水稻长芒基因LA1(Long Awn 1)的遗传分析与基因定位

为研究水稻芒的遗传调控机制,本研究在‘日本晴’/‘93-11’染色体片段代换系群体中筛选出一个长芒材料‘CSSL14’,研究了其主要农艺性状和长芒的遗传方式,并对长芒基因LA1进行了基因定位。结果表明‘CSSL14’的芒长、芒着生率、分蘖数和单株产量与‘93-11’存在极显著(p<0.01)或显著(p<0.05)差异,分别为‘93-11’的2.98倍、2.82倍、0.68倍和0.76倍。遗传分析表明‘CSSL14’的长芒表型受一对半显性基因LA1控制。通过图位克隆的方法,将LA1定位在第4染色体长臂标记M3和M4之间12.14 kb的范围内,该定位区间内只有1个预测的候选基因Os04g0518800,与已知的野生稻长芒基因An-2/LABA1等位。本研究结果为进一步研究LA1的功能提供了参考。     

小麦顶端小穗退化突变体asd1基因定位

穗粒数是小麦产量三要素建成的关键因子,深入挖掘穗部发育调控基因有助于培育高产小麦品种。以小麦品种京411为野生型,经EMS诱变获得了表型稳定的小穗退化突变体asd1 (apical spikelet degeneration 1)。该突变体表现顶端小穗明显退化,穗长缩短了约40%,结实小穗数减少了约35%,穗粒数显著减少了54%,同时株高也明显降低。利用京411×asd1遗传群体的F2和F3代表型数据分析表明,顶端小穗退化性状受1对主效隐性基因控制。采用混合群体分离分析法(BSA),结合测序所得SNP位点,在7A染色体上开发了7个KASP标记,将目标突变基因定位在7A染色体短臂9.91 Mb物理区间内,遗传距离为17.62 cM,推断该区段存在一个新的控制小麦花器官发育及穗部形态发育的重要基因。本研究所鉴定的小麦穗发育控制区段有助于深入解析小麦小穗形成的遗传基础,为进一步揭示小麦产量形成的分子机理提供突变基因。     

甜瓜果皮颜色遗传分析及基因定位

为探究甜瓜皮色性状的遗传规律，定位目标性状关联的遗传位点，选用黄皮材料B432 和绿皮材料B168、B421 为亲本，构建6 世代遗传群体(P1、P2、F1、F2、BC1P1、BC1P2)，用于分析甜瓜皮色性状的遗传规律；同时，利用BSA-seq 和全基因组重测序技术，定位控制甜瓜皮色的基因。结果表明，甜瓜皮色由2对基因控制，其中绿色对白色具有显性上位性效应，白色对黄色为显性。同时，将皮色相关基因分别定位于4 号染色体和10 号染色体的0.02~5.7 Mb和0.08~9.5 Mb区间。试验初步定位了控制甜瓜皮色的基因，为后续进行基因精细定位提供依据，为开展甜瓜皮色的分子标记辅助选择奠定基础。     

小麦花粉致死基因Ki的SSR标记分析

小麦雄性不育主要是通过花粉的败育表现,其不育材料对小麦杂种优势的利用研究具有重要意义和价值,国外研究表明,某些特定普通小麦品种间杂交F₁表现的花粉部分不育现象,受控于核基因组花粉致死基因Ki,为了筛选小麦花粉致死基因Ki的连锁标记,利用现代分子生物学技术通过定位该基因,克隆出花粉致死基因连锁标记片段,为小麦雄性不育种质材料的转育提供有效的选择标记。对小麦花粉致死基因Ki进行了分子标记定位,以‘中国春’和澳大利亚春小麦品种的BC₁F₁代作为定位群体,利用分离群体分组分析法(BSA)对位于小麦6B染色体上85对SSR引物进行多态性筛选,具有多态性的引物再通过BC₁F₁定位群体进行验证,从中筛选出与目的基因连锁的2个SSR标记Xgwm626和Xgpw4138。运用Mapmaker 3.0软件进行连锁分析。结果表明,Xgwm626和Xgpw4138与Ki基因的遗传距离分别为9.2 cM和6.9 cM,且2个SSR标记位于目的基因两侧,并将Ki定位于小麦6BL染色体上。研究结果为Ki基因的分子标记辅助选择和进一步精细定位奠定了基础。     

基于大白菜近等基因系的抗根肿病QTL QS_B3.1的验证

根肿病是影响大白菜生长发育及其产量的一个重要病害。本研究在前人定位出抗根肿病QTL QS_B3.1的基础上,以相同的抗根肿病芜菁自交系‘Siloga’为供体亲本,大白菜自交系‘91-12A’为受体亲本,通过对回交和自交群体的分子标记前景和背景选择,从BC4F3群体中筛选出遗传背景恢复为‘91-12A’,且只含有QS_B3.1位点的大白菜近等基因系。对BC4F3群体进行根肿病抗性鉴定,抗病植株与感病植株的分离比例为3:1,证明QS_B3.1抗病位点表现为显性单基因遗传。BC4F3群体的QS_B3.1连锁标记分析表明,抗病植株均含有QS_B3.1位点,不含QS_B3.1位点的植株均表现为感病,且QS_B3.1位点缩小在A3染色体的一个2.89 Mb区间内。这一发现为今后芸薹属作物的抗根肿病品种的选育以及该基因的精细定位和克隆提供了有力的依据。     

利用普通六倍体小麦和西藏半野生小麦杂交衍生的重组自交系定位小麦芒长QTL

芒长是普通小麦的重要农艺性状,受多个基因控制。本研究利用长芒的普通小麦郑麦9023与无芒的西藏半野生小麦Q1028构建一个重组自交系群体(186个株系);采用SSR和DAr T分子标记,构建覆盖小麦全基因组的遗传图谱(2597 cM)。基于重组自交系群体两年芒长表型数据,采用ICIM作图法对小麦芒长性状进行QTL定位分析。共检测到2个与芒长相关的QTL,即Qwa.sau-4AS和Qwa.sau-5AL。它们分别位于4AS和5AL染色体上,可分别解释7.4%和27.3%的表型变异。这2个QTL效应可能分别来源于钩芒基因Hd与抑芒基因B1。利用连锁标记进行基因型分析,表明Qwa.sau-4AS与Qwa.sau-5AL对芒长的抑制效果具有累加效应,且Qwa.sau-5AL效应强于Qwa.sau-4AS。本研究将为精细定位及克隆这2个QTL奠定基础。     

谷子花药颜色基因Siac1的精细定位

为从分子水平上揭示谷子花药颜色性状的遗传基础，以‘E1005’为母本，‘品资39号’为父本构建F2分离群体，利用集团分离分析法(BSA)结合隐性群体分析法(RCA)，对谷子花药颜色基因Siac1进行精细定位。遗传分析表明，F2植株黄色花药与白色花药分离比例符合3:1的孟德尔分离规律，表明白色花药性状由一对隐性核基因控制。利用SSR和SV标记将Siac1初定位于第VI 染色体上标记GSA07025和GSA07037之间约282 kb的区间内。进一步利用根据亲本重测序结果新开发的InDel标记，最终将Siac1精细定位于标记MRI579和MRI583之间约94.7 kb区段内。生物信息学分析表明，该区间共有10个开放阅读框，初步推测Seita.6G227100、Seita.6G227200、Seita.6G227300和Seita.6G227900为花药颜色性状的候选基因。本研究为克隆Siac1基因、解析花药颜色发育机制奠定了一定基础。     

调控小麦重要农艺性状基因的染色体定位

为了研究调控小麦重要农艺性状基因的染色体分布,进一步解析控制小麦重要农艺性状基因的遗传基础,本研究以一套"中国春-人工合成小麦"染色体代换系为材料,在大田条件下,对不同株系小麦的株高、穗长和穗数等重要农艺性状进行调查。通过同一性状不同株系间的差异显著性分析,对调控株高、穗长和穗数的基因进行了染色体定位。研究结果表明:1 B、2 B、3 A、4 A、6 A、6 D和7 D染色体上可能携带有调控小麦株高的位点;1 B、1 D、2 B、2 D、5 A、6 A、6 D和7 D染色体上可能携带有调控小麦穗长的基因位点;3 A和6 D染色体上可能携带有调控小麦成穗数的位点。本研究有利于进一步理解调控小麦农艺性状的遗传基础,并对小麦分子育种实践具有一定的指导意义。     

玉米雄穗分枝数主效QTL定位及qTBN5近等基因系构建

立足于发掘玉米雄穗分枝数优异基因资源, 利用郑单958骨干亲本郑58和昌7-2构建的188个重组自交系(recombinant inbred line, RIL)家系群体, 结合288个多态性分子标记构建的连锁图谱和2年玉米雄穗分枝数表型数据, 运用完备复合区间作图法进行QTL定位, 共检测到5个控制玉米雄穗分枝数的一致性主效QTL, 分别位于玉米5条染色体上。通过连续回交及分子标记辅助选择构建了位于bin 5.05的控制雄穗分枝数主效QTL-qTBN5近等基因系(near isogenic line, NIL), 对基因遗传效应进行了验证, 并将qTBN5进一步定位在13.2 Mb区间之内, 为玉米雄穗分枝数主效基因的精细定位及分子育种奠定基础。     

小麦芒长抑制基因B1近等基因系的鉴定及遗传分析

芒是小麦穗部重要的光合器官之一。本研究以一对芒长度存在差异的近等基因系SN051-1(长芒)与SN051-2(短芒)为材料,对其形态性状、穗和旗叶光合能力进行了调查,对芒长性状进行了遗传分析和分子标记分析。结果表明,SN051-1与SN051-2在抽穗期、开花期、株高、穗长、每株穗数、小穗数和穗粒数等性状方面均表现一致,仅芒的长度差异明显;SN051-1穗部的光合效率高于SN051-2穗部的光合效率,其千粒重也高于SN051-2;遗传分析证明二者芒性的遗传由单基因控制,短芒为显性。此外,我们筛选获得一个与芒长性状紧密连锁的、位于5A染色体长臂的SSR标记Xgwm291,与该基因间的遗传距离为4.99cM。因此,我们初步推断SN051-1与SN051-2可能是为位于5A染色体长臂的芒抑制基因B1的近等基因系。     

Molecular and physical mapping of genes affecting awning in wheat

Quantitative trait loci (QTL) for three traits related to awning (awn length at the base, the middle and the top of the ear) in wheat were mapped in a doubled‐haploid line (DH) population derived from the cross between the cultivars ‘Courtot’ (awned) and ‘Chinese Spring’ (awnless) and grown in Clermont‐Ferrand, France, under natural field conditions. A molecular marker linkage map of this cross that was previously constructed based on 187 DH lines and 550 markers was used for the QTL mapping. The genome was well covered (more than 95%) and a set of anchor loci regularly spaced (one marker every 20.8 cM) was chosen for marker regression analysis. For each trait, only two consistent QTL were identified with individual effects ranging from 8.5 to 45.9% of the total phenotypic variation. These two QTL cosegregated with the genes Hd on chromosome 4A and B2 on chromosome 6B, which are known to inhibit awning. The results were confirmed using ‘Chinese Spring’ deletion lines of these two chromosomes, which have awned spikes, while ‘Chinese Spring’ is usually awnless. No quantitative trait locus was detected on chromosome 5A where the B1 awn‐inhibitor gene is located, suggesting that both ‘Courtot’ and ‘Chinese Spring’ have the same allelic constitution at this locus. The occurrence of awned speltoid spikes on the deletion lines of this chromosome suggests that ‘Chinese Spring’ and ‘Courtot’ have the dominant B1 allele, indicating that B1 alone has insufficient effect to induce complete awn inhibition.     

Isolation of a Spontaneous Chromosome Translocation in Common Wheat

The genes Ms2 for male sterility and Rht10 for dominant dwarfing located on the short arm of chromosome 4D in common wheat arc closely linked. Male sterile, dwarf F₁ plants from the cross of male sterile‘Chinese Spring’× dwarf‘Ai-bian’were backcrossed with the variety‘Chinese Spring, From this offspring a spontaneous chromosome translocation was isolated resulting in a recombinant male sterile and dwarf genotype.     

Chromosomal location of genes affecting tissue-culture response in wheat

Six ‘Chinese Spring/Triticum spelta’ substitution lines for chromosomes 1A, 1D (duplicates), 3D (duplicates), 6D, and one ‘Chinese Spring/ Marquis’ substitution line for chromosome 2B were studied for tissue-culture response (TCR). The results reported here indicate that chromosomes 2B and 6D are critical for TCR, whereas chromosome ID affects callus weight only. Chromosomes 1A and 3D were not found to be critical, however, these chromosomes may carry genes with minor effects.     

Comparison of two fertility restoration systems against photoperiod-sensitive cytoplasmic male sterility in wheat

A ‘two‐line system’ using photoperiod‐sensitive cytoplasmic male sterility (PCMS) caused by Aegilops crassa cytoplasm under a long‐day photoperiod ( 15 h) has been proposed as a new means of producing hybrid varieties in common wheat. The PCMS line is maintained by self‐pollination under short‐day conditions, and hybrid seeds can be produced through outcrossing of the PCMS line with a pollinator under long‐day conditions. Two kinds of fertility restoration systems against the PCMS are known. One is involved with a set of multiple fertility‐restoring (Rf) genes in the wheat cultivar ‘Norin 61’ located on (at least) chromosomes 4A, 1D, 3D and 5D. The other is controlled by a single dominant major Rf gene, Rfd1, located on the long arm of chromosome 7B in the wheat cultivar ‘Chinese Spring’. To examine the degree of fertility restoration by these two systems, nine PCMS lines were crossed with ‘Norin 61’ and ‘Chinese Spring’ as the restorer lines, and the F₁ hybrids were investigated. The degree of fertility restoration was estimated by comparing the seed set rates in the F₁ hybrids having the Ae. crassa cytoplasm and those with normal cytoplasm. The results revealed that the fertility restoration ability of a set of multiple Rf genes in ‘Norin 61’ was higher than that of the Rfd1 gene in ‘Chinese Spring’.     

Chromosome location of genes affecting polyphenol oxidase activity in seeds of common and durum wheat

This study used cytogenetic stocks to investigate the chromosomal location of genes responsible for polyphenol oxidase (PPO) activity in common and durum wheat seeds. Substitution lines of chromosome 2A of hexaploid varieties ‘Cheyenne’, ‘Thatcher’ and ‘Timstein’ in ‘Chinese Spring’ showed significantly higher PPO activity than all other substitution lines of the same variety, with the exception of substitutions of ‘Cheyenne’ chromosome 3A and ‘Thatcher’ chromosome 4B. Substitution lines of chromosome 2A of Triticum turgidum var. dicoccoides and of chromosome 2D of ‘Chinese Spring’ into the tetraploid variety ‘Langdon’ showed a significant increase in PPO activity relative to all other substitution lines in Langdon. The gene(s) responsible for high PPO activity in chromosome 2D from ‘Chinese Spring’ was mapped on the long arm within a deletion that represents 24% of the distal part of the arm. This study shows that genes located in homoeologous group 2 play a major role in the activity of PPO in wheat.     

干旱胁迫下小麦脯氨酸积累相关基因的染色体定位

对于旱胁迫和对照条件下中国春-Hope代换系和中国春-长穗偃麦草代换系的叶片脯氨酸含量进行了测定，通过方差分析表明：普通小麦可能在4B、5A和5D染色体上有控制干旱胁迫下脯氨酸积累的基因存在，6B和6D染色体上可能有抑制脯氨酸积累的基因存在。在测定中国春-长穗偃麦草代换系的叶片脯氨酸含量后，确定小麦5A和5D染色体上有     

甘蓝型油菜开花相关基因的鉴定及进化与表达分析

开花是开花植物繁衍后代的前提,控制开花时间对农作物获得高产稳产具有重要影响。然而,关于甘蓝型油菜基因组水平上开花相关基因的信息报道较少。本研究对甘蓝型油菜开花相关的基因进行了鉴定、特征分析、进化与表达模式分析。结果表明,基因组水平上共鉴定到甘蓝型油菜1173个开花相关基因,这些基因分为9类,且不均匀地分布在染色体上;与白菜(AA,2n=20)和甘蓝(CC,2n=18)相比,甘蓝型油菜(AACC,2n=38)经过自然杂交和染色体加倍后,使开花相关基因的数目显著扩增;选择压力分析表明,糖代谢信号途径的基因比自发途径的开花相关基因受到的选择压力更大;仍有一些开花相关基因在拟南芥和油菜基因组内非常保守。甘蓝型油菜基因数目的扩增和功能分化导致其开花调控机制更加复杂,本研究为油菜开花途径提供更多的信息,也为阐明拟南芥和油菜开花基因的进化关系指明了方向。     

利用异源六倍体(A~rA~rA~nA~nC~nC~n)与甘蓝种间杂交合成甘蓝型油菜的新方法

利用亲本种的遗传变异是改良油菜的重要途径,本研究提出一种利用甘蓝拓宽甘蓝型油菜遗传多样性的新方法。以甘蓝型油菜(AnAnCnCn)品种中双11号为母本,与白菜型油菜(ArAr)品系SWU07杂交,经染色体加倍获得异源六倍体(ArArAnAnCnCn),再与甘蓝(CoCo)杂交,创建出具有亲本种遗传成分的新型甘蓝型油菜(ArAnCnCo)。该六倍体连续3个世代核型稳定,各世代中的自交和自由授粉结实率无显著差异,花粉育性在94.6%～98.8%之间,3个世代自交平均结实率为每角果5.47粒,自由授粉平均结实率为每角果7.93粒;各世代六倍体(ArArAnAnCnCn)与不同类型甘蓝杂交平均结实率分别为每角果0.05、0.04、0.05粒,世代间无显著差异,且六倍体与栽培、野生甘蓝杂交结实性无显著差异,可交配性不受六倍体世代及甘蓝类型的影响。尽管该六倍体与甘蓝可交配性较低,但仍可在田间条件下成功杂交,获得新型甘蓝型油菜(ArAnCnCo),表明以ArArAnAnCnCn六倍体为桥梁与甘蓝杂交,是一种有效导入甘蓝遗传成分、创建新型甘蓝型油菜的新方法。     

Intergeneric Transfer (Rye to Wheat) of a Gene(s) for Russian Wheat Aphid Resistance

An octoploid triticale was derived from the F, of a Russian wheat aphid-resistant rye, ‘Turkey 77’, and ‘Chinese Spring’ wheat. The alloploid was crossed to common wheat, and to ‘Imperial’ rye/‘Chinese Spring’ disomic addition lines. F₂, progeny from these crosses were tested for Russian wheat aphid resistance and C-banded. A resistance gene(s) was found to be associated with chromosome arm IRS of the ‘Turkey 77’ rye genome. A monotelosomic IRS (‘Turkey 77’) addition plant was then crossed with the wheat cultivar ‘Gamtoos’, which has the 1BL.1RS ‘Veery’ translocation. Unlike the IRS segment in ‘Gamtoos’, the ‘Turkey 77’-derived 1 RS telosome did not express the rust resistance genes Sr31 and Ar26, which could then be used as markers. From the F, a monotelosomic 1 RS addition plant that was also heterozygous for the 1BL. 1 RS translocation was selected and testerossed with an aphid-susceptible common wheat, ‘Inia 66’ Meiotic pairing between the rye arms resulted in the recovery of five euploid Russian-wheat-aphid-resistant plants. One recombinant also retained Sr31 and Lr26 and was selfed to produce translocation homozygotes.     

The Transfer of Thinopyrum-Derived Leaf-rust Resistance from Common Wheat to Durum Wheat.

The leaf rust resistance gene on chromosome 7AL of ‘Chinese Spring’ transfer no. 12 derived from Thinopyrum ponticum, was transferred to durum wheat by standard backcrossing. In ‘Agatha’ and ‘Indis’ a leaf rust resistance gene from Thinopyrum ponticum and Thinopyrum ponticum respectively, is found on a translocated segment on chromosome arm 7DL. The use of the ‘Langdon’ disomic D-chromosome substitution lines for 7A and 7B resulted in the recovery of tetraploid leaf-rust resistant lines from the crosses with ‘Agatha’ in the B₂F₁ generation. Tetraploid lines carrying the ‘Indis’ translocation segment were recovered in the B₂F₂ generation. The F₂ segregation ratios for rust resistance after selfing or back-crossing generally fitted a 1: 1 ratio indicating non-transmission of the translocation segments in the male gametes. Homozygous resistant plants were not obtained. Meiotic instability was observed in 28 chromosome B₂ F₂ derivatives of the crosses between ‘Chinese Spring’ transfer no. 12 and durum wheat.