2Ai-2染色体在小麦部分同源染色体代换背景中的遗传

用中间偃麦草2Ai-2染色体特异的EST-PCR标记检测5个小麦-中间偃麦草二体异代换系(包括端体代换系)与普通小麦中国春(CS)杂交后代群体,研究外源染色体2Ai-2通过杂种向后代的传递率及其结构变异,并用基因组原位杂交进行验证。结果表明,第二部分同源群不同染色体代换背景对外源染色体传递的影响不同,在2B代换系的杂种中外源染色体或片段显示优先传递,而在2D代换系的杂种中其传递力则较低,2B代换背景更有利于2Ai-2染色体或片段的传递;外源染色体在杂种后代传递过程中会发生变异,在多数组合中,变异出现在着丝粒处;与短臂相比,外源染色体长臂更容易在世代中丢失;端体代换系中的外源染色体端体在杂种后代传递过程中容易丢失,且也会发生结构变异。基因组原位杂交结果证明了分子标记跟踪外源染色体的可靠性。     

rDNA和端粒重复序列鉴定马铃薯和茄子体细胞杂种染色体丢失和融合

植物体细胞杂交是植物种质资源创制的重要方法。体细胞杂种在原生质体再生的过程中染色体会产生非常多的遗传变异。研究体细胞杂种的染色体行为为马铃薯体细胞杂种的创制和利用提供理论基础。本研究采用rDNA和端粒重复序列作为探针进行原位杂交(fluorescence in situ hybridization),并结合基因组原位杂交(genomic in situ hybridization),对马铃薯和茄子体细胞杂种染色体组成和变异进行了分析。原位杂交结果表明,体细胞杂种中存在马铃薯和茄子融合的染色体和双着丝粒染色体,并发现部分融合染色体是由马铃薯和茄子2号染色体末端对末端融合得到的。重排的双着丝粒染色体的着丝粒一个来源于马铃薯,一个来源于茄子。此外,体细胞杂种中来源于茄子的5S rDNA在体细胞杂种再生及稳定的过程中全部丢失。研究结果表明马铃薯与茄子在进行体细胞杂交的过程中,染色体是不稳定的,容易造成融合后代出现双着丝粒和染色体重排等现象。体细胞杂种的染色体会通过染色体重排、双着丝粒、rDNA均一化等多种形式使其染色体趋于稳定。     

莪术CPD染色和45S rDNA荧光原位杂交核型分析

为了对莪术[Curcuma zedoaria (Christm.) Roscoe]的染色体进行识别并对该物种基因组的结构及进化进行初步研究,利用改进的火焰干燥法及荧光原位杂交技术,对莪术中期染色体的长度,着丝粒的位置及随体的数目进行分析。PI和DAPI组合（CPD）染色后和相继的45S rDNA探针荧光原位杂交结果显示,莪术具有五对45S rDNA位点,三对位于8,22,31号染色体末端的CPD带区,二对位于4,30号染色体的短臂上。第五号短臂为富含GC对的非45S rDNA位点。该实验建立了莪术的经典核型,为非整倍体,核型公式为2n＝62+1=40m+12sm+1m,其核型不对称性为2A型。     

组织培养中大葱染色体倍性变异的研究

采用大葱茎尖分生组织直接成苗及分化丛生苗、茎盘诱导愈伤组织培养再生植株,通过染色体压片,对大葱愈伤组织及幼苗染色体数目变化进行了研究。结果表明,茎尖分生组织培养的幼苗及丛生苗遗传稳定,其染色体未发生倍性变异,均为2n=16;愈伤组织及其再生苗遗传稳定性较差,愈伤组织染色体数变异率为43.4%,其中单倍体占6.7%、三倍体占2.5%、四倍体占10%、五倍体占4.2%、六倍体占3.3%、七倍体占4.2%、八倍体占3.3%、非整倍体占9.2%;愈伤组织分化苗染色体变异率为11.7%,其中单倍体占6.7%,三倍体占1.7%,四倍体占3.3%。     

甘蓝自交不亲和基因MLPK与SSP的FISH定位

利用FISH技术, 对自交不亲和基因MLPK与SSP在甘蓝有丝分裂前中期染色体、减数分裂早粗线期染色体以及伸长DNA纤维等3种分辨率水平的靶DNA载体上进行物理定位。结果表明, 在有丝分裂前中期, MLPK探针信号位于一对近中着丝粒同源染色体的短臂中部, 距着丝粒的百分距离约为53.41±3.16;SSP探针信号位于一对具有随体的近端着丝粒同源染色体的长臂端部, 距着丝粒的百分距离约为78.36±4.26。综合3种载体上的FISH结果表明, MLPK与SSP在甘蓝染色体组中可能都只有一个同源序列座位, 具有在单倍体基因组中的单拷贝性。重复FISH杂交表明, MLPK与5S rDNA位于同一对染色体。依据Armstrong的核型分析标准, 初步判断MLPK与SSP分别位于甘蓝的2号和7号染色体, 与S位点不存在连锁关系。另从比较基因组学角度对定位结果进行了讨论。     

基于寡核苷酸探针套painting的中国春非整倍体高清核型及应用

基于寡核苷酸探针套painting的染色体鉴定技术简单、经济和高效, 可以促进小麦品种及亲缘物种染色体识别和变异体鉴定, 提高染色体工程效率。我们前期开发了寡核苷酸探针套, 包含pAs1-1、pAs1-3、AFA-4、(GAA)₁₀和pSc119.2-1共5个探针。本研究通过一次荧光原位杂交(FISH), 对源于17个非整倍体的18份材料分析发现, 其中14个染色体组成正确, 可以清晰识别相应的缺体、四体和端体。还构建了基于寡核苷酸探针套涂染的、能准确识别3个基因组和7个部分同源群染色体的高清核型, 发现4个非整倍体发生变异, 其中从N5BT5D中鉴定出一个可能的小片段相互易位系T6AS·6AL-6DL和T6DS·6DL-6AL。进一步对7个地方品种、10个栽培品种(系)和1个人工合成小麦分析, 发现15条染色体存在多态性, 涉及6条B组(除4B)、5条A组(除1A和3A)和4条D组(1D、2D、4D和7D)染色体, 可以清晰识别我国小麦生产上广泛应用的3种易位类型(T1RS·1BL、T6VS·6AL及相互易位T1RS·7DL和T7DS·1BL), 省去了基因组原位杂交(GISH)程序。另外, 对5个亲缘物种分析发现, 该探针套可以识别栽培一粒小麦、硬粒小麦Langdon、荆州黑麦、长穗偃麦草(2n=2x=14)全部和中间偃麦草30条染色体, 并构建了这5个物种的核型。本研究结果证实该寡核苷酸探针套可以有效用于小麦及亲缘物种染色体鉴定, 高清晰的中国春非整倍体核型为小麦染色体工程提供了参考标准。     

二倍体野燕麦染色体的C-带分析

采用C-带技术对二倍体野燕麦根尖细胞染色体进行了带型分析,以研究该野燕麦染色体的C-带特点.结果表明:二倍体野燕麦具有7对染色体,其上共有35条带,其中长臂具有带纹19条,包括13条中间带(I),6条末端带(T);短臂具有8条带纹,包括2条中间带(I),6条末端带(T),另外还有l条随体带(S)以及7条着丝点带(C),其带型公式为2 n=14=2CIT+ +2 CIT+8 CI+ T+2 CI+ T+S.二倍体野燕麦染色体组成为CC,核型为2A,属于较对称核型,进化指数为7.     

提莫菲维小麦染色体的C-带分析

对提莫菲维小麦的根尖细胞染色体进行C-带分析,以明确提莫菲维小麦的染色体C-带带型特点。结果表明:提莫菲维小麦具有14对染色体,其染色体带型公式为:2 n=28=4 IT++4 IT++6 CIT++6 I+2 IT+2 CI+2 CIT+S+2 CIS,共包括98条带,其中长臂具有57条带纹,包括50条中间带(I),7条端带(T);短臂具有35条带纹,包括30条中间带(I),3条端带(T),2条随体带(S);另外还有着丝点带(C)6条。提莫菲维小麦G组染色体的异质化程度明显高于A组染色体,G组染色体的C-带带型与普通小麦B组染色体非常相似,因此G组染色体可能与B组染色体存在部分同源性。     

基于寡核苷酸探针套painting的小麦“中国春”非整倍体高清核型及应用

基于寡核苷酸探针套painting的染色体鉴定技术简单、经济和高效,可以促进小麦品种及亲缘物种染色体识别和变异体鉴定,提高染色体工程效率。我们前期开发了寡核苷酸探针套,包含p As1-1、p As1-3、AFA-4、(GAA)10和p Sc119.2-1共5个探针。本研究通过一次荧光原位杂交(FISH),对源于17个非整倍体的18份材料分析发现,其中14个染色体组成正确,可以清晰识别相应的缺体、四体和端体。还构建了基于寡核苷酸探针套涂染的、能准确识别3个基因组和7个部分同源群染色体的高清核型,发现4个非整倍体发生变异,其中从N5BT5D中鉴定出一个可能的小片段相互易位系T6AS·6AL-6DL和T6DS·6DL-6AL。进一步对7个地方品种、10个栽培品种(系)和1个人工合成小麦分析,发现15条染色体存在多态性,涉及6条B组(除4B)、5条A组(除1A和3A)和4条D组(1D、2D、4D和7D)染色体,可以清晰识别我国小麦生产上广泛应用的3种易位类型(T1RS·1BL、T6VS·6AL及相互易位T1RS·7DL和T7DS·1BL),省去了基因组原位杂交(GISH)程序。另外,对5个亲缘物种分析发现,该探针套可以识别栽培一粒小麦、硬粒小麦Langdon、荆州黑麦、长穗偃麦草(2n=2x=14)全部和中间偃麦草30条染色体,并构建了这5个物种的核型。本研究结果证实该寡核苷酸探针套可以有效用于小麦及亲缘物种染色体鉴定,高清晰的中国春非整倍体核型为小麦染色体工程提供了参考标准。     

着丝粒DNA序列的分离和筛选方法研究进展

着丝粒是染色体的重要组成部分,是染色体复制、细胞分裂和维持遗传稳定性的必要结构,其功能保守但DNA序列高度进化.最初的研究是通过超高速离心的方法分离得到着丝粒序列,其后随着基因组酶切、染色体显微切割、基因组文库筛选、着丝粒特异结合免疫蛋白等方法的应用,进一步促进了大批物种的着丝粒DNA序列分离,加深了人们对着丝粒结构和功能的认识.近年研究发现,着丝粒存在失活、分化、重排等多种异常现象,着丝粒DNA参与并受复杂的表观调控,着丝粒的结构与功能再次成为研究的热点之一.因此,本研究回顾了着丝粒DNA序列的分离和筛选方法的发展历程,简述不同方法的机制,并分析各种方法的优点、缺点和局限,以期有助于着丝粒功能及调控的研究.     

Elymus canadensis×Secale cereale Amphiploids. II. Chromosome Constitutions and Pairing of Open-Pollinated Progeny

Eleven C₂ and two C₃ 0pen-pollinated plains from Elymus canadensis × Secale cereale amphiploid plants (2n = 6x = 42, SSHHRR) were examined for chromosome constitution and meiosis. Chromosome numbers of the progeny varied: 2n = 26, 27, 28, 36, 37, 39, 40, and 41. Elimination of portions of genome constituents were made at random and were irregular in all o the progeny. Monosomic (2n = 41) and nullisomic (2n = 40) plants lost one to two E. canadensis or S. cereale chromosomes and showed average of 17 to 18 bivalents and 4 to 5 univalents per cell at Ml. The C₂, aneuploid plants with 36 to 41 chromosomes seemed to result from selfing or intercrossing among; the C₁ amphiploid plants, while the plants of 2n = 26 to 2S (6–9 II + 10–141) might originate from outcrosses of the C_l amphiploid to S. cereale. Bivalent pairing might be preferentially intragenomic (S-S, H-H, or R-R). The occurrence of multivalents indicates a low potential of both intragenomic and intragenomic pairing; Pollen of the lour plants showed poor stainability (1 to 13 %) and no seed set in any of the progeny.     

Genome composition of triploid lily cultivars derived from sexual polyploidization of Longiflorum × Asiatic hybrids (<Emphasis Type="Italic">Lilium</Emphasis>)

About 19 cultivars, which had originated from backcrosses between F1 LA (Longiflorum × Asiatic) hybrids (2n = 2x = 24) as female parents and Asiatic cultivars as male parents (2n = 2x = 24), were analyzed with genomic in situ hybridization. 17 of them were triploid (2n = 3x = 36), and two aneuploid (2n = 3x + 1 = 37). The triploid cultivars had resulted from the functional 2n eggs produced by the female parents (F1 hybrids) because first division restitution (FDR) occurred in their meiosis during megasporogenesis. Similarly, the aneuploid cultivars had originated from viable 2n + 1 eggs. The extra chromosome in cultivar 041555 or 041572 resulted from one univalent or one half-bivalent which might have lagged behind when the sister chromatids of the other univalents and half-bivalents were segregating during the FDR process in their LA hybrid parents, respectively. That the majority of cultivars possessed recombinant chromosomes showed that intergenomic recombination might play an important role during the selection of the cultivars directly from BC1 progenies. That five cultivars of the 15 recombinant cultivars only had reciprocal recombinant chromosomes and 10 cultivars had non-reciprocal recombinant chromosomes indicates that the latter are more important. Because 9 of the 10 non-reciprocal recombinant cultivars possessed substitutions for recombinant segments, it also indicated that such substitutions could be an important source for the genetic variation in the sexual triploid BC1 progenies. In such cases there was a potential for the expression of the recessive genes of the backcross parent in a nulliplex (aaa) condition in the substituted segments. Genetic variation resulting from such nulliplex loci might have played a role in the selection of some of the cultivars.     

Aneuploids of perennial ryegrass (Lolium perenne)

Summary Aneuploid plants of perennial ryegrass (Lolium perenne L.) with 2n=15 to 30 chromosomes were obtained by crossing a near-triploid (2n=3x+1=22) with a diploid or on open-pollination with diploids and tetraploids. Aneuploids occurred with a frequency of 83% in near triploid × diploid progeny and 92% on open-pollination with diploid and tetraploid plants. Aneuploid plants with 15 to 18 chromosomes resembled diploids in morphology and those with 19 to 30 chromosomes were akin to tetraploids. Meiotic studies suggested that most aneuploid plants resulted from transmission of aneuploid egg cells (n=8 to 23). Aneuploid plants with 2n=27 to 30 chromosomes in the progeny of 22×14 cross originated from unreduced egg cells. Plants with 19 to 21 chromosomes were recovered only by immature seed culture. Aneuploid plants with 26 to 30 chromosomes and triploids (2n=21) had higher pollen fertility and bigger seeds than plants with 15 to 22 chromosomes.     

Effect of Azolla on Irrigated Rice in Brazil

A 1-year study was conducted in 1983/84 at 2 experimental sites in Brazil to determine the effect of Azolla green-manure (AO), A. intercrop (OA) and their combination (AA) on rice yield in comparison to mineral fertilization with urea. Nitrogen sources were combined with 4 rice sowing/planting systems.
On terraced terra-roxa soil (Paleudalf) in subtropical northern Paraná State, transplanted rice (T) yielded 8.66 t · ha⁻¹ compared to pregerminated (P), direct-sown (D) and conventionally sown (C) rice with 7.92; 7.73 and 7.48 t · ha⁻¹, respectively. N-source treatments yielded 9.33; 8.54 and 7.34 t · ha⁻¹ for AA, OA and AO compared to 8.46; 7.98 and 6.05 for 100, 50 and 0 kg N · ha⁻¹, respectively. Fertilizer-nitrogen equivalence (FNE) of Azolla treatments compared to urea broadcast in 3 applications ranged between 0 and more than 100 kg N · ha⁻¹.
On hydromorphic latosol (Ustic Dystropept) in tropical Goiás State, rice yields were 4.07; 2.52; 1.46 and. 1.33 t · ha⁻¹ for systems T, P, C and D, respectively. N-source treatments yielded 2.79; 1.98 and 1.78 t · ha⁻¹ for AA, AO and OA compared to 3.43; 2.63 and 1.46 t · ha⁻¹ for 60; 30 and 0 kg N · ha⁻¹ as urea broadcast in 2 applications, respectively. FNE of Azolla was between 0 and 56 kg N · ha⁻¹.     

转甜菜碱醛脱氢酶基因马铃薯的抗旱耐盐性

通过根癌农杆菌介导法将甜菜碱醛脱氢酶(BADH)基因导入马铃薯栽培品种甘农薯2号, 经PCR、Southern杂交和Northern杂交证明BADH基因已整合到马铃薯基因组中并在转基因植株中转录和表达。测定表明对照植株没有BADH酶活性, 各转化株系在胁迫前后BADH酶活性近似, 在2~11 U之间。BADH酶活性与叶片的相对电导率呈一定的负相关(y= –3.7738x+57.083, r=0.989^**)。在NaCl和PEG胁迫下, 转基因植株生长正常, 株高比对照提高0.41~1.00 cm, 单株重量比对照增加10%~35%, 说明外源BADH基因的导入提高了马铃薯植株对干旱和盐碱的抗性。     

Fertile somatic hybrids of Solanum etuberosum (+) dihaploid Solanum tuberosum and their backcrossing progenies: relationships of genome dosage with tuber development and resistance to potato virus Y

The wild non-tuberous species Solanumetuberosum is resistant to biotic andabiotic stresses, but is very difficult tocross with cultivated potato. Therefore,interspecific somatic hybrids between adihaploid clone of potato S.tuberosum (2n=2x=24, AA genome) and thediploid species S. etuberosum(2n=2x=24, EE genome) were produced byprotoplast fusion. Among the 7 fertilefusion hybrids analysed by genomic insitu hybridisation (GISH), three groups ofplants were found with the genomicconstitution of AAEE, AAEEEE and AAAAEE.Four fusion hybrids had exactly theexpected chromosome composition, while eachof the three aneuploid hybrids had lost twochromosomes of S. etuberosum. Twobackcross progenies were developed, andGISH analysis was applied to analysetransmission of the parental chromosomesinto the sexual generations. BC₁hybrids derived from the crosses of thehexaploid somatic hybrids with tetraploidpotato were pentaploid with thetheoretically expected genomic compositionor with slight deviation from thisexpectation. In the three BC₂ hybridsanalysed by GISH seven to 12 chromosomes ofS. etuberosum were detected in thepredominant S. tuberosum background.No recombinant chromosomes in the hybridswere detected. Genome dosage affects tuberformation in hybrids and their progenies,but has less effect on resistance to potatovirus Y (PVY) in fusion hybrids. Severalgenotypes of the fusion hybrids andBC₁ progeny did not show viralinfection even in the graftingexperiments.     

Developing rice lines possessing neutral alleles at sterility loci to improve the width of compatibility

To improve the width of compatibility for overcoming various sterilities in inter‐subspecific hybrid rice, some elite lines combining several sterility‐neutral genes were developed and the effects on mitigating various hybrid sterilities were tested. From Akihikari// IR36/Dular, neutral genes at ga11 and six sterility loci, S5, S7, S8, S9, S15 and S16, were combined and elite lines were obtained in their successive progeny. Four of the lines tested were confirmed to combine the neutral alleles S5‐n, S7‐n, S8‐n, S9‐n, S15‐n and S16‐n at the sterility loci and, among them, two harboured an additional gamete abortion‐neutral allele, ga11‐n. F₁s, which used the lines and various testers as parents, mitigated the spikelet sterilities by six sterility loci and gamete abortion by a gametophyte gene, ga11. These lines could be selectively used as parents or donors to increase the width of compatibility of rice varieties for improving fertility in inter‐subspecific hybrid rice breeding.     

转甜菜碱醛脱氢酶基因马铃薯的抗旱耐盐性

通过根癌农杆菌介导法将甜菜碱醛脱氢酶(BADH)基因导入马铃薯栽培品种甘农薯2号, 经PCR、Southern杂交和Northern杂交证明BADH基因已整合到马铃薯基因组中并在转基因植株中转录和表达。测定表明对照植株没有BADH酶活性, 各转化株系在胁迫前后BADH酶活性近似, 在2~11 U之间。BADH酶活性与叶片的相对电导率呈一定的负相关(y= –3.7738x+57.083, r=0.989^**)。在NaCl和PEG胁迫下, 转基因植株生长正常, 株高比对照提高0.41~1.00 cm, 单株重量比对照增加10%~35%, 说明外源BADH基因的导入提高了马铃薯植株对干旱和盐碱的抗性。     

Karyotypes and chromosome association in aneuploid varieties of Japanese garden iris,Iris ensata Thunb

Summary Karyotypes, chromosome association and pollen fertility of aneuploid varieties (2n=25), Ochibagoromo, Matsusakatsukasa and Isehomare in Iris ensata were analysed and compared with those of eu-diploid varieties (2n=24), Shishinden, Kachô and Asahimaru. The somatic chromosome complement of the aneuploid varieties consisted of 11 pairs and 3 singles of chromosomes and that of the eu-diploid varieties 12 pairs of chromosomes. The singles of chromosomes in the aneuploid varieties had similarity with one another and with a pair of chromosomes in the eu-diploid varieties. The high frequency of normal association was present in the eu-diploid varieties, and this indicated that 12 pairs of chromosomes had full homology between each other. In contrast, the mean chromosome association per cell in an aneuploid variety Ochibagoromo was 4.615_I+10.067_II+0.077_III+0.005_IV, indicating that the chromosome complement of this variety consisted of 11 pairs and 3 singles and that these singles had partial homology among them. The eu-diploid varieties exhibited high pollen fertility due to their regularity of chromosome association; the aneuploid varieties considerably lower fertility, i.e. 28.2% for Ochibagoromo, 31.8% for Isehomare and 43.8% for Matsusakatsukasa. The primary cause for the low fertility of these varieties seemes to be the partial homology among 3 single chromosomes. Finally, the origin and the development of the aneuploid varieties were discussed.     

江苏不同熟期粳稻品种的齐穗期和安全播期预测

为明确当前江苏各地不同熟期粳稻品种的安全播期,以江苏的4个熟期类型的5个常规粳稻品种为材料,在江苏连云港(34°83′N)、淮安(33°34′N)、扬州(32°25′N)和苏州(31°18′N)等4地,进行自5月10日起每10天1期,共8个播期的播种试验,得出各播期的相应齐穗期。以齐穗期温光预测模型y=a＋b₁x₁＋b₂x₂拟合其实得的播期与齐穗期资料。用该模型拟合4个试验点、5个供试品种计20组数据,得出20个预测式,其拟合度R²在0.9927~0.9998之间,均达极显著水平。用各试点所在地近25年各年粳稻品种安全齐穗期及逐日平均温度,依齐穗期光温模型预测式经多次迭代推得各年的安全播期,进而求得90%保证率的安全播期并作各地生产应用分析。在江苏淮北的北部,麦稻两熟田水稻的可播栽始期为6月15日,中熟中粳的安全播期为6月21日,此类品种可用于该地直播;其他各熟期类型品种安全播期均早于当地可播栽始期,故不能用于直播。在淮北南部稻麦两熟田的可播栽始期为6月12日左右,中熟中粳和迟熟中粳的安全播期分别在7月4日和6月22日,此两类品种可用于该地麦茬直播;早熟晚粳安全播期在6月17日、18日,在大面积生产中因接茬时间过紧应慎用于麦茬直播;中熟晚粳的安全播期为6月8日,不可用于直播。在苏中南部,水稻可播栽始期为6月8至11日,中熟中粳、迟熟中粳、早熟晚粳类型两品种的安全播期分别在7月12日、3日、6月25日和28日,可用于该地直播;中熟晚粳的安全播期为6月11日,用于直播接茬时间太紧,不可应用。在苏南,水稻的可播栽始期为6月5日,供试4熟期类型品种的安全播期分别为7月18日、13日、9日至10日和7月3日,仅考虑安全齐穗各熟期类型品种均可用于麦茬直播,但因中粳类型品种直播稻生育期过短、产量不高,不宜应用。