Somatic hybridization as a tool for tomato breeding

Protoplast fusion can be used to produce somatic hybrids of species that cannot be obtained by sexual hybridization. The possibility to introgress genes from Solanum species into the cultivated tomato species Lycopersicon esculentum, and to obtain novel cytoplasm-nucleus combinations (cybrids) was considered as an important strategy to extend the genetic variation available for tomato breeding. Somatic hybrids between L. esculentum and other Lycopersicon species, as well as between L. esculentum and Solanum or Nicotiana species, have been produced. Specific mutants, genotypes with antibiotic resistances, and metabolic inhibition by iodoacetate or iodoacetamide and irradiation were used for the selection of hybrids. In addition, the improvement of protoplast culture techniques and the use of the favourable tissue culture traits derived from species such as L. peruvianum, which have been introduced into tomato by classical breeding, allowed the efficient recovery of somatic hybrids. However, the occurrence of somatic incongruity in fusion combinations of L. esculentum and Solanum and even more in L. esculentum and Nicotiana, did not allow the production of true cybrids and/or fertile hybrids, indicating the importance of both cytoplasm-nucleus and nucleus-nucleus interactions in somatic incongruity. Another problem with fusions between distantly related species is the strongly reduced fertility of the hybrids and the very limited homoeologous recombination between chromosomes of the parental species. Partial genome transfer from donor to recipient through microprotoplast (+) protoplast fusion, and the production of monosomic or disomic chromosome addition lines, light overcome some of these problems. In symmetric somatic hybrids between L. esculentum and S. tuberosum the occurrence of limited somatic and meiotic recombination was demonstrated. Fertile progeny plants could be obtained, though at a low frequency, when embryo rescue was performed on a large scale after backcrossing hexaploid somatic tomato (+) potato hybrids with a tetraploid potato genotype. The potential value of genomic in situ hybridization (GISH) and RFLPs for the analysis of the genome/chromosome composition of the hybrids has been demonstrated for intergeneric somatic hybrids between Lycopersicon and Solanum.Abbreviations cpDNA chloroplast DNA - mtDNA mitochondrial DNA     

Rapid Estimation of Glucosinolate Thermal Degradation Rate Constants in Leaves of Chinese Kale and Broccoli ( Brassica oleracea ) in Two Seasons

Kinetic modeling was used as a tool to quantitatively estimate glucosinolate thermal degradation rate constants. Literature shows that thermal degradation rates differ in different vegetables. Well-characterized plant material, leaves of broccoli and Chinese kale plants grown in two seasons, was used in the study. It was shown that a first-order reaction is appropriate to model glucosinolate degradation independent from the season. No difference in degradation rate constants of structurally identical glucosinolates was found between broccoli and Chinese kale leaves when grown in the same season. However, glucosinolate degradation rate constants were highly affected by the season (20-80% increase in spring compared to autumn). These results suggest that differences in glucosinolate degradation rate constants can be due to variation in environmental as well as genetic factors. Furthermore, a methodology to estimate rate constants rapidly is provided to enable the analysis of high sample numbers for future studies.     

Phytate, calcium, iron, and zinc contents and their molar ratios in foods commonly consumed in China

A total of 60 food samples commonly consumed in China were analyzed for phytate using the anion-exchange method and for calcium, iron, and zinc using atomic absorption spectrophotometry. The foods analyzed included those based on cereal grains and soybean. Phytate contents expressed on a wet weight basis ranged from 0 for foods made from starches to 1878 mg/100 g for dried stick-shaped soybean milk film. The calcium contents were between 2.08 mg/100 g for ground corn and 760.67 mg/100 g for diced fried soybean curd. The lowest values of iron and zinc were 0.04 mg/100 g for Panjin pearl rice cooked with discarding extra water and 0.08 mg/100 g for potato and bean starches, while the highest values of iron and zinc were observed in dried stick-shaped soybean milk film. Although many foods were relatively rich in calcium, zinc, and iron, many also contained a higher level of phytate. Of the 60 food samples, 34 foods had a phytate/calcium molar ratio >0.24, 53 foods had a phytate/iron molar ratio >1, 31 foods had a phytate/zinc molar ratio >15, and only 7 foods had a phytate x calcium/zinc >200. Phytate in foods impair the bioavailability of calcium, iron, and zinc, which to some extent depends upon food processing and cooking methods.     

A Genetic Linkage Map of Brassica rapa Based on AFLP Markers

A F2 mapping population was developed by crossing a Chinese cabbage-pe-tsai variety CC156 and an oil type Rapid cycling RC144 which were different from each other in morphology, maturity, self-compatibility, plant height, etc. Using 244 AFLP markers a map was constructed containing 10 main linkage groups covering a total distance of 857 cM,corresponding to 3.5 cM per marker. Length of linkage groups varied from 43 to 125 cM and the number of AFLP markers linkage to each group ranged from 7 to 41.     

番茄植株与白粉病菌互作过程中叶片胞间蛋白变化的初步分析

利用SDS -PAGE方法分析番茄抗白粉病过程中番茄叶片胞间蛋白 (IntercellularProtein)的变化趋势 ,比较了含有Ol 1的抗病品种和感病品种间的差异 ,从分泌蛋白的角度研究了番茄抗白粉病的机理。     

利用cDNA．AFLP技术鉴定甘蓝显性核不育基因相关表达序列

 利用cDNA—AFLP技术， 比较分析了一个甘蓝与两个青花菜自交系回交转育的显性核基因雄性不育材料与对应可育亲本植株花蕾发育过程中基因表达的差异。将花蕾混合提取RNA合成eDNA建立6个eDNA池，分析128个弓l物组合获得了26000个片段，共鉴定24个片段与雄性不育相关，其中13条表现为质的差异，11条表现为量的差异；将其中引物组合A16T15产生的300 bp左右的差异片段进行克隆测序，BLAST结果表明，该序列与花粉特异性相关的硫氧还蛋白氨基酸序列同源性达89％ 。