植物抗寒相关功能与调控基因研究进展

低温是严重影响农业生产的重要因素之一,尤其是在高海拔的冷凉地区。近年来随着抗寒基因工程的发展,有关植物抗寒性的研究得到了很大的进展。本研究从抗寒相关的功能基因和调控基因两方面入手,归纳了就近几年国内外关于植物的抗寒相关功能基因（冷诱导基因、脂肪酸去饱和代谢关键酶基因和抗氧化酶基因等）和调控基因（AP2/EREBP、NAC、MYB、WRKY和bZIP转录因子）并提出了展望,以期为人们进一步认识和利用植物抗寒相关基因提供参考,为植物抗寒机理的研究和植物抗寒育种提供依据,期望随着研究的深入能够培育出多抗寒性植物新品种。     

香蕉幼苗叶片响应低温胁迫的比较蛋白质组学研究

香蕉是中国热带地区重要的经济作物,香蕉产业受寒害的影响极为严重。明确香蕉植株响应低温胁迫的分子调控机制有可能为培育和筛选出相对抗寒的香蕉品系提供研究基础。应用比较蛋白质组学对7℃低温处理0、3、5和7天的巴西蕉幼苗叶片总蛋白进行分析,发现有85个蛋白质点的表达丰度在低温胁迫后发现明显变化,通过质谱成功地鉴定了其中的82个蛋白,这些蛋白质主要参与蛋白质的加工及翻译后修饰、糖与能量代谢、光合作用等生理学过程。研究结果暗示低温环境下,香蕉幼苗叶片可能通过改变光合作用相关酶、糖类与能量代谢相关酶的表达量来调节能量与碳代谢,保证碳养分供应及吸收,同时通过超氧化物歧化酶清除系统来提高香蕉抵御低温的能力。研究结果将为研究香蕉抗寒的分子机制提供新线索,为香蕉抗寒育种提供新的候选蛋白。     

基于RNA-seq的香蕉枯萎病菌Cat1基因敲除突变体分析

本研究通过RNA-seq技术对Δcat1突变体菌株和Foc4野生型菌株的转录组进行了比较分析。为探明Cat1基因敲除后对香蕉枯萎病菌转录组的影响。预测到新转录本2 354个,其中能够预测到基因功能的有1 095个。Cat1基因敲除后,敲除突变体的基因表达相较于野生型菌株发生很大变化。差异表达基因GO功能富集发现,差异基因表达主要体现在蛋白复合物、细胞质组分、细胞蛋白代谢过程、ATP结合和转运活性等相关方面。KEGG分析发现,敲除突变体与野生型菌株的差异表达基因主要集中在核糖体合成、RNA转运,香蕉处理后差异表达基因集中在抗生素生物合成、次生代谢物生物合成等通路。Cat1基因敲除后,一些能量转运酶、加氧酶、氨基酸转移酶活动加强,一些激酶、氧化酶、蛋白酶受香蕉诱导活性增加。Cat1的敲除导致多种糖转运蛋白的大幅下调表达,且大大影响锌脂蛋白和细胞周期蛋白等表达,从而对菌株生命活动和致病力产生影响。Cat1敲除后,其他过氧化氢酶类的表达量补偿性增加,但催化生成过氧化氢的SOD表达也增加,可能是敲除突变体致病力减弱的原因之一。本研究为进一步揭示香蕉枯萎病菌的致病机理提供理论依据。     

香蕉分子育种研究进展

香蕉是世界重要的粮食作物和经济作物,对经济社会发展具有重要作用。然而香蕉主栽品种多为三倍体,难以通过传统育种方式获得优良新品种。随着生物技术的快速发展,利用生物技术手段对香蕉进行遗传改良就成了解决问题的有效途径之一。本综述了近几年来香蕉分子标记辅助育种、功能基因组学及基因工程等三方面的研究进展,希望为通过生物技术手段培育香蕉新品种提供一定的参考。     

香蕉SPS基因家族的系统进化分析

蔗糖磷酸合成酶(sucrose phosphate synthase, SPS)是调控蔗糖合成途径的关键酶之一,SPS受SPS基因家族编码。本研究基于香蕉基因组数据库,鉴定出3个香蕉SPS基因,分布在4、6、9号染色体上,命名为MaSPS1～MaSPS3基因,其蛋白氨基酸数目在1 043～1 061 aa之间,分子量介于116.36～118.89 kD之间,理论等电点在5.86～6.33之间,均为不稳定的亲水性蛋白,都不存在信号肽,蛋白二级结构都主要由α-螺旋和无规则卷曲组成。Ma SPS1和MaSPS2蛋白主要分布于细胞质,而MaSPS3蛋白主要分布于细胞核,都不存在跨膜结构区。3个MaSPS基因外显子和内含子数量分别为13～14和12～13。3个MaSPS蛋白均有10个相同基序,且都具有糖基转移酶结构域、蔗糖合成酶结构域和蔗糖-6-磷酸磷酸水解酶等3个保守区域。进化树分析发现MaSPS1和Ma SPS3聚类到A亚家族,MaSPS2被聚类到C亚家族。研究结果将为深入研究MaSPS基因的功能及调控香蕉果实发育和成熟过程中糖代谢奠定基础。     

香蕉乙醇脱氢酶基因的克隆及其逆境胁迫表达

香蕉乙醇脱氢酶基因的克隆及在逆境胁迫下的表达分析,将为进一步研究ADH在香蕉中的功能奠定基础。本研究从香蕉果实抑制差减文库中获得一条香蕉乙醇脱氢酶基因片段,采用RACE技术获得其全长,命名为MaADH。MaADH的cDNA全长1140 bp,编码379个氨基酸。生物信息学分析该基因编码的蛋白分子量为40.7 kDa,等电点为7.09。保守结构域分析发现,该基因具有MDR保守结构域,包含22个NAD结合位点、11个底物结合位点和4个锌结合位点。系统进化树分析表明,MaADH与拟南芥和甘蓝亲缘关系较近。MaADH在盐胁迫和低温胁迫处理的香蕉苗中上调表达;在干旱胁迫下该基因是先上调表达,随后下调表达;在伤害胁迫下是先下调表达后上调表达,但变化不明显。研究说明,香蕉中的乙醇脱氢酶基因在香蕉适应盐、低温、干旱和伤害等逆境中发挥重要的作用。     

基于转录组金银花WRKY转录因子的挖掘与分析

WRKY转录因子是植物抗逆应答过程中最为常见的蛋白家族。为了挖掘金银花抗寒相关的WRKY基因,本研究基于已有的转录组数据,利用植物转录因子数据库和BioEdit对WRKY进行筛选及保守结构域分析,对筛选出的WRKY转录因子利用ExPASy进行理化性质分析,利用PSORT进行亚细胞定位预测,NetPhos进行磷酸化位点分析并且利用MEME数据库对WRKY基因的氨基酸进行序列分析,运用MEGA软件对筛选的金银花WRKY转录因子基因和21个已知抗寒的WRKY基因进行序列同源比对,并构建系统进化树。结果表明:金银花中筛选的30个WRKY基因的蛋白为85～721个氨基酸,理论等电点的范围为4.85到9.76。所有LjWRKY基因编码的蛋白中只有LjWRKY6为稳定蛋白,其余均属于不稳定蛋白,所有蛋白均属于亲水性蛋白。亚细胞定位预测结果,LjWRKY所有蛋白定位于细胞核。除LjWRKY23不具有Try磷酸化位点,其它所有氨基酸均具有Ser、Thr和Try磷酸化位点。LjWRKY蛋白比较保守,WRKYGQK没有发生任何变异,且包含三类WRKY转录因子。系统进化树发现,有12个WRKY基因与已知抗寒基因有同源性,推测其参与了金银花低温逆境下的反应。研究结果可以通过筛选的WRKY基因,进行进一步的转基因验证,进而为植物抗寒分子育种提供分子基础。     

香蕉BADH基因序列及表达特性分析

甜菜碱醛脱氢酶(BADH)是植物体内甜菜碱合成过程中的关键酶,对植物抵御逆境具有重要作用。为研究香蕉BADH基因序列及表达特性,本研究利用香蕉基因数据库对香蕉BADH基因序列及蛋白序列进行生物学信息分析,采用qTR-PCR技术对香蕉幼苗中BADH基因进行表达分析。结果表明:MaBADH基因属单克隆基因,含有15个外显子,14个内含子;顺式调控元件预测显示在MaBADH启动子区域存在15种激素和逆境胁迫相关的顺式调控元件;蛋白结构域和功能分析有一个甜菜碱醛脱氢酶结构域具有氧化还原酶活性;亚细胞定位在叶绿体中,多重序列比对发现其具有N-端信号肽和C-端信号肽两种信号肽;系统进化树显示其与水稻、玉米、菠萝亲缘关系最近。基因表达分析发现MaBADH具有组织特异表达特性,在叶片中相对表达量最高,假茎次之,根最低;此外,茉莉酸甲酯能够诱导香蕉幼苗根和叶中MaBADH差异表达,其中对叶片的诱导能力更强。本研究为激素信号调控甜菜碱分子保护机制和利用基因工程提高香蕉抗逆性提供了参考依据。     

香蕉MaWRKY28基因的克隆及其功能分析

为探究香蕉WRKY28基因响应Foc-TR4侵染的作用及调节机制,本研究从抗病‘桂蕉9号’品种中克隆了香蕉MaWRKY28基因;利用ExPASy、MEGA 6.0等软件对其蛋白序列进行理化性质分析及系统进化树的构建;采用q RT-PCR分析了该基因在抗(‘桂蕉9号’)、感(‘威廉斯’)香蕉品种受Foc-TR4侵染不同时间后的表达量变化;构建过表达MaWRKY28基因载体,转化拟南芥,并检测该基因在转化植株中的表达量。结果表明,从‘桂蕉9号’中克隆了一个WRKY28基因,命名为MaWRKY28 (GenBank登录号为MK941141)。MaWRKY28基因编码区全长999 bp,编码332个氨基酸,属于不稳定的分泌蛋白,具有典型的WRKY结构域;系统进化树分析表明,香蕉与海枣(Phoenix dactylifera)、油棕(Elaeis guineensis)的同源性最高,相似性高达87%;qRT-PCR结果显示,在Foc-TR4侵染的香蕉根系过程中,MaWRKY28基因呈上调表达趋势,且在抗病品种中的表达量整体高于感病品种;筛选获得的7株阳性转化拟南芥植株中,MaWRKY28基因的相对表达量较野生型均显著提高。综上说明,MaWRKY28基因在香蕉抗枯萎病菌侵染过程中参与了抗病相关过程,且能在异源受体拟南芥中成功转化并高效表达。本研究结果为进一步研究香蕉抗病品种的抗性机理提供了帮助。     

植物抗寒工程中脂肪酸去饱和酶研究进展

低温是影响植物生长的重要因素之一。本文介绍了多不饱和脂肪酸与植物抗寒性的正相关关系,并从脂酰-ACP去饱和酶、脂酰-CoA去饱和酶、脂酰-脂去饱和酶等几个方面综述了近几年里与植物抗寒性相关的脂肪酸去饱和酶基因的克隆、功能鉴定、表达调控等方面的研究进展。也讨论了一些对不饱和脂肪酸和植物耐低温间因果关系存在争议的研究报道。展望了应用基因工程技术培育出抗寒抗冻性较强的林业木材品种。     

Location of a high-lysine gene and the DDT-resistance gene on barley chromosome 7

Summary The high-lysine gene in Risø mutant 1508 conditions an increased lysine content in the endosperm via a changed protein composition, a decreased seed size, and several other characters of the seed. The designation lys3a, lys3b, and lys3c, is proposed for the allelic high-lysine genes in three Risø mutants, nos 1508, 18, and 19. Linkage studies with translocations locate the lys3 locus in the centromere region of chromosome 7. A linkage study involving the loci lys3 and ddt (resistance to DDT) together with the marker loci fs (fragile stem), s (short rachilla hairs), and r (smooth awn) show that the order of the five loci on chromosome 7 from the long to the short chromosome arm is r, s, fs, lys3, ddt. The distance from locus r to locus ddt is about 100 centimorgans.     

Biological Activity and Quantification of Suspected Allelochemicals from Alfalfa Plant Parts

Autotoxicity restricts reseeding of alfalfa (Medicago sativa L.) after alfalfa until autotoxic chemical(s) breaks down or is dispersed into external environments. A series of aqueous extracts from leaves, stems, roots and seeds of alfalfa ‘Vernal’ were bioassayed against alfalfa seedlings of the same cultivar to determine their autotoxicity. The highest inhibition was found in the extracts from the leaves. Extracts at 40 g dry tissue l^?1 from alfalfa leaves were 15.4, 17.5 and 28.7 times more toxic to alfalfa root growth than were those from roots, stems and seeds, respectively. A high‐performance liquid chromatography (HPLC) analysis with nine standard compounds showed that the concentrations and compositions of allelopathic compounds depended on the plant parts. In leaf extracts that showed the most inhibitory effect on root growth, the highest amounts of allelochemicals were detected. Among nine phenolic compounds assayed for their phytotoxicity on root growth of alfalfa, coumarin, trans‐cinnamic acid and o‐coumaric acid at 10^?3 m were most inhibitory. The type and amount of causative allelochemicals found in alfalfa plant parts were highly correlated with the results of the bioassay, indicating that the autotoxic effects of alfalfa plant parts significantly differed.     

Simultaneous Determination of Four Phenolic Acids in Radix Salviae Miltiorrhizae Formula Granules by QAMS

[Objectives]This study aimed to establish a QAMS(quantitative analysis of multi-components by single-marker)method for simultaneous determination of four phenol...     

Changes in Seed Yield and Quality with Maturity in Onion (Allium cepa L., cv. 'Early Cream Gold')

Development of onion (Allium cepa L., cv. ‘Early Cream Gold’) seed under cool climate conditions in Tasmania, Australia occurred over a longer duration than previously reported, but similar patterns of change in yield components were recorded. In contrast to previous studies, umbel moisture content declined from 85 to 67 % over 57 days while seed moisture content decreased from 85 to 31 %. Seed yield continued to increase over the duration of crop development, with increasing seed weight compensating for seed loss resulting from capsule dehiscence in the later stages of maturation. Germination percentage was high and did not vary significantly from 53 to 77 days after full bloom (DAF), but mean germination time declined and uniformity of germination increased significantly over the same time period. The percentage abnormal seedlings declined with later harvest date, resulting in highest seed quality at 77 DAF. The results of this study suggest that the decision to harvest cool climate onion seed crops before capsule dehiscence will result in a loss of potential seed yield and quality.     

Pollen and pollination experiments. III. The viability of apple and pear pollen as affected by irradiation and storage

Summary Apple and pear pollen was irradiated with doses of 0, 50, 100, 250 and 500 krad (gamma rays) and stored at 4°C and 0–10% r.h. From the in-vitro germination percentages an average LD 50 dose of about 220 krad was estimated. For both irradiated and untreated pollen a close and corresponding lineair relationship existed between germination percentage and pollen tube growth.Irradiated pollen was much more sensitive to dry storage conditions than untreated pollen, resulting in less germination and more bursting. Apparently, irradiation caused the pollen cell membrane to lose its flexibility faster than normal. Rehydration of dry-stored, irradiated pollen in water-saturated air restored germination percentages up to their initial levels. The importance of this procedure in germination trials is stressed.     

Water Extraction Process of Chinese Herbal Compound Man Gan Ning

[Objectives]To optimize the water extraction process of Chinese Herbal Compound Man Gan Ning and establish a method for its extraction and content determination...     

Present status and future strategy in breeding faba beans (Vicia Faba L.) for resistance to biotic and abiotic stresses

Progress is being made, mainly by ICARDA but also elsewhere, in breeding for resistance to Botrytis, AScochyta, Uromyces, and Orobanche; and some lines have resistance to more than one pathogen. The strategy is to extend multiple resistance but also to seek new and durable forms of resistance. Internationally coordinated programs are needed to maintain the momentum of this work.Tolerance of abiotic stresses leads to types suited to dry or cold environments rather than broad adaptability, but in this cross-pollinated species, the more hybrid vigor expressed by a cultivar, the more it is likely to tolerate various stresses.     

Optimization of Extraction Technology and Determination of Content of Total Phenols of Leaves in Acanthopanax giraldii Harms

[Objectives] To determine the optimum extraction technology for total phenols of leaves in Acanthopanax giraldii Harms.[Methods]The single factor test and ortho...     

Cytoplasmic male sterility,resistance to gall mite and mildew,and season of leafing out in black currants

Summary Cytoplasmic male sterility (cms) is described in the F₁ hybrids Ribes × carrierei (R. glutinosum albidum × R. nigrum) and R. sanguineum × R. nigrum. In backcrosses to R. nigrum, progenies with R. glutinosum cytoplasm were either all male sterile, or segregated for full male fertility (F) and complete (S) and partial (I) male sterility. Ratios of F:I+S suggested that two linked genes controlled cms, F plants being dominant for one (Rf ₁) and recessive for the other (Rf ₂).Segregation for cms in relation to three linded genes, Ce (resistance to the gall mite, Cecidophyopsis ribes), Sph ₃(resistance to American gooseberry mildew, Sphaerotheca mors-uvae) and Lf ₁(one of two dominant additive genes controlling early season leafing out) indicated that Rf ₁and Rf ₂were in this linkage group. The gene order and approximate crossover values appeared to be: % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXafv3ySLgzGmvETj2BSbqef0uAJj3BZ9Mz0bYu% H52CGmvzYLMzaerbd9wDYLwzYbItLDharqqr1ngBPrgifHhDYfgasa% acOqpw0xe9v8qqaqFD0xXdHaVhbbf9v8qqaqFr0xc9pk0xbba9q8Wq% Ffea0-yr0RYxir-Jbba9q8aq0-yq-He9q8qqQ8frFve9Fve9Ff0dme% aabaqaciGacaGaamqadaabaeaafaaakeaacaWGdbGaamyzamaamaaa% baGaaiiiaiaacccacaGGWaGaaiOlaiaacgdacaGG0aGaaiiiaiaacc% caaaGaaiiiaiaacccacaGGGaGaamOuaiaadAgaliaaigdakmaamaaa% baGaaiiiaiaacccacaGGGaGaaiiiaiaaccdacaGGUaGaaiOmaiaacs% dacaGGGaGaaiiiaiaacccacaGGGaGaaiiiaaaacaWGsbGaamOzaSGa% aGOmaOWaaWaaaeaacaGGGaGaaiiiaiaacccacaGGGaGaaiiiaiaacc% cacaGGGaGaaiiiaiaacccaaaGaamitaiaadAgaliaaigdakmaamaaa% baGaaiiiaiaacccacaGGGaGaaiiiaiaacccacaGGGaGaaiiiaiaacc% cacaGGGaGaaiiiaiaacccacaGGGaaaaiaadofacaWGWbGaamiAaSGa% aG4maaaa!6E4D!\[Ce\underline { 0.14 } Rf1\underline { 0.24 } Rf2\underline { } Lf1\underline { } Sph3\]. Crossover values of 0.36 for Ce-Lf ₁, and 0.15 for Lf ₁-Sph ₃were estimated from the relative mean differences in season of leafing out between seedlings dominant and recessive for Ce and Sph ₃.It is suggested that competitive disadvantage of lf ₁-carrying gametes and/or zygotes at low temperatures may be implicated in the almost invariable deficit of plants dominant for the closely linked mildew resistance allele Sph ₃. Poor performance of lf ₁- (and possibly lf ₂-) carrying gametes and young zygotes during periods of low temperature at flowering might also account for the liability of some late season cultivars and selections to premature fruit drop (running off).     

Screening techniques and sources of resistance to parasitic angiosperms

Parasitic angiosperms cause great losses in many important crops under different climatic conditions and soil types. The most widespread and important parasitic angiosperms belong to the genera Orobanche, Striga, and Cuscuta. The most important economical hosts belong to the Poaceae, Asteraceae, Solanaceae, Cucurbitaceae, and Fabaceae. Although some resistant cultivars have been identified in several crops, great gaps exist in our knowledge of the parasites and the genetic basis of the resistance, as well as the availability of in vitro screening techniques. Screening techniques are based on reactions of the host root or foliage. In vitro or greenhouse screening methods based on the reaction of root and/or foliar tissues are usually superior to field screenings and can be used with many species. To utilize them in plant breeding, it is necessary to demonstrate a strong correlation between in vitro and field data. The correlation should be calculated for every environment in which selection is practiced. Using biochemical analysis as a screening technique has had limited success. The reason seems to be the complex host-parasite interactions which lead to germination, rhizotropism, infection, and growth of the parasite. Germination results from chemicals produced by the host. Resistance is only available in a small group of crops. Resistance has been found in cultivated, primitive and wild forms, depending on the specific host-parasite system. An additional problem is the existence of pathotypes in the parasites. Inheritance of host resistance is usually polygenic and its transfer is slow and tedious. Molecular techniques have yet to be used to locate resistance to parasitic angiosperms. While intensifying the search for genes that control resistance to specific parasitic angiosperms, the best strategy to screen for resistance is to improve the already existing in vitro or greenhouse screening techniques.