hewardieae are continuous with compound septal bundles and placental bundles in the lower part. Putative ventral bundles occur in the alternate position in the Tricyrteae and putative placental bundles in the opposite. position in the Petrosavieae. The dichtomously branched stigma in each carpel of the Tricyrteae is supplied by a bifurcated dorsal bundle.     

Enterovirus 71 3C proteolytically processes the histone H3 N-terminal tail during infection

Highlights
1. The N-terminal tail of histone H3 is specifically cleaved during EV71 infection.
2. Viral protease 3C is identified as a protease responsible for proteolytically processing the N-terminal H3 tail.
3. Our finding reveals a new epigenetic regulatory mechanism for Enterovirus 71 in virus-host interactions.     

Detection of EBV and HHV6 in the Brain Tissue of Patients with Rasmussen’s Encephalitis

Rasmussen’s encephalitis (RE) is a rare pediatric neurological disorder, and the exact etiology is not clear. Viral infection may be involved in the pathogenesis of RE, but conflicting results have reported. In this study, we evaluated the expression of both Epstein-Barr virus (EBV) and human herpes virus (HHV) 6 antigens in brain sections from 30 patients with RE and 16 control individuals by immunohistochemistry. In the RE group, EBV and HHV6 antigens were detected in 56.7% (17/30) and 50% (15/30) of individuals, respectively. In contrast, no detectable EBV and HHV6 antigen expression was found in brain tissues of the control group. The co-expression of EBV and HHV6 was detected in 20.0% (6/30) of individuals. In particular, a 4-year-old boy had a typical clinical course, including a medical history of viral encephalitis, intractable epilepsy, and hemispheric atrophy. The co-expression of EBV and HHV6 was detected in neurons and astrocytes in the brain tissue, accompanied by a high frequency of CD8⁺ T cells. Our results suggest that EBV and HHV6 infection and the activation of CD8⁺ T cells are involved in the pathogenesis of RE.     

Perinatal Vertical Transmission of Chikungunya Virus in Ruili,a Town on the Border between China and Myanmar

正Dear Editor,Chikungunya virus (CHIKV), an arbovirus in the family of Togaviridae, genus Alphavirus, is transmitted by the A.aegyptii or A. albopictus mosquito, and causes disease in humans characterized by fever, rash, and arthralgia (Silva and Dermody 2017; Suhrbier 2019). It was first reported in 1953 in Tanzania, and caused only a few outbreaks and sporadic cases in Africa and Asia in last century. However, in the epidemic in 2004, CHIKV acquired mutations that conferred enhanced transmission by the A. albopictus mosquito(Schuffenecker et al. 2006). Since then, it has successively caused outbreaks in Africa, the Indian Ocean, South East Asia, the South America, and Europe (Zeller et al. 2016).     

Development of a Novel Reverse Transcription Loop-Mediated Isothermal Amplification Method for Rapid Detection of SARS-CoV-2

In conclusion, the novel visual RT-LAMP assay is a simple, rapid, and sensitive approach for detection of SARS-CoV-2, and it is ready for application in primary care and community hospitals or health care centers, and even patients' own houses in response to the current SARS-CoV-2 epidemic because the assay does not require sophisticated equipment and skilled personnel. Furthermore, it is also ready to be used in fields for screening samples from wild animals and environments to facilitate the identification of potential intermediate hosts that mediate the cross-species transmission of SARS-CoV-2 from bats to humans.