A protocol with a high rate of transformation and regeneration of `Hibush' eggplant (Solanum melongena L.) has been developed. This protocol used leaves of in vitro-grown seedlings as a source of explants. The shoot regeneration culture medium contained 0.1 μm thidiazuron (TDZ) combined with 10 to 20 μm N6-[isopentyl] adenine (2iP). Adding TDZ significantly improved regeneration efficiency and produced a mean of 15 buds and 3 to 4 shoots per explant. When explants were cocultivated with Agrobacterium tumefaciens strains Q10, Q20, Q30, Q40, Q201, Q202, Q203, or Q204 containing the native cryIIIB Bacillus thuringiensis (Bt), neomycin phosphotransferase (NPTII), and β-glucuronidase (uidA) genes, a callus/bud regeneration frequency of 38.8% was observed on the selection medium. Kanamycin at 50 μg·mL-1 was most effective in selecting for transgenic buds and shoots. Augmentin at 300 μg·mL-1 was used to eliminate A. tumefaciens. Augmentin also enhanced shoot proliferation. A transformation/regeneration efficiency of 20.8% was observed for shoot production. More than 400 putative transgenic plants have been produced with this method. From 50 putative transgenic plants, gene integration has been confirmed with Southern blot analysis and progeny tests.
Sharon Billings, Gojko Jelenkovic, Chee-Kok Chin and Jodi Eberhardt
V.M. Russo and T.D. Abney
The effect of soil CO2 on the development of vegetable crops is not well-understood. An inexpensive and simple method for monitoring soil CO2 levels is needed to study those effects. A soil gas extraction apparatus was constructed from polyvinyl chloride (PVC) pipe, tygon tubing, and Plexiglas. The apparatus was placed into soil covered with black plastic or spray-on mulch or left bare. Gas samples were collected twice weekly after canopy closure of eggplant (Solanum melongena L., cv Black Bell) and continued through the last harvest. A vacuum pump was used to pull gas samples from 16 inches (41 cm) below the soil surface for collection in an airtight foil bag. The CO2 levels, recorded over time and between treatments, was determined with detector tubes available commercially and compared to gas chromatography results. Detector tube CO2 levels were comparable to the samples from the same bags measured by gas chromatography. This system was able to monitor differences in soil CO2 levels between treatments and over time.
M. Moriondo, M. Bindi and T. Sinclair
Crop growth simulation models have been mainly developed to simulate final yield reliably. Thus, a main challenge in these models is the definition of a stable method for expressing the growth of harvested organs (e.g., fruit, seed, tuber, etc.). Generally, two approaches have been used: growth rate analysis of harvested organs [yield growth rate (YGR)] and analysis of harvest index (HI) increase over time (dHI/dt). This work aims to: 1) examine whether YGR and dHI/dt increase linearly over much of growing period, and 2) compare the two growth indices in terms of stability across a number of treatments, in order to identify which is the best indicator of harvest-organ growth. This analysis has already been performed for a large number of field crops, including wheat (Triticum aestivum L.), sunflower (Helianthus annuus L.), soybean [Glycine max L. (Merr.)], and pea (Pisum sativum L.), but it has never been attempted in crops where final yield is not simply seeds. In this study, YGR and dHI/dt performances for tomato (Lycopersicum esculentum Mill.), potato (Solanum tuberosum L.), and eggplant (Solanum melongena L.) were compared using 21, 18, and 4 datasets, respectively. Results indicated that both descriptors of harvest-organ growth increased linearly for most of the growth period, whilst the comparison among the two variables in terms of stability showed that, although a direct statistical test failed, dHI/dt was more suitable to describe harvest-organ growth (smaller coefficient of variability) under a large range of crop management conditions (e.g., irrigation, sowing date, planting density, and water salt concentration).
Jaume Prohens, José M. Blanca and Fernando Nuez
Eggplant (Solanum melongena L.) was introduced by the Arabs into Spain. Since then, many local cultivars have arisen. These materials are grouped in four cultivar groups: “round,” “semi-long,” “long,” and “listada de Gandía.” We studied the morphological and molecular [amplified fragment length polymorphism (AFLP)] diversity of a collection of 28 Spanish traditional cultivars of eggplant. Four eggplant accessions from different origins were used as controls and three scarlet eggplant (Solanum aethiopicum L.) accessions as outgroups. Morphology and AFLP markers showed that S. melongena and S. aethiopicum are separate taxonomic entities, and that, compared to controls, Spanish eggplants are very variable, indicating that the Iberian Peninsula can be regarded as a secondary center of diversity. Morphological differences were found among cultivar groups in traits other than those used for the grouping although, in some cases, accessions from different cultivar groups shared a similar general morphology. Eggplant cultivar groups also showed some genetic differences, which are revealed in the gene diversity statistics (GST = 0.30). Nonetheless, no individual AFLP markers specific and universal to one cultivar group could be found. “Round” cultivars were genetically more diverse than the other cultivar groups. A positive correlation (r = 0.68) was found between morphological and molecular distances. However, correlations between geographical and either morphological or molecular distances were low. Results suggest that evolution of eggplants in Spain has involved frequent hybridizations and a frequent movement and exchange of seeds. Structure of diversity among regions indicates that most of the diversity can be collected in single selected regions. All these results have important implications in eggplant germplasm conservation and breeding.
Fotios Bletsos, Costas Thanassoulopoulos and Demetrios Roupakias
Eggplant (Solanum melongena L.) seedlings (`Tsakoniki') were grafted by hand on the Verticillium dahliae Kleb. resistant wild species Solanum torvum Sw. (GST) and Solanum sisymbriifolium Lam. (GSS). Grafted and nongrafted eggplants were transplanted to a fumigated soil with methyl bromide and to infested soil with microsclerotia of V. dahliae. Grafted plants were more vigorous, as measured by plant height, main stem diameter, and root system weight, than the nongrafted `Tsakoniki'. This resulted in an increased early production (GST, 45.5%; GSS, 18.4%) and late production (GST, 69.3%; GSS, 59.2%) as compared to the noninfected controls. The mean yield reduction (over years) in early production caused by the disease, as compared to the controls grown in fumigated soil, was 29.4%, 36.6%, and 77.9% for eggplant grafted on S. torvum, S. sisymbriifolium, and nongrafted plants, respectively. This yield reduction in total production was 6.9%, 20.5%, and 56.8%, respectively. The disease incidence in ungrafted plants was 96% and 100% during early and late harvest periods. In contrast, the disease incidence in grafted plants was significantly lower, averaging 28.1% (GST) and 52.6% (GSS) in early production, and 37.6% and 79.3%, respectively, in late production. Solanum torvum was found more resistant than S. sisymbriifolium, because grafted infected plants developed mild symptoms, as indicated by significantly lower leaf symptom index (average value 1.2 and 2.22) and disease index (average value 1.55 and 3.38), respectively. In conclusion, grafting of eggplant on either wild species had positive effects on growth, production, and verticillium wilt control.
John R. Stommel and Bruce D. Whitaker
Eggplant (Solanum melongena L.) is ranked among the top ten vegetables in terms of oxygen radical absorbance capacity due to its fruit's phenolic constituents. Several potential health promoting effects have been ascribed to plant phenolic phytochemicals. We report here a first evaluation of phenolic acid constituents in eggplant fruit from accessions in the USDA eggplant core subset. The core subset includes 101 accessions of the cultivated eggplant, S. melongena, and 14 accessions representing four related eggplant species, S. aethiopicum L., S. anguivi Lam., S. incanum L., and S. macrocarpon L. Significant differences in phenolic acid content and composition were evident among the five eggplant species and among genotypes within species. Fourteen compounds separated by HPLC, that were present in many but not all accessions, were identified or tentatively identified as hydroxycinnamic acid (HCA) derivatives based on HPLC elution times, UV absorbance spectra, ES-—MS mass spectra, and in some cases proton NMR data. These phenolics were grouped into five classes: chlorogenic acid isomers, isochlorogenic acid isomers, hydroxycinnamic acid amide conjugates, unidentified caffeic acid conjugates, and acetylated chlorogenic acid isomers. Among S. melongena accessions, there was a nearly 20-fold range in total HCA content. Total HCA content in S. aethiopicum and S. macrocarpon was low relative to S. melongena. A S. anguivi accession had the highest HCA content among core subset accessions. Chlorogenic acid isomers ranged from 63.4% to 96% of total HCAs in most core accessions. Two atypical accessions, S. anguivi PI 319855 and S. incanum PI500922, exhibited strikingly different HCA conjugate profiles, which differed from those of all other core subset accessions by the presence of several unique phenolic compounds. Our findings on eggplant fruit phenolic content provide opportunities to improve eggplant fruit quality and nutritive value.
Qi Chen, Gojko Jelenkovic, Chee-Kok Chin, Sharon Billings, Jodi Eherhardt, Joseph C. Goffreda and Peter Day
Three constructs of a coleopteran toxic cryIIIB Bacillus thuringiensis gene were engineered and incorporated into eggplant (Solanum melongena L.). Southern blot analysis of the eight primary transformants and segregational analysis of their R, progenies indicated that the chimeric cryIIIB constructs in each of the transgenic plants were stably incorporated at a single locus or at multiple sites within the same linkage group and that they were regularly transmissible to the progeny. The results of Northern blot and RNase protection analyses demonstrated that transcription of the cryIIIB mRNA takes place in plant cells, but only a small amount of the expected entire length transcripts were produced. The amount of the 5' end mRNA fragment produced was at least 30 to 40 times more abundant than the amount of the 3' end mRNA fragment. This could be interpreted to mean that either the two ends of the mRNA are of different stability or that the transcription process is often interrupted and only a few mRNAs complete the entire process to the end. When the transgenic plant mRNA was reverse-transcribed, amplified by polymerase chain reaction, and hybridized to the cryIIIB probe, two smaller molecular weight mRNA species were identified. Thus, the preponderance of the cryIIIB mRNA in transgenic plants exists as a truncated species, a situation similar to that of cryI genes when expressed in transgenic plants. Seedlings from the eight independent transgenic plants were tested for Coleopteran insect resistance. However, they did not demonstrate any significant resistance to the first and second instar larvae of the Colorado potato beetle (Leptinotarsa decemlineata Say).
Ya-Long Qin, Xiao-Chun Shu, Wei-Bing Zhuang, Feng Peng and Zhong Wang
Breed. 2 6 861 866 Magioli, C. Rocha, A.P.M. de Oliveira, D.E. Mansu, E. 1998 Efficient shoot organogenesis of eggplant ( Solanum melongena L.) induced by thidiazuron Plant Cell Rpt. 17 661 663 Matsuoka, H. Hinata, K. 1979 NAA-induced organogenesis and
Md. Mizanur Rahim Khan, Mst. Hasnunnahar and S. Isshiki
Solanum amphidiploids and their resistance to bacterial wilt Sci. Hort. 49 181 196 Bletsos, F. Roupakias, D. Tsaktsira, M. Scaltsoyjannes, A. 2004 Production and characterization of interspecific hybrids between three eggplant ( Solanum melongena L
Dalia Taher, Mohamed Rakha, Srinivasan Ramasamy, Svein Solberg and Roland Schafleitner
. Scaltsoyjannes, A. 2004 Production and characterization of interspecific hybrids between three eggplant ( Solanum melongena L.) cultivars and Solanum macrocarpon L Scientia Hort. 101 11 21 Bostanian, N.J. Trudeau, M. Lasnier, J. 2003 Management of the two