Inheritance of resistance to potato virus Y in garden pepper (Capsicum annuum L.)

Summary Bell pepper suffers considerable losses from a strain of potato virus Y (PVY^o-sbp). Crosses were attempted between two resistant lines Perennial and S41-1 and two highly susceptible bell pepper commercial cultivars California Wonder and Yolo Wonder. Studies of F₁'s, F₂'s, back crosses and F₃'s indicated that Perennial and S41-1 carry a recessive gene imparting resistance to potato virus Y.     

Difference between USA and French isolates of tobacco etch virus and pepper mottle virus displayed by doubled haploid line analysis

Summary Doubled haploid peppers resistant in France to specific strains of tobacco etch virus (TEV) and pepper mottle virus (PeMV) were indexed for resistance to USA strains of TEV and PeMV. The doubled haploids were inoculated when four to six true leaves had developed. The peppers were indexed after an incubation period, and a disease index was calculated. Plants without viral symptoms were reinoculated. Plants challenged to TEV were inoculated four times. Doubled haploids, TEV-resistant in France, were susceptible to the USA strain by the fourth screening. All doubled haploid lines showed TEV symptoms after the fourth inoculation. Two doubled haploids lines, no. 4 and no. 8, had about 6% resistance to TEV after the fourth inoculation. Doubled haploid line no. 5 was 100% resistant to PeMV. The results confirm that the USA PeMV and the USA TEV isolates are different pathotypes than the French ones used originally to screen the doubled haploids. In addition, the use of doubled haploids to identify pathotypes of PeMV and TEV is demonstrated.     

Inheritance and stability of the virus-resistant gene in the progeny of transgenic sweet potato

Viral diseases of sweet potato are very prevalent and often seriously damaging to the plants. In particular, the severe strain of the sweet potato feathery mottle virus (SPFMV‐S) causes ‘obizyo‐sohi’ disease in Japan. In order to confer viral resistance against SPFMV using current biotechnology, a transgenic sweet potato has been produced, introducing hygromycin‐resistant (hpt) and SPFMV‐S coat protein (CP) genes, which have shown a significant resistance to SPFMV‐S. In the breeding programme, it is important to confirm that the viral resistance conferred in T₀ plants can be inherited by their progeny. In the present study, progeny were obtained from crosses between the transgenic T₀ and a non‐transgenic variety of sweet potato. The results showed that the CP gene was inherited by the next generation and that the stability of viral resistance was also confirmed. Thus, this production system for the virus‐resistant transgenic sweet potato is useful in practical breeding.     

烟草种质资源抗马铃薯Y病毒病鉴定方法比较

便于年度间和研究者之间比较的抗病性鉴定方法,是筛选抗性稳定的抗病资源的基础。本文通过温室内人工接种,优化比较了烟草种质资源抗马铃薯Y病毒病的抗性鉴定方法。病情指数、相对病情指数、相对抗性指数、病情发展曲线下面积四种评价方法的比较结果表明,相对病情指数可直观反映品种的抗性,便于年度间和研究者之间的结果比较。高压喷枪摩擦接种和蚜虫饲毒接种的鉴定结果基本一致。通过温室人工摩擦接种,筛选出高抗资源NC55和NC102、抗病资源VSCR和TI245,CV91和Oxford 207表现为中抗、台烟6号表现为中感、NC297和云烟97表现为感病、Coker176表现为高感。抗病亲本NC55、VSCR与感病优良亲本F1组合均表现感病或高感,表明NC55和Virginia SCR抗源的抗性为隐性遗传。     

Allelism of genes controlling resistance to TMV in Capsicum L.

Summary The genes for resistance to pepper strains of TMV in five C. chinense Jacq. accessions, the PI numbers 152225, 159236, 315008, 315023 and 315024, were investigated for allelism. The resistance of these five C. chinense accessions was found to be inherited monogenically and to be partially dominant. The resistance genes in these accessions appeared to be allelic and were also found to be allelic with the known alleles L¹ and L. It is proposed to use the symbol L³ for these resistance genes.     

Relationship between tolerance and resistance to pepper mottle virus in a cross between Capsicum annuum L. × Capsicum chinense Jacq.

Summary Progenies of a cross between pepper cultivar Delray Bell (Capsicum annuum L.) tolerant to pepper mottle virus (PeMoV) and P.I. 159236 (Capsicum chinense Jacq.), resistant to PeMoV were evaluated in greenhouse experiments. The F₁ generation was susceptible to PeMoV, whereas the backeross generations to both parents and the F₂ segregated in a ratio of 1:1. This indicates that PeMoV resistance is controlled at the same locus in both parents or at two closely linked loci. Each parent is homozygous for one locus and the homozygous condition of either allele results in failure to support virus; in heterozygous condition as observed in the F₁ generation, the effect of a single allele is insufficient even when one allele of each type is present, resulting in systemic infection.The abstract of this paper was presented at the IVth Eucarpia Capsicum meetings held in October at Wageningen, Netherlands.Florida Agricultural Experiment Stations Journal Series Paper No. 3175.     

辣椒轻斑驳病毒(PMMoV)新疆加工型辣椒分离物的鉴定和致病型分析

为明确侵染新疆南疆巴州加工型辣椒主产区的辣椒轻斑驳病毒(PMMoV)的致病型,利用双抗体夹心酶联免疫吸附法(DAS-ELISA)、反转录聚合酶链式反应(RT-PCR)和基因克隆、序列分析对南疆巴州加工型辣椒主产区的辣椒病样进行PMMoV的检测及其致病型鉴定。结果表明,从辣椒植株、椒果及种子样品中均检测到PMMoV。通过对预期576 bp大小的3个PMMoV扩增产物进行克隆、测序和序列分析表明,PMMoV新疆加工型辣椒分离物CP基因的核苷酸和氨基酸序列与已报道的PMMoV分离物具有较高同源性,分别为89.0%~99.2%和95.5%~100.0%;其中,与PMMoV以色列分离物EF434393同源性最高,PMMoV新疆各分离物之间CP基因高度同源。依据CP基因序列及系统发育分析将PMMoV新疆加工型辣椒分离物划分为P_1,2致病型。     

Resistance to potato virus Y (pathotype 1–2) in Capsicum annuum and Capsicum chinense is controlled by two independent major genes

Summary The genetic basis of the resistance to a pepper strain of potato virus Y (PVY pathotype 1–2) was investigated in two lines: Capsicum annuum Criollo de Morellos 334 and Capsicum chinense PI 159236. F1, backcrosses, and F2 populations were produced using C. annuum Magda as the susceptible parent. Segregation ratios indicated that the resistance in C. annuum Criollo de Morellos 334 is governed by a nuclear, single dominant gene with a very high but incomplete penetrance. On the other hand, the resistant response of C. chinense PI 159236 is associated with the presence of a major recessive gene with an apparently complete penetrance. The failure in recovering or detecting PVY from/in the inoculated leaves of both resistant genotypes is strongly suggestive that both genes are acting by preventing the multiplication of the virus in the leaf tissue. Both mechanisms of resistance closely resemble either an operational immunity or a single-cell hypersensitive reaction to PVY pathotype 1–2. The name Ry 1–2 is suggested for the resistance gene from Criollo de Morellos 334. The gene for resistance to PVY pathotype 1–2 identified in C. chinense PI 159236 may be the same designated et ^c1, which is mentioned to be allelic to the et ^av locus. The phenotypic expression of the et ^av gene was characterized in C. annuum Avelar as a tolerant but not immune or hypersensitive reaction against some potyviruses in Florida. These data suggest that a critical reexamination of the allelic relationships at the locus et should be performed.     

Somaclonal variation of regenerated plants in chili pepper (Capsicum annuum L.)

The morphological and genetic variations in somaclones of chili pepper (Capsicumannuum L.) derived from tissue culture were evaluated. Cotyledonary node explants of cultivars, Shishitou and Takanotsume, were cultured on Murashige and Skoog (MS) medium supplemented with benzyladenine (BA)5 mg/l for shoots regeneration and regenerated shoots were rooted on MS medium supplemented with naphthalene acetic acid(NAA) 0.1 mg/l and indol-3-butyric acid(IBA) 0.05 mg/l. The regenerated plants(R₀) were selfed to obtain seeds for next generation (R₁ lines). Qualitative characters were studied in R₀generation and both qualitative and quantitative characters were studied in R₁ generation. In R₀ generation, variations were noticed in plant growth habit, stem color, flower color and color of unripe fruits, and expression of anthocyanin in unripe fruits. Comparison among the R₁ lines and their parents were made for morphological and agronomic characters. Significant variation among R₁ lines and differences between R₁ lines and their parents were observed. Genetic variations among three somaclones were revealed by random amplified polymorphic DNA (RAPD) analysis. Variation, such as early flowering and increase of yield components, is an indication of the response to selection for any specific character. Occurrence of productive variants among somaclones of established cultivars, like Shishitou and Takanotsume, indicates the possibility of their improvement through somaclonal variation. This revised version was published online in July 2006 with corrections to the Cover Date.     

Quantity production of anther-derived haploids from a multiple disease resistant tobacco hybrid. I. Frequency of plants with resistance or susceptibility to tobacco mosaic virus (TMV), potato virus Y (PVY), and root knot (RK)

Summary Methods are described for producing large numbers of haploid plantlets from anthers of a flue-cured tobacco hybrid with monogenic resistance to tobacco mosaic virus, (TMV), potato virus Y (PVY) and root knot (RK), respectively. Additional details are given on colchicine treatment for converting haploids to doubled haploids (DH's) and on the frequency of spontaneous DH's among untreated plantlets. Disparate genetic ratios of TMV-resistant to TMV-susceptible plants were obtained among colchicine-treated haploid plantlets, induced DH's and untreated haploids when compared with F₂ and BC₁ progenies. Haploids (gametes) with the gene for TMV resistance occurred more frequently than expected and plantlets with the gene for RK resistance occurred less frequenctly than expected. Transmission of the gene for PVY resistance differed only slightly from Mendelian expectations. These unexpected ratios, in addition to the frequent occurrence of plastid chimeras among anther-derived plantlets, strengthened our conviction that haploidy is somehow associated with mutation.Joint contribution from the Departments of Genetics, Crop Science and Plant Pathology, North Carolina State University, and the Tobacco Research Laboratory, Agricultural Research, Science and Education Administration, U.S. Department of Agriculture, Oxford, North Carolina. Paper No. 5576 of the Journal Series of the North Carolina Agricultural Experiment Station, Raleigh, North Carolina.     

4种病毒抑制剂对昭通烟草番茄斑萎病毒病和马铃薯Y病毒病的防治效果

番茄斑萎病毒病(Tomato spotted wilt virus, TSWV)和马铃薯Y病毒(Potato virus Y,PVY)是云南烟草生产上的主要病毒病,本研究旨在筛选有效的药剂防控烟草番茄斑萎病毒病和马铃薯Y病毒病,从而减少烟草经济损失。通过小区试验,分别研究了1%香菇多糖水剂、3%超敏蛋白微粒剂、5%氨基寡糖素水剂和2%嘧肽霉素水剂对田间烟草番茄斑萎病毒病和马铃薯Y病毒病的防治效果。结果表明：试验所选的4种病毒抑制剂对烟草番茄斑萎病毒病和马铃薯Y病毒病均具有一定的防控作用,1%香菇多糖、3%超敏蛋白、5%氨基寡糖素和2%嘧肽霉素对烟草TSWV的防治效果分别为：31.11%~39.90%、54.34%~59.91%、8.69%~38.21%和22.75%~43.32%,4种药剂对烟草PVY的防治效果分别为55.08%~71.06%、68.10%~82.24%、37.76%~55.36%和58.07%~68.86%,其中,3%超敏蛋白的防效最好,其烟草TSWV和PVY防治效果分别高于50%和60%,其次是2%嘧肽霉素,对烟草TSWV和PVY防治效果分别高于22%和58%。防治烟草番茄斑萎病毒病和马铃薯Y病毒病以3%超敏蛋白微粒剂的防治效果最佳,其次是2%嘧肽霉素水剂。     

Genetic analysis of broad spectrum resistance to potyviruses using doubled haploid lines of pepper (Capsicum annuum L.)

Summary Genetic analysis of resistance to PVY in androgenetic doubled haploid lines, F1, F2 and backcross progenies of the Mexican pepper line, CM 334 (Capsicum annuum L.), was performed. Three reaction types were observed when seedlings were inoculated with several PVY strains of different pathotypes and with an American PeMV strain. Resistant genotypes never showed systemic symptoms although some individuals sporadically developed necrotic local lesions on inoculated cotyledons. Susceptible genotypes exhibited either a typical systemic mosaic or a systemic necrosis that caused the death of the inoculated seedlings. Segregation analyses indicated that resistance to pepper potyviruses in CM 334 is conferred by two genes. The first one, tentatively named Pr4, is dominant and confers the resistance to all now known pathotypes of PVY and to PeMV. The second one, tentatively named pr5, is recessive; it confers only the resistance to common strains of PVY. The systemic necrotic response is conferred by an independent dominant gene, tentatively named Pn1.     

马铃薯Y病毒株系分类及中国大田马铃薯感染的马铃薯Y病毒株系谱研究进展

为了更科学、合理地检测、检疫马铃薯Y病毒(PVY)株系,和全面掌握侵染中国大田马铃薯的PVY株系情况,总结了PVY株系的分类方法,分析了中国大田马铃薯感染的PVY株系谱。认为目前广泛使用的血清型划分法、基因组重组与否划分法、PTNRD效应划分法、过敏反应互作基因划分法,以及Singh等提出的株系群划分法都无法对PVY株系予以完全合理的划分。提出有必要鉴定PVY基因组中决定马铃薯病理效应的基序并通过对基序测序来鉴定PVY株系,通过对株系间基因组差异区段的短序列测序来鉴定PVY株系是目前最接近基序测序分类法的思路。指出感染中国大田马铃薯的PVY目前有PVY^O、PVY^N、PVY^NTN、PVY^N:O、PVY^N-Wi和PVY^NW这6种株系,隶属于2个株系群PVY^O和PVY^N,其中PVY^N株系和PVY^N株系群病样占绝大多数,以非重组株系为主,但重组株系已占一定比例,其发展趋势值得关注。     

马铃薯Y病毒的株系分化及检测方法研究进展

马铃薯Y病毒是烟草上的主要病毒之一。目前中国关于PVY分子变异的报道还较少,但变异株系的出现应该引起科研工作者的高度重视。笔者简述PVY的株系分化进程,并从检测技术的优缺点及应用等方面总结PVY检测的指示植物法、酶联免疫法、聚合酶链式反应、核酸杂交等几种方法。指出随着植物种质资源的引进和生态条件的改变,PVY变异株系将不断出现,这对株系检测方法提出了更高的要求,因此在实际应用中要综合运用各种检测方法提高检测的准确性。     

Inheritance of resistance to anthracnose (Colletotrichum capsici) at seedling and fruiting stages in chili pepper (Capsicum spp.)

Inheritance of resistance to anthracnose at fruiting and seedling stages was studied in two F₂ populations from a cross between Capsicum annuum cv. ‘Bangchang’ and Capsicum chinense‘PBC932’. The first F₂ was used to study anthracnose resistance at fruiting stage on mature green and ripe red fruit, and the second F₂ was used to study the resistance at both seedling and fruiting stages. Fruit inoculation was performed on detached fruit using a microinjector. Disease severity was assessed on a 0–9 scale at 7 days after inoculation. Seedling inoculation was performed using a drop method on detached leaves of 4‐week‐old seedlings. Disease severity was assessed on a 1–9 scale at 3 days after inoculation. The distribution of the disease scores of green and red fruit, and seedlings in both F₂ populations suggested a single gene model for each trait. Three different recessive genes were responsible for the three resistances from this cross. Linkage analysis suggested that the resistances at green and red fruit were linked (recombination frequency 0.25), and that the seedling resistance was not linked to the fruit resistances.     

Identification of RAPD markers linked to the Ns locus in potato

Using the RAPD method and bulked segregant analysis we identified four RAPD markers linked to a dominant gene Ns, responsible for a hypersensitive reaction of potato (Solanum tuberosum L.) to potato virus S (PVS) infection. The markers OPE15⁵⁵⁰, OPJ13⁵⁰⁰, OPG17⁴⁵⁰ and OPH19⁹⁰⁰ were found to be closely linked to the Ns gene in diploid potato clones. They are situated at 2.6, 3.3, 4.6 and 6.6 cM from Ns, respectively. As a source of the gene, clone G-LKS 678147/60, which is known to carry Ns transferred from S. tuberosum ssp. andigena was used. These RAPD markers were not amplified in resistant tetraploid clones containing Ns derived from the clone MPl65 118/3, also having an andigenum origin. This suggests that there may be two separate loci of Ns in the sources identified, or different alleles with the same specificity at a single locus, or that the genetic background of tetraploids tested results in different RAPD amphlification patterns.