Comparison of Newly Synthetic Hexaploid Wheat with Its Donors on SSR Products

Microsatellites or SSRs as powerful genetic markers have widely been used in genetics and evolutionary biology in common wheat. Because of the high polymorphism, newly synthesized hexaploid wheat has been used in the construction of genetic segregation population for SSR markers, However, data on the evolution of microsatellites during the polyploidization event of hexaploid wheat are limited. In this study, 66 pairs of specific to A/B genome SSR patterns among newly synthesized hexaploid wheat, the donor tetraploid wheat and Aegilops tauschii were compared. The results indicated that most SSR markers were conserved during the polyploidization events of newly synthetic hexaploid wheat, from Triticum turgidum and Ae. tauschii. Over 70% A/B genome specific SSR markers could amplify the SSR sequences from the D genome ofAe. tauschii. Most amplified fragments from Ae, tauschii were detected in synthetic hexaploid at corresponding positions with the same sizes and patterns as in its parental Ae. tauschii. This suggested that these SSR markers, specific for A/B genome in common wheat, could amplify SSR products of D genome besides A/B genome in the newly synthesized hexaploid wheat, that is, these SSR primers specific for A/B genome in common wheat were nonspecific for the A/B genome in the synthetic hexaploid wheat. In addition, one amplified Ae. tauschii product was not detected in the newly synthetic hexaploid wheat. An extra-amplified product was found in the newly synthetic hexaploid wheat. These results suggested that caution should be taken when using SSR marker to genotype newly synthetic hexaploid wheat.

Effect of HMW-GS 6 + 8 and 1.5 + 10 from Synthetic Hexaploid Wheat on Wheat Quality Traits

To determine the effect of 6 ＋ 8 and 1.5 ＋ 10 HMW-GS of synthetic hexaploid wheat （SHW） on main quality parameters of wheat, a set of recombinant inbred lines （RILs） derived from the cross between a SHW with N, 6 ＋ 8, 1.5 ＋ 10 HMW-GS and a cultivar Chuanyu 12-1 （CY 12-1） with 1, 7 ＋ 8, 2 ＋ 12 were planted in three environments in 2005 and 2006 and totally 16 quality parameters were tested for each line. Significant differences in all tested quality parameters but flour yield were observed between the two parents. The mean values of the RILs were intermediate to the parents for grain and protein parameters and some farinograph parameters, flour water absorption （FWA）, and farinograph softening （SOF） but beyond parents at dough stability time （DST）, breakdown time （BRT）, quality number （QN）, noodle score （NS）, and loaf volume （LOV）. All of the quality traits, especially in grain hardness （GH）, zeleny sedimentation volume （SED）, and most of farinograph parameters had significant difference between the different HMW-GS components. The effects of different alleles of HMW-GS at same locus （Glu-A1 or Glu-B1 or GIu-D1） on the different quality parameters were also different and affected by the other two loci. For most of parameters tested, 6 ＋ 8 was better than 7 ＋ 8 and there was no difference between 1.5 ＋ 10 and 2 ＋ 12. End-use quality was greatly influenced by components of HMW-GS. The components of 1, 6 ＋ 8, 1.5 ＋ 10 had the highest LOV and bread score （BS） values, whereas the components of 1, 7＋ 8 and 1.5 ＋ 10 had the highest NS values. Noodle score performed a positive linear relationship with falling number （FN） and its relationships to other quality parameters were affected by environments. Loaf volume had a significant negative relationship to SOF and positive associations with most of quality parameters. It could be concluded that HMW-GS 6＋ 8 from SHW had better overall quality characteristics than 7 ＋ 8, whereas the effects of 1.5 ＋ 10 on quality was different in respect to quality parameters and the HMW-GS components. Synthetic hexaploid wheat with subunits 6 ＋ 8 and 1.5 ＋ 10 had the potentials to improve the end-use quality of wheat cultivars.

Identification of QTLs for Yield-Related Traits in the Recombinant Inbred Line Population Derived from the Cross Between a Synthetic Hexaploid Wheat-Derived Variety Chuanmai 42 and a Chinese Elite Variety Chuannong 16

Synthetic hexaploid wheat （SHW） represents a valuable source of new resistances to a range of biotic and abiotic stresses. A recombinant inbred line （RIL） population with 127 recombinant inbred lines derived from a SHW-derived variety Chuanmai 42 crossing with a Chinese spring wheat variety Chuannong 16 was used to map QTLs for agronomic traits including grain yield, grains per square meter, thousand-kernel weight, spikes per square meter, grain number per spike, grains weight per spike, and biomass yield. The population was genotyped using 184 simple-sequence repeat （SSR） markers and 34 sequence-related amplified polymorphism （SRAP） markers. Of 76 QTLs （LOD〉2.5） identified, 42 were found to have a positive effect from Chuanmai 42. The QTL QGy.saas-4D.2 associated with grain yield on chromosome 4D was detected in four of the six environments and the combined analysis, and the mean yield, across six environments, of individuals carrying the Chuanmai 42 allele at this locus was 8.9% higher than that of those lines carrying the Chuannong 16 allele. Seven clusters of the yield-coincident QTLs were detected on 1A, 4A, 3B, 5B, 4D, and 7D.

Quantitative trait loci analysis for root traits in synthetic hexaploid wheat under drought stress conditions

Synthetic hexaploid wheat(SHW),possesses numerous genes for drought that can help breeding for drought-tolerant wheat varieties.We evaluated 10 root traits at seedling stage in 111 F9 recombinant inbred lines derived from a F2 population of a SHW line(SHW-L1)and a common wheat line,under normal(NC)and polyethylene glycol-simulated drought stress conditions(DC).We mapped quantitative trait loci(QTLs)for root traits using an enriched high-density genetic map containing 120370 single nucleotide polymorphisms(SNPs),733 diversity arrays technology markers(DArT)and 119 simple sequence repeats(SSRs).With four replicates per treatment,we identified 19 QTLs for root traits under NC and DC,and 12 of them could be consistently detected with three or four replicates.Two novel QTLs for root fresh weight and root diameter under NC explained 9 and 15.7%of the phenotypic variation respectively,and six novel QTLs for root fresh weight,the ratio of root water loss,total root surface area,number of root tips,and number of root forks under DC explained 8.5–14%of the phenotypic variation.Here seven of eight novel QTLs could be consistently detected with more than three replicates.Results provide essential information for fine-mapping QTLs related to drought tolerance that will facilitate breeding drought-tolerant wheat cultivars.

Detection of Genetic Diversity in Synthetic Hexaploid Wheats Using Microsatellite Markers

Ninety-five synthetic hexaploid wheats （2n = 6x = 42, AABBDD） were analyzed using 45 microsatellite markers to investigate the potential genetic diversity in wheat breeding programs. A total of 326 alleles were detected by these microsatellite primer pairs, with an average of 6.65 alleles per locus. The polymorphic information content （PIC）, Simpson index （SI）, and genetic similarity （GS） coefficient showed that the D genome is of the highest genetic diversity among the A, B, and D genomes in the synthetic hexaploid wheats. The results also indicated that the synthetic hexaploid wheat is an efficient way to enrich wheat genetic backgrounds, especially to use the genetic variations of the D genome from Aegilops squarrosa for wheat improvement. The UPGMA dendogram, based on a similarity matrix by a simple matching coeff＇lcient algorithm, delineated the above accessions into 5 major clusters and was in accordance with the available pedigree information. The results demonstrated the utility of microsatellite markers in detecting DNA polymorphism and estimating genetic diversity.

Molecular characterization of secaloindoline genes in introduced CIMMYT primary hexaploid triticale

In order to widen gene germplasm for kernel hardness in triticale, 60 synthetic hexaploid triticales were tested by the single kernel characterization system(SKCS) and secaloindoline alleles were identified by sequencing. Phenot^ing showed that frequencies of soft, mixed and hard genotypes were 43.3%, 48.3%, and 8.4%, respectively. Genotyping identified three known secaloindoline-a alleles and four known secaloindoline-b alleles. Three new Sina-Rl alleles were designated Sina-Rld, Sina-Rle and Sina-Rlf. Compared to Sina-Dlc, Sina-Rld showed four point mutations causing changes in four amino acids, Sina-Rle had one point mutation causing an alanine to glycine substitution, and Sina-Rlf possessed five point mutations but produced the same amino add sequence as Sina-Rld. Two new Sinb-Rl alleles were discovered and designated Sinb-Rle and Sinb-Rl/. Compared to Sinb-Rla, Sinb-Rle possessed a triplet-code insertion and four point mutations causing a cysteine insertion and two amino acid substitutions, and Sinb-Rl/possessed three point mutations causing a cysteine insertion and a change of arginine to glycine.Association of hardness index with secaloindoline alleles indicated t±iat SKCS of the Sina-Rld genotype was significantly lower than that of Sina-Rle, and Sinb-Rle was significantly lower than that of the Sinb-Rld genotype. A total of eight allelic combinations of secaloindoline genes were identified; Sma-Rld/Sinb-Rle and Sina-Rle/Sinb-Rld were relatively prevalent in the triticales surveyed. The results provide valuable information for further use of these germplasms in triticale breeding program due to the diverse polymorphism in secaloindoline genes.

Genetic Analysis and Molecular Tagging a Novel Yellow Rust Resistance Gene Derived from Synthetic Hexaploid Wheat Germplasm M08

Yellow rust of wheat （caused by Puccinia striiformis Westend. f. sp. tritici Eriks.） has been periodically epidemic and severely damaged wheat production in China. The development of resistant cultivars could be an effective way to reduce yield losses of wheat caused by yellow rust. Rust reaction tests and genetic analysis indicated that M08, the synthetic hexaploid wheat derived from hybridization between Triticum durum （2n = 6X = 28; genome AABB） and Aegilops tauschii （2n = 2X = 14; genome DD）, showed resistance to current prevailing yellow rust races at seedling stage, which was controlled by a single dominant gene, designated as YrAm. Bulked segregant analysis was used to identify microsatellite markers linked to gene YrAm in an F2 population derived from cross M08 （resistant） × Jinan 17 （susceptible）. Three microsatellite marker loci Xgwm77, Xgwm285, and Xgwml31 located on chromosome 3B were mapped to the YrAm locus. Xgwml31 was the closest marker locus and showed a linkage distance of 7.8 cM to the resistance locus. Thus, it is assumed that YrAm for resistance to yellow rust may be derived from Triticum durum and is located on the long arm of chromosome 3B.

Application of Synthetic Hexaploid Wheat Derived from T.Durum, Ae.taushii in Common Wheat Breeding for FHB Resistance

The F 1 and F 4 plants of 'synthetic hexaploid wheat/common wheat'crosses and part of their parents were inoculated with Fusarium graminearum to evaluate FHB resistance.The results showed tht the scab resistance in the F 1 varied with the synthetic wheat accessions used as crossing parents.In the F 4,some resistant head lines were generated from the crosses,although their parents had different scab resistance levels.It indicated that synthetic hexaploid wheat are useful in wheat breeding for scab resistance.

Broadening the genetic base of Brassica juncea by introducing genomic components from B.rapa and B.nigra via digenomic allohexaploid bridging

A narrow genetic base has hindered improvement of Brassica juncea(A^(j)A^(j)B^(j)B^(j)).In this study,large-scale genomic components were introduced from diploid ancestor species into modern B.juncea using a digenomic hexaploid strategy.The hexaploids A^(j)A^(j)A^(r)A^(r)B^(j)B^(j) and A^(j)A^(j)B^(j)B^(j)B^(n)B^(n) were first developed from B.juncea×B.rapa(A^(r)A^(r))and B.juncea×B.nigra(B^(n)B^(n)),and then crossed with dozens of B.nigra and B.rapa,respectively.Both types of hexaploid showed high pollen fertility and moderate seed set throughout the S_(1) to S_(3) generations,and could be crossed with diploid progenitor species under field conditions,in particular for the combination of A^(j)A^(j)B^(j)B^(j)B^(n)B^(n)×B.rapa.Thirty A^(j)A^(r)B^(n)B^(j)-type and 31 A^(j)A^(r)B^(n)B^(j)-type B.juncea resources were generated,of which the A^(j)A^(r)B^(n)B^(j) type showed higher fertility.Of these new-type B.juncea resources,97 individual plants were genotyped with 42 simple sequence repeat markers,together with 16 current B.juncea accessions and 30 hexaploid plants.Based on 180 polymorphic loci,the new-type B.juncea resources and current B.juncea were separated clearly into distinct groups,with large genetic distance between the new-type B.juncea resources and current B.juncea.Our study provides a novel approach to introducing large-scale genomic components from diploid ancestor species into B.juncea.

Variations in the quality parameters and gluten proteins in synthetic hexaploid wheats solely expressing the Glu-D1 locus

This study evaluated the quality potential of seven synthetic hexaploid wheats(2 n=6 x=42, AABBDD) expressing only allelic variation at Glu-D1 of Aegilops tauschii(SHWSD). Major quality parameters related to dough strength, gluten proteins(including high-molecular-weight glutenin subunits(HMW-GS) and low-molecular-weight glutenin subunits(LMW-GS), gliadins), and their ratios between SHWSD and the weak gluten wheat control Chuannong 16(CN16) were measured in at least three environments(except STD7). The zeleny sedimentation value(ZSV), dough development time(DDT), dough stability time(DST), and farinograph quality number(FQN) of SHWSD were considered stable under different environments, with their respective ranges being 8.00–17.67 mL, 0.57–1.50 min, 0.73–1.80 min, and 9.50–27.00. The ZSV, DDT, DST, and FQN of SHWSD were smaller than those of CN16, suggesting that SHWSD had a weaker dough strength than CN16. Although SHWSD had a lower gluten index than CN16, its wet and dry gluten contents were similar to or even higher than those of CN16 in all environments tested. The protein content of grains(12.81–18.21%) and flours(14.20–20.31%) in SHWSD was higher than that in CN16. The amount of HMW-GS in SHWSD sharply decreased under the expression of fewer HMW-GS genes, and the LMW-GS, gliadins, and total glutenins were simultaneously increased in SHWSD in comparison with CN16. Moreover, SHWSD had higher ratios of LMWGS/glutenin and gliadin/glutenin but a lower ratio of HMW-GS/glutenin than CN16. These results provide necessary information for the utilization of SHWSD in weak-gluten wheat breeding.

The association between the allelic state of <i>Vp</i>-1<i>B</i>and pre-harvest sprouting tolerance in red-seeded hexaploid triticale

The core collection of red-seeded winter hexaploid triticale with different pre-harvest sprouting (PHS) resistance has been evaluated for the allelic structure of the gene VIVIPAROUS-1B (Vp-1B) with STS molecular marker. The discovered structure of the collection was as follows: 50.0% and 41.7% of the collection carries Vp-1Bа and Vp-1Bc alleles, respectively, while 8,3% possesses both of them. As a result of the seed color estimation, the collection has been divided into two groups: with dark red seeds and light red seeds. The allele Vp-1Bc has appeared to be associated with PHS resistance while Vp-1Ba with PHS susceptibility in the triticale accessions with light red seeds only. The influence of the seed color and allelic state of Vp-1B on PHS resistance in triticale is discussed.

Cloning and Diversity Analysis of TaHKT2;2 in Hexaploid Wheat

In order to study the roles of members of HKT gene fanfily in wheat, TaHKT2 ; 2 was isolated by using homologous cloning strategy and screening genomic BAC library. TaHKT2; 2 genes were mapped on chromosomes 7A, 7B and 7D, named as TaHKT2; 2-7A, TaHKT2; 2-7B, and TaHKT2; 2-7D, respectively. TaHKT2 ; 2 and TaHKT2 ; 1 had the same genetic structure, composed of three exons and two introns, and formed a cluster with TaHKT2 ; 1 on the phylogenetic tree of plant HKT transporters. The coding sequences of TaHKT2 ; 2-7A, TaHKT2 ; 2-7B, and TaHKT2 ; 2-7D were 1 602, 1 602 and 1 596 bp long, respectively, but TaHKT2 ;2-7D cDNA sequence was not isolated by RT-PCR in eight wheat varieties. The natural diversity of TaHKT2 ;2 genes was analyzed by cloning and sequencing from 12 wheat varieties. The results showed that TaHKT2;2-7A was found to be more diverse than TaHKT2; 2-7B and TaHKT2; 2-7D. Only a few bases changed in the alleles of TaHKT2 ; 2 genes in wheat. No amino-acid natural variation lay in the P-loops of deduced protein sequences of all alleles of TaHKT2 ; 2 in 12 wheat varieties. The identity of coding sequences was nmch higher than that of 5＇ flanking regions of TaHKT2 ; 2 genes. TaHKT2 ; 2 nfight be selected over the comse of wheat domestication and belonged to domestication gene.

Phenotypic, Cytological and Molecular (AFLP) Analyses of the Cotton Synthetic Allohexaploid Hybrid (<i>G. hirsutum</i>×<i>G. longicalyx</i>)^²

The wild cotton diploid species (2n = 2x = 26) are important sources of useful traits such as high fiber quality, resistance to biotic and abiotic stresses etc., which can be introgressed into the cultivated tetraploid cotton Gossypium hirsutum L (2n = 4x = 52), for its genetic improvement. The African wild diploid species G. longicalyx Hutchinson and Lee could be used as donor of the desirable traits of fiber fineness and resistance to reniform nematode. However, hybridization of wild diploid species and cultivated tetraploid cotton encounters a sterility problem of the triploid (2n = 3x = 59), mainly due to ploidy. The restoration of the fertility can be done by creating an allohexaploid (2n = 6x = 78) through the doubling with colchicine of the sterile triploid chromosomes. With this method, a synthetic allohexaploid hybrid (G. hirsutum × G. longicalyx)2 has been obtained. This genotype was studied using phenotypic, cytological and molecular (AFLP) analyses in order to confirm its hybridity and its caryotype, and also to verify the expression of the desirable traits coming from G. longicalyx. The studied genotype showed a quite good level of pollen fertility (83%), and apart from larger seeds and some minor seedling anomalies, most of its morphological characteristics were intermediate between the two parental species. It had 78 chromosomes, proving its hexaploid status. Molecular analysis revealed 136 AFLP loci in this hexaploid, all from G. hirsutum and G. longicalyx, demonstrating its hybrid status. In addition, the hexaploid exhibited the useful traits of G. longicalyx with regard to its remarkable fiber fineness and its high resistance to the reniform nematode. This allohexaploid hybrid constitutes an interesting agronomic material, which can be used as a bridge for the transfer of useful agronomic traits from wild species to varieties of G. hirsutum.

Chromosome Based Strategies to Decipher the Structure and Evolution of the Hexaploid Wheat Genome: Chromosome 3B,a Case Study

With 17% of all crop area, wheat is the staple food for 40% of the world’s population. Improvement in bread wheat quality and yield in the context of sustainable agriculture is needed in the next decades to meet human

Haplotype-resolved chromosome-level genome of hexaploid Jerusalem artichoke provides insights into its origin,evolution,and inulin metabolism

Jerusalem artichoke(Helianthus tuberosus)is a global multifunctional crop.It has wide applications in the food,health,feed,and biofuel industries and in ecological protection;it also serves as a germplasm pool for breeding of the global oil crop common sunflower(Helianthus annuus).However,biological studies of Je-rusalem artichoke have been hindered by a lack of genome sequences,and its high polyploidy and large genome size have posed challenges to genome assembly.Here,we report a 21-Gb chromosome-level as-sembly of the hexaploid Jerusalem artichoke genome,which comprises 17 homologous groups,each with 6 pseudochromosomes.We found multiple large-scale chromosome rearrangements between Jerusalem artichoke and common sunflower,and our results show that the hexaploid genome of Jerusalem artichoke was formed by a hybridization event between a tetraploid and a diploid Helianthus species,followed by chromosome doubling of the hybrid,which occurred approximately 2 million years ago.Moreover,we iden-tied more copies of actively expressed genes involved in inulin metabolism and showed that these genes may still be undergoing loss of function or sub-or neofunctionalization.These genomic resources will pro-mote further biological studies,breeding improvement,and industrial utilization of Helianthus crops.

六倍体小黑麦×六倍体小麦杂交后代中染色体遗传与结构变异鉴定

六倍体小黑麦是普通小麦品种遗传改良的重要基因资源,可以拓宽小麦的遗传基础。本研究以六倍体小黑麦为供体向普通小麦转移黑麦染色质,以探明六倍体小黑麦×六倍体小麦杂交、回交后代的染色体遗传特性,为小黑麦种质材料的后续研究和利用奠定基础。以六倍体小黑麦16引171为母本,六倍体小麦川麦62为父本配制杂交及回交组合,利用非变性荧光原位杂交技术(non-denaturing florescence in situ hybridization,ND-FISH)对F1、BC1F1和BC1F2植株进行细胞学跟踪鉴定。结果表明,杂种F1回交结实率为2.61%;BC1F1植株2R染色体传递频率最高;BC1F2植株中黑麦染色体在后代的传递率为6R>4R>2R,小麦背景中5B-7B相互易位染色体在BC1F2植株中表现出严重偏分离。在BC1F1和BC1F2植株中观察到24种结构变异染色体,包括染色体片段、等臂易位染色体、易位染色体以及双着丝粒染色体,且部分BC1F2植株的种子表现粒长和千粒重均优于六倍体小麦亲本川麦62。因此,在利用六倍体小黑麦作为桥梁向普通小麦导入黑麦遗传物质时,应尽量采取多次回交的方式,使D组染色体迅速恢复,保证后代育性的恢复,同时关注染色体结构变异材料的潜在应用价值。

花生栽培种和野生种Arachissp.30119六倍体杂种的创制与鉴定

【目的】花生野生种包含许多优异的抗病虫基因,是栽培种改良的重要基因资源库,将野生种染色质导入栽培种是花生远缘杂交研究的重要目的。野生种A.sp.30119对多种花生病害具有抗性,研究其与栽培种的杂种后代,为明确A.sp.30119的身份和未来能够利用其优异抗性提供依据。【方法】利用异源四倍体花生栽培品种白突131与二倍体野生种A.sp.30119杂交,通过胚拯救获得种间杂种F1(W1212),但F1不结实。为了揭示W1212不结实的原因并获得可育的后代,先利用根尖细胞有丝分裂中期和花粉母细胞染色体制片,观察其染色体数目和减数分裂染色体联会情况,再利用试管苗染色体加倍方法对W1212进行加倍处理,最终收获4个单粒荚果,将其中一个荚果的种子组织培养成完整植株并命名为Am1212。利用顺序GISH/FISH和SSR标记分析Am1212的染色体组成,并观察调查其表型特征。最后,利用rDNA FISH随机分析8个Am1212的F3代植株的有丝分裂中期染色体数目,评价其染色体遗传稳定性。【结果】白突131与A.sp.30119的杂种一代W1212花粉母细胞减数分裂中期Ⅰ的染色体平均构型为1Ⅲ+6Ⅱ+15Ⅰ,其染色体不能正常配对,表现为高度不育,染色体加倍处理后W1212下针枝条的花粉育性显著提高。白突131、A.sp.30119和Am1212的顺序GISH/FISH分析结果表明,A.sp.30119可能为A基因组二倍体野生种。Am1212有60条染色体,包含白突131与A.sp.30119的全部染色体,证实其为六倍体杂种后代。但Am1212自交F3代有37.5%的植株发生了染色体数目变异。通过分子标记筛选和表型调查,获得17个特异追踪A.sp.30119的显性和共显性标记,明确了Am1212的遗传特性。【结论】创制了一个新的六倍体花生Am1212,该六倍体整合了野生种染色质,同时,Am1212也拥有了小荚果等不利性状,且染色体遗传稳定性较差,因此,未来育种利用过程中,需要结合精准的染色体鉴定技术,打破不良连锁,获得具有补偿效应且包含有利性状的染色体变异材料。

六倍体小黑麦新品系T-133引种鉴定及特性分析

小黑麦是小麦和黑麦属间人工杂交形成的新物种,与小麦和黑麦相比,小黑麦的生物产量及蛋白质、赖氨酸含量高,适口性更好,可作为优质禾本科牧草,以促进饲草多元化发展。为了丰富甘肃省饲草种类,给农牧交错区提供高产稳产、耐盐碱、抗寒旱、抗病虫的小黑麦新品种,2013年从CIMMYT引进了六倍体小黑麦新品系T-133,并经2014—2020年连续水旱鉴定、品比试验、生产试验进行引种鉴定。在2020年甘肃省不同生态区生产试验中,平均折合籽粒产量7814.94 kg/hm^(2),比对照品种宁春4号增产17.45%;平均生物学产量22.39 t/hm^(2),比对照品种石大1号增产12.92%。该品系为粮草兼用型,春性,生育期100~109 d,株高115~120 cm,穗长10.0~10.5 cm,可育小穗数21~24个,穗粒数45~50粒,千粒重47~56 g。富含铁、锌等微量元素,品质优良,抗病性强。适宜在甘肃河西、中部及生态区域相似的青海、宁夏等高寒旱区种植。

Establishment of a transformation system in close relatives of wheat under the assistance of TaWOX5

Species closely related to wheat are important genetic resources for agricultural production,functional genomics studies and wheat improvement.In this study,a wheat gene related to regeneration,TaWOX5,was applied to establish the Agrobacterium-mediated transformation systems of Triticum monococcum,hexaploid triticale,and rye(Secale cereale L.)using their immature embryos.Transgenic plants were efficiently generated.During the transformation process,the Agrobacterium infection efficiency was assessed by histochemical staining forβ-glucuronidase(GUS).Finally,the transgenic nature of regenerated plants was verified by polymerase chain reaction(PCR)-based genotyping for the presence of the GUS and bialaphos resistance(bar)genes,histochemical staining for GUS protein,and the QuickStix strip assay for bar protein.The transformation efficiency of T.monococcum genotype PI428182 was 94.4%;the efficiencies of four hexaploid triticale genotypes Lin456,ZS3297,ZS1257,and ZS3224 were 52.1,41.2,19.4,and 16.0%,respectively;and the transformation efficiency of rye cultivar Lanzhou Heimai was 7.8%.Fluorescence in situ hybridization(FISH)and genomic in situ hybridization(GISH)analyses indicated that the GUS transgenes were integrated into the distal or near centromere(proximal)regions of the chromosomes in transgenic T.monococcum and hexaploid triticale plants.In the transgenic hexaploid triticale plants,the foreign DNA fragment was randomly integrated into the AABB and RR genomes.Furthermore,the transgene was almost stably inherited in the next generation by Mendel’s law.The findings in this study will promote the genetic improvement of the three plant species for grain or forage production and the improvement of cereal species including wheat for functional genomics studies.

利用人工合成小麦基因资源实现产量突破的育种实践

【目的】人工合成小麦是科学家模拟小麦进化过程,利用四倍体小麦与二倍体节节麦杂交、染色体加倍而成的新型六倍体小麦资源,集合了双亲的优良性状,可作为桥梁改良现代小麦。【方法】回顾了四川小麦80多年的育种历程,对利用人工合成小麦基因资源实现产量水平突破的方法技术进行了分析,希望为进一步利用小麦近缘属种育种应用提供参考。【结果】利用大群体有限回交法和重组自交系育种法改良初级人工合成小麦及其衍生系,育成了产量提升近30%的小麦品种川麦42及衍生品种川麦104,维持四川小麦产量台阶20余年。【结论】种质资源发掘、育种方法技术创新,是实现产量新突破有效途径。