小麦穗发芽鉴定方法的比较与分析

穗发芽是小麦生产中较为严重的灾害之一,易受外界环境的影响,一旦发生不仅会影响产量,而且还会严重影响小麦的品质,因此培育抗穗发芽的小麦品种至关重要。该研究通过对65份小麦材料进行穗发芽试验,比较分析了小麦穗发芽抗性的常用方法,即籽粒发芽法、整穗发芽法和大田穗发芽法。结果表明:三种方法之间均呈极显著正相关关系,而且在1%水平上均存在极显著性差异;发芽指数与籽粒发芽率的相关性最高,能够更好地评价小麦材料的休眠特性,但不能得出材料的总体抗性;籽粒发芽法和整穗发芽法的变异程度相对较小,试验条件更易控制,可作为小麦穗发芽抗性评价的简易方法;多数参试材料的平均籽粒发芽率平均整穗发芽率平均大田穗发芽率,且三者差异程度均达到极显著水平,这说明麦穗的外部结构及外部环境对小麦穗发芽的影响显著。因此,籽粒发芽法可以从休眠性方面,对小麦种子资源进行初步筛选;整穗发芽法可用于穗发芽抗性的进一步鉴定和验证,评价小麦材料穗发芽的综合抗性;大田穗发芽法较易受自然条件的影响、变异程度较大,其结果可以作为室内发芽试验的参考数据。     

小麦Vp-1基因RNA干扰表达载体的构建及遗传转化

小麦成熟期穗发芽是世界性的自然灾害,严重影响小麦的产量和品质.Viviparous-1(Vp-1)是促进胚成熟和休眠的主要转录调节因子,与小麦穗发芽抗性有着密切的关系.本实验根据小麦Vp-1基因序列,以植物表达载体pAHC25为基础,成功构建了含有反向重复序列的RNA干扰表达载体pAHC-WVpRi.采用基因枪法轰击小麦品种新春9号幼胚材料1825个,共获得34株T0再生植株.利用Bar基因引物和干扰片段特异引物对再生植株进行PCR检测,获得Bar基因和干扰片段均为阳性的植株3株,转化率为0.16%.本研究为深入分析Vp-1基因功能,进而通过分子育种进行小麦穗发芽抗性的遗传改良提供了科学依据.     

冬小麦穗发芽抗性及其遗传研究

1987—1989年在人工模拟降雨室对123个小麦品种进行了成熟期穗发芽抗性鉴定。重点研究了13个品种的穗发芽率、籽粒发芽率、籽粒含水量,籽粒吸水速率和α-淀粉酶活性的动态变化。并通过6个抗性不同品种的双列杂交,初步探讨了穗发芽抗性的遗传特点。结果表明:红粒品种普遍抗穗发芽,但白粒品种中也存在不少抗源;开花后35—40天是鉴定穗发芽抗性的适宜时期;这个对期的仔粒吸水速率阳α-淀汾酶活性是抗性鉴定的可靠指标;穗发芽抗性是遗传性状,存在母、子体抗性因子互作效应。     

黄河中游地区节节麦抗穗发芽的鉴定与分析

小麦穗发芽是小麦生产中的主要灾害和重要问题,在普通小麦中缺乏抗穗发芽的品种资源。本试验通过对35份黄河中游地区节节麦、14份国外节节麦及部分小麦品种的发芽率的测定及抗性多样性分析,综合评价了黄河中游地区节节麦的穗发芽抗性状况。结果表明,节节麦穗发芽抗性普遍高于小麦品种,黄河中游地区节节麦的抗穗发芽能力优于国外材料,其中以T005、T007、T008、T016、T030、T062、T065、T068、T069、T072和T085等11个材料的抗穗发芽能力最强,是小麦穗发芽改良优异的抗源材料。     

RSP抗穗发芽基因育种利用研究初报

利用农艺性状优良、优质的红粒小麦品种绵阳11以及2个白粒、极易穗发芽(常年穗发芽在50%以上)的小麦品系YY2和88-1643与穗发芽抗性来源于长休眠节节麦的人工合成小麦RSP杂交,对3个组合的F2单株和F3株系的穗发芽测试,从RSP×绵阳11中筛选出15个与RSP相当的纯合抗性株系和27份穗发芽接近0的F3单株;从RSP×YY2和RSP×88-1643组合中共筛选出5份穗发芽在7%以下的白粒株系.这些株系或单株相对于RSP的高秆、晚熟等不利性状已有较大改良,为节节麦抗穗发芽基因向优质或白粒小麦转移研制出了更容易利用的中间材料.     

小麦叶片水分利用效率及相关生理性状基因的染色体定位

利用中国春-埃及红代换系对控制小麦水分利用效率、光合速率、蒸腾速率、POD活性以及SOD活性等的基因进行了染色体定位。结果表明,控制高水分利用效率的基因可能位于5A和5D染色体上;控制高光效的基因可能位于3A和3D染色体上;控制高蒸腾速率的基因可能位于7B染色体上;诱导POD和SOD活性增强的有利培因可能分别位于7D和6D、2B染色体上。这些研究结果可以为小麦机抗旱节水的遗传育种研究提供一定参号信息。     

小麦-冰草衍生后代 3558-2 穗部相关性状的遗传分析和QTL定位

从普通小麦Fukuho与冰草(Agropyron cristatum,2n=4x=28,PPPP)Z559的衍生系中发现3558-2具有小穗数、小穗粒数和穗粒数多的优异性状.为了揭示衍生系3558-2优异性状的遗传特征,本研究对其与小麦品种京4841间的282个F2单株的穗长、小穗数、小穗粒数、穗粒数等穗部相关性状进行了遗传分析和QTL定位.主基因+多基因混合遗传模型分析结果显示小麦穗部相关性状都符合数量性状特征.利用单标记分析将穗部相关性状的QTL主要定位于小麦1 A染色体上,同时发现在小麦的2A、5B和5D染色体上也有QTL分布.通过加密标记重点构建了1 A染色体短臂的遗传连锁图,利用复合区间作图法解析了小麦1AS染色体上的穗部相关性状的QTL效应,发现在1A染色体上存在与穗长、小穗数、小穗粒数和穗粒数相关的重要QTL各1个,解释变异度分别为14.41%、5.15%、14.84%和10.87%.本研究发现在3558-2的1 AS染色体上成簇分布着涉及穗长、小穗教、小穗粒数和穗粒数重要性状的QTL,这一结果对指导进一步研究与利用3558-2具有重要意义.     

CRISPR/Cas9技术编辑MPK7和MPK14基因创制抗穗发芽水稻新种质

穗发芽对籼稻生产危害严重.编辑休眠调控基因,创制高休眠性新种质,进而提高穗发芽抗性,是探索改良穗发芽抗性的新途径.泰丰B(TB)是籼型优质杂交稻保持系,主要缺点是种子休眠性偏低,易受穗发芽危害.MPK7/14具有抑制粳稻种子休眠作用,尚不清楚是否适用于籼稻品种.本研究利用CRISPR/Cas9技术编辑泰丰B(TB)的M...     

不同生态区小麦品种的穗发芽抗性评价

本研究对来自不同生态区的137个小麦品种进行穗发芽抗性鉴定,计算相对发芽指数,并分析这些品种穗部籽粒性状、品质指标、吸胀萌发后0～72 h α-淀粉酶活性及其基因表达量与穗发芽抗性之间的关系。结果表明: 长江中下游麦区小麦的平均发芽指数最低,抗穗发芽品种最多,其次是长江上游麦区,黄淮麦区抗穗发芽品种相对较少。红粒品种小麦的相对发芽指数低于白粒品种,相对发芽指数与籽粒长度、宽度呈极显著正相关,与小穗数呈显著正相关,与穗型、穗色、穗长、小穗密度、穗粒数、千粒重无显著相关性。相对发芽指数与容重呈极显著负相关,与面团形成时间和出粉率呈显著负相关,与蛋白质含量、湿面筋含量、吸水率、稳定时间、沉降值、拉伸面积、延展性、最大阻力无显著相关性。不同品种的α-淀粉酶活性随吸胀萌发时间的延长呈上升趋势,萌发24～72 h的相对发芽指数与α-淀粉酶活性呈极显著正相关,穗发芽中抗以上品种萌发48 h后α-淀粉酶活性聚类分析结果与穗发芽鉴定结果一致。萌发后各时段α-淀粉酶基因表达量与相对发芽指数呈极显著正相关。     

香附水提液对小麦幼苗生理活性酶的影响

鉴于中草药在抗菌、杀菌,抑制细胞分裂等方面的作用,利用中草药来抑制小麦穗发芽或许是一种新的途径和方法。为了初步研究香附水提液在小麦种子萌发过程中对幼苗生理活性酶的影响,采用室内培养皿培养法,分析不同浓度的香附水提液浸种后对小麦幼苗的α-淀粉酶含量、叶绿素含量和过氧化氢酶活性的作用,结果表明α-淀粉酶含量、叶绿素含量随水提液浓度的增加而降低,过氧化氢酶活性含量则随之递增,并且以香附水提液浓度为120 g/L和150 g/L的处理差异显著,此为研究开发抑制小麦穗发芽的中草药生物抑制剂提供试验依据。     

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.