多环境下陆地棉(Gossypium hirsutum L.)重组自交系铃重与衣分性状的QTL分析

本研究利用以SGK9708为母本,0-153为父本构建的196个陆地棉重组自交系(F6:8)构建了包含186个标记,总长827.84cM,标记间平均距离4.45cM,覆盖棉花基因组18.6%的遗传连锁图谱,并对7个环境下的铃重和衣分性状进行QTL定位和上位性互作分析。利用两种分析软件(WinQTLcart2.5和QTLNetwork2.0)共同定位了多个环境下稳定表达的5个主效QTLs(qBW-1-1,qBW-1-2,qLP-2-1,qLP-2-2和qLP-4-2)。利用QTLNetwork2.0分别检测到4对铃重上位性互作QTLs和7对衣分上位性互作QTLs,以背景位点间的互作和加性效应位点与背景位点间的互作为主。除主效QTL外,上位性效应也是陆地棉铃重和衣分性状的重要遗传基础。本研究定位的5个主效QTLs为选择高铃重、高衣分品种的棉花分子标记辅助育种提供了重要依据。

棉花(Gossypium hirsutum L.)原生质体培养的体细胞胚胎发生及植株再生

以陆地棉(G.hirsutum L.)3118、晋棉4号和柯字棉312等3个品种为材料,取种子无菌苗的下胚轴诱导愈伤组织,建立胚性细胞悬浮培养系。以2％纤维素酶Ono-zuka RS和0.1％离析软化酶Y-23组成的混合酶液,从细胞悬浮培养物游离出原生质体。用含低融点琼脂糖的K_3培养基包埋原生质体,采用园柱及薄层漂浮平板培养方式。3个品种的原生质体培养都得到了愈伤组织,其中晋棉4号和柯字棉312品种的愈伤组织转到低激素水平或无激素的MS-2培养基上诱导产生胚状体,胚状体在无激素的MS-1培养基上形成了植株。

基因枪介导的海岛棉(Gossypium barbadense L.)茎尖遗传转化体系的建立

以新疆海岛棉品种新海13号的茎尖为转化受体,采用基因枪介导法,研究DNA包裹浓度、微载体种类、前渗处理时间、轰击条件、筛选方法等对茎尖转化的影响,建立了基因枪法介导的海岛棉茎尖转化体系。研究结果表明,采用1.5μg·μL-1的质粒DNA包裹1.0μm金粉微载体,前渗处理12 h,轰击压力为7.584 MPa(1100 psi),轰击距离为6 cm,后渗处理16 h,恢复处理24 h,在120 mg·L-1卡那霉素浓度下直接筛选35 d。在添加4g·L-1活性炭粒的生根培养基中诱导抗性幼苗生根,获得抗性再生植株。通过PCR和RT-PCR检测,共得到5株转抗除草剂基因EPSPS的阳性植株。该研究体系的建立为海岛棉的遗传转化奠定了基础,为海岛棉的育种工作提供了材料。

施氮量对不同开花期棉(Gossypium hirsutum L．)铃纤维细度和成熟度形成的影响

为兼顾试验的重复性和生态区域性,选用高品质棉(科棉1号)和常规棉(美棉33B)品种为材料,于2005年分别在江苏南京(118°50'E,32°02'N,长江流域下游棉区)和江苏徐州(117°11'E,34°15'N,黄河流域黄淮棉区)设置施氮量(低氮N 0 kg/hm2;适氮N 240 kg/hm2;高氮N 480 kg/hm2)试验,研究施氮量对不同开花期棉铃纤维细度、成熟度和马克隆值形成的影响。结果表明,(1)施氮量显著影响棉纤维细度、成熟度和马克隆值的形成过程,但三者在不同开花期对氮素水平的响应不同,施氮量与开花期对棉纤维细度、成熟度和马克隆值的形成存在互作效应。8月10日前开花的棉铃,铃期[花后0～50 d(DPA)]日均温在23.3℃以上,纤维细度、马克隆值以N 0 kg/hm2施氮量下最大,棉纤维马克隆值与纤维细度的相关性较大;8月25日开花的棉铃(铃期日均温在20.8～23.3℃之间),纤维成熟度、马克隆值以N 240 kg/hm2施氮量下最大;9月10日开花棉铃(铃期日均温低于20.8℃),纤维细度、成熟度和马克隆值均以N 480 kg/hm2最大,棉纤维马克隆值与纤维成熟度的相关性增强。(2)影响不同开花期间纤维细度、成熟度和马克隆值的主要因素是铃期日均温;最终纤维细度、成熟度和马克隆值在不同施氮量之间的变异与不同开花期(铃期日均温不同)间的变异比较,前者显著小于后者。综上,因开花期不同而形成的铃期日均温是决定纤维细度、成熟度和马克隆值的最重要因素,施氮量可通过对位叶叶氮浓度NA影响棉纤维细度、成熟度和马克隆值的形成过程,增加施氮量可减小上述指标在不同开花期间的差异。

棉花(Gossypium hirsutum L.)花粉壁的发育

用光镜和透射电镜观察研究了棉花花粉壁的发育过程.棉花花粉壁的发生始于四分孢子时期,四分体形成后,在小孢子的质膜与胼胝质壁之间逐渐形成多糖性质的原外壁.游离小孢子时期,在一定间隔的原外壁中小孢子质膜表面积累外壁物质并形成基粒棒,之后在基粒棒的下部和上部分别横向延展并接合形成基足层和覆盖层.花粉内壁发生时期较晚,大约在大液泡形成之前.但内层和外层花粉壁均在小孢子有丝分裂之前同时建成.构建花粉壁的物质主要来自绒毡层的周原质团和小孢子原生质体的代谢分泌.小孢子胞质中在四分体时期形成的巨型内质网复合体是较为特殊的细胞结构,在游离小孢子时期,巨型内质网不断产生大量的内含微粒物的运输小泡,这种小囊泡表现出向质膜趋向运动并进一步与质膜融合.推测由内质网复合体产生的这些小囊泡是小孢子原生质体向质膜外运输花粉壁构建物质的主要形式.

利用重组自交系进行陆地棉(GossypiumhirsutumL.)棉籽油分含量和蛋白质含量的QTL定位

本研究利用以0—153为父本和SGK9708为母本构建的196个陆地棉重组自交系（F6：8）为材料对棉籽油分含量和蛋白质含量进行了遗传分析和QTL定位。通过四个环境下的群体材料的棉籽油分含量和蛋白质含量分析表明棉籽油分含量和蛋白质含量均为典型数量性状，其中棉籽油分含量存在超低亲本的超亲分离，而其蛋白质含量呈现超高亲本的超亲分离。相关性分析显示棉籽油分含量和蛋白质含量呈极显著负相关，同步提高两者在棉籽的的含量较为困难。基于包含186个标记，总长827．84cM，标记间平均距离4．45cM，覆盖棉花基因组18．6％的遗传连锁图谱，应用WinQTLcart2．5软件对四个环境下的棉籽油分含量和蛋白质含量进行了QTL定位，共检测到8个油分含量QTLs，解释表型变异5．42％～13．15％，其中稳定的QTL1个。4个蛋白质含量QTLs，解释表型变异4．35％～14．93％。本研究结果可为进行陆地棉种子营养品质性状的分子遗传改良奠定基础。

Screening of drought resistance indices and evaluation of drought resistance in cotton(Gossypium hirsutum L.)

Sixteen cotton cultivars widely planted in China were sowed under five different drought concentrations(0,2.5,5,7.5,and 10%)using PEG6000 to screen the indices of drought resistance identification and explore the drought resistance of different cotton cultivars.Eighteen physiological indices including root,stem,and leaf water contents(RWC,SWC,and LWC),net photosynthetic rate(Pn),the maximum photochemical quantum yield(Fv/Fm),the actual photochemical quantum yield(ΦPSII),non-photochemical quenching coefficient(NPQ),leaf water potential(LWP),osmotic potential(Ψs),leaf relative conductivity(REC),leaf proline content(Pro),leaf and root soluble protein contents(LSPC and RSPC),leaf and root malondialdehyde(MDA)contents(LMDA and RMDA),root superoxide dismutase,peroxidase,and catalase activities(RSOD,RPOD,and RCAT)were measured.Results indicated the 18 physiological indices can be converted into five or six independent comprehensive indices by principal component analysis,and nine typical indices(Fv/Fm,SWC,LWP,Pro,LMDA,RSPC,RMDA,RSOD,and RCAT)screened out by a stepwise regression method could be utilized to evaluate the drought resistance.Moreover,the 16 cotton cultivars were divided into four types:drought sensitive,drought weak sensitive,moderate drought resistant,and drought resistant types.The resistance ability of two selected cotton cultivars(drought resistant cultivar,Dexiamian 1;drought sensitive cultivar,Yuzaomian 9110)with contrasting drought sensitivities were further verified by pot experiment.Results showed that the responses of final cotton biomass,yield,and yield composition to drought were significantly different between the two cultivars.In conclusion,drought resistant cultivar Dexiamian 1 and drought sensitive cultivar Yuzaomian 9110 were screened through hydroponics experiment,which can be used as ideal experimental materials to study the mechanism of different cotton cultivars with contrasting drought sensitivities in response to drought stress.

Relationship between plant canopy characteristics and photosynthetic productivity in diverse cultivars of cotton(Gossypium hirsutum L.)

Genotype and plant type affect photosynthetic production by changing the canopy structure in crops.To analyze the mechanism of action of heterosis and plant type on canopy structure in cotton(Gossypium hirsutum L.),we had selected two cotton hybrids(Shiza 2,Xinluzao 43) and two conventional varieties(Xinluzao 13,Xinluzao 33) with different plant types in this experiment.We studied canopy characteristics and their correlation with photosynthesis in populations of different genotypes and plant types during yield formation in Xinjiang,China.Canopy characteristics including leaf area index(LAI),mean foliage tilt angle(MTA),canopy openness(DIFN),and chlorophyll relative content(SPAD).The results showed that LAI and SPAD peak values were higher and their peak values arrived later,and the adjustment capacity of MTA during the flowering and boll-forming stages was stronger in Xinluzao 43,with the normal-leaf,pagoda plant type,than these values in other varieties.DIFN of Xinluzao 43 remained between0.09 and 0.12 during the flowering and boll-forming stages,but was lower than that in the other varieties during the boll-opening stage.Thus,these characteristics of Xinluzao 43 were helpful for optimizing the light environment and maximizing light interception,thereby increasing photosynthetic capability.The photosynthetic rate and photosynthetic area were thus affected by cotton genotype as changes in the adjustment range of MTA,increases in peak values of LAI and SPAD,and extension of the functional stage of leaves.Available photosynthetic area and canopy light environment were affected by cotton plant type as changes in MTA and DIFN.Heterosis expression and plant type development were coordinated during different growth stages,the key to optimizing the canopy structure and further increasing yield.

Somatic Embryogenesis and Plant Regeneration from Two Recalcitrant Genotypes of Gossypium hirsutum L.

An improved protocol has been developed for somatic embryogenesis and plant regeneration of recalcitrant cotton cultivars. High callus frequencies and embryogenic tissue were developed in MSB medium supplemented with gradient concentrations of KT and 2,4-D, their concentration decreasing from 0.1 to 0.01 mg·L^-1. Somatic embryos were successfully incubated in 1/2 macronutrient MSB suspension supplemented with 0.5 g· L^-1 glutamine and 0.5 g·L^-1 asparagine. Decrease in macronutrient concentration of MSB significantly alleviated browning and was beneficial to suspension cells. Transformation of somatic embryos into plants was induced in MSB medium supplemented with 3% sucrose, 0.5 g·L^-1 glutamine, 0.5 g·L^-1 asparagine, and 6.0 g·L^-1 agar. The effect of sucrose as carbohydrate was better than that of glucose for plant germination. Using this protocol, regenerated plantlets from the CCRI521 and Zhongzhi86-6 reached to as much as 19.6 and 18.5% somatic embryos, respectively.

Identification of Organic Substances Associated with Tissue Senescence in Upland Cotton (Gossypium spp. L.) Based on GC-MS Analysis

Premature senescence in crop production,especially occurred at the late growth stage,generally results in a reduction in yield and quality.Therefore,it is beneficial for yield and quality to properly delay senescence of plant tissues during the late developmental stage.In this study,it was observed that the chlorophyll content and photosynthetic rate were gradually decreased along leaf growth progression,and the rates of reduction were promoted by drought.Based on gas chromatography-mass spectrometry （GC-MS） analysis,total eight,five,seven,and five kinds of organic compounds that putatively associated with the tissue senescent progression were identified in leaves,fruit branches,petals,and sepals,respectively.It was found that the identified organic compound,such as a-pinene,b-pinene,and pentadecane were present in different tissues.Among the total ten organic substances identified to be related with the leaf senescence,half were specifically detected in the drought treatment.These results suggest some biochemical pathways associated with the leaf senescence are distinctly regulated by drought.The identified organic compounds in the tested tissues showed three types on the performance pattern based on the contents along with the senescent progression,including gradually increasing,decreasing,and a curve with one single peak.Thus,during the senescence process in tissues,a subset of metabolic substances occur modifications on the quantities,reflecting a complicate biochemical reactions are initiated via the senescence signals.Further analysis of the important organic substances will be helpful for elucidation of the tissue senescence mechanism at the biochemical level and provide a new insight of the senescence signaling transductions in cotton.

Comparative Analysis of Salinity-Induced Proteomic Changes in Cotton (Gossypium hirsutum L.)

Salt stress on cotton varieties of distinct salinity tolerance can induce expression of different proteins. Zhong 07, a salt-tolerant variety and Zhong s9612, a salt-sensitive variety, were utilized as experimental materials. The leaves of trefoil seedlings treated with or without 0.4% NaCl for 24 h were harvested for whole-protein extraction. Two-dimensional technology, combined with mass spectroscopy (MS) analysis and protein database searching, was employed to detect differentially expressed proteins and determine their identities and biological functions. Compared with the control, Zhong 07 showed 10 differentially expressed proteins under salt stress, of which 6 were upregulated and 4 were downregulated. Meanwhile, 12 differentially expressed proteins were detected in Zhong s9612 under salt stress, of which 10 were upregulated and 2 were downregulated. In the matrix-assisted laser desorption-ionization/time of flight-time of flight/MS analysis, 14 differentially expressed proteins were successfully identified, including the ribulose-1, 5-bisphosphate carboxylase/oxygenase (RuBisco) large subunit-binding protein subunit alpha (RuBisco α), luminal binding protein (LBP), heat shock protein 70 (Hsp1, 2, 3), pathogenesis-related protein class 10 (PR-10), quinoneoxidoreductase-like protein (QOR), S-adenosylmethioninesyn-thetase (SAMS), enolase (EN), and RuBisco large subunit-binding protein subunit beta (RuBisco β). Cellular function is ultimately executed by proteins, and cotton varieties with different salt tolerance can be influenced by salt stress to various degrees, which can provide certain theoretical foundation for the identification of salt tolerance of cotton varieties. The findings also provide some proteins, such as the RuBisco large subunit binding proteins α and β subunits, OEE2 protein, HSP70, and S-adenosylmethionine synthetase, which can be used as protein markers of salt-to-lerance before- and post-treatment, making a big difference in salt-tolerance identification in cotton.

Molecular Cloning and Characterization of Three Novel Genes Related to Fatty Acid Degradation and Their Responses to Abiotic Stresses in Gossypium hirsutum L.

Fatty acid metabolism is responsible not only for oilseed metabolism but also for plant responses to abiotic stresses. In this study, three novel genes related to fatty acid degradation designated GhACX, Gh4CL, and GhMFP, respectively, were isolated from Gossypium hirsutum acc. TM-1. The phylogenetic analysis revealed that amino acid sequences of GhACXand GhMFP have the highest homology with those from Vitis vinifera, and Gh4CL has a closer genetic relationship with that from Camellia sinensis. Tissue- and organ-specific analysis showed that the three genes expressed widely in all the tested tissues, including ovules and fiber at different developing stages, with expressed preferentially in some organs. Among them, GhACX showed the most abundant transcripts in seeds at 25 d post anthesis （DPA）, however, GhMFP and Gh4CL have the strongest expression level in ovules on the day of anthesis. Based on real-time quantitative RT-PCR, the three genes were differentially regulated when induced under wounding, methyl jasmonate （MeJA）, cold, and abscisic acid （ABA） treatments. The characterization and expression pattern of three novel fatty acid degradation related genes will aid both to understand the roles of fatty acid degradation related genes as precursor in stress stimuli and to elucidate the physiological function in cotton oilseed metabolism.

Selection and Characterization of a Novel Glyphosate Tolerant Upland Cotton(Gossypium hirsutum L.) Mutant(R1098)

Stepwise selection approach was adopted to obtain glyphosate-tolerant upland cotton mutant(R1098) from the embryogenic calli of Coker 312(Gossypium hirsutum L.).The calli were transferred to selection medium and multi-step selection pressure process was carried out until the

An Integrated Genetic,Physical and Transcript Map of Homoeologous Chromosomes 12 and 26 in Upland Cotton(Gossypium hirsutum L.)

While Upland cotton(Gossypium hirsutum L.) represents 95% of the world production,its genetic improvement is hindered by the shortage of effective genomic tools and resources.The

Genome-wide identification and expression analysis of the GhIQD gene family in upland cotton(Gossypium hirsutum L.)

Background:Calmodulin(CaM)is one of the most important Ca^(2+)signaling receptors because it regulates diverse physiological and biochemical reactions in plants.CaM functions by interacting with CaM-binding proteins(CaMBPs)to modulate Ca^(2+)signaling.IQ domain(IQD)proteins are plant-specific CaMBPs that bind to CaM by their specific CaM binding sites.Results:In this study,we identified 102 GhIQD genes in the Gossypium hirsutum L.genome.The GhIQD gene family was classified into four clusters(Ⅰ,Ⅱ,Ⅲ,andⅣ),and we then mapped the GhIQD genes to the G.hirsutum L.chromosomes.Moreover,we found that 100 of the 102 GhIQD genes resulted from segmental duplication events,indicating that segmental duplication is the main force driving GhIQD gene expansion.Gene expression pattern analysis showed that a total of 89 GhIQD genes expressed in the elongation stage and second cell wall biosynthesis stage of the fiber cells,suggesting that GhIQD genes may contribute to fiber cell development in cotton.In addition,we found that 20 selected GhIQD genes were highly expressed in various tissues.Exogenous application of MeJA significantly enhanced the expression levels of GhIQD genes.Conclusions:Our study shows that GhIQD genes are involved in fiber cell development in cotton and are also widely induced by MeJA.Thw results provide bases to systematically characterize the evolution and biological functions of GhIQD genes,as well as clues to breed better cotton varieties in the future.

Genetic Dissection of Net Effects Between Yield and Its Components in Sea Island Cotton (Gossypium barbadense L.)

The number of bolls, individual boll weight, and lint percentage are three important yield components of lint yield of cotton. In the present study, nine parents, twenty F1, and twenty F2 crosses of intraspecific hybrids of sea island cotton （Gossypium barbadense L.） were grown at Tarim University, Alar, Xinjiang, China, in 2000 and 2001. Lint yield and its three component traits were measured and analyzed by an extended conditional mixed linear model approach. Lint percentage made the largest contribution to additive, additive x environment, and dominance x environment variations for lint yield. The contribution ratios of number of bolls, individual boll weight, and combined contribution of these two traits to additive x environment and dominance x environment variations for lint yield were not statistically significant. Lint yield of different parents could be affected differently by lint percentage. Lint yield of some parents was closely correlated with lint percentage, whereas for other parents, the behavior of individual boll weight and number of bolls played much more important roles on lint yield than that of lint percentage. It was shown by the conditional and conventional predicted additive x environment interaction effects of parents that the environment condition could influence different parents with varied effects.

Genetic Diversity in the Environmental Conditioning of <i>Gossypium hirsutum</i>and <i>Gossypium barbadense</i>Cultivars

Enzyme adaptations to temperature occur constantly as temperature patterns modulate diurnally and seasonally. These adaptations entail qualitative and/or quantitative metabolic changes that often provide a competitive advantage, impact adjustment to new environments, and effect the survival of the species. Changes in isozymes or allozymes, changes in enzyme concentration, modification by substrate and effectors, and metabolic regulation of enzyme function without changing enzyme composition are all possible strategies for adaptation to changes in temperature. The degree of adaptation among cotton cultivars to a specific thermal regime may be difficult to determine from phenotypic responses of the plants. The present study evaluated the thermal sensitivity of Gossypium hirsutum L. and Gossypium barbadense L. cultivars following growth under distinct thermal environments. The metabolic fitness of Gossypium hirsutum L. and Gossypium barbadense L. cultivars showed that the Gossypium hirsutum L. cultivars grown in a 28&deg;C/20&deg;C day/night cycle tended to be better equipped to cope with a 16 h - 38&deg;C treatment than the same cultivars grown in a 38&deg;C/32&deg;C day/night cycle. The Gossypium barbadense L. cultivars, on the other hand, grown in a 38&deg;C/32&deg;C day/night cycle tended to be equipped to cope with a 16 h - 38&deg;C treatment than the same cultivars grown in a 28&deg;C/20&deg;C day/night cycle. The Gossypium hirsutum L. line TX 303 is an exception to these general trends as its responses were similar to the Gossypium barbadense L. St. Vincent and Pima S-7 cottons.

Construction of Molecular Linkage Map of Cultivated Allotetraploid Cotton (Gossypium hirsutum L.×G. barbadense L. )with SSR and RAPD Markers

A permanent doubled haploid population fromthe crossing of G.hirsutum × G.barbadensewere developed by means of Vsg,virescentlymarked semigamy line in sea island cotton,which was characterized by a cytologicalmechanism for developing haploids with certainconvenience,and thus constructed

Cloning and Function Characteristic of GhDWF4,an Ortholog of Arabidopsis DWF4 from Upland Cotton(Gossypium hirsutum L.)

As one of the longest cells characterized in plant kingdom,cotton fibers were regarded as an ideal material for studying plant cell growth and development.In recent years,several reports revealed

Evaluation of genetic diversity in short duration cotton(Gossypium hirsutum L.)

Background: Cotton(Gossypium hirsutum L.) is an important fiber crop in Bangladesh. Genetic diversity among the genotypes of a germplasm has a great importance for cotton breeding. An experiment was carried out at the experimental field of Cotton Research, Training and Seed Multiplication Farm, Sreepur, Gazipur during the cropping season of 2015-2016 with 100 genotypes to evaluate genetic diversity of cotton genotypes for short duration using field performance.Results: The genotypes under study were grouped into ten clusters through multivariate analysis using GENSTAT-5.Cluster III contained maximum number of genotypes(16) while cluster X contained the least number of genotypes(7).The inter cluster distances were larger than intra cluster distances in all cases suggesting wider genetic diversity among the genotypes of different clusters. The maximum and minimum inter cluster distances were observed between clusters II and V(10.78) and clusters VIII and IX(3.30), respectively. The results indicated diverse and close relationship among the genotypes of those clusters. Earliness index, single boll weight and days to boll opening showed the higher contribution to the genetic divergence among 19 characters.Conclusion: Based on the results of genetic diversity and earliness index, the genotypes from cluster Ⅱ could be used as parent in hybridization program for the development of short duration cotton variety.