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951.
Laura Toppino Giampiero Valè Giuseppe Leonardo Rotino 《Molecular breeding : new strategies in plant improvement》2008,22(2):237-250
The two eggplant relatives Solanum aethiopicum gr. Gilo and Solanum aethiopicum gr. Aculeatum (=Solanum integrifolium) carry resistance to the fungal wilt disease caused by Fusarium oxysporum f. sp. melongenae, a worldwide soil-borne disease of eggplant. To introgress the resistance trait into cultivated eggplant, the tetraploid
somatic hybrids S. melongena + S. aethiopicum and S. melongena + S.
integrifolium were used. An inheritance study of the resistance was performed on advanced anther culture-derived androgenetic backcross
progenies from the two somatic hybrids. The segregation fitted a 3 resistant (R): 1 susceptible (S) ratio in the selfed populations
and a 1R:1S ratio in the backcross progenies for the trait derived from S. aethiopicum and S. integrifolium. These ratios are consistent with a single gene, which we designated as Rfo-sa1, controlling the resistance to Fusarium oxysporum f. sp. melongenae. The allelic relationship between the resistance genes from S. aethiopicum and S. integrifolium indicate that these two genes are alleles of the same locus. Bulked Segregant Analysis (BSA) was performed with RAPD markers
on the BC3/BC5 resistant advanced backcross progenies, and three RAPD markers associated with the resistance trait were identified. Cleaved
Amplified Polymorphic Sequences (CAPSs) were subsequently obtained on the basis of the amplicon sequences. The evaluation
of the efficiency of these markers in predicting the resistant phenotype in segregating progenies revealed that they represent
useful tools for indirect selection of Fusarium resistance in eggplant. 相似文献
952.
Question: Which factors determine diversity of native and alien vascular plant species in semi‐natural dry grasslands? Location: Northern limestone Alps to the southern rim of the Bohemian massif in northern Austria. Methods: In 70 randomly chosen dry grassland patches (0.008 ha ‐ 7 ha) we sampled a complete inventory of vascular plant species at each site. We analysed the correlation between species diversity of natives, archaeophytes (pre‐1500 aliens) and neophytes (post‐1500 aliens). We used GLM to study the relationship of species number (natives, neophytes, archaeophytes) to five explanatory variables (altitude, within habitat diversity, habitat diversity of adjacent areas, within land‐use diversity and land‐use in adjacent areas). Orthogonal components of these variables were derived with a PCA and used in the models. We also tested the influence of minimum residence time (MRT) and the covariables origin, mode of introduction and life form on the number of grassland sites with neophytes with analogous GLMs. Results: Native species diversity species was positively correlated with the species diversity of new, but not old invaders. GLM explains 70% of the variance in the number of native species. Patch size explained the largest part of the variation in the number of native species. PCA axes 1 and 3 were significantly related to the number of native species. Axis 1was related to on‐site habitat and land‐use diversity. The GLM of the archaeophyte diversity explains 18% of the variance. Altitude and presence of fields and grassland in the neighbourhood mainly explained archaeophyte species diversity. The GLM of neophyte diversity explains 12% of the variance. The number of neophytes was positively related to that of archaeophytes. Only PCA axis 3, which is mainly influenced by adjacent land‐use types, showed a relationship with neophytes. MRT, mode of introduction and region of origin (but not life form) were significantly related to the number of grassland sites invaded by neophytes, explaining 35% of the variance. Conclusion: Most factors governing native species diversity are not significantly related to alien species diversity. Additional determinants of the local scale diversity of alien species exist such as region of origin and historical factors (MRT, mode of introduction). 相似文献
953.
The colonization process of tomato roots inoculated separately or/and simultaneously by a pathogenic Fusarium oxysporum f. sp. lycopersici strain Fol8 and the protective F. oxysporum strain Fo47, genetically tagged with the red and green fluorescent protein genes, respectively, was studied in a hydroponic culture. Plants were coinoculated with Fol8 and Fo47 at two conidial concentration ratios of 1/1 and 1/100, in which biological control was not effective or effective, respectively. First observation of fungi on root was possible 48 h after inoculation at a high inoculum level and 5 days post inoculation at the lower concentration of inoculum. The pattern of root colonization was similar for both strains with the initial development of hyphal network on the upper part of taproot, followed by the growth of hyphae towards the elongation zone, lateral roots and root apices. Finally, the whole elongation zone and root apex were invaded by both strains but no specific infection sites were observed. When coinoculated, both strains could grow very closely or even at the same spot on the root surface. At the nonprotective ratio, Fol8 was the successful colonizer, but application of Fo47 at a concentration 100 times >Fol8 delayed vessel colonization by the pathogen. 相似文献
954.
A Gram-negative, deep brown-pigmented Gammaproteobacteria, strain IPL-1(T), capable of oxidizing indole was isolated from a lindane-contaminated site and subjected to a polyphasic taxonomic study. Most of the physiological and biochemical properties, major fatty acids (C(18:1)omega7c, C(16:1)omega7c/iso C(15:0) 2OH and C(16:0)), estimated DNA G+C content (67.2mol%) and 16S rRNA gene sequence analysis showed that strain IPL-1(T) belonged to the genus Pseudomonas. Strain IPL-1(T) exhibited highest 16S rRNA gene sequence similarity with Pseudomonas pseudoalcaligenes (99.0%), followed by Pseudomonas alcaliphila (98.7%), Pseudomonas oleovorans (98.3%), Pseudomonas nitroreducens (98.0%), Pseudomonas mendocina (97.6%) and Pseudomonas stutzeri (97.4%). However, the DNA-DNA relatedness values between strain IPL-1(T) and the closely related taxa were between 22% and 61%. On the basis of differential phenotypic characteristics and genotypic distinctiveness, strain IPL-1(T) should be classified within the genus Pseudomonas as a novel species, for which the name Pseudomonas indoloxydans is proposed. The type strain is IPL-1(T) (=MTCC 8062(T)=JCM 14246(T)). 相似文献
955.
Chiara Angelone 《Geobios》2008,41(4):445
Prolagus italicus n. sp., a new endemic Pliocene species of peninsular Italy, is described here, adding new details to the knowledge of this widespread and long-lasting ochotonid genus. Several dental morphodimensional characters suggest a close relationship between P. italicus and P. sorbinii (evaporitic and postevaporitic Messinian, central Italy). On the other hand, P. italicus shares with other Plio-Pleistocene Prolagus species of continental Europe a large size and some peculiar characters of dental occlusal surface. Actually, an evolutionary trend can be detected in Plio-Pleistocene species of the genus Prolagus. The value of P. italicus in biochronology is quite consistent, as this species seems to mark MN17 in central Italy. Moreover, some morphodimensional differences between P. italicus populations have been identified: this can help to infer relative chronological positions to the fossil sites in which P. italicus is present. Some morphological characters present in one of the two available P. italicus populations are apparently related to ecological more than to evolutionary factors: this may be a starting point for in-depth palaeoecological studies related to the genus Prolagus. The presence of P. italicus in the Italian peninsula may have prevented the entrance of other species of western European affinity. 相似文献
956.
Jens von dem Bussche Reto Spaar Hans Schmid Boris Schr?der 《Journal of Ornithology》2008,149(4):529-544
We present here a multiscale modelling approach to predict the current and future spatial distribution of Ring Ouzel (Turdus torquatus) and Blackbird (T. merula) in Switzerland. Species distribution models (SDMs) are applied on three different scales in order to analyse the scale-dependency
of predictors that describe the species’ realised niche. While the models on the macro- and mesoscales (grid of 100 and 1
km2, respectively) cover the entire country, our small-scale models are based on a small set of territories. Ring Ouzels occur
at altitudes above 1000 m a.s.l. only, while Blackbirds occur from the lowlands up to the timberline. Although both species
coexist on the macro- and mesoscales, a direct niche overlap on territory scale is rare. Small-scale differences in vegetation
cover and structure seem to play a dominant role in habitat selection. On the macroscale, however, we observed a high dependency
on bioclimatic variables that mainly represent the altitudinal range and the related forest structure preferred by both species.
Applying the models to climate change scenarios, we predict a decline of suitable habitat for the Ring Ouzel with a simultaneous
median altitudinal shift of 440 m until 2070. In contrast, the Blackbird is predicted to benefit from higher temperatures
and expand its range to higher elevations. Based on the species distribution models we (1) demonstrate the scale-dependency
of environmental predictors, (2) quantify the scale-dependent habitat requirements of Blackbird and Ring Ouzel and (3) predict
the altitudinal range shift of both species as related to climate change scenarios. 相似文献
957.
Alfredo A. Carlini Alfredo E. Zurita Gustavo J. Scillato-Yané Rodolfo Sánchez Orangel A. Aguilera 《Pal?ontologische Zeitschrift》2008,82(2):139-152
One of the basal Glyptodontidae groups is represented by the Propalaehoplophorinae (late Oligocene — middle Miocene), whose genera (Propalaehoplophorus, Eucinepeltus, Metopotoxus, Cochlops, andAsterostemma) were initially recognized in Argentinian Patagonia. Among these,Asterostemma was characterized by its wide latitudinal distribution, ranging from southernmost (Patagonia) to northernmost (Colombia, Venezuela) South America. However, the generic assignation of the Miocene species from Colombia and Venezuela (A.? acostae, A. gigantea, andA. venezolensis) was contested by some authors, who explicitly accepted the possibility that these species could correspond to a new genus, different from those recognized in southern areas. A new comparative study of taxa from Argentinian Patagonia, Colombia and Venezuela (together with the recognition of a new genus and species for the Pliocene of the latter country) indicates that the species in northern South America are not Propalaehoplophorinae, but represent the first stages in the cladogenesis of the Glyptodontinae glyptodontids, the history of which was heretofore restricted to the late Miocene — early Holocene of southernmost South America. Accordingly, we propose the recognition of the new genusBoreostemma for the species from northern South America and the restriction ofAsterostemma to the Miocene of Patagonia. Thus, the available data indicate that the Glyptodontinae would in fact have arisen in the northernmost regions of this continent. Their arrival to more southerly areas coincides with the acme of the “Age of Southern Plains”. The Propalaehoplophorinae are geographically restricted to Patagonia. 相似文献
958.
Chemistry and weak antimicrobial activities of phomopsins produced by mangrove endophytic fungus Phomopsis sp. ZSU-H76 总被引:1,自引:0,他引:1
Three metabolites named phomopsin A (1), B (2) and C (3), together with two known compounds cytosporone B (4) and C (5), were isolated from the mangrove endophytic fungus, Phomopsis sp. ZSU-H76 obtained from the South China Sea. Their structures were elucidated by spectroscopic methods, mainly by 1D and 2D NMR spectroscopic techniques. The medium-sized cyclic phenol ether based on 1 or 2 is rare in natural products. In bioassays, compounds 1, 2, and 3 had no significant antibiotic activities, but compounds 4 and 5 inhibited two fungi Candida albicans and Fusarium oxysporum with an MIC ranging from 32 to 64 microg/ml. 相似文献
959.
Caffeine and related purine alkaloids: biosynthesis, catabolism, function and genetic engineering 总被引:4,自引:0,他引:4
Details of the recently elucidated biosynthetic pathways of caffeine and related purine alkaloids are reviewed. The main caffeine biosynthetic pathway is a sequence consisting of xanthosine-->7-methylxanthosine-->7-methylxanthine-->theobromine-->caffeine. Genes encoding N-methyltransferases involved in three of these four reactions have been isolated and the molecular structure of N-methyltransferases investigated. Pathways for the catabolism of caffeine have also been studied, although there are currently no reports of enzymatic and genetic studies having been successfully carried out. Metabolism of purine alkaloids in species including Camellia, Coffea, Theobroma and Ilex plants is summarised, and evidence for the involvement of caffeine in chemical defense and allelopathy is discussed. Finally, information is presented on metabolic engineering that has produced coffee seedlings with reduced caffeine content, and transgenic caffeine-producing tobacco plants with enhanced disease resistance. 相似文献
960.
During our studies on Malaysian Laurencia species, brominated metabolites, tiomanene, acetylmajapolene B, and acetylmajapolene A were isolated from an unrecorded species collected at Pulau Tioman, Pahang along with known majapolene B and majapolene A. Acetylmajapolene A was a mixture of diastereomers as in the case of majapolene A. Tiomanene may be a plausible precursor for acetylmajapolenes B and A. In addition, three known halogenated sesquiterpenes and two known halogenated C15 acetogenins were found from other two unrecorded species collected at Pulau Karah, Terengganu and Pulau Nyireh, Terengganu, respectively. Some of these halogenated metabolites showed moderate antibacterial activity against some marine bacteria. 相似文献