转codA基因提高番茄植株的耐热性

以野生型番茄(cv. Moneymaker)和转codA番茄为材料,用不同温度(25、30、35、40、45和50℃)分别处理2 h,测定叶片净光合速率(P_n)、PSII最大光化学效率(F_v/F_m)、过氧化氢(H₂O₂)含量、丙二醛(MDA)含量、相对电导率(REC)和抗氧化酶活性等生理指标;42℃高温处理0、3和6 h后,检测热响应基因的表达量以及D1蛋白的含量,研究高温胁迫对上述参数的影响,探讨转codA基因提高番茄叶片耐热性的机制。。结果表明,高温胁迫下,转codA基因番茄叶片P_n和F_v/F_m的抑制程度明显低于野生型,H₂O₂、MDA的积累量以及REC均低于野生型,而且明显增强了过氧化氢酶(CAT)、超氧化物歧化酶(SOD)、过氧化物酶(POD)和抗坏血酸过氧化物酶(APX)的活性。此外,转codA基因番茄叶片中抗氧化酶基因和热胁迫基因的表达水平均高于野生型,而D1蛋白的降解水平低于野生型。转codA基因番茄体内合成的甜菜碱提高了转基因番茄的耐热性,这与提高和维持较高的抗氧化酶活性、促进热激响应基因的表达及减缓D1蛋白的降解等有关。     

Inheritance of shelf life and other quality traits of tomato fruit estimated from F<Subscript>1</Subscript>’s,F<Subscript>2</Subscript>’s and backcross generations derived from standard cultivar, <Emphasis Type="Italic">nor</Emphasis> homozygote and wild cherry tomato

A tomato cultivar with high quality fruit and a long shelf life is a main goal in tomato breeding and it would be achieved using wild germplasm. The objective of this work was to explore the inheritance for fruit quality traits, especially fruit shelf life, in three tomato crosses using a standard Argentinean cultivar (Ca, cv ‘Caimanta’), a ripening mutant (nor, homozygous for the nor gene) of Solanum lycopersicum, and a wild cherry type (Ce, LA1385 of S. lycopersicum var. cerasiforme). The wild parent had a shorter fruit shelf life than the mutant genotype but higher than Ca. When the Ce genotype was analyzed in hybrid combination, the F₁ (Ca×Ce) was similar to the wild genotype for shelf life whereas the F₁ (nor × Ce) had a longer shelf life. Both F₁ crosses and backcrosses to the cherry type genotype had significantly lower fruit weight than the cultivated genotypes but higher than the cherry type parent. In the F₂ analysis, it was found that the inheritance underlying quality traits is complex since non allelic interactions were detected. A significant additive genetic variance was found for fruit shelf life as well as for other fruit quality traits in each cross. The genetic parameters analyzed by mean values and variances in parental, F₁ and F₂ and backcross generations indicated that the cross between the normal ripening cultivar and LA1385 of S. lycopersicum var. cerasiforme offers the best possibility to obtain long shelf life tomato genotypes with good fruit quality.     

Development of Bruchid-Resistant Mungbean Line Using Wild Mungbean Germplasm in Thailand

A mungbean (V. radiata) line (BC₃F₃ generation) which is resistant to two species of bruchid beetles (Callosobruchus chinensis and C. maculatus) was successfully developed in Thailand using a wild mungbean variety (V. radiata var. sublobata). One accession (TC1966) of wild mungbean was found to be completely resistant to C. chinensis and C. maculatus occurring at Chainat Field Crops Research Center in Thailand. The resistance was controlled by a single dominant gene (R). A breeding program to develop a bruchid-resistant mungbean cultivar with good agronomic characters under the environmental conditions of Thailand was initiated in 1987.‘Chainat 60’ (‘CN60’), a recommended mungbean cultivar in Thailand, was crossed with TC1966 to incorporate the resistance gene. Agronomic characters of the hybrids were improved by recurrent backcrossing using ‘CN60’ as a pollen parent. Seed yield per plant, days to flowering, and seed size of the bruchid-resistant BC₃F₂ population reached the level of ‘CN60’ after three consecutive backcrossings. Bruchid-resistant line (BC₃F₃, R/R) was selected from individual BC₃F₂ plants.     

Genetics of morphological traits in wild wheat,Triticum turgidum var.dicoccoides

Summary The mode of inheritance, linkage groups, and chromosomal location of 23 morphological and 4 biochemical traits were characterized in the wild tetraploid emmer wheat,Triticum turgidum var.dicoccoides. These traits were described and their mode of inheritance was determined by their segregation in four F₂ populations derived from crosses between four var.dicoccoides accessions and a tetraploiddurum cultivar. Linkage groups among the genes encoding for these traits were determined or postulated, and their chromosomal location was deduced by linkage to previously located genes. The genetic control of the following traits was characterized and is first reported here: black keel; hairy leaf sheath; hairy auricles; hairy rachilla; hairy kernel brush; obtuse flag leaf; and curved neck/peduncle. The linkage data indicated that developmentally-related genes tended to occur in clusters.     

Inter-subspecific maps of non-brittle rachis genes btr1/btr2 using occidental, oriental and wild barley lines

Brittle rachis of wild barley is controlled by two dominant complementary genes, Btr1 and Btr2, and mutation in either locus (btr1 or btr2) results in the non-brittle rachis of cultivated barley. In this study, a simple monogenic inheritance of non-brittle rachis was demonstrated, and moreover differentiation of multiple dominant alleles for either Btr1 or Btr2 among cultivated and wild barley lines was suggested. Two amplified-fragment-length polymorphism (AFLP) linkage maps of the genes were constructed using wild × btr1-type cultivar and wild × btr2-type cultivar F₂ populations. The order of AFLPs and the btr1/btr2 locus was constant between the wild × cultivar maps and a cultivar × cultivar map previously constructed. No suppression of recombination due to the inter-subspecific crosses was noticed in the interval studied. The btr1 locus and all AFLP loci were separated in the wild × btr1-type cultivar F₂ map, but the btr2 locus and eight AFLP loci did not recombine in the wild × btr2-type cultivar F₂ map, thus slightly different levels of affinity between parental cultivars with the wild line was suggested at the btr1/btr2 locus.     

Location of genes for high grain protein percentage and other quantitative traits in wild wheat Triticum turgidum var. dicoccoides

Summary The genetic control of grain protein percentage (GPP) in the wild tetraploid wheat, Triticum turgidum var. dicoccoides, was determined by crossing four accessions of this taxonomic variety with durum cultivar Inbar, and analyzing the parents, F₁ and F₂ populations. Reciprocal crosses indicated no cytoplasmic effect on GPP. The F₂ variation was continuous in all crosses, showing no transgressive segregation. However, crosses between different accessions of var. dicoccoides showed transgressive segregation indicating the presence of different genes for high GPP in these accessions. Grain protein percentage was mostly codominant with high GPP, showing either no dominance, or a weak dominance. Heritability coefficients (broad sense) ranged from 0.30 to 0.53. Correlation coefficients between GPP and yield components were usually significantly negative, with the exception of the number of spikelets per spike, and in some crosses, grain weight.The number and chromosomal location of genes coding for high GPP were determined by the association between GPP and 27 markers (23 morphological and 4 biochemical markers). For this purpose, the genetic control of these markers, their linkage groups and chromosomal location were studied. At least four loci for high GPP that segregated in the F₂ populations are suggested: one on chromosome arm 1AS, marked by the black glume gene (Bg); one on 1BS, marked by the HMW gliadin locus Gli-B1; one on group 5, marked by the genes for beaked glume (Bkg) and toothed palea (Tp); and one on group 7, marked by the kinky neck gene (Kn). The relationship between GPP and several yield components was studied in a similar manner. In general, loci of markers that correlated positively with high GPP were not correlated with a decrease in yield components. Moreover, several loci of var. dicoccoides were associated with an increase in yield components.The utilization of markers for chromosomal location of genes coding for quantitative traits is compared to the technique of aneuploid analysis, commonly used in wheat. The significance of the above findings for breeding is discussed.     

The transformation of the photo-thermo sensitive genic male-sterile line 261S of rice via an expression vector containing the anti-Waxy gene

Transgenic photo-thermo sensitive genic male sterility Oryza sativa L. cv. “261S” plants with the anti-Waxy gene were successfully obtained using an Agrobacterium tumefaciens-mediated co-transformation method. Marker-free homozygous transgenic lines with the anti-Waxy gene were obtained. The setting seed rates of the transgenic plants via self-pollination or via crossing with the restorer line WX99075 rice and the 1000-grain weight of the transgenic plants and the F₂ hybrid seeds obtained by crossing the transgenic or non-transgenic plants with the restorer line WX99075 rice, and the number of panicles of the transgenic plants and yields of the F₂ hybrid rice, were analysed. Quality indexes of the transgenic plants and of the F₂ hybrid seeds were analysed. Our researches results indicate that hybrid female and hybrid descendant edibility could be improved via the introduction of the anti-Waxy gene, but the grain yields of the reserve seeds via self-pollination of the transgenic photo-thermo sensitive genic sterile lines and of the hybrid rice were not affected.     

Identification of a novel recessive gene for resistance to powdery mildew (Blumeria graminis f. sp. hordei) in barley (Hordeum vulgare)

One of the most important diseases of barley (Hordeum vulgare) is powdery mildew, caused by Blumeria graminis f. sp. hordei. Spring barley line 173-1-2 was selected from a Moroccan landrace and revealed broad-spectrum resistance to powdery mildew. The objective of this study was to map and characterize the gene for seedling powdery mildew resistance in this line. After crossing with the susceptible cultivar ‘Manchuria’, genetic analysis of F₂ and F₃ families at the seedling stage revealed powdery mildew resistance in line 173-1-2 conditioned by a single recessive gene. Molecular analysis of non-segregating homozygous resistant and homozygous susceptible F₂ plants conducted on the DArTseq platform (Diversity Arrays Technology Pty Ltd) identified significant markers which were converted to allele-specific PCR markers and tested among 94 F₂ individuals. The new resistance gene was mapped on the long arm of chromosome 6H. No other powdery mildew recessive resistance gene has been located on 6H so far. Therefore, we concluded that the 173-1-2 barley line carries a novel recessive resistance gene designated as mlmr.     

Breeding of transgenic rice restorer line for multiple resistance against bacterial blight, striped stem borer and herbicide

In this paper, we described the breeding of transgenic rice restorer line for multiple resistance against bacterial blight, striped stem borer (SSB) and herbicide by conventional crossing of two transgenic parental lines transformed independently with different genes. Two stable transgenic rice lines used as donor parents were developed, one was Zhongguo91 which contained cry1Ab gene (for insect resistance) and bar gene (for tolerance of herbicide), and the other was Yujing6 which contained Xa21 gene (resistance to bacterial blight). The elite restorer line Hui773 was used as recipient and crossed with the two stable transgenic rice lines. Then five successive backcrosses were made using Hui773 as recurrent parent. Two rice elite restorers, T773-1 expressing cry1Ab and bar genes and T773-2 expressing Xa21 gene, were obtained, which were confirmed by PCR analysis and testing selectable marker genes in the hybrid progenies. The cross was made between T773-1 and T773-2 to select stable restorer line carrying Xa21, cry1Ab and bar genes. Finally, we obtained transgenic restorer line T773 with good agronomic traits and obvious multiple resistance to Xanthomonas oryzae pv. oryzae, striped stem borer (Chilo suppressalis) and herbicide. The hybrid F₁ generation produced from the cross between transgenic restorer line T773 and a corresponding male sterile line Zaohua2A maintained obvious resistance to rice bacterial blight, rice leaffolder and striped stem borer, and showed significant heterosis. Our results indicate that it is feasible to develop transgenic hybrid rice cultivar through breeding transgenic restorer lines.     

Crossability and cytology of hybrid progenies in the cross between Brassica campestris and three wild relatives of B. oleracea,B. bourgeaui,B. cretica and B. montana

Summary Crossability and cytology were examined in F₁, F₂, B₁ and hybridsplants of F₁ hybrids of Brassica campestris and three wild relatives of B. oleracea, B. bourgeaui, B. cretica and B. montana, respectively. The F₂ plants were obtained after self-and open pollination of the F₁ hybrids. The B₁ and hybrid plants were produced after the F₁ hybrids backcrosses with B. campestris and crossed with B. napus, respectively. After crossing the F₁ hybrids, many seeds of the F₂, B₁ and hybrid plants were harvested. Multivalent formation was high in the chromsome configuration for the PMCs of F₂, B₁ and hybrid plants, suggesting that crossing over might occur between them. Many different types of aneuploids were obtained in the progenies of the F₂, B₁ and hybrid plants. It is suggested that different types of normal egg cells may be produced by one-by-one or little-by-little chromosome addition. The possibility is discussed of gene transfer from B. bourgeaui, B. cretica and B. montana, to cultivated plants, B. campestris and B. napus.     

Identification of segregation-distortion-neutral alleles to improve pollen fertility of indica-japonica hybrids in rice (Oryza sativa L.)

The genetics of resistance to Ascochyta blight (Ascochyta fabae f. sp. fabae) was studied in two populations of faba bean (Vicia faba). Plants of a resistant population, ILB 752, and a susceptible one, NEB 463, were screened for their reaction to the pathogen and the results were quantified on a scale of 0–5. Crosses were made between plants both within and between accessions and the F₁ and F₂ generations assessed in a field trial 21 and 45 days after inoculation. Disease scores were greater at 45 days than at 21 days and they were not significantly affected by the presence of susceptible spreader rows in part of the trial. ILB 752 carried a major dominant gene conferring resistance while NEB 463 carried the recessive allele for susceptibility. Furthermore, a minority of plants of NEB 463 appeared to carry at least one pair of complementary recessive genes, also conferring resistance. Most of the plants of ILB 752 were homozygous for the dominant resistance gene and a few were heterozygous. Reciprocal crosses behaved identically, indicating the absence of maternal effects in the expression of Ascochyta blight resistance in faba beans. The results show that it is important to confirm the level of heterozygosity for the resistance genes in this partially outbreeding species before crossing is commenced. The major dominant gene for resistance, identified in ILB 752, has clear potential for use in breeding for Ascochyta blight resistance. The minor genes identified in NEB 463 also show the potential for accumulating resistance through mass selection. This revised version was published online in July 2006 with corrections to the Cover Date.     

Characterization of transgenic male sterility in alfalfa

Dependable male sterility would help to make hybrid cultivar development a reality in alfalfa once higher levels of heterosis are attained. Alfalfa plants obtained by genetic transformation with a construct containing the Barnase gene under the control of a tobacco anther tapetum specific promoter were studied. Vacuolization and degeneration of the tapetal cell cytoplasm at a premeiotic stage of development were observed in all five transformed plants (T₀)examined, but the severity of the abnormalities varied greatly among pollen sacs of a genotype. During the meiotic stage, some pollen sacs showed reduction in size, and the tapetum generally appeared thinner when compared to those of the non transgenic plants; tapetal cells showed abnormal vacuolization and signs of cytoplasm degeneration. Despite this, some microspores were formed and some pollen grains were shed in all the T₀ plants, but these were highly variable in size and had very low in vitro germinability. Self-fertility was negligible. The T₀ plants were crossed with one or two unrelated non transgenic male-fertile plants. Mendelian segregation was observed with two exceptions. Instability of the trait in F₁ progenies was noticed, varying for different T₀ parents. F₁ plants exhibiting higher sterility than the primary transformants were observed, indicating that it should be possible to obtain good male sterile plants by backcrossing this trait into different genetic backgrounds. The possible use of this transgenic male sterility in alfalfa breeding is briefly discussed. This revised version was published online in July 2006 with corrections to the Cover Date.     

Inheritance of the Powdery Mildew Resistance Mlk in Wheat

The inheritance of the Mlk powdery mildew resistance originating from ‘Heine 2174.50’ was analyzed by crossing the Mlk resistant cultivar ‘Ralle’× cv. ‘Amor’ (highly susceptible) and vice versa and by observing the reactions of F₁- and F₂-plants after inoculation with two different Mlk avirulent powdery mildew isolates. In all cases, a 3 (resistant): I (susceptible) segregation was found in F₂. The reactions of the F₂plants against the two powdery mildew isolates were identical in each case. Therefore, it is supposed that one dominant resistant gene is responsible for the resistant reactions against these two isolates. These results support the earlier assumption of Heun and Fischbeck (1987b) that the whole Mlk resistance pattern is controlled by a single gene.     

Inheritance of Waxlessness in Kohlrabi (Brassica oleracea L. var. gongyloides) and its Utilization in Hybrid Seed Production

By genetic analysis of selfed progenies and reciprocal F₁, F₂ and B₁: populations of crosses of a waxless mutant and three waxy plants two recessive genes were identified in kohlrabi (Brassica oleracea L. var. gongyloides), causing waxlessness independently from each other. Gene a is responsible for glossy waxless and gene b tor dull waxless plants. To be able to form a wax layer a plant must have both genes in the dominant constitution, i.e. A.B. (“complementary gene effect). Some segregation results which deviate from expectation could indicate a potential linkage between one of the two wax loci and the incompatibility locus. Both genes can be used as markers m hybrid breeding of cole crops as well as in basic research.     

Genetic studies in four interspecific hybrids of the genus oryza

The paper reports the results of genetic studies made in four interspecific hybrids of the genus Oryza, and the data are employed to discuss the inter-relationships between the different species. The characters of wild parents were found to be dominant in the F₁ hybrids.In O. sativa (variety Fukoku) × O. perennis subsp. balunga, the inheritance of the eight characters studied was found to be of the same nature as that of complementary, modifying, duplicating and polygenic types involving two or three genes. In O. perennis (Cuban type) × O. perennis subsp. balunga, the interesting feature was the occurrence of recessive characters (typical of cultivated rices) in the F₂ population, even though the two parents carried the dominant wild characters. This should be possible only by the operation of duplicate genes and such a mode of inheritance was observed for three characters. No definite Mendelian ratios could be got for the remaining five characters studied. The appearance of characters of cultivated rices has been suggested to point to the ability of O. perennis to give rise to O. sativa through natural crossing and selection. In O. glaberrima × O. perennis subsp. balunga, the ten characters studied segregated in monogenic or digenic fashion. When digenic, these characters exhibited complementary or inhibitory factor interactions. In O. glaberrima × O. breviligulata, the simple mode of inheritance in the F₂ generation has been suggested to indicate the close relationship of the two species.Some of the general features of the hybrids and segregating populations studied were the vigorous and fertile F₁s followed by the appearance of weak and unthrifty plants in the F₂ generation and the tendency for the parental characters to inherit together. The appearance of plants looking similar to O. sativa var. fatua in the F₂ populations of O. sativa × O. perennis, and of O. stapfii in the F₂s of O. glaberrima × O. perennis has been supposed to provide further evidence on the hybrid origin of these two forms.     

Semi-dominant genes confer additive tolerance to metribuzin in narrow-leafed lupin (<Emphasis Type="Italic">Lupinus angustifolius</Emphasis> L.) mutants

Narrow-leafed lupin (Lupinus angustifolius L.) is a grain legume well-adapted to sandy acid soils in a Mediterranean climate. Improved metribuzin tolerance in lupin cultivars is considered essential to protect crops from herbicide damage in Australia. This paper reports on the inheritance of metribuzin tolerance in two induced mutants Tanjil-AZ-33 and Tanjil-AZ-55 over the susceptible wild type cv. Tanjil. Both mutants were highly tolerant to 800 g/ha metribuzin with no foliage damage, but cv. Tanjil died and reciprocal F₁ hybrids had intermediate tolerance with foliage damage. The F₂ populations of both crosses, Tanjil-AZ-33 × Tanjil and Tanjil-AZ-55 × Tanjil, had a segregation ratio of 1:2:1 for highly tolerant: damaged:dead plants. Progeny tests (F₃) of selected F₂ single plants confirmed that highly tolerant F₂ plants were homozygous and damaged F₂ plants were heterozygous. Clearly a single semi-dominant gene conferred metribuzin tolerance in both mutants. An allelism test revealed that the two mutants had two non-allelic tolerance genes with F₂ plants segregating in a 15:1 ratio for survival and death at 800 g/ha metribuzin. The tolerance gene in Tanjil-AZ-33 was designated as Mt3 and the gene in Tanjil-AZ-55 as Mt5. At 4,000 g/ha metribuzin, 1/16 of F₂ plants from the cross between the two mutants had no herbicide damage, suggesting the additive effects of the two tolerance genes, whilst the rest were damaged or dead. Combining these two tolerance genes, Mt3 and Mt5, increased tolerance further by approximately five-fold.     

Inheritance of internode length,plant form,and annual habit in a cross of cabbage and broccoli (Brassica oleracea var. capitata L. and var. italica Plenck.)

Summary When an inbred line of cabbage, Brassica oleracea L. var. capitata L., was crossed with an inbred line of broccoli B. oleraceae var. italica, the F₁ progeny were vigorous late annuals. All F₁ × broccoli backcross plants and 92% of the 3260 F₂ plants were annuals, while 40% of the F₁ × cabbage backcross plants were biennials. Annual habit is thus dominant and controlled by more than a single gene. Number of days to bud appearance in annuals varied continuously, and was primarily additive in inheritance. F₁ data suggested partial dominance for lateness but this was not supported by the F₂. Internode length was also continuous in distribution and primarily additive in inheritance, but with some dominance for short internodes in the F₁. Cabbage head forming ability was recessive and multigenic, with 2% of the F₂ plants forming heads, of which none were of commercial type and about half bolted as annuals. There was a significant chi square association between biennial habit and tendency for cabbage head formation. Clasping habit of terminal leaves was recessive to open leaves, multigenic, and associated with both cabbage heading and biennial habit.Technical Paper 4836, Oregon Agricultural Experiment Station; from an M.S. thesis by the senior author.     

Chloroplast-DNA variation in the wild and cultivated olives (Olea europaea L.) of Morocco

The male sterile plants that segregated in a BC₅F₂ of `C. sericeus × C. cajan var. TT-5' population were maintained by sib mating. The male sterile plants were crossed with ICPL-85012.Approximately 50% of the F₁ plants were sterile. F₂ plants derived from the fertile F₁ plants did not segregate for male sterility. The reciprocal hybrid i.e. ICPL-85012 × Fertile derivatives from C. sericeus × TT-5, did not express male sterility. However, among the 12 F₂ plant to row progenies, two segregated 25% male sterile plants and remaining 10 did not segregate. The segregation pattern in subsequent progenies revealed that the sterility was under control of a single recessive allele. Studies on the backcross and their BC₁F₂ and BC₁F₃progenies revealed another sterility gene which was found to be dominant in inheritance. This paper shows that what was thought to be cytoplasmic male sterility from C. sericeus cytoplasm is actually a single dominant gene possibly acting in concert with a single recessive gene to mimic cytoplasmic male sterility. This revised version was published online in July 2006 with corrections to the Cover Date.