Identification of Molecular Markers for the Thinopyrum intermedium Chromosome 2Ai-2 with Resistance to Barley Yellow Dwarf Virus

The wheat_ Thinopyrum intermedium addition lines Z1,Z2 contain a pair of Th. intermedium chromosomes 2Ai_2 carrying the gene with resistance to barley yellow dwarf virus (BYDV). Genomic in situ hybridization (GISH) was used to analyze the chromosome constitution of Z1,Z2 by using genomic DNA probes from Th. intermedium and Pseudoroegneria strigosa . The results showed that the chromosome constitution of either Z1 or Z2 composes of 42 wheat chromosomes and two Th. intermedium chromosomes (2Ai_2). The 2Ai_2 chromosome is St_E intercalary translocation, in which the E genomic chromosome segment translocated into the middle region of the long arm of chromosome belonging to St genome. With the genomic DNA probe of Ps. strigosa , the GISH pattern specific to the 2Ai_2 chromosome may be used as a molecular cytogenetic marker. A detailed RFLP analysis on Z1, Z2 and their parents was carried out by using 12 probes on the wheat group 2 chromosomes. Twenty RFLP markers specific to the 2Ai_2 chromosome were identified. Two RAPD markers of OPR16 -350 and OPH09 -1580 , specific to the 2Ai_2 chromosome, were identified from 280 RAPD primers. These molecular markers could be used to assisted_select translocation lines with small segment of the 2Ai_2 chromosome and provide tools to localize the BYDV resistance.

普通小麦-百萨偃麦草(Thinopyrum bessarabicum)二体异附加系的选育与鉴定

为转移与利用百萨偃麦草耐盐、抗病等优良基因 ,用普通小麦中国春 百萨偃麦草双倍体与中国春杂交 ,通过染色体C 分带、分子原位杂交并结合减数分裂中期Ⅰ的染色体配对分析 ,从回交后代中选育出一套小麦 百萨偃麦草二体异附加系。对这套异附加系进行的鉴定与分析表明 ,各附加系除添加了一对百萨偃麦草染色体外 ,小麦的 2 1对染色体未见明显变化。各附加系所添加的百萨偃麦草染色体在减数分裂中期Ⅰ配对基本正常 ,仅有少量单价体 ,其自交后代中外源染色体亦能正常传递。这说明所培育的这套二体异附加系在细胞学上已相对稳定 ,暂分别编号为DAJ1 、DAJ2 、DAJ3、DAJ4 、DAJ5、DAJ6 和DAJ7。

长穗偃麦草(Thinopyrum ponticum)幼苗对盐旱胁迫的生理响应

盐渍土主要分布于干旱、半干旱地区,植物的生长同时受到旱和盐的胁迫。本研究以长穗偃麦草(Thinopyrum ponticum)为材料,采用盆栽方法,探究了盐、旱及其互作对长穗偃麦草幼苗生长和生理特性的影响,以期为长穗偃麦草在盐碱地的种植提供理论依据。试验设置4个土壤含盐量水平:0 g·kg^(−1)、4 g·kg^(−1)、8 g·kg^(−1)和12 g·kg^(−1);3个干旱水平:土壤含水量为田间持水量的75%~85%(常规灌水)、55%~65%(中度干旱)和35%~45%(重度干旱),共12个处理,以常规灌水和无NaCl添加为对照。试验测定了长穗偃麦草幼苗的生物量及叶绿素SPAD值、光合参数、抗氧化物酶活性和地上、地下部Na^(+)、K^(+)含量。结果表明:干旱胁迫和盐胁迫均可使长穗偃麦草的生长受到抑制,但盐旱互作可提高根/冠比,长穗偃麦草仍可在重度干旱和高盐胁迫(12 g·kg^(−1))下存活。干旱或盐胁迫使长穗偃麦草叶绿素含量、净光合速率、气孔导度和蒸腾速率下降,但这些指标在盐旱互作下高于常规灌水下的同一盐分处理。适当的盐分和干旱胁迫提高长穗偃麦草叶片SOD、POD、CAT活性,高盐则降低;重度干旱和高盐胁迫提高了叶片MDA含量。长穗偃麦草地上部Na^(+)、K^(+)含量和K^(+)/Na^(+)比高于根部;干旱和盐分胁迫下,长穗偃麦草根部和地上部Na^(+)含量增加,K^(+)含量减少但依然维持在较高水平,干旱处理显著提高了盐胁迫下根部Na^(+)含量,但根部K^(+)/Na^(+)相对稳定,地上部K^(+)/Na^(+)显著下降。上述结果表明,长穗偃麦草在重度干旱和高盐胁迫下的存活特征可能与其具有发达的根系、高根/冠、完善的抗氧化系统以及根系Na^(+)积累和根系稳定的K^(+)/Na^(+)有关,但要获得一定的生物量仍需要适度的干旱和低盐条件。

Heterosis and Combining Ability for Major Yield Traits of a New Wheat Germplasm Shannong 0095 Derived from Thinopyrum intermedium

The wheatgrass, Thinopyrum intermedium （Host） Barkworth ＆ DR Dewey, shows many beneficial characteristics, such as big spikes and high resistance to many diseases. To transfer the beneficial genes of this species, many wheat- Thinopyrum intermedium alien chromosome lines were developed. Of them, Shannong 0095 （SN0095）, a disomic substitution, has long spikes and flag-leaves, and thus may be an important genetic resource for wheat yield improvement. In order to realize its heterosis and combining ability on major yield traits, a 7 ×7 complete diallel design was made according to Griffing＇s Method-1. The results showed that heterosis for spike length （SPL）, flag-leaf area （FLA）, number of spikes per plant （NSP）, number of spikelets per spike （NSL）, kernels per spike （KPS）, 1 000-kernel weight （TKW） and grain yield per plant （GYP） existed in all the crosses by SN0095, but heterobeltiosis occurred only for KPS, TKW, and GYP. The relative mid-parent heterosis （RMH） and relative high-parent heterosis （RHH） for GYP, which valued as high as 35.32 and 29.92% respectively, were the highest among all the traits mearsured. Though additive and non-additive gene effects and cytoplasmic effects （or cytoplasmic-nuclear interaction effects） were found in governing all the traits measured above, additive gene action played a predominant role. The results also showed that SN0095 was the best-general combiner for SPL and FLA, and high-general combiner for NSP amongst all the parents. Estimates of specific combining ability （SCA） showed that SN0095 could also make high-SCA combinations for GYP, such as SN0095 × Jimai 19 （JMI9）. SN0095 could be a unique and important parent in hybrid wheat breeding programs.

Molecular Mapping of Two Novel Stripe Rust Resistant Genes YrTp1 and YrTp2 in A-3 Derived from Triticum aestivum × Thinopyrum ponticum

Loss of variety resistance to stripe rust （Puccinia striiformis Westend f. sp.tritici） is an important factor causing massive periodical epidemic of rust in wheat production. Creation and development of new races of rust pathogen have led to serious crisis of resistance loss in widely planted varieties. This has quickened the search for new resistance resources. Molecular marker could facilitate the identification of the location of novel genes. A line A-3 with high resistance （immune） to currently epidemic yellow rust races （CY29, 31, 32） was screened out in offspring of Triticum aestivura x Thinopyrum ponticum. Segregation in F2 and BC1 populations indicated that the resistance was controlled by two independent genes： one dominant and one recessive. SSR markers were employed to map the two resistant genes in the F2 and BC1 populations. A marker WMC477-167bp located on 2BS was linked to the dominant gene with genetic distance of 0.4 cM. Another marker WMC364-2os bp located on 7BS was linked to the recessive-resistant gene with genetic distance of 5.8 cM. The two genes identified in this paper might be two novel stripe rust resistant genes, which were temporarily designated as YrTpl and YrTp2, respectively. The tightly linking markers facilitate transfer of the two resistant genes into the new varieties to control epidemic of yellow rust.

THINOPYRUM BESSARABICUM和THINO-PYRUM ELONGATUM的基因组关系研究

对 2个八倍体 C.S- Thinopyrum bessarabicum( AABBDDJJ,2 n=8x=56)和 Goshawk( GHK) - Thinopyrum elongatum( AABBDDEE,2 n=8x=56)的根尖细胞染色体进行 C-分带 ,从中分检出 Th.bessarabicum和 Th.elongatum的各自染色体进行核型分析 ,结果表明 :Th.bessarabicum和 Th.elongatum的大多数染色体都具有端带 ,但 Th.bessarabicum的端带更强 ,很少有中间带 ;而 Th.elongatum的染色体除 E1外其它染色体的端带较弱 ,而且带纹较丰富 ,有较多的中间带。对 C.S- Th.bessarabicum和 GHK- Th.elongatum进行有性杂交 ,其杂交种F1的 PMC染色体在 MI的平均配对构型为 1 5.50 + 5.0 3 [+ 1 4.2 0 ○ + 0 .40 + 0 .2 1 ,其中 Th.bessarabicum和 Th.elongatum染色体平均配对成 2 .5个二价体 ,由 C-分带显示大多数 Th.bessarabicum和 Th.elongatum染色体呈单价体状态。因此推断 ,Th.bessarabicum和 Th.

Molecular cytogenetic characterization of a novel wheat-Thinopyrum intermedium introgression line tolerant to phosphorus deficiency

Thinopyrum intermedium has been used as a resource for improving resistance to biotic and abiotic stresses and yield potential in common wheat. Wheat line SN304 was derived from a cross between common wheat cultivar Yannong 15 and Th. intermedium. Genomic in situ hybridization(GISH) produced no hybridization signal in SN304 using Th. intermedium genomic DNA as a probe, but fluorescence in situ hybridization(FISH) using oligonucleotides AFA-3, AFA-4, pAs1-1, pAs1-3, pAs1-4, pAs1-6, pSc119.2-1,and(GAA)10 as probes detected hybridization signals on chromosomes 2 A, 7 A, 2 B, 3 B, 6 B, and 7 B in SN304 that differed from Yannong 15. Results of specific markers also indicated that there were Th. intermedium chromatin introgressions on different chromosomes in SN304. In a hydroponic culture experiment, SN304 not only produced more biomass and higher stem and leaf dry weight but also accumulated more phosphorus than Yannong 15 under phosphorus-deficiency stress. Moreover, SN304 produced a lower pH and released more organic acids, especially oxalic acid, than Yannong 15, which suggests that SN304 exudates enabled more absorbance of P than Yannong 15 under comparable conditions.The results indicate that SN304 is a wheat-Th. intermedium introgression line with tolerance to phosphorus-deficiency stress.

长穗薄冰草(Thinopyrum ponticum)对盐碱胁迫的生理响应

实验采用不同浓度(以于土重0.3%、0.5%、0.7%和0.9%计)Na_2SO_4、NaCl、NaHCO_3、Na_2CO_3,Na_2SO_4:NaCl=1:1、NaHCO_3:Na_2CO_3=1:1和Na_2SO_4:NaCl:NaHCO_3:Na_2CO_3=1:1:1:1对长穗薄冰草进行胁迫,研究长穗薄冰草对盐碱胁迫的生理响应。结果表明:根系活力、SOD活性随盐碱浓度的增加逐渐下降,脯氨酸含量呈上升趋势,叶绿素含量除Na_2SO_4处理组外,呈先上升后下降的趋势。其中碱性盐(NaHCO_3、Na_2CO_3、NaHCO_3:Na_2CO_3=1:1、Na_2SO_4:NaCl:NaHCO_3:Na_2CO_3=1:1:1:1)对长穗薄冰草的胁变效应较中性盐(Na_2SO_4、NaCl、Na_2SO_4:NaCl=1:1)大,以Na_2SO_4处理组对长穗薄冰草的影响最小,0.7%Na_2CO_3是长穗薄冰草正常生长的临界浓度。

Elimination of the yellow pigment gene PSY-E2 tightly linked to the Fusarium head blight resistance gene Fhb7 from Thinopyrum ponticum

Fhb7 is a major gene that was transferred from Thinopyrum ponticum to chromosome 7D of wheat(Triticum aestivum)and confers resistance to both Fusarium head blight(FHB)and Fusarium crown rot(FCR).However,Fhb7 is tightly linked to the PSY-E2 gene,which causes yellow flour,limiting its application in breeding.To break this linkage,marker K-PSY was developed for tagging PSY-E2 and used with Fhb7 markers to identify recombination between the two genes.Screening 21,000 BC1F2 backcross progeny(Chinese Spring ph1bph1b*2/SDAU 2028)revealed two Fhb7^(+)wheat-Tp7el_(2)L lines,Shannong 2–16and Shannong 16–1,that carry a desired truncated Fhb7^(+)translocation segment without PSY-E2.The two lines show levels of resistance to FHB and FCR similar to those of the original translocation line SDAU 2028,but have white flour.To facilitate Fhb7 use in wheat breeding,STS markers were developed and used to isolate Fhb7 on a truncated Tp7el_(2) translocation segment.Near-isogenic lines carrying the Fhb7^(+)segment were generated in the backgrounds of three commercial cultivars,and Fhb7^(+)lines showed increased FHB and FCR resistance without yield penalty.The breakage of the tight linkage between Fhb7 and PSY-E2 via homoeologous recombination provides genetic resources for improvement of wheat resistance to FHB and FCR and permit the large-scale deployment of Fhb7 in breeding using marker-assisted selection.

Characterization of novel wheat-Thinopyrum ponticum introgression lines derived from partial amphiploid AUS6770 for resistance to stripe rust

The wild decaploid species Thinopyrum ponticum(Podp.)Barkworth&D.R.Dewey is an important source of genes against biotic and abiotic stresses affecting wheat.The wheat–Th.ponticum partial amphiploid AUS6770 shows resistance to multiple diseases,including stripe rust,stem rust,and powdery mildew.Mitotic chromosomes of AUS6770 were characterized by non-denaturing-fluorescence in situ hybridization(ND-FISH),and the individual Th.ponticum chromosomes 1Ae to 7Ae were karyotypically distinguished by Oligo-FISH painting using bulked oligo pools based on wheat-barley collinear regions.A novel stripe rust resistant line A155,derived from AUS6770,was found to have 44 chromosomes,including a pair of 2Ae chromosomes and a pair of 6B-6Ae translocations.To detect plants with transfer of resistance genes from A155 to wheat chromosomes,1770 plants were developed from F2–F5 progenies of A155 crossed with the susceptible wheat cultivar MY11 and characterized with ND-FISH using multiple probes.A high frequency of transmission of chromosome 2Ae was observed,and 31 types of 2Ae chromosomal aberrations were identified using ND-FISH.Ten chromosomal bins on the 2Ae chromosome were determined from the deletion and translocation lines based on genome-based PCR markers.In combination with the evaluation of disease resistance,the gene(s)for stripe rust resistance was located on the FL0.79–1.00 of 2AeS and covers the corresponding region of 0–58.26 Mb in the reference genome of Th.elongatum.The newly identified wheat-Th.ponticum 2Ae translocation lines can be exploited as potential germplasm in wheat breeding for stripe rust resistance.

Thinopyrum ponticum and Th. intermedium: the promising source of resistance to fungal and viral diseases of wheat

Thinopyrum ponticum and Th. intermedium provide superior resistance against various diseases in wheat （Ttricum aestivum）. Because of their readily crossing with wheat, many genes for disease resistance have been introduced from the wheatgrasses into wheat. Genes for resistance to leaf rust, stem rust, powdery mildew, Barley yellow dwarf virus, Wheat streak mosaic virus, and its vector, the wheat curl mite, have been transferred into wheat by producing chromosome translocations. These genes offer an opportunity to improve resistance of wheat to the diseases; some of them have been extensively used in protecting wheat from damage of the diseases. Moreover, new resistance to diseases is continuously detected in the progenies of wheat-Thinopyrum derivatives. The present article summaries characterization and application of the genes for fungal and viral disease-resistance derived from Th. ponticum and Th. intermedium.

Molecular Cytogenetic Characterization of Wheat-Thinopyrum elongatum Addition,Substitution and Translocation Lines with a Novel Source of Resistance to Wheat Fusarium Head Blight

Thinopyrum elongatum （2n = 2x = 14, EE）, a wild relative of wheat, has been suggested as a potentially novel source of resistance to several major wheat diseases including Fusarium Head Blight （FHB）. In this study, a series of wheat （cv. Chinese Spring, CS） substitution and ditelosomic lines, including Th. elongatum additions, were assessed for Type II resistance to FHB. Results indicated that the lines containing chromosome 7E of Th. elongatum gave a high level of resistance to FHB, wherein the infection did not spread beyond the inoculated floret. Furthermore, it was determined that the novel resistance gene（s） of 7E was located on the short-ann （7ES） based on sharp difference in FHB resistance between the two 7E ditelosomic lines for each arm. On the other hand, Th. elongatum chromosomes 5E and 6E likely contain gene（s） for susceptibility to FHB because the disease spreads rapidly within the inoculated spikes of these lines. Genomic in situ hybridization （GISH） analysis revealed that the alien chromosomes in the addition and substitution lines were intact, and the lines did not contain discernible genomic aberrations. GISH and multicolor-GISH analyses were further performed on three trans- location lines that also showed high levels of resistance to FHB. Lines TA3499 and TA3695 were shown to contain one pair of wheat-Th. elongatum translocated chromosomes involving fragments of 7D plus a segment of the 7E, while line TA3493 was found to contain one pair of wheat-Th, elongatum translocated chromosomes involving the D- and A-genome chromosomes of wheat. Thus, this study has established that the short-arm of chromosome 7E of Th. elongatum harbors gene（s） highly resistant to the spreading of FHB, and chromatin of 7E introgressed into wheat chromosomes largely retained the resistance, implicating the feasibility of using these lines as novel material for breeding FHB-resistant wheat cultivars.

Mapping of a BYDV resistance gene from Thinopyrum intermedium in wheat background by molecular markers

The wheat line H960642 is a homozygous wheat-Thinopyrum intermedium translocation line with resistance to BYDV by genomie in situ hybridization (GISH) and RFLP analysis. The genomie DNA of Th. intermedium was used as a probe, and eonunon wheat genomie DNA as a blocking in GISH experiment. The results showed that the chromosome segments of Th. intermedium were transferred to the distal end of a pair of wheat chromosomes. RFLP analysis indicated that the transloeation line H960642 is a T7DS·7DL-7XL translocation by using 8 probes mapped on the homoeologous group 7 in wheat. The tranalocation breakpoint is located between Xpsr680 and Xpsr965 about 90—99 cM from the centromere. The RFLP markers psr680 and psr687 were closoly linked with the BYDV resistance gene. The gene is located on the distal end of 7XL around Xpsr680 and Xpsr687.

Molecular Cytogenetic Characterization and Stem Rust Resistance of Five Wheat-Thinopyrum ponticum Partial Amphiploids

Partial amphiploids created by crossing common wheat （Triticum aestivum L.） and Thinopyrum ponticum （Podp.） Barkworth ＆ D. R. Dewey are important intermediates in wheat breeding because of their resistance to major wheat diseases. In this study, we examined the chromosome compositions of five Xiaoyan-series wheat-Th, ponticum partial amphiploids （Xiaoyan 68, Xiaoyan 693, Xiaoyan 784, Xiaoyan 7430, and Xiaoyan 7631） using GISH, multicolor-GISH, and multicolor-FISH. We found several chromosome changes in these lines. For example, wheat chromosomes 1B and 2B were added in Xiaoyan 68 and Xiaoyan 7430, respectively, while wheat chromosome 6B was eliminated from Xiaoyan 693 and Xiaoyan 7631. Chromosome rearrangements were also detected in these amphiploids, including an interspecific translocation involving chromosome 4D and some intergenomic translocations, such as A--B and A--D translocations, among wheat genomes. Analysis of the Th. ponticum chromosomes in the amphiploids showed that some lines shared the same alien chromosomes. We also evaluated these partial amphiploids for resistance to nine races of stem rust, including TTKSK （commonly known as Ug99）. Three lines, Xiaoyan 68, Xiaoyan 784, and Xiaoyan 7430, exhibited excellent resistance to all nine races, and could therefore be valuable sources of stem rust resistance in wheat breeding.

Utilization of blue-grained character in wheat breeding derived from Thinopyrum poticum

The blue grain trait in common wheat （Triticum aestivum L., 2n = 6x = 42, AABBDD）, which is caused by blue pigments in the aleurone layer, was originally derived from the tall wheatgrass （Thinopyrum ponticum Liu ＆ Wang = Agropyron elongatum, 2n = 10x = 70, StStStStEeEeEbEbEXEx） during chromosome engineering research. Over the last few decades, there have been continued interests in the genetic mechanism of this blue coloration and the practical utilization of the blue aleurone character as a phenotypic marker. This article reviews the research history and the recent progress of the studies on blue-grained wheat, with emphases on genetic and biochemical analysis and practical applications of blue-grained wheat.

Development and utilization of new sequenced characterized amplified region markers specific for E genome of Thinopyrum

Species containing E genome of Thinopyrum offered potential to increase the genetic variability and desirable characters for wheat improvement. However, E genome specific marker was rare. The objective of the present report was to develop and identify sequenced characterized amplified region （SCAR） markers that can be used in detecting E chromosome in wheat background for breeding purpose. Total 280 random amplified polymorphic DNA （RAPD） primers were amplified for seeking of E genome specific fragments by using the genomic DNA of Thinopyrum elongatum and wheat controls as templates. As a result, six RAPD fragments specific for E genome were found and cloned, and then were converted to SCAR markers. The usability of these markers was validated using a number of E- genome-containing species and wheat as controls. These markers were subsequently located on E chromosomes using specific PCR and fluorescence in situ hybridization （FISH）. SCAR markers developed in this research could be used in molecular marker assisted selection of wheat breeding with Thinopyrum ehromatin introgressions.

Establishment and characterization of a complete set of Triticum durum-Thinopyrum elongatum monosomic addition lines with resistance to Fusarium head blight in wheat

Durum wheat(Triticum durum Desf.,2n=28,AABB),which is mainly used to make pasta,is the second cultivated wheat variety worldwide.However,the durum wheat production is severely affected by a number of diseases,such as Fusarium head blight(FHB)and stem rust(Klindworth et al.,2017;Zhao et al.,2018).Thinopyrum elongatum(2n=4x=28),a close relative of wheat.

Agronomic assessment of two populations of intermediate wheatgrass—Kernza^(®)(Thinopyrum intermedium)in temperate South America

Background Kernza®intermediate wheatgrass is a perennial grain and forage crop that can provide several ecosystem services.Major research efforts focused on Kernza have taken place in high latitudes.The goal of this study was to evaluate,for the first time,the agronomic performance of Kernza in a low-latitude region with mild winters.Methods A KS-cycle 4 Kernza population(A)was planted in spring in Wisconsin,USA,and selected in one cycle for lower vernalization requirements,obtaining a new population(B).These two populations,at three nitrogen(N)fertilization rates,were evaluated in a full factorial,completely randomized field experiment in Uruguay over 2 years.Results The populations were similar in grain yields and flowering time in the 1st year,but population B had 63%lower grain yield in the 2nd year and 20%lower forage yield throughout the experiment.Increasing the N rate to 160 kg ha−1 led to a 63%increase in grain yield and 28%increase in forage yield across populations.Forage yields and nutritive values were similar to those reported in the northern hemisphere.However,grain yields for both the 1st(316 kg ha−1)and 2nd year(41 kg ha−1)were lower due to reduced flowering and weed competition.Conclusions Expansion of Kernza to lower-latitude regions will require further breeding to improve reproductive performance.

西农979中长穗偃麦草(Thinopyrum ponticum)的遗传成分分析

西农979是我国黄淮麦区优质高产、早熟耐寒兼抗赤霉病的小麦新品种。十倍体长穗偃麦草(Thinopyrum ponticum)7E染色体携带有抗赤霉病和抗叶锈病等多种抗性基因。为明确西农979品种的遗传基础,以西农979及其主要供体亲本小偃6号、早优504、陕229、陕213和西农881为材料进行系谱分析,结果表明,西农979及其主要供体亲本陕229、陕213、西农881均为小偃6号的衍生系;小偃6号是十倍体长穗偃麦草的衍生系。在此基础上,利用十倍体长穗偃麦草7E染色体上106个特异分子标记进行分析,发现有6个标记在西农979和小偃6号中扩增出了十倍体长穗偃麦草的特异片段,西农979和小偃6号均携带有十倍体长穗偃麦草7E染色体短臂上分子标记Xwmc653-Xwmc809之间的75.10～77.46cM区段,标记Xcfd31-Xgwm350之间的86.16～87.32cM区段,以及7E染色体长臂标记Xmag1932-Xdauk144之间的147.71～149.51cM区段。结果表明,西农979携带的十倍体长穗偃麦草7E染色体上的遗传物质源自小偃6号,这为进一步研究和利用西农979提供了理论参考。