Cloning of a Resistance Gene Analog from Wheat and Development of a Codominant PCR Marker for Pm21

To Investigate the mechanism of resistance to wheat （Triticum aestivum L.） powdery mildew, suppression subtractlve hybridization was conducted between an isogenic resistant line carrying Pm21 and its recurrent parent Yangmal 5 to Isolate the resistance relative genes. A cDNA fragment specifically expressed in the resistant line was obtained and its full length was cloned by in silico cloning and RT-PCR. This gene encoded a deduced protein of 219 amino acids with a leucine-rich repeat （LRR） motif, often found In plant resistance genes, and was designated as Ta-LRR2. Ta-LRR2 had an increased expression level in the resistant line after Inoculation with Erysiphe graminis DC. f. sp. tritici Marchal. PCR analysis with different cytogenetlc stocks suggested that Ta-LRR2 was specifically associated with chromosome arms 6VS and 6AS. Linkage analysis further showed that Ta-LRR2 could be used as a resistance gene analog polymorphism marker of Pm21 for marker-assisted selection in germplasm enhancement and breeding practice. Moreover, how to Isolate Pm21 based on the Information obtained for Ta-LRR2 is discussed.     

等离子体浸没N＋ 注入对豌豆胚芽细胞的诱变效应

报道了等离子体浸没N＋注入豌豆种子后,引起M1胚芽细胞畸变效应。初步研究结果表明：此种方法能抑制纺锤体形成,诱发胚芽细胞核畸变和染色体畸变。提出等离子体浸没离子注入可以作为一种经济、有效的诱变育种方法。 Abstract: Preliminary results indicated that the pea seeds after implantation with plasma immersion ion was not only restrained spindle form but also induced plumule cell nuclear and chromosomal aberration.Being an economical and available method plasma immersion ion implantation in mutagenic breeding is proposed.     

影响动物肉质性状主要候选基因的研究进展

随着分子生物学在动物遗传育种中的应用,对数量性状主效基因的研究成为必然。本文对影响肉质的脂肪酸结合蛋白基因、肥胖基因、leptin 基因、黑素皮质受体基因、脂蛋白脂酶基因、激素敏感脂酶基因的国内外研究状况加以综述。 Progress in Candidate Genes Influencing Meat Quality Traits in Chickens QIU Xue-mei1,3,LI Ning1,DEND Xue-mei2,WU Chang-xin2 1.The National Laboratories for Agrobiotechnology,China Agricultural University,Beijing 100094,China; 2.College of Animal Science and Technology,China Agricultural University,Beijing 100094,China; 3.College of Animal Science and Technology,Heilongjiang August First Land Reclamation University,Mishan 158308,China Abstract:As the molecular biology has been applied in animal genetics and breeding,it is important that we research major genes on quantitative traits for animal breeding by transgenic technology.In this paper,the research advance of FABP genes,obese gene,leptin gene,MCRs genes,LPL gene,HSL gene affecting meat quality in animals are reviewed. Key words：animal; meat quality; candidate gene     

Bachelor groups in primate multilevel society facilitate gene flow across fragmented habitats

In the face of ongoing habitat fragmentation,many primate species have experienced reduced gene flow resulting in a reduction of genetic diversity,population bottlenecks,and inbreeding depression,including golden snub-nosed monkeys Rhinopithecus roxellana.Golden snub-nosed monkeys live in a multilevel society composed of several 1 male harem units that aggregate to form a cohesive breeding band,which is followed by one or more bachelor groups composed of juvenile,subadult,and adult male members.In this research,we examine the continuous landscape resistance surface,the genetic diversity and patterns of gene flow among 4 isolated breeding bands and 1 all-male band in the Qinling Mountains,China.Landscape surface modeling suggested that human activities and ecological factors severely limit the movement of individuals among breeding bands.Although these conditions are expected to result in reduced gene flow,reduced genetic diversity,and an increased opportunity for a genetic bottleneck,based on population genetic analyses of 13 microsatellite loci from 188 individuals inhabiting 4 isolated breeding bands and 1 all-male band,we found high levels of genetic diversity but low levels of genetic divergence,as well as high rates of gene flow between males residing in the all-male band and each of the 4 breeding bands.Our results indicate that the movement of bachelor males across the landscape,along with their association with several different breeding bands,appears to provide a mechanism for promoting gene flows and maintaining genetic diversity that may counteract the otherwise isolating effects of habitat fragmentation.     

Comparative studies on histological and ultra-structure of the pituitary of different ploidy level fishes

The histological and ultra-structure of the pituitary in diploid red crucian carp(Carassius auratus red var.),triploid crucian carp and allotetraploid hybrids within and after the breeding season were comparatively studied.The result showed that there were six endocrine cell types in the pituitary of these three kinds of fishes,and there was an obvious difference in cell size among different ploidy level fishes.As for the same type of pituitary cells,the cell size was increased gradually with the in- creasing ploidy level.In the breeding season,the allotetraploid hybrids had higher proportion of go- nadotropin cells(GTH)than triploids,and the triploids had higher proportion of GTH than diploids.The results were related to the earlier sexual maturity of allotetraploid hybrids and sterility of triploid cru- cian carp.On the other hand,among the three kinds of fishes,the proportion of somatotropin(STH) cells in triploids crucian carp was the highest,whereas that in allotetraploid hybrids was the lowest. The results might be connected with the faster growth rate of triploids and slower growth rate of al- lotetraploid hybrids.In addition,in GTH cells of meso-adenohypophysis after the breeding season, there were many endocrine particles in triploids,while those endocrine particles were released from the cells in allotetraploids and diploids.This result showed that the sterility of triploid crucian carp might be related to the hormone which was not released from the GTH cells.In a word,the present study indicated that the differences in the structure of pituitary among different ploidy level fishes contributed to their difference in the growth rate and gonadal development.     

表达尾穗苋凝集素基因的转基因烟草对桃蚜(Myzus persicae)繁殖的影响(英文)

To investigate the possible function of the agglutinin from Amaranthus caudatus L. (ACA) in plant defending against insect pests, ACA cDNA was cloned by RT-PCR and the 5‘ and 3‘ sequences were confirmed by rapid amplification of cDNA ends (RACE). The phloem-specific expression vector of ACA gene, pBCACAc, was constructed based on the plant binary vector pBC438 and transfered into tobacco plants via Agrobacterium-mediated transformation method. Results from PCR and Southern blotting analysis showed that AOA gene was integrated into the genomes of transformed plants and the transgene integration varied from one to four estimated copies per genome. Western blotting analysis indicated that ACA gene was transcribed and translated in the transgenic plants. The bioassay of Myzus persicae Sulzer on detached leaves demonstrated that the 78% transgenic tobacco plants displayed an average aphid-resistant rate of more than 75%. Some apterous progeny of M. persicae were found dead on the resistant plants. These results indicate that ACA gene should be an effective aphid-resistant gene and could be valuable for application in crop breeding for aphid resistance.     

ATP-binding cassette transporter enhances tolerance to DDT in Tetrahymena

The reuse of dichlorodiphenyltrichloroethane(DDT) as an indoor residual spray was permitted by the World Health Organization in 2007, and approximately 14 countries still use DDT to control disease vectors. The extensive exposure of insects to DDT has resulted in the emergence of DDT resistance, especially in mosquitoes, and the mechanism for this resistance in mosquitoes has been widely reported. Spraying can also introduce DDT directly into surface water, and DDT can subsequently accumulate in microorganisms, but the mechanism for the resistance to DDT degradation in microorganisms is unclear. Using whole-genome microarray analysis, we detected an abcb15 gene that was up-regulated in a specific manner by DDT treatment in T. thermophile. The deduced ABCB15 peptide sequence had two transmembrane domains(TMDs) and two nucleotide-binding domains(NBDs) to form the structure TMD-NBD-TMD-NBD, and each NBD contained three conserved motifs: Walker-A, C-loop, and Walker-B, which indicated the T. thermophila abcb15 was a typical ABC transporter gene. The expression of ABCB15 fused with a C-terminal green fluorescent protein was found to be on the periphery of the cell, suggesting that ABCB15 was a membrane pump protein. In addition, cells with abcb15 partially knocked down(abcb15-KD) grew slower than wild-type cells in the presence of 256 mg L-1 DDT, indicating the tolerance of abcb15-KD strain to DDT exposure was decreased. Thus, we suggest that in Tetrahymena, the membrane pump protein encoded by ABCT gene abcb15 can enhance the tolerance to DDT and protect cells from this exogenous toxin by efficiently pumping it to the extracellular space.     

水稻空间技术育种的研究

为探讨空间条件对水稻育种的影响,利用返回式卫星搭载水稻干种子,返地种植,考察分析了12个亲本品种后代的性状表现及遗传与变异情况。结果表明：空间条件诱变的后代性状具有多样性变异和多向性遗传,且能稳定遗传,并有超亲遗传现象,诱变后代具有变异类型多、变异频率高、特殊突变体、育种周期短等特点。为进一步开发利用空间技术育种,在研究实践的基础上,提出了程序化、规范化、可操作性强的水稻空间育种技术规范。 Abstract:In order to inquire into the influences of space conditions on rice breeding,the dry seeds of 12 rice varieties were carried by recoverable satellite.After recovery,these seeds were sowed in the yield,the inheritance and variation of the characters of their progenies were observed and analysed.The results showed that the characters of the progenies mutated under space conditions segregated and varied in many adpects and directions,and the segregated and varied characters were heritable.These progenies posoessed significant transgressive inheritance,a plenty of variation types.and variation.was characterized by short breeding period.The resulfs in this study indicated that space technology breeding could be developed and used as a new method of mutation breeding.     

Characterization of Wheat Random Amplified Polymorphic DNA Markers Associated with the H11 Hessian Fly Resistance Gene

In Tunisia, the Hessian fly Mayetiola destructor Say is a major pest of durum wheat （Triticum durum Desf.） and bread wheat （T. aestivum L.）. Genetic resistance is the most efficient and economical method of control of this pest. To date, 31 resistance genes, designated H1-H31, have been identified in wheat. These genes condition resistance to the insect genes responsible for virulence. Using wheat cultivars differing for the presence of an individual Hessian fly resistance gene and random amplified polymorphic DNA （RAPD） analysis, we have identified a polymorphic 386-bp DNA marker （Xgmib1-1A.1） associated with the H11 Hessian fly resistance gene. Blast analysis showed a high identity with a short region in the wild wheat （T. monococcum） genome, adjacent to the leaf rust resistance Lr10 gene. A genetic linkage was reported between this gene （Lr10） and Hessian fly response in wheat. These data were used for screening Hessian fly resistance in Tunisian wheat germplasm. Xgmib1-1A.1-like fragments were detected in four Tunisian durum and bread wheat varieties. Using these varieties in Hessian fly breeding programs in Tunisia would be of benefit in reducing the damage caused by this fly.     

Seasonal radiation interception, dry matter production and yield determination for a semi-leafless pea (Pisum sativum) breeding selection under contrasting field conditions

Radiation interception, dry matter accumulation, flower and pod production and yield were measured for a semi-leafless pea (Pisum sativum) breeding selection (BS3) on three contrasting sites. Differences in soil moisture availability were largely responsible for a three-fold difference in yield between sites. Radiation interception was related to dry matter production by calculating photosynthetic efficiencies. In the absence of lodging, crop canopies converted intercepted radiation into dry matter with constant efficiency (?) throughout the season; under conditions of moisture stress ? was reduced. Serious lodging during the post-flowering period on one site resulted in a mean seasonal photosynthetic efficiency (?) 17% lower than ?. The ability of the pea crop canopy to intercept radiation was related also to yield components.     

Quantitative trait loci for lodging resistance,plant height and partial resistance to mycosphaerella blight in field pea (Pisum sativum L.)

With the development of genetic maps and the identification of the most-likely positions of quantitative trait loci (QTLs) on these maps, molecular markers for lodging resistance can be identified. Consequently, marker-assisted selection (MAS) has the potential to improve the efficiency of selection for lodging resistance in a breeding program. This study was conducted to identify genetic loci associated with lodging resistance, plant height and reaction to mycosphaerella blight in pea. A population consisting of 88 recombinant inbred lines (RILs) was developed from a cross between Carneval and MP1401. The RILs were evaluated in 11 environments across the provinces of Manitoba, Saskatchewan and Alberta, Canada in 1998, 1999 and 2000. One hundred and ninety two amplified fragment length polymorphism (AFLP) markers, 13 random amplified polymorphic DNA (RAPD) markers and one sequence tagged site (STS) marker were assigned to ten linkage groups (LGs) that covered 1,274 centi Morgans (cM) of the pea genome. Six of these LGs were aligned with the previous pea map. Two QTLs were identified for lodging resistance that collectively explained 58% of the total phenotypic variation in the mean environment. Three QTLs were identified each for plant height and resistance to mycosphaerella blight, which accounted for 65% and 36% of the total phenotypic variation, respectively, in the mean environment. These QTLs were relatively consistent across environments. The AFLP marker that was associated with the major locus for lodging resistance was converted into the sequence-characterized amplified-region (SCAR) marker. The presence or absence of the SCAR marker corresponded well with the lodging reaction of 50 commercial pea varieties.Communicated by H. F. Linskens     

Growth and Photosynthesis of Mutant Pea Seedlings

The recessive of gene, producing tendrils in place of leaves,and the recessive st gene, reducing stipule size, produce phenotypesof pea that are termed leafless (afafstst) and semi-leafless(afafStSt). Photosynthesis and growth of these two types werecompared with the conventional phenotype (AfAfStSt) during thefirst 9 days of post-emergent growth. The conventional seedlingshowed faster net photosynthesis per unit dry weight than theleafless phenotype, whilst the semi-leafless seedlings wereintermediate. Differences in dark respiration were small butleafless seedlings had significantly higher rates soon afteremergence. Where the three phenotypes used were isogenic, except for ofand st, the rates of shoot growth were in the same ranking orderas net CO₂ uptake. With three other genotypes, representingthe three phenotypes, more similar shoot growth was found betweenthe conventional and semi-leafless phenotype, possibly becauseof compensating differences in embryonic axis size. The ratesof growth of roots and the rates of dry weight loss from thecotyledons showed no consistent differences between phenotypes. The results are discussed in relation to the potential for thesemi-leafless phenotype as an alternative to the conventionalphenotype for the dried pea crop. Pea seedling, Pisum sativum, leafless pea, photosynthesis, seedling growth     

一个新的水稻小粒矮秆基因的分子标记定位及效应分析

从水稻(Oryza safjva L．)半矮秆品种蜀恢I62中发现一份小粒矮秆突变体“I62d”。对I62d与4个半矮秆品种杂交F1和F2代的遗传分析表明,I62d的矮生性由一对隐性基因控制。以II-32B／162d F2代作定位群体,用分子标记将I62d突变基凶定位丁水稻第3染色体短臂,该基因与微卫星标记RM218和RMI57之间的遗传距离分别为3．5cM和10．0cM。同时,利用近等基因系分析了该基因的表型效应,结果表明它可使株高降为正常高度的1／4左右,籽粒降为正常大小的1／4左右,并使叶片显著缩短、加宽,结实率显著降低。我们认为162d突变基因是一个新的水稻小粒矮秆某因,暂命名为dI62(t）。     

The root activity of cereals and peas when grown in pure stands and mixtures

Lithium was used as a non-radioactive tracer to investigate the root activity of two cereals (wheat and barley), and of two contrasting cultivars of pea (leafy and semi-leafless), both in pure stands and in mixtures. The mixtures included combinations of each cereal with each pea cultivar in single rows, alternative rows and cross-drilled. Total lithium uptake (mg m^-2) was higher for wheat than for barley, and higher for semi-leafless pea than for leafy peas. Growing cereals with peas reduced the total lithium uptake by peas, compared with pure stands, especially in alternate-row mixtures. Growing peas with cereals only reduced the total Li uptake by cereals when they were cross-drilled. The Li uptake by wheat, barley and peas generally decreased with soil depth in a similar manner; however, semi-leafless peas absorbed proportionately more Li from close to the soil surface than did leafy peas. Both pea cultivars absorbed more Li at 10–20 cm depth when grown in intimate mixtures with cereals, compared with less intimate mixtures or pure stands. The potential of lithium as a non-radioactive tracer in mixed-cropping studies is briefly discussed.     

半无叶型菜豌豆革质膜、甜度性状遗传研究及利用

对半无叶型菜豌豆革质膜、甜度性状的遗传规律进行了研究,结果表明：半无叶型菜豌豆革质膜受两对相对基因控制,F1表现大块革质膜,F2分离出大块革质膜、小块革质膜和无革质膜三种类型,分离比例为9：6：1,并经F2~3试验验证,属于基因互作的积加作用。糖度为数量性状遗传,F2单株间呈连续变异,符合正态分布。选育出的半无叶型菜豌豆新品种“须菜1号”高产、优质,其嫩荚鲜食,嫩卷须作为龙须菜,嫩茎叶也是一种优质蔬菜。     

Marker assisted pea breeding: <Emphasis Type="Italic">eIF4E</Emphasis> allele specific markers to <Emphasis Type="Italic">pea seed-borne mosaic virus</Emphasis> (PSbMV) resistance

Traditional plant breeding relies upon crosses and subsequent selection of genotypes to meet desirable traits. The incorporation of marker-assisted selection into breeding strategies would result in a reduction in the number of offspring to be propagated, selected and tested. In the case of pea (Pisum sativum L.), the testing of resistance to viral pathogens such as pea seed-borne mosaic virus (PSbMV) is included in the breeding process. Resistance to the common strains of PSbMV is conferred by a single recessive gene (eIF4E), localized on LG VI (sbm-1 locus). We have analyzed for variation in the eIF4E genomic sequences from 43 pea varieties and breeding lines, reported as donors of resistance. This enabled a comprehensive investigation of the eIF4E gene structure and mutations responsible for PSbMV resistance were identified. Subsequently, PCR-based and gene-specific single nucleotide polymorphism and co-dominant amplicon length polymorphism markers were developed. All together 60 accessions were analyzed using sequence data and/or allele specific DNA markers. Developed allele specific markers were reproducibly amplified across a broad spectra of pea varieties and breeding lines. These were found to be 100% accurate in detecting the presence of the respective alleles when compared to symptomology and ELISA, testing (74% reliable). Hence, these molecular markers will substantially speed-up PSbMV diagnosis and resistance breeding processes in pea.     

Utilization of Stiff Culm Trait of Rice smos1 Mutant for Increased Lodging Resistance

Although the introduction of semi-dwarf trait into rice has led to improved lodging resistance making it capable of supporting high grain yield, lodging still remains a concern when attempting to further increase the grain yield of rice. However, improving the lodging resistance in rice by depending on the semi-dwarf trait alone is possible only up to a certain limit, beyond which other traits may be needed for reinforcement. To search for alternative traits relating to high lodging resistance, we identified 9 rice mutant lines possessing improved culm strength. To evaluate whether such lines can be useful for breeding lodging resistant rice, small organ size1 (smos1) mutant having increased lodging resistance but low tiller number and low grain yield, was chosen as a representative for a breeding trial. smos1 was crossed with ST-4 (from the Stock rice collection of Nagoya University Togo field #4), a cultivar with high tiller number and high grain yield, and from their progeny, LRC1 (lodging resistance candidate-1) was selected. Although the low tiller number trait of smos1 was not fully reversed in LRC1, this was compensated by an increase in grain weight per panicle, thereby resulting in high grain yield per plant. This important attribute of LRC1 was further enhanced by the improved lodging resistance trait inherited from smos1. Such improved lodging resistance in LRC1 and smos1 was revealed to be mainly due to increased culm diameter and culm thickness, which led to a high section modulus (SM) value, a parameter defining the physical strength of the culm. Since smos1 possesses high breaking-type lodging resistance which is different from semi-dwarf plants with high bending-type lodging resistance, an alternative approach of using thick culm lines for the creation of rice with increased lodging resistance is hereby proposed.     

Solar radiation interception by leafless, semi-leafless and leafed peas (Pisum sativum) under contrasting field conditions

Foliage composition, photosynthetic area index (PAI) and radiation interception were measured for crop canopies of leafless (var. Filby), semi-leafless (var. BS3) and leafed (var. Birte) peas (Pisum sativum). Tendrils and petioles contributed more than 60% of total leaf area for leafless peas but less than 30% for semileafless and leafed pea canopies. PAI was related to radiation interception by calculating attenuation coefficients which indicated that leafless peas intercepted more radiation per unit PAI than either semi-leafless or leafed peas. Data interpretation, however, was complicated because of difficulties in estimating the tendril and petiole surface area contribution to PAI. Radiation interception was related to dry matter accumulation by calculating photosynthetic efficiencies. Leafless and semi-leafless peas converted intercepted radiation into dry matter as efficiently as leafed peas. Under conditions of moisture stress, leafed and leafless peas both intercepted radiation more effectively but converted it into dry matter with reduced photosynthetic efficiency.     

Microsatellite markers for powdery mildew resistance in pea (Pisum sativum L.)

Powdery mildew is a common disease of field pea, Pisum sativum L., and is caused by the ascomycete fungus Erysiphe pisi. It can cause severe damage in areas where pea is cultivated. Today breeders want to develop new pea lines that are resistant to the disease. To make the breeding process more efficient, it is desirable to find genetic markers for use in a marker-assisted selection (MAS) strategy. In this study, microsatellites (SSR) were used to find markers linked to powdery mildew resistance. The resistant pea cultivar '955180' and the susceptible pea cultivar 'Majoret' were crossed and F2 plants were screened with SSR markers, using bulked segregant analysis. A total of 315 SSR markers were screened out of which five showed linkage to the powdery mildew resistance gene. No single marker was considered optimal for inclusion in a MAS program. Instead, two of the markers can be used in combination, which would result in only 1.6% incorrectly identified plants. Thus SSR markers can be successfully used in marker-assisted selection for powdery mildew resistance breeding in pea.