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1.
Identification of two major resistance genes against race IE-1k of Magnaporthe oryzae in the indica rice cultivar Zhe733 总被引:1,自引:0,他引:1
S. Lee Y. Wamishe Y. Jia G. Liu M. H. Jia 《Molecular breeding : new strategies in plant improvement》2009,24(2):127-134
The race IE-1k of Magnaporthe oryzae recovered from the Southern US overcomes the resistance (R) gene Pita. The objectives of the present study were to identify and tag R genes to IE-1k for rice breeding. TM2, S1, 94071, and B isolates of the race IE-1k were used to identify and map R genes from a resistant indica rice cultivar Zhe733 using a recombinant inbred line population from a cross of the genetic
stock KBNTlpa1-1 and Zhe733. The ratio of 3 resistant:1 susceptible in 162 RIL of an F10-11 KBNTlpa1-1/Zhe733 (K/Z) population indicated that two major R genes in Zhe733 confer resistance to IE-1k. A total of 118 polymorphic simple sequence repeat markers were analyzed in 162
F10-11 individuals of the K/Z population to determine chromosomal locations of the loci conferring resistance to race IE-1k using
composite interval mapping. Two major R genes temporarily designated as Pi42(t) and Pi43(t) each providing complete resistance to IE-1k were identified on chromosomes 8 and 11, respectively. RILs containing Pi42(t) and Pi43(t) were also resistant to other US races IB-1, IB-45, IB-49, IB-54, IC-17, IE-1, IG-1, and IH-1. The Pi42(t) gene was mapped between RM310 and RM72, and the location of Pi43(t) was closely associated with two flanking SSR markers RM1233 and RM224 on chromosome 11 in a chromosomal region carrying
the resistance gene Pi1. Two molecular markers RM72 and RM1233 identified in this study should be useful for fine mapping and for facilitating incorporation
of Pi42(t) and Pi43(t) into advanced breeding lines by marker-assisted selection.
The authors S. Lee and Y. Wamishe contribute equally to this work. 相似文献
2.
Timothy D. Metz Richard T. Roush Juliet D. Tang Anthony M. Shelton Elizabeth D. Earle 《Molecular breeding : new strategies in plant improvement》1995,1(4):309-317
We usedAgrobacterium tumefaciens to transform flowering stalk explants of five genotypes of broccoli with a construct containing the neomycin phosphotransferase gene and aBacillus thuringiensis (Bt) gene [CryIA(c) type] optimized for plant expression. Overall transformation efficiency was 6.4%; 181 kanamycin-resistant plants were recovered. Of the 162 kanamycin-resistant plants tested, 112 (69%) caused 100% morality of 1st-instar larvae of aBt-susceptible diamondback moth strain. Southern blots of some resistant transformants confirmed presence of theBt gene. Selected plants that gave 100% mortality of susceptible larvae allowed survival of a strain of diamondback moth that had evolved resistance toBt in the field. F1 hybrids between resistant and susceptible insects did not survive. Analysis of progeny from 26 resistant transgenic lines showed 16 that gave segregation ratios consistent with a single T-DNA integration. Southern analysis was used to verify those plants possessing a single T-DNA integration. Because these transgenic plants kill susceptible larvae and F1 larvae, but serve as a suitable host for resistant ones, they provide an excellent model for tests ofBt resistance management strategies. 相似文献
3.
Magnaporthe grisea, the blast fungus is one of the main pathological threats to finger millet crop worldwide. A systematic search for the blast
resistance gene analogs was carried out, using functional molecular markers. Three-fourths of the recognition-dependent disease
resistance genes (R-genes) identified in plants encodes nucleotide binding site (NBS) leucine-rich repeat (LRR) proteins. NBS-LRR homologs have
only been isolated on a limited scale from Eleusine coracana. Genomic DNA sequences sharing homology with NBS region of resistance gene analogs were isolated and characterized from resistant
genotypes of finger millet using PCR based approach with primers designed from conserved regions of NBS domain. Attempts were
made to identify molecular markers linked to the resistance gene and to differentiate the resistant bulk from the susceptible
bulk. A total of 9 NBS-LRR and 11 EST-SSR markers generated 75.6 and 73.5% polymorphism respectively amongst 73 finger millet
genotypes. NBS-5, NBS-9, NBS-3 and EST-SSR-04 markers showed a clear polymorphism which differentiated resistant genotypes
from susceptible genotypes. By comparing the banding pattern of different resistant and susceptible genotypes, five DNA amplifications
of NBS and EST-SSR primers (NBS-05504, NBS-09711, NBS-07688, NBS-03509 and EST-SSR-04241) were identified as markers for the blast resistance in resistant genotypes. Principal coordinate plot and UPGMA analysis
formed similar groups of the genotypes and placed most of the resistant genotypes together showing a high level of genetic
relatedness and the susceptible genotypes were placed in different groups on the basis of differential disease score. Our
results provided a clue for the cloning of finger millet blast resistance gene analogs which not only facilitate the process
of plant breeding but also molecular characterization of blast resistance gene analogs from Eleusine coracana. 相似文献
4.
Tongtong Jin Jinlong Yin Tao Wang Song Xue Bowen Li Tingxuan Zong Yunhua Yang Hui Liu Mengzhuo Liu Kai Xu Liqun Wang Guangnan Xing Haijian Zhi Kai Li 《植物学报(英文版)》2023,65(3):838-853
Soybean mosaic virus (SMV) is one of the most devastating viral pathogens of soybean (Glycine max (L.) Merr). In total, 22 Chinese SMV strains (SC1–SC22) have been classified based on the responses of 10 soybean cultivars to these pathogens. However, although several SMV-resistance loci in soybean have been identified, no gene conferring SMV resistance in the resistant soybean cultivar (cv.) Kefeng No.1 has been cloned and verified. Here, using F2-derived F3 (F2:3) and recombinant inbred line (RIL) populations from a cross between Kefeng No.1 and susceptible soybean cv. Nannong 1138-2, we localized the gene in Kefeng No.1 that mediated resistance to SMV-SC3 strain to a 90-kb interval on chromosome 2. To study the functions of candidate genes in this interval, we performed Bean pod mottle virus (BPMV)-induced gene silencing (VIGS). We identified a recombinant gene (which we named RSC3K) harboring an internal deletion of a genomic DNA fragment partially flanking the LOC100526921 and LOC100812666 reference genes as the SMV-SC3 resistance gene. By shuffling genes between infectious SMV DNA clones based on the avirulent isolate SC3 and virulent isolate 1129, we determined that the viral protein P3 is the avirulence determinant mediating SMV-SC3 resistance on Kefeng No.1. P3 interacts with RNase proteins encoded by RSC3K, LOC100526921, and LOC100812666. The recombinant RSC3K conveys much higher anti-SMV activity than LOC100526921 and LOC100812666, although those two genes also encode proteins that inhibit SMV accumulation, as revealed by gene silencing in a susceptible cultivar and by overexpression in Nicotiana benthamiana. These findings demonstrate that RSC3K mediates the resistance of Kefeng No.1 to SMV-SC3 and that SMV resistance of soybean is determined by the antiviral activity of RNase proteins. 相似文献
5.
Zelaya IA Owen MD Vangessel MJ 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2004,110(1):58-70
N-(phosphonomethyl)glycine (glyphosate) resistance was previously reported in a horseweed [Conyza (=Erigeron) canadensis (L.) Cronq.] population from Houston, DE (P
0
R
). Recurrent selection was performed on P
0
R
, since the population was composed of susceptible (5%) and resistant (95%) phenotypes. After two cycles of selection at 2.0 kg ae glyphosate ha–1, similar glyphosate rates that reduced plant growth by 50%, glyphosate rates that inflicted 50% mortality in the population, and accumulations of half of the maximum detectable shikimic acid concentration were observed between the parental P
0
R
and the first (RS1) and second (RS2) recurrent generations. In addition, RS1 and RS2 did not segregate for resistance to glyphosate. This suggested that the RS2 population comprised a near-homozygous, glyphosate-resistant line. Whole-plant rate responses estimated a fourfold resistance increase to glyphosate between RS2 and either a pristine Ames, IA (P
0
P
) or a susceptible C. canadensis population from Georgetown, DE (P
0
S
). The genetics of glyphosate resistance in C. canadensis was investigated by performing reciprocal crosses between RS2 and either the P
0
P
or P
0
S
populations. Evaluations of the first (F1) and second (F2) filial generations suggested that glyphosate resistance was governed by an incompletely dominant, single-locus gene (R allele) located in the nuclear genome. The proposed genetic model was confirmed by back-crosses of the F1 to plants that arose from achenes of the original RS2, P
0
P
, or P
0
S
parents. The autogamous nature of C. canadensis, the simple inheritance model of glyphosate resistance, and the fact that heterozygous genotypes (F1) survived glyphosate rates well above those recommended by the manufacturer, predicted a rapid increase in frequency of the R allele under continuous glyphosate selection. The impact of genetics on C. canadensis resistance management is discussed. 相似文献
6.
RFLP and RAPD markers linked to the rosy leaf curling aphid resistance gene (Sd1) in apple 总被引:10,自引:0,他引:10
P. Roche F. H. Alston C. Maliepaard K. M. Evans R. Vrielink F. Dunemann T. Markussen S. Tartarini L. M. Brown C. Ryder G. J. King 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1997,94(3-4):528-533
Sd
1 is a dominant gene for resistance to biotypes 1 and 2 of the rosy leaf curling aphid, Dysaphis devecta Wlk., which can cause economic damage to apple trees. This report describes the identification of three RFLP and four RAPD
markers linked to Sd
1 in a cross between the D. devecta susceptible variety ‘Prima’ (sd
1
sd
1) and the resistant variety ‘Fiesta’ (Sd
1
sd
1). Potted trees were artificially infested in the glasshouse, and the ratio of resistant:susceptible plants supported the
hypothesis that the resistance was under the control of a single dominant gene. The position of the gene was mapped to a single
locus on a ‘Fiesta’ chromosome, within 2 cM of three tightly linked RFLP markers (MC064a, 2B12a and MC029b); the four RAPD
markers were located further away (between 13 and 46 cM). This is the first report of molecular markers for an aphid resistance
gene in tree fruit crops. The potential application of these markers in a marker-assisted resistance breeding programme is
discussed.
Received: 1 July 1996/Accepted: 23 August 1996 相似文献
7.
W. A. Van Giessen C. Mollema K. D. Elsey 《Entomologia Experimentalis et Applicata》1995,76(3):271-286
SARAH (Software for theAssessment of antibioticResistance toAleyrodidae inHost plants) is a deterministic simulation model of whitefly population growth based on whitefly life-history components determined
on individual plants. The life-history components recorded were oviposition rate, adult survival, pre-adult survival, developmental
period, and sex ratio. The simulation model serves as a tool to combine these components and to obtain a single criterion
for (antibiotic) resistance. The criterion used was the decrease in simulated intrinsic population growth rate, r
s
, relative the r
s
value determined on a susceptible control genotype. This model-based evaluation method was tested using the greenhouse whitefly,Trialeurodes vaporariorum Westwood, on tomato and the sweetpotato whitefly,Bemisia tabaci Gennadius, on tomato, eggplant, collard, and pepper.
To study its consistency over time, the evaluation method was repeated six times forT. vaporariorum on a susceptible and a resistant tomato cultivar. Simulated intrinsic population growth rate was more consistent in indicating
resistance than any of the individual life-history components. Of tenL. hirsutum accessions tested for resistance toT. vaporariorum, three exhibited r
s
values that were significantly lower than those for the susceptible control. In addition, on these tenL. hirsutum accessions, a significant positive correlation was observed between r
s
and sex ratio (# females/# males).
Four host plant species (tomato, collard, eggplant, and pepper) were evaluated for resistance toB. tabaci. All life-history components and r
s
values varied among host species, while a negative r
s
value was observed forB. tabaci on pepper.
A high correlation was found between results from a sensitivity analysis of SARAH and results from a sensitivity analysis
of a validated whitefly population simulation model by Yanoet al. (1989a). Significant correlations were found for the relationships between oviposition rate, adult survival, or pre-adult
survival and r
s
, indicating that none of these life-history components can be omitted from the test procedure. This model-based evaluation
method offers a standardized way to quantify levels of antibiotic resistance to whiteflies and will enhance efficiency in
breeding programs. 相似文献
8.
甜菜夜蛾抗氯氟氰菊酯品系相对适合度、抗性生化机理及抗性遗传方式 总被引:7,自引:2,他引:7
比较了甜菜夜蛾Spodoptera exigua 抗氯氟氰菊酯品系和敏感品系的繁殖和生长发育特征。结果表明:抗性品系幼虫发育历期延长、蛹重减轻、化蛹率和产卵量降低,抗性品系的适合度为0.61,抗性品系在繁殖和生长发育上存在明显的生存劣势。用两品系3龄幼虫分别测定胡椒基丁醚(PBO)、增效磷SV1)、脱叶磷(DEF)和顺丁烯二酸二乙酯(DEM)对氯氟氰菊酯的增效作用,抗性品系增效倍数与敏感品系增效倍数之比分别为14.1、14.8、2.3和2.3倍,胡椒基丁醚和增效磷对氯氟氰菊酯增效作用最明显,表明多功能氧化酶参与了甜菜夜蛾对氯氟氰菊酯的抗性。抗性品系3龄幼虫酯酶和谷胱甘肽S-转移酶的活性分别为敏感品系的1.05倍和0.91倍, 抗性品系5龄幼虫多功能氧化酶O-脱甲基活性为敏感品系的1.05倍,两品系间3种酶的活性差异不显著,表明甜菜夜蛾对氯氟氰菊酯的抗性与酯酶、谷胱甘肽S-转移酶及多功能氧化酶O-脱甲基酶活性无关。用剂量对数死亡机率值回归线分析法研究甜菜夜蛾对氯氟氰菊酯的抗性遗传规律,表明甜菜夜蛾对氯氟氰菊酯的抗性为常染色体遗传、多基因控制;正、反交后代的显性度分别为0.61和0.43,抗性遗传为不完全显性。 相似文献
9.
Alida F. Janmaat Ping Wang Wendy Kain Jian-Zhou Zhao Judith Myers 《Applied microbiology》2004,70(10):5859-5867
The genetic inheritance of resistance to a commercial formulation of Bacillus thuringiensis subsp. kurstaki was examined in a Trichoplusia ni colony initiated from a resistant population present in a commercial vegetable greenhouse in British Columbia, Canada. Progeny of F1 reciprocal crosses and backcrosses between F1 larvae and resistant (PR) and susceptible (PS) populations were assayed at different B. thuringiensis subsp. kurstaki concentrations. The responses of progeny of reciprocal F1 crosses were identical, indicating that the resistant trait was autosomal. The 50% lethal concentration for the F1 larvae was slightly higher than that for PS, suggesting that resistance is partially recessive. The responses of both backcross progeny (F1 × PR, F1 × PS) did not correspond to predictions from a single-locus model. The inclusion of a nonhomozygous resistant parental line in the monogenic model significantly increased the correspondence between the expected and observed results for the F1 × PR backcross but decreased the correspondence with the F1 × PS backcross results. This finding suggests that resistance to B. thuringiensis subsp. kurstaki in this T. ni population is due to more than one gene. 相似文献
10.
Motoki Shimizu Ryo Fujimoto Hua Ying Zi-jing Pu Yusuke Ebe Takahiro Kawanabe Natsumi Saeki Jennifer M. Taylor Makoto Kaji Elizabeth S. Dennis Keiichi Okazaki 《Plant molecular biology》2014,85(3):247-257
Fusarium yellows caused by Fusarium oxysporum f. sp. conglutinans is an important disease of Brassica worldwide. To identify a resistance (R) gene against Fusarium yellows in Chinese cabbage (Brassica rapa var. pekinensis), we analyzed differential expression at the whole genome level between resistant and susceptible inbred lines using RNA sequencing. Four hundred and eighteen genes were significantly differentially expressed, and these were enriched for genes involved in response to stress or stimulus. Seven dominant DNA markers at putative R-genes were identified. Presence and absence of the sequence of the putative R-genes, Bra012688 and Bra012689, correlated with the resistance of six inbred lines and susceptibility of four inbred lines, respectively. In F2 populations derived from crosses between resistant and susceptible inbred lines, presence of Bra012688 and Bra012689 cosegregated with resistance, suggesting that Bra012688 and Bra012689 are good candidates for fusarium yellows resistance in Chinese cabbage. 相似文献
11.
Inheritance of partial leaf rust and stripe rust resistance of a Thatcher wheat 90RN2491, earlier reported to carry two doses
of the gene pairLr34-Yr18 and the reference line RL6058 (6*Thatcher/PI58548) for theLr34-Yr18 gene pair was studied against predominant and highly virulent Indian races. Thatcher derivatives 90RN2491 and RL6058 were
intercrossed as well as crossed with the leaf rust and stripe rust susceptible Indian cultivar WL711. The F1, F2 and F3 generations from these crosses were assessed for rust severity against leaf rust race 77-5 and stripe rust race 46S119. The
F2 and F3 generations from the crosses of RL6058 and 90RN2491 with WL711, segregated 15 resistant : 1 susceptible (F2) and 7 homozygous resistant : 8 segregating : 1 homozygous susceptible (F3) ratios, respectively, both for leaf rust and stripe rust severity. Therefore, partial resistance against each of the leaf
rust and stripe rust races in both RL6058 and 90RN2491 is ascribed to two independently inherited dominant genes. One of the
two genes for leaf rust and stripe rust resistance in 90RN2491 and RL6058 isLr34 and the linked geneYr18, respectively. The second leaf rust resistance gene in both the Thatcher lines segregated independently of stripe rust resistance.
Therefore, it is notLr34 and it remains unidentified. 相似文献
12.
13.
Mapping of SMV resistance gene Rsc-7 by SSR markers in soybean 总被引:8,自引:0,他引:8
Soybean mosaic virus (SMV) is one of the most prevalent pathogens that limit soybean production. In this study, segregation
ratios of resistant plants to susceptible plants in P1, P2, F1, F2 populations of Kefeng No. 1 (P1)×Nannong 1138-2 (P2) and derived RIL populations, were used to study the inheritance of resistance to the SMV strain SC-7. Populations Kefeng
No. 1 and F1 were found to be completely resistant to this SMV strain while Nannong 1138-2 was susceptible to it. The F2 and RIL populations segregated to fit a ratio of 3:1 and 1:1for resistant plants to susceptible ones, respectively. These
results indicated that a single dominant gene, designated as Rsc-7, controlled resistance to the SMV strain SC-7 in Kefeng No.1. SSR markers were used to analyze the RIL population and MAPMAKER/EXP
3.0b was employed to establish linkage between markers and this resistance gene. Combining the data of SSRs and resistance
identification, a soybean genetic map was constructed. This map, covering 2625.9 cM of the genome, converged into 24 linkage
groups, consisted of 221 SSR markers and the resistance gene Rsc-7. The Rsc-7 gene was mapped to the molecular linkage group G8-D1b+W. SSR markers Satt266, Satt634, Satt558, Satt157, and Satt698 were
found linked to Rsc-7 with distances of 43.7, 18.1, 26.6, 36.4 and 37.9 cM, respectively. 相似文献
14.
Fu‐Qiang Zhao Qi Li Guo‐Yue Chen Jun Li Hou‐Yang Kang Yi Wang Xing Fan Li‐Na Sha Yong‐Hong Zhou Hai‐Qin Zhang 《Journal of Phytopathology》2017,165(3):157-161
The Roegneria kamoji accession ZY 1007 was resistant to the mixed predominant races of Puccinia striiformis f.sp. tritici (Pst) in China based on field tests at adult‐plant stage. The seedling resistance evaluation of ZY 1007 showed that it was resistant to stripe rust physiological strains CYR29, CYR33 and PST‐V26, which were the predominant races of Pst in China. The female parent R. kamoji cv. Gansi No.1 (susceptible to Pst) was crossed with ZY 1007 (resistant to Pst). Parents, F1 and F2 populations were tested in a field inoculated with the mixed urediniospores. ZY 1007 and all the observed 11 F1 hybrid plants were resistant, while plants of Gansi No.1 were susceptible. Among the 221 F2 plants, 168 plants were resistant and 53 were susceptible, and the segregation of resistant and susceptible plants fits 3R:1S ratio (χ2 = 0.074, P > 0.75). It confirmed that the resistance of stripe rust in ZY 1007 was controlled by a single dominant gene and temporarily designated as YrK1007. 相似文献
15.
The R1 gene conferring race-specific resistance to Phytophthora infestans in potato is located on potato chromosome V. 总被引:5,自引:0,他引:5
Christiane Leonards-Schippers Werner Gieffers Francesco Salamini Christiane Gebhardt 《Molecular & general genetics : MGG》1992,233(1-2):278-283
Summary Late blight in potato is caused by the fungusPhytophthora infestans and can inflict severe damage on the potato crop. Resistance toP. infestans is either based on major dominantR genes conferring vertical, race-specific resistance or on minor genes inducing horizontal, unspecific resistance. A dihaploid potato line was identified which carried theR1 gene, conferring vertical resistance to allP. infestans races, with the exception of those homozygous for the recessive virulence allele of the locusV1. The F1 progeny of a cross between this resistant parent P(R1) and P(r), a line susceptible to all races, was analysed for segregation ofR1 and of restriction fragment length polymorphism (RFLP) markers distributed on the potato RFLP map comprising more than 300 loci. TheR1 locus was mapped to chromosome V in the interval between RFLP markers GP21 and GP179. The map position ofR1 was found to be very similar to the one ofRx2, a dominant locus inducing extreme resistance to potato virus X. 相似文献
16.
Ping Wang 《Plant biotechnology journal》2017,15(10):1322-1330
Development of resistance to the insecticidal toxins from Bacillus thuringiensis (Bt) in insects is the major threat to the continued success of transgenic Bt crops in agriculture. The fitness of Bt‐resistant insects on Bt and non‐Bt plants is a key parameter that determines the development of Bt resistance in insect populations. In this study, a comprehensive analysis of the fitness of Bt‐resistant Trichoplusia ni strains on Bt cotton leaves was conducted. The Bt‐resistant T. ni strains carried two genetically independent mechanisms of resistance to Bt toxins Cry1Ac and Cry2Ab. The effects of the two resistance mechanisms, individually and in combination, on the fitness of the T. ni strains on conventional non‐Bt cotton and on transgenic Bt cotton leaves expressing a single‐toxin Cry1Ac (Bollgard I) or two Bt toxins Cry1Ac and Cry2Ab (Bollgard II) were examined. The presence of Bt toxins in plants reduced the fitness of resistant insects, indicated by decreased net reproductive rate (R0) and intrinsic rate of increase (r). The reduction in fitness in resistant T. ni on Bollgard II leaves was greater than that on Bollgard I leaves. A 12.4‐day asynchrony of adult emergence between the susceptible T. ni grown on non‐Bt cotton leaves and the dual‐toxin‐resistant T. ni on Bollgard II leaves was observed. Therefore, multitoxin Bt plants not only reduce the probability for T. ni to develop resistance but also strongly reduce the fitness of resistant insects feeding on the plants. 相似文献
17.
Identification of the novel recessive gene pi55(t) conferring resistance to Magnaporthe oryzae 总被引:2,自引:0,他引:2
XiuYing He XinQiong Liu Li Wang Ling Wang Fei Lin YongSheng Cheng ZhaoMing Chen YaoPing Liao QingHua Pan 《中国科学:生命科学英文版》2012,55(2):141-149
The elite rice cultivar Yuejingsimiao 2 (YJ2) is characterized by a high level of grain quality and yield, and resistance
against Magnaporthe oryzae. YJ2 showed 100% resistance to four fungal populations collected from Guangdong, Sichuan, Liaoning, and Heilongjiang Provinces,
which is a higher frequency than that shown by the well-known resistance (R) gene donor cultivars such as Sanhuangzhan 2 and 28zhan. Segregation analysis for resistance with F2 and F4 populations indicated the resistance of YJ2 was controlled by multiple genes that are dominant or recessive. The putative
R genes of YJ2 were roughly tagged by SSR markers, located on chromosomes 2, 6, 8, and 12, in a bulked-segregant analysis using
genome-wide selected SSR markers with F4 lines that segregated into 3 resistant (R):1 susceptible (S) or 1R:3S. The recessive R gene on chromosome 8 was further mapped to an interval ≈1.9 cM/152 kb in length by linkage analysis with genomic position-ready
markers in the mapping population derived from an F4 line that segregated into 1R:3S. Given that no major R gene was mapped to this interval, the novel R gene was designated as pi55(t). Out of 26 candidate genes predicted in the region based on the reference genomic sequence of the cultivar Nipponbare,
two genes that encode a leucine-rich repeat-containing protein and heavy-metal-associated domain-containing protein, respectively,
were suggested as the most likely candidates for pi55(t). 相似文献
18.
Host plant resistance is an important strategy for managing root-knot nematode (Meloidogyne incognita) in cotton (Gossypium L.). Here we report evidence for enhanced resistance in interspecific crosses resulting from transgressive segregation of
clustered gene loci. Recently, a major gene, rkn1, on chromosome 11 for resistance to M. incognita in cv. Acala NemX was identified using an intraspecific G. hirsutum cross with susceptible cv. Acala SJ-2. Using interspecific crosses of Acala NemX × susceptible G. barbadense cv. Pima S-7, F1, F2, F2:3, backcross, and testcross Acala NemX × F1 (Pima S-7 × SJ-2), parental entries and populations were inoculated in greenhouse tests with M. incognita. Genetic analyses based on nematode-induced root galling and nematode egg production on roots, and molecular marker analysis
of the segregating interspecific populations revealed that gene rkn1 interacted with a gene (designated as RKN2) in susceptible Pima S-7 to produce a highly resistant phenotype. RKN2 did not confer resistance in Pima S-7, but when combined with rkn1 (genotype Aa or aa), high levels of resistance were produced in the F1 and segregating F2, F3, and BC1F1 populations. One SSR marker MUCS088 was identified tightly linked to RKN2 within 4.4 cM in a NemX × F1 (Pima S-7 × SJ-2) testcross population. Using mapped SSR markers and interspecific segregating populations, MUCS088 linked
to the transgressive gene from the susceptible parent and was located in the vicinity of rkn1 on chromosome 11. Diverse genome analyses among A and D genome diploid and tetraploid cottons revealed that marker MUCS088
(165 and 167 bp) is derived from G. arboreum, A2 diploid genome. These results demonstrated that a highly susceptible parent contributed to nematode resistance via transgressive
segregation. Derived highly resistant lines can be used as improved resistance sources in cotton breeding, and MUCS088 can
be used to monitor RKN2 introgression in diverse populations. The close genomic location of the transgressive resistance determinants provides an
important model system for studying transgressive segregation and epistasis in plants. 相似文献
19.
T. Wai R. Grumet 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1995,91(4):699-706
The inbred cucumber (Cucumis sativus L.) line TMG-1 is resistant to three potyviruses:zucchini yellow mosaic virus (ZYMV), watermelon mosaic virus (WMV), and the watermelon strain of papaya ringspot virus (PRSV-W). The genetics of resistance to WMV and the relationship of WMV resistance to ZYMV resistance were examined. TMG-1 was crossed with WI-2757, a susceptible inbred line. F1, F2 and backcross progeny populations were screened for resistance to WMV and/or ZYMV. Two independently assorting factors conferred resistance to WMV. One resistance was conferred by a single recessive gene from TMG-1 (wmv-2). The second resistance was conferred by an epistatic interaction between a second recessive gene from TMG-1 (wmv-3) and either a dominant gene from WI-2757 (Wmv-4) or a third recessive gene from TMG-1 (wmv-4) located 20–30 cM from wmv-3. The two resistances exhibited tissue-specific expression. Resistance conferred by wmv-2 was expressed in the cotyledons and throughout the plant. Resistance conferred by wmv-3 + Wmv-4 (or wmv-4) was expressed only in true leaves. The gene conferring resistance to ZYMV appeared to be the same as, or tightly linked to one of the WMV resistance genes, wmv-3. 相似文献
20.
The results of the apple breeding for digenic resistance to scab (1979–2000), which is more long-term than the monogenic breeding, have been reviewed. The hybrid seeds obtained from the reciprocal crossing between the V
f and V
m resistance gene donors served as the original material. The seed progeny yielded by backcrosses between these hybrids and the susceptible cultivars were examined (age—first true leaves) using inoculation in a greenhouse. The following criteria were proposed for breeding parental forms and the cultivars of the V
f
v
f
V
m
v
m genotype: (1) phenotype segregation in the progeny of three resistant: one susceptible seedling and (2) the presence in the progeny of two types of resistant seedlings: those with the class 1 resistance (points and spots—hypersensitivity) typical of the V
m gene and those with the class 2–3 resistance (chlorotic and necrotic spots) typical of the V
f gene. 相似文献