粳稻蒸煮食味品质相关性状的QTL分析

以沈农265和丽江新团黑谷杂交衍生的重组自交系群体(RILs)为实验材料,对12个粳稻(Oryza sativa subsp.japonica)蒸煮食味品质相关性状进行QTL分析。共检测到29个蒸煮食味品质相关的QTLs,分布于除第8染色体外的11条染色体上,LOD值介于2.50–16.47之间,加性效应值为–132.69–471.85,单个QTL贡献率为10.36%–73.24%。在第6染色体RM508–RM253区域检测到1个蒸煮营养食味品质多效性QTL簇,其中q AC6表型贡献率最大,解释73.24%的表型变异;在第10染色体PM166–RM258区域检测到2个与蒸煮食味品质相关的QTLs,分别是控制口感的q CTS10和综合评分的q CCS10。此外,检测到15个与RVA特征谱相关的QTLs,在第6染色体RM253–RM402区域检测到3个与RVA谱特征值相关的QTLs,表型贡献率均大于12%。这些定位结果将为粳稻蒸煮食味相关品质的分子遗传机理研究奠定基础。     

水稻幼苗中胚轴长度QTL及与Fe2+浓度的互作效应的遗传分析

应用珍汕97B/密阳46的RIL群体及其构建的分子连锁图谱,在4个浓度的FeSO4处理下发芽,测定中胚轴长度。采用QTLMapper基因定位软件检测控制中胚轴长度的加性效应QTLs和加性×加性上位性QTLs,分别在1、2、3、4、5、6、7、8、9、11、12等染色体上定位了27个控制中胚轴长度的QTLs,其中在第1、5、9等3条染色体上定位了6个具有加性效应的QTLs。在CK和FeSO41.79mmol/L浓度下,在第5染色体长臂相邻区间检测到1个加性效应QTL,其增效等位基因来自于父本密阳46,它能使中胚轴伸长0.042cm(CK)、0.172cm(1.79mmol/L),贡献率分别为4.3%和11.4%;在高浓度FeSO4(7.16mmol/L和14.32mmol/L)下分别在1、5、9染色体上检测到的4个加性效应QTL,贡献率为3.5%～10.4%,3个QTL中来自于母本珍汕97B的等位基因使中胚轴伸长0.024～0.046cm,1个QTL来自父本的增效等位基因使中胚轴伸长0.033cm。同时在第5染色体长臂上检测到具有显著的加性效应与Fe2 互作效应的QTL1个。     

杂交水稻亲本明恢63对纹枯病水平抗性的QTL定位

利用240份源于组合珍汕97／明恢63的重组自交群体（F11、F12）,连续两年进行2重复的随机区组田间试验,运用改进的纹枯病人工接种鉴定的方法,调查其纹枯病病级,结合该组合F9群体构建的分子标记遗传连锁图谱,运用区间作图法对抗纹枯病QTLs进行了定位。两年在第5染色体的相邻区间C624－C246（1999年）和C246－RM26（2000年）上各检测到一个抗纹枯病QTL,两者一个LOD值置信区间存在较大的重叠,而且LOD峰值位点很接近,推测它们可能是同一个QTL。两年在第9染本上均检测到一个QTL,分别位于C472－R26389（1999年）和RM247－RM242（2000年）区间上,两区间相距9．8cM。两年检测到的所有抗纹枯病QTLs均业自明恢63。     

两个水稻骨干恢复系重要农艺性状的遗传基础研究

水稻骨干恢复系是指在杂交稻育种中广泛应用的一类恢复系。探明骨干恢复系的遗传基础,发掘其重要农艺性状基因/QTL,对分子标记辅助选择水稻恢复系育种具有重要应用价值。本研究以生产上广泛应用的三系骨干恢复系成恢727和两系骨干恢复系9311为亲本,培育了具有250个系的重组自交系群体。分别在2015年三亚和2016年合肥两个环境下进行了9个重要农艺性状表型和SSR分子标记基因型鉴定,用SAS9.2分析表型数据,用QTL Ici Mapping v4.1进行QTL定位分析。在三亚和合肥两个环境下共检测到39个QTL,三亚检测到16个,分布于第1、2、4、7、8、10、11和12染色体上;合肥检测24个,分布于第1、2、3、7、8、9、10和12染色体上。其中qPH1-1在三亚和合肥两个环境下都能检测到,加性效应分别为-1.75和-2.46。在检测到的39个QTL中,有24个QTL的增效等位基因来自恢复系成恢727,15个QTL的增效等位基因来自9311。共计有26个QTL曾被前人定位,13个属于尚未见文献报道的新QTL。另外,在RM279~RM521、RM336~RM3534、RM25~RM547、RM553~RM160、RM222~RM271区段内检测到5个多效性QTL位点。其中RM25~RM547位点与已经克隆的基因Ghd8位置相近。RM553~RM160位点是一个新的多效性位点,分别控制每穗实粒数、单株产量和结实率,而且效应和表型变异贡献率都较大。其余3个位点在前人的研究中分别有所报道,但其多效性则是在本研究中首次发现。在本研究新发掘到的QTL中,控制穗数的QTL qPN12-1,控制穗长的QTL qPL1-2和qPL10-1,控制总粒数的QTL qSNP2-1和qSNP10-1,控制结实率的QTL qSF3-1,控制千粒重QTL qTGW7-1和控制产量的QTL qGY1-1效应均比较大,解释的表型遗传变异比例也较高。本研究的结果将会为相关性状QTL的精细定位、克隆和育种应用奠定基础。     

利用籼粳回交群体分析水稻粒形性状相关QTLs

水稻谷粒的外观性状对稻米外观品质存在重要的影响。该研究利用SSR标记,以回交群体Balilla／NTH∥Balilla为作图群体,构建了水稻12条染色体的连锁图,该遗传图谱包括：108个分子标记,平均图距为11．9cM。以构建的遗传图谱为基础,采用区间作图法对谷粒外观性状,包括粒长、粒宽和粒形进行了数量性状基因(QTL)定位。结果表明,粒长、粒宽和粒形在回交群体中均呈近似的正态分布,表现出典型的数量性状特征。QTL定位结果表明,第12染色体上RM101-RM270区间内存在一个与粒长性状相关的QTL,(qGL-12),加性效应约为0．26mm,贡献率为16．7％。在第2和第3染色体上RM154-RM211和RM257-RM175区问内,分别检测到qGW-2和qGW-3两个位点与粒宽性状有关,加性效应为分别为-0．10mm和-0．12mm,贡献率分别为11．5％和16．6％。对于粒形性状,共检测到3个QTLs,qLW-2、qLW-6和qLW-7,分别位于第2、6和7染色体上。其中qLW-2和qLW-7的加性效应分别约为0．09和0．10,两个QTLs分别可解释表型变异的12．7％和18．3％;而qLW-6的加性效应约为-0．13,可解释粒形变异的11．5％。文中还讨论了粒形和稻米外观品质同时改良的可能性。     

利用水稻重组自交系群体定位谷粒外观性状的数量性状基因

用区间作图和混合线性模型的复合区间作图两种方法,对水稻（Oryza sativa L）珍汕97和明恢63组合的重组自交系群体的谷粒外观性状－粒长,粒宽和粒形进行了数量性状基因（QTL）定位,用区间作图法在LOD≥2．4水平上（近拟于a=0.005),1998年对粒长,粒宽和粒形分别检测到6,2放2个QTLs,1999年对以上3个性状分别检测到3,2和2个QTLs,其中7个QTLs在两年均检测到,位于第3染色体RG393－C1087区间的QTL效应大,同时影响粒长和粒形,两年贡献分别为57．5％,61．4％和26．7％,29．9％,位于第5染色体RG360－C734B区间的QTL效应大,同时影响粒宽和粒形,两年贡献率分别为44．2％,53．2％和32．1％和36．0％,用混合线性模型的复合区间作图法在P＝0．005水平上,对粒长,粒宽和粒形分别检测到8,5和5个QTLs,共解释各自性状变异的58．81％,44．75％和57．47％,只检测到1个QTL与环境之间存在的显互作。     

水稻籽粒γ-氨基丁酸含量的QTL定位分析

本研究以低含量γ-氨基丁酸的宁农黑粳为母本,高含量γ-氨基丁酸的高粱稻-1为父本,构建F2群体,获得了216个F2单株。利用130个SSR标记构建了一张F2群体的SSR标记连锁图谱,覆盖基因组长度为2406.9 cM,连锁群长度在129.5～360.7 cM之间,标记间的平均距离为18.5 cM,并进一步开展控制水稻γ-氨基丁酸含量的QTL定位研究。结果表明:共检测到7个QTL位点,分别位于第8号和第9号染色体上,其中qGABA8-2、qGABA8-3、qGABA9-1的贡献率依次为10%、11%和9%。对3个贡献率大的QTL位点进行复合区间作图,当LRS为25.6时,在RM342～RM515处可能存在较为可靠的QTL,初步将qGABA8定位在标记RM342与RM515之间的326 kb区间内。利用InDel标记对目标区间加密,将该区间进一步缩小到183 kb区间内,位于标记RM342和G121之间。本研究结果可进一步通过构建次级群体对该基因进行精细定位及图位克隆,同时,研究中筛选出的SSR标记和设计的InDel标记可快速筛选水稻育种材料中富γ-氨基丁酸的基因型,加快育种进程。     

水稻籽粒锌含量的QTL 定位

锌元素的营养失衡已成为影响人类健康的最重要因素之一, 籽粒锌含量的QTL(quantitative trait loci)定位对研究富锌水稻的遗传育种具有重要的意义。以水稻(Oryza sativa L.)亲本奉新红米和明恢100杂交的145个株系的F2群体为实验材料, 利用92个SSR(simple sequence repeat)标记对水稻籽粒锌含量进行了QTL定位, 共检测到3个QTLs , 分别定位于第3、6和11染色体上, 对表型变异的贡献率分别为4.97%、12.75%和7.74%。其中位于第3染色体上的分子标记RM186和RM168之间的QZN3对表型变异的贡献率最大, 其增效等位基因来自亲本明恢100, 表现为部分显性。3个QTLs 的联合贡献率为25.46%, 具有基因累加效应。该研究结果有利于深入理解水稻锌含量的遗传基础, 为锌含量的QTL精细定位、基因克隆和分子标记辅助选择提供依据。     

水稻幼苗活力性状的低温反应数量性状基因座检测

以籼粳交“密阳23/吉冷1号”的F2：3代200个家系作为作图群体,在12℃冷水胁迫下,进行苗高、苗鲜重和苗干重等水稻幼苗活力性状的低温反应鉴定,并利用由SSR标记构建的分子连锁图谱为基础,对冷水胁迫下苗高、苗鲜重和苗干重以及它们的低温反应指数进行了数量性状基因座（QTLs）检测。研究结果表明,低温胁迫下上述幼苗活力性状在F3家系群中均表现为接近正态的连续分布,表现为由多基因控制的数量性状;在第1、2、7、8和12染色体上,检测到与幼苗活力性状的低温反应相关的QTL共12个,对表型变异的贡献率范围为5．2％-17．9％,其中位于第2染色体RM262-RM263区间和第12染色体RM270-RM17区间的与低温下苗高相关的qCSH2和qCSH12,以及位于第12染色体RM19-RM270区间和第1染色体RM129-RM9区间的分别控制低温下苗干重及其低温反应指数的qSDW12和qCSDW1对表型变异的贡献率较大,分别为16．6％、17．9％、15．9％和16．2％。其增效等位基因均来自吉冷1号,前两者均表现为加性效应,后两者分别表现为显性和超显性。     

水稻耐亚铁毒QTLs的定位

亚铁毒是潜育性水稻土中限制水稻产量的主要因子。利用龙杂8503／IR64的F2和等价的F3群体,在营养液中培养来定位耐亚铁毒的QTLs。通过构建101SSR标记的遗传连锁图谱来确定耐亚铁毒QTLs的位置和特性。借助叶片棕色斑点指数、株高和最大根长3个性状,利用营养液在水稻苗期来评价F2单株、F3群体和亲本龙杂8503、IR64,共检测到叶片棕色斑点指数、株高和最大根长的QTLs20个,分布在水稻的10条染色体上,表明这些性状受多基因控制。控制叶片棕色斑点指数的QTLs分别定位在第1染色体的RM315-RM212、第2染色体的RM6-RM240和第4染色体的RM252-RM451之间。与前人的研究结果比较发现：1）位于第4染色体RM252-RM451之间的控制叶片棕色斑点指数的QTL与水稻功能图谱上控制叶绿素含量减少的QTL的位置一致。另一个位于第1染色体的RM315-RM212之间的控制叶片棕色斑点指数的QTL与水稻功能图谱上位于C178-R2635之间控制叶绿素含量的QTL连锁。2）位于第2染色体RM6-RM240之间的第3个控制叶片棕色斑点指数的QTL与位于RZ58-CD0686的控制钾吸收的QTL连锁。     

Molecular mechanisms of seed dormancy

Seed dormancy is an important component of plant fitness that causes a delay of germination until the arrival of a favourable growth season. Dormancy is a complex trait that is determined by genetic factors with a substantial environmental influence. Several of the tissues comprising a seed contribute to its final dormancy level. The roles of the plant hormones abscisic acid and gibberellin in the regulation of dormancy and germination have long been recognized. The last decade saw the identification of several additional factors that influence dormancy including dormancy-specific genes, chromatin factors and non-enzymatic processes. This review gives an overview of our present understanding of the mechanisms that control seed dormancy at the molecular level, with an emphasis on new insights. The various regulators that are involved in the induction and release of dormancy, the influence of environmental factors and the conservation of seed dormancy mechanisms between plant species are discussed. Finally, expected future directions in seed dormancy research are considered.     

The control of seed germination in Trollius ledebouri A model of seed dormancy

Treatment of Trollius ledebouri seeds with gibberellins A₄+A₇ promotes germination. The efficacy of the treatment is dependent upon the duration of imbibition in distilled water prior to GA₄₊₇ application. Presoaking increases both the final percentage germination attained and also its rate of achievement. No presoaking effect is exhibited by seeds induced to germinate by testa removal in the absence of GA₄₊₇. Active washing of Trollius seeds enhances the presoaking effect and the eluent from washed seeds is inhibitory to germination. The results support the hypothesis that the presoaking effect exhibited by Trollius is the result of the leaching of a germination inhibitor from the seeds which is antagonistic to GA₄₊₇. Additionally, treatment of Trollius seeds with the gibberellin-biosynthesis inhibitor (2-chloroethyl)-trimethylammonium chloride (CCC) prior to testa removal retards germination. The inhibitory effect of CCC on germination is overcome by GA₄₊₇. Although CCC inhibits embryo growth during the presoaking of intact seeds, it does not affect the increased sensitivity of presoaked seeds to GA₄₊₇. Therefore, although endogenous gibberellins may be involved in the germination process, they do not contribute to the presoaking phenomenon. The expansion of isolated endosperm tissue is not affected by CCC. However, the chemical markedly inhibits endosperm expansion in intact seeds and implicates the embryo as both the site of production of the germination inhibitor and of gibberellin. These results are discussed in relation to previous studies and a model is presented to account for the characteristics of germination in Trollius.Abbreviations GA gibberellin - CCC (2-chloroethyl)-trimethylammonium chloride     

Germination inhibitors in the pine seed coat

Inhibitors from (Pinus pinea L.) seed coats were separated using paper chromatography, thin layer chromatography, and a Sephadex G-10 column. The inhibitory activity was resolved into several fractions. One of these behaved similarly to abscisic acid. It has exhibed the same properties as ABA in thin-layer chromatography, paper chromatography, and Sephadex G-10 chromatography and in UV absorption and fluorescence spectra. These germination inhibitors, present in the seed coats, are involved in the regulation of P. pinea seed germination.Abbreviations ABA abscisic acid - TLC thin-layer chromatography     

Differences in properties of peanut seed lectin and purified galactose- and mannose-binding lectins from nodules of peanut

Two lectins were purified by affinity chromatography from mature peanut (Arachis hypogaea L.) nodules, and compared with the previously characterised seed lectin of this plant. One of the nodule lectins was similar to the seed lectin in its molecular weight and amino-acid composition and ability to bind derivatives of galactose. However, unlike the seed lectin, this nodule lectin appeared to be a glycoprotein and the two lectins were only partially identical in their reaction with antibodies prepared against the seed lectin. The other nodule lectin also appeared to be a glycoprotein but bound mannose/glucose-like sugar derivatives, and differed from the seed lectin in molecular weight, antigenic properties and amino-acid composition.Abbreviations Gal galactose - Gle glucose - GNL galactose-binding nodule lectin - Fru fructose - MNL mannosebinding nodule lectin - M _r rerative molecular mass - PBS phosphate-buffered saline - PSL peanut seed lectin - SDS sodium dodecyl sulphate - Sorb sorbitol     

RFLP analysis of soybean seed protein and oil content

Summary The objectives of this study were to present an expanded soybean RFLP map and to identify quantitative trait loci (QTL) in soybean [Glycine max (L.) Merr.] for seed protein and oil content. The study population was formed from a cross between a G. max experimental line (A81-356022) and a G. soja Sieb. and Zucc. plant introduction (PI 468916). A total of 252 markers was mapped in the population, forming 31 linkage groups. Protein and oil content were measured on seed harvested from a replicated trial of 60 F₂-derived lines in the F₃ generation (F₂₃ lines). Each F₂₃ line was genotyped with 243 RFLP, five isozyme, one storage protein, and three morphological markers. Significant (P<0.01) associations were found between the segregation of markers and seed protein and oil content. Segregation of individual markers explained up to 43% of the total variation for specific traits. All G. max alleles at significant loci for oil content were associated with greater oil content than G. soja alleles. All G. soja alleles at significant loci for protein content were associated with greater protein content than G. max alleles.     

Punicic acid: A potential compound of pomegranate seed oil in Type 2 diabetes mellitus management

Diabetes is one of the most prevalent diseases in the worldwide. Type 2 diabetes mellitus (T2DM), the most common form of the disease, has become a serious threat to public health and is a growing burden on global economies. Due to the unexpected adverse effects of antidiabetic medicines, the use of nutraceuticals as a complementary therapy has drawn extensive attention by investigators. In this issue, a novel nutraceutical, Punicic acid (PA)—the main ingredient of pomegranate seed oil (PSO) that has potential therapeutic effects in T2DM—has been investigated. PA is a peroxisome proliferator-activated receptor gamma agonist, and unlike synthetic ligands, such as thiazolidinediones, it has no side effects. PA exerts antidiabetic effects via various mechanisms, such as reducing inflammatory cytokines, modulating glucose homeostasis, and antioxidant properties. In this review, we discussed the potential therapeutic effects of PSO and PA and represented the related mechanisms involved in the management of T2DM.     

Soil seed banks in dry Afromontane forests of Ethiopia

Abstract. The soil seed bank was investigated in four dry Afromontane forests of Ethiopia. At least 167 plant species were identified in the 0–9 cm soil layer with total densities ranging between 12 300 and 24 000 seeds/m². Herbs were represented with the largest numbers of species and seeds in the seed bank, while the contribution of tree species was generally low. The overall vertical distribution of seeds was similar at all sites with the highest densities occurring in the upper three cm of soil and gradually decreasing densities with increasing depth. Relatively high densities also occurred in the litter layer. There were large differences in depth distribution between species, suggesting differences in seed longevity. A large number of species in dry Afromontane forests evidently store quantities of seeds in the soil and this is in contrast to the situation in most tropical rain forests, dry lowland forests and savannas, where both the number of seeds and the number of species are relatively small. It is possible that the strongly seasonal and unpredictable climate of this region may have selected for high levels of dormancy, and that herb regeneration is associated with small scale disturbance. The fact that most of the dominant tree species do not accumulate seeds in the soil suggests that their regeneration from seed would be unlikely if mature individuals disappeared. Most tree species have relatively large seeds and poor long-distance dispersal; this implies that restoration of Afromontane forests after destruction would be difficult. Since there is a diverse seed bank of the ground flora, this component of the vegetation would have a better chance of reestablishing. However, because most cleared forest land is used for agricultural crop production, it is probable that the seed bank will be depleted in only a few years. Therefore, the future of the Afromontane forest flora seems to depend on the successful conservation of the few fragments of remaining natural forest.