小麦叶锈病抗性基因在山西的有效性研究

采自山西省各地的小麦叶锈菌菌株分别接种在含有已知抗叶锈病基因的小麦近等基因系(或单基因系)上,测定其毒性频率,根据已知抗病基因对叶锈菌群体的抗性程度,对其进行抗性效能的评价。结果表明：抗性基因Lr9、Lr19、Lr24、Lr38的毒性频率较低,分别为23．08％、16．03％、12．82％和1．92％,为山西省小麦叶锈菌的有效抗病基因。在发现的诸多毒性类型中,THT、THK、PHT、TRT的出现频率居前四位,分别为19．23％、8．97％、7．05％、5．77％,为山西省目前小麦叶锈菌群体中的优势毒性类型。     

Marker-assisted selection for leaf rust resistance genes Lr19 and Lr24 in wheat (Triticum aestivum L.)

Leaf rust caused by Puccinia recondita f.sp. tritici is a wheat disease of worldwide importance. Wheat genotypes known to carry specific rust resistance genes and segregating lines that originated from various cross combinations and derived from distinct F2 lineage, so as to represent a diverse genetic background, were included in the present study for validation of molecular markers for Lr19 and Lr24. STS markers detected the presence of the leaf rust resistance gene Lr19 in a Thatcher NIL (Tc*Lrl9) and Inia66//CMH81A575 and of the gene Lr24 in the genotypes Arkan, Blue Boy II, Agent and CI 17907. Validation of molecular markers for Lr19 and Lr24 in parental lines, followed by successful detection of these genes in F3 lines from various cross combinations, was carried out. The molecular test corresponded well with the host-pathogen interaction test response of these lines.     

Inheritance of leaf rust and stem rust resistance in 'Roblin' wheat.

The Canadian common wheat (Triticum aestivum L.) cultivar 'Roblin' is resistant to both leaf rust (Puccinia recondita Rob. ex. Desm.) and stem rust (Puccinia graminis Pers. f. sp. tritici Eriks. and E. Henn.). To study the genetics of this resistance, 'Roblin' was crossed with 'Thatcher', a leaf rust susceptible cultivar, and RL6071, a stem rust susceptible line. A set of F6 random lines was developed from each cross. The random lines and the parents were grown in a field rust nursery artificially inoculated with a mixture of P. recondita and P. graminis isolates and scored for rust reaction. The same material was tested with specific races of leaf rust and stem rust. These data indicated that 'Roblin' has Lr1, Lr10, Lr13, and Lr34 for resistance to P. recondita and Sr5, Sr9b, Sr11, and possibly Sr7a and Sr12 for resistance to P. graminis. In a 'Thatcher' background, the presence of Lr34 contributes to improve stem rust resistance, which appears also to occur in 'Roblin'.     

Genetic studies of leaf and stem rust resistance in six accessions of Triticum turgidum var. dicoccoides.

Six accessions of Triticum turgidum var. dicoccoides L. (4x, AABB) of diverse origin were tested with 10 races of leaf rust (Puccinia recondita f.sp. tritici Rob. ex Desm.) and 10 races of stem rust (P. graminis f.sp. tritici Eriks. &Henn.). Their infection type patterns were all different from those of lines carrying the Lr or Sr genes on the A or B genome chromosomes with the same races. The unique reaction patterns are probably controlled by genes for leaf rust or stem rust resistance that have not been previously identified. The six dicoccoides accessions were crossed with leaf rust susceptible RL6089 durum wheat and stem rust susceptible 'Kubanka' durum wheat to determine the inheritance of resistance. They were also crossed in diallel to see whether they carried common genes. Seedlings of F1, F2, and BC1F2 generations from the crosses of the dicoccoides accessions with RL6089 were tested with leaf rust race 15 and those from the crosses with 'Kubanka' were tested with stem rust race 15B-1. The F2 populations from the diallel crosses were tested with both races. The data from the crosses with the susceptible durum wheats showed that resistance to leaf rust race 15 and stem rust race 15B-1 in each of the six dicoccoides accessions is conferred by a single dominant or partially dominant gene. In the diallel crosses, the dominance of resistance appeared to be affected by different genetic backgrounds. With one exception, the accessions carry different resistance genes: CI7181 and PI 197483 carry a common gene for resistance to leaf rust race 15. Thus, wild emmer wheat has considerable genetic diversity for rust resistance and is a promising source of new rust resistance genes for cultivated wheats.     

Molecular markers for leaf rust resistance genes in wheat

Over 100 genes of resistance to rust fungi: Puccinia recondita f. sp. tritici, (47 Lr - leaf rust genes), P. striiformis (18 Yr - yellow rust genes) and P. graminis f. sp. tritici (41 Sr - stripe rust genes) have been identified in wheat (Triticum aestivum L.) and its wild relatives according to recent papers. Sixteen Lr resistance genes have been mapped using restriction fragments length polymorphism (RFLP) markers on wheat chromosomes. More than ten Lr genes can be identified in breeding materials by sequence tagged site (STS) specific markers. Gene Lrk 10, closely linked to gene Lr 10, has been cloned and its function recognized. Available markers are presented in this review. The STS, cleaved amplified polymorphic sequence (CAPS) and sequence characterized amplified regions (SCAR) markers found in the literature should be verified using Triticum spp. with different genetic background. Simple sequence repeats (SSR) markers for Lr resistance genes are now also available.     

河南省16个主栽小麦品种抗叶锈基因分析

为了明确河南省小麦品种的抗叶锈性及抗叶锈基因的分布,为小麦品种推广与合理布局、叶锈病防治及抗病育种提供依据,本研究利用2015年采自河南省的5个小麦叶锈菌流行小种混合菌株,对近几年河南省16个主栽小麦品种进行了苗期抗性鉴定,然后选用12个小麦叶锈菌生理小种对这些品种进行苗期基因推导,同时利用与24个小麦抗叶锈基因紧密连锁(或共分离)的30个分子标记对该16个品种进行了抗叶锈基因分子检测。结果显示,供试品种苗期对小麦叶锈菌混合流行小种均表现高度感病;基因推导与分子检测结果表明,供试品种可能含有Lr1、Lr16、Lr26和Lr30这4个抗叶锈基因,其中先麦8号含有Lr1和Lr26;郑麦366和郑麦9023含有Lr1;西农979和怀川916含有Lr16;中麦895、偃展4110、郑麦7698、平安8号、众麦1号、周麦16、衡观35和矮抗58含有Lr26;周麦22中含有Lr26,还可能含有Lr1和Lr30;豫麦49-198和洛麦23可能含有本研究中检测以外的其他抗叶锈基因。因此,河南省主栽小麦品种的抗叶锈基因丰富度较低,今后育种工作应注重引入其他抗叶锈性基因,提高抗叶锈性,有效控制小麦叶锈病。     

Leaf rust resistance genes of wheat: identification in cultivars and resistance sources

Thirty-seven wheat cultivars originating from seven European countries were examined by using sequence tagged site (STS) markers for seven Lr (leaf rust = brown rust) resistance genes against the fungal pathogen of wheat Puccinia recondita f. sp. tritici (Lr9, Lr10, Lr19, Lr24, Lr26 and Lr37). Additionally, 22 accessions with various Lr genes from two germplasm collections were tested. A Scar (sequence-characterized amplified region) marker for Lr24 and a CAPS (Cleaved Amplified Polymorphic Sequence) marker for Lr47 were also used to identify those genes in the wheat accessions. Each marker amplified one specific DNA fragment. Three Lr gene markers were identified in wheat cultivars (Lr10, Lr26 and Lr37). Another four markers (Lr9, Lr19, Lr24 and Lr47) were found in breeding lines carrying leaf rust resistance genes. The results were compared with leaf rust resistance gene postulations made in previous studies, based on multipathotype testing. Markers for Lr10, Lr26 and Lr37 may be useful in marker-assisted breeding.     

山东省12个主栽小麦品种(系)抗叶锈性分析

本研究旨在明确山东省12个小麦主栽品种(系)抗叶锈性及抗叶锈基因,为小麦品种推广与合理布局、叶锈病防治及抗病育种提供依据。利用2015年采自山东省的5个小麦叶锈菌流行小种的混合小种对这些材料进行苗期抗性鉴定,然后选用15个小麦叶锈菌生理小种对这些品种(系)进行苗期基因推导,并利用与24个小麦抗叶锈基因紧密连锁(或共分离)的30个分子标记对其进行抗叶锈基因分子检测。结果显示,山东省12个主栽小麦品种(系)苗期对该省2015年的5个小麦叶锈菌混合流行小种均表现高度感病。通过基因推导与分子检测发现,济南17含有Lr16,矮抗58和山农20含有Lr26,其余济麦系列、烟农系列、良星系列等9个品种(系)均未检测到所供试标记片段。此外,本研究还对山东省3个非主栽品种进行了检测,结果发现,中麦175含有抗叶锈基因Lr1和Lr37,含有成株抗性基因;皖麦38只检测到Lr26,济麦20未检测到所供试标记片段。综合以上结果,山东省主栽小麦品种(系)所含抗叶锈基因丰富度较低,尤其不含有对我国小麦叶锈菌流行小种有效的抗锈基因,应该引起高度重视,今后育种工作应注重引入其他抗叶锈基因,提高抗叶锈性。     

The mechanism and inheritance of adult plant leaf rust resistance in 12 wheat lines.

Twelve lines of wheat (Triticum aestivum L.) were developed that had susceptible infection types to leaf rust (Puccinia recondita Rob. ex Desm. f.sp. tritici) race UN 15 in the seedling stage but were resistant in the adult plant stage in the field. The lines were developed from four crosses, each involving four parents (eight in total) that had originally been selected for adult plant or field resistance to stem rust (Puccinia graminis Pers. f.sp. tritici Eriks, and Henn.). The objectives of the present study were to determine the mechanism of resistance to leaf rust and its inheritance in the 12 lines. The 12 lines were grown in an artificially inoculated field nursery in Saskatoon, coefficients of infection (CI) were determined at four dates, and the areas under the disease progress curve (AUDPC) were calculated. Four representative lines were grown in a growth chamber to measure the latent period and pustule size at the two-leaf and flag-leaf stages. Eight lines were crossed and backcrossed to a susceptible check and the parents, F1, F2, F3, and BC1F2 generations were grown in a field nursery. The 12 lines showed wide ranges in CI and AUDPC but all were significantly more resistant than the susceptible check. The four lines studied in the growth chamber had longer latent periods and smaller pustules than the susceptible check at both stages. The differences tended to be greater at the flag-leaf stage. The inheritance studied showed that resistance was recessive or partially recessive and was controlled by two or more genes in each line of the eight lines. In three of the eight lines, Lr34 may be one of the genes and in the other five both Lr13 and Lr34 could be present. However, additional genes are clearly involved. A single gene by itself had only a small effect, but in two and three gene combinations the effects appeared to be greater. This type of resistance appears to occur frequently and may be durable because its complex inheritance may make it more difficult for the rust fungus to overcome. It should be used in breeding wheat for areas where leaf rust is a major problem.     

Histopathology of Leaf Rust Infection and Development in Wheat Genotypes containing Lr12 and Lr13

Evidence exists that certain genes for resistance to leaf rust in wheat, e.g. Lr13 and Lr34 , may interact with other genes to condition higher levels of resistance than that conferred by each gene individually. In this study, the hypothesis that Lr12 and Lr13 , both genes for adult plant resistance to Puccinia recondita Roberge ex. Desmaz f. sp. tritici Eriks. and Henn., interact to confer an improved level of resistance, was investigated using fluorescence and phase-contrast microscopy. Flag leaf segments of monogenic and digenic Thatcher lines, sampled 64 and 240 h post-inoculation, were stained with Uvitex 2B and screened, using fluorescence microscopy, for development of infection structures or host response. To study cell wall appositions, specimens were stained with trypan blue and a solution of picric acid in methyl salicylate. Aborted penetration, consisting of nonpenetrating appressoria and aborted substomatal vesicles, showed that inhibition of fungal growth in wheat lines containing Lr12 and/or Lr13 was activated, to a certain degree, before haustoria were formed. At 240 h after inoculation colony size indicated that fungal colonies in the Lr gene combination lines were generally smaller than in the parents, but not necessarily smaller than those in a line with Lr13 only. Host cell necrosis was more frequently associated with infection sites, specifically of pathotype UVPrt2, in the combination lines than in the parents. The morphology of cell wall appositions varied considerably from a narrow, luminous zone slightly wider in the centre, to a thick central part opposite the haustorium mother cell, sharply decreasing towards both ends. Histological assessments could, however, not conclusively prove pronounced resistance enhancement or unconventional resistance mechanisms due to combining the genes Lr12 and Lr13 .     

Genetic control of effective juvenile resistance to leaf rust in collection accessions of Triticum aestivum L

Of 153 accessions reported to be resistant to leaf rust (Puccinia recondita Rob. ex. Desm.), only 70 were not affected by a pooled P. recondita population. According to phytopathological tests (inoculation with test clones), 14 accessions contained the Lr19 gene; 36, the Lr24 gene; 1, the Lr41 gene; and 19 presumably had the Lr9 gene. The presence of these resistance genes was confirmed by hybrid analysis for 26 accessions. Of 28 accessions reported to carry new effective resistance genes other than the known genes, 23 were affected by the P. recondita population. In four of the other five accessions, resistance proved to be controlled by known genes. Possible causes of false identification of new effective leaf rust resistance genes in wheat are discussed.     

新疆的小麦品种（系）苗期和成株期抗叶锈性鉴定

对来自新疆的104个小麦品种、高代品系及35个含有已知抗叶锈基因载体品种,在苗期接种12个中国小麦叶锈菌生理小种进行抗叶锈基因推导分析和分子检测;2007-2008年和2008-2009年连续2年度对这些材料进行成株抗叶锈性鉴定并筛选慢叶锈性品种。研究结果显示,在41个品种中共鉴定出6个已知抗叶锈基因Lr26、Lr34、Lr50、Lr3ka、Lr1和Lr14a,其中Lr26存在于21个品种中,Lr34在17个品种被发现,Lr1和Lr14a分别存在于3个品种中,还有2个品种携带Lr3ka以及1个品种携带Lr50。2年田间抗叶锈性鉴定筛选出7个慢叶锈性品种,可用于小麦抗病育种。     

8个小麦育种亲本抗叶锈基因分析

选取19个小麦叶锈菌生理小种对8个小麦育种亲本进行成株期和苗期抗叶锈病鉴定及基因推导,同时利用与24个抗叶锈基因紧密连锁或共分离的31个分子标记进行分子检测。推测出L83#-5与L83#-6含有Lr1,可能含有Lr2c和Lr42;L/PL2003-1含有Lr1,可能含有Lr2c、Lr28和Lr42;贵农13号可能含有Lr28;92R137可能含有Lr2c和Lr28;L201含有Lr1,可能含有Lr2c、Lr16和Lr28;TM可能含有Lr41和其他抗叶锈基因。研究结果表明,测试的8个小麦育种亲本中TM的抗叶锈性最好,具有很好的抗叶锈病应用潜力,可作为小麦抗叶锈病育种的重要抗源。     

Resistance gene analogs within an introgressed chromosomal segment derived from Triticum ventricosum that confers resistance to nematode and rust pathogens in wheat

A resistance (R) gene-rich 2S chromosomal segment from Triticum ventricosum contains a cereal cyst nematode (CCN; Heterodera avenae) R gene locus CreX and a closely linked group of genes (Sr38, Yr17, and Lr37) that confer resistance to stem rust (Puccinia graminis f. sp. tritici), stripe rust (P. striiformis f. sp. tritici), and leaf rust (P. recondita f. sp. tritici) when introgressed into wheat. The 2S chromosomal segment from T. ventricosum is further delineated in translocations onto chromosome 2A of bread wheat, where the rust genes are retained but not the CreX gene. Using these critical genetic stocks, we have isolated family members of R gene analogs that are associated with either the 2S segment from T. ventricosum carrying the CreX locus or the rust genes. Derivatives of the Cre3 candidate R gene sequence and a rice (Oryza sativa) R gene analog that mapped to the 2S homologous chromosome groups in wheat were used to isolate related gene sequences from T. ventricosum that contain a nucleotide binding site-leucine rich repeat domain. The potential of these gene sequences as entry points for isolating candidate genes or gene family members of the CreX or rust genes and their further applications to plant breeding are discussed.     

Pathogenic Specialization of Puccinia triticina in Andalusia from 1998 to 2000

Wheat leaf rust (Puccinia triticina) is becoming a serious concern in Spanish wheat, especially on durum wheat where acreage has enormously increased. Host resistance is the preferred method of disease control, but the virulence spectrum of the leaf rust population in Spain is currently unknown. In order to deploy effective Lr genes, this study was conducted to characterize the virulence spectrum of leaf rust in Andalusia (Spain). Isolates were obtained from surveys of wheat fields across Andalusia from 1998 to 2000. From 56 isolates phenotyped, 35 pathotypes were identified. Virulence to Lr10, Lr11, Lr14a, Lr14b and Lr18 was high (>96%), while virulence to Lr9 and Lr24 were not found. None of the isolates collected from durum wheat were virulent to Lr1, Lr3, Lr3ka, Lr3bg, Lr15, Lr16 and Lr17, while many of the isolates collected on bread wheat showed virulence on these genes, indicating a certain specialization in the leaf rust infecting durum wheat. Population dynamics of current wheat leaf rust pathotypes in terms of mutation and migration are discussed.     

小麦遗传背景对黑麦抗叶锈基因Lr26的抗性表达的影响

利用1套从小麦纯系和黑麦自交系培育出的1R附加系、代换系和易位系,研究了1RS上的抗叶锈基因Lr26在小麦中的表达。结果发现,1R二体附加系和纯合1RS/1BL易位系高抗小麦叶锈病;而其小麦亲本、1R(1B)代换系和1BS/1RL易位系重感叶锈病。这一结果指出了黑麦染色体臂1RS上的抗小麦叶锈病基因Lr26在小麦中的表达受小麦染色体臂1BL上的基因的强烈影响,指出了外源基因在小麦中的表达可受染色体臂或基因水平上的相互作用的制约。文中讨论了外源基因与小麦遗传背景相互作用在小麦育种中的意义。     

陇南地区不同海拔区域内小麦条锈菌群体遗传多样性的分析

小麦条锈病是世界范围内小麦上最重要的流行性病害之一,可造成严重的产量损失。陇南地区是我国小麦条锈菌主要越夏易变区和新小种发源地,了解该地区不同海拔高度区域内条锈菌遗传多样性有重要意义。本研究采用TP-M13-SSR荧光标记技术对11个种群330个小麦条锈菌分离株基因组DNA进行了SSR标记分析。不同海拔区域的条锈菌遗传多样性有明显的差异,高山区的遗传多样性比较丰富,半山区次之,川道区相对比较低。不同生态区域内,小麦条锈菌群体遗传分化程度不同,高山区和半山区遗传分化程度大,基因流小,川道区群体遗传分化程度比较小,基因流大。来自不同海拔区域的菌系具有相同的基因型,这一结果从分子水平证明了在陇南地区小麦条锈菌在山区与川地之间存在广泛的菌源交流,可就地完成周年循环。     

15个小麦农家品种抗叶锈基因分析

本研究旨在明确小麦农家品种中可能含有的抗叶锈病基因,为抗源的选择和利用提供理论依据。以15个小麦农家品种、感病对照品种郑州5389和36个含有已知抗叶锈病基因的载体品种为材料,苗期接种19个具有鉴别力的叶锈菌生理小种进行基因推导,同时利用12个与抗叶锈病基因紧密连锁的分子标记进行分析。为明确其成株期抗性,分别于2016-2017年和2017-2018年在河北保定对小麦农家品种、感病对照品种郑州5389与慢锈品种SAAR进行田间接种,调查并记录田间严重度及普遍率。基因推导和分子标记检测结果显示,在15个小麦农家品种中共检测到7个抗叶锈病基因,其中部分品种还有多个抗性基因,如红狗豆含有Lr1和Lr46;黄花麦含有Lr13和Lr34;大白麦含有Lr14b和Lr26;洋麦含有Lr37和Lr46;成都光头含有Lr34和Lr46;墨脱麦和西山扁穗含有Lr26和Lr46。部分品种含有1个成株期慢叶锈病抗性基因,如同家坝小麦、武都白茧儿、边巴春麦-6、白花麦含有Lr34;红抢麦、白扁穗和白火麦含有Lr46。这些携带有效抗叶锈病基因的农家品种,可为小麦抗叶锈病育种提供抗源。     

小麦品系5R618抗叶锈基因的初步定位

5R618是高抗叶锈病小麦品系。为了确定该品系所携带的抗叶锈基因,以5R618与感病小麦品种郑州5389杂交获得F1,自交获得F2分离群体以及F2∶3家系,用叶锈菌生理小种THJP对亲本、F2分离群体以及F2∶3家系进行叶锈抗性鉴定,然后进行分子标记分析。结果显示,5R618对生理小种THJP的抗病性由1对显性基因控制,该基因暂命名为Lr5R。经过亲本和抗感池间分子标记筛选以及F2∶3家系的标记检测,Lr5R定位于染色体3DL上,barc71和STS24-16是Lr5R最近的2个标记,遗传距离分别为0.9 c M和2.1 c M。     

Resistance to wheat leaf rust and stem rust in Triticum tauschii and inheritance in hexaploid wheat of resistance transferred from T. tauschii.

Twelve accessions of Triticum tauschii (Coss.) Schmal. were genetically analyzed for resistance to leaf rust (Puccinia recondita Rob. ex Desm.) and stem rust (Puccinia graminis Pers. f.sp. tritici Eriks. and E. Henn.) of common wheat (Triticum aestivum L.). Four genes conferring seedling resistance to leaf rust, one gene conferring seedling resistance to stem rust, and one gene conferring adult-plant resistance to stem rust were identified. These genes were genetically distinct from genes previously transferred to common wheat from T. tauschii and conferred resistance to a broad spectrum of pathogen races. Two of the four seedling leaf rust resistance genes were not expressed in synthetic hexaploids, produced by combining tetraploid wheat with the resistant T. tauschii accessions, probably owing to the action of one or more intergenomic suppressor loci on the A or B genome. The other two seedling leaf rust resistance genes were expressed at the hexaploid level as effectively as in the source diploids. One gene was mapped to the short arm of chromosome 2D more than 50 cM from the centromere and the other was mapped to chromosome 5D. Suppression of seedling resistance to leaf rust in synthetic hexaploids derived from three accessions of T. tauschii allowed the detection of three different genes conferring adult-plant resistance to a broad spectrum of leaf rust races. The gene for seedling resistance to stem rust was mapped to chromosome ID. The degree of expression of this gene at the hexaploid level was dependent on the genetic background in which it occurred and on environmental conditions. The expression of the adult-plant gene for resistance to stem rust was slightly diminished in hexaploids. The production of synthetic hexaploids was determined to be the most efficient and flexible method for transferring genes from T. tauschii to T. aestivum, but crossing success was determined by the genotypes of both parents. Although more laborious, the direct introgression method of crossing hexaploid wheat with T. tauschii has the advantages of enabling selection for maximum expression of resistance in the background hexaploid genotype and gene transfer into an agronomically superior cultivar.