Identification of novel small RNAs in tomato (<Emphasis Type="Italic">Solanum lycopersicum</Emphasis>)

To date, the majority of plant small RNAs (sRNA) have been identified in rice, poplar and Arabidopsis. To identify novel tomato sRNAs potentially involved in tomato specific processes such as fruit development and/or ripening, we cloned 4,018 sRNAs from tomato fruit tissue at the mature green stage. From this pool of sRNAs, we detected tomato homologues of nine known miRNAs, including miR482; a poplar miRNA not conserved in Arabidopsis or rice. We identified three novel putative miRNAs with flanking sequence that could be folded into a stem-loop precursor structure and which accumulated as 19-24nt RNA. One of these putative miRNAs (Put-miRNA3) exhibited significantly higher expression in fruit compared with leaf tissues, indicating a specific role in fruit development processes. We also identified nine sRNAs that accumulated as 19–24nt RNA species in tomato but genome sequence was not available for these loci. None of the nine sRNAs or three putative miRNAs possessed a homologue in Arabidopsis that had a precursor with a predicted stem-loop structure or that accumulated as a sRNA species, suggesting that the 12 sRNAs we have identified in tomato may have a species specific role in this model fruit species. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

绢蒿属8种植物果实微形态特征及其分类学意义

为寻找绢蒿属系统学的新证据,应用解剖镜和扫描电镜对我国8种绢蒿属植物的果实微形态特征进行了比较观察。结果表明,绢蒿属8种植物果实形状相似性较高,呈倒卵形或长倒卵形,直或稍弯曲;果脐圆形,常偏向一侧;顶端中央均可见花柱残留物,边缘具衣领状环;果实表面纹饰为搓板状和不规则皱褶纹饰。这些果实微形态特征中,果实的表面纹饰具有一定的差异,特别是次级结构,可作为绢蒿属植物区分种的参考性状之一。     

Evaluation of Eupatorium cannabinum Linn. oil in enhancement of shelf life of mango fruits from fungal rotting

Essential oils extracted from 17 higher plants belonging to different families were screened against Botryodiplodia theobromae and Colletotrichum gloeosporioides causing stem end rot disease and anthracnose disease in mango respectively. The essential oil of Eupatorium cannabinum was found to be fungitoxic in nature against both the mango-rotting fungi. Eupatorium oil was standardized through physico-chemical and fungitoxic properties. Gas Liquid Chromatography (GLC) analysis of the oil led to the identification of 16 components, which represented 77.97% of the oil. Germacrene D (16.11%) was found to be the major component. The oil showed a broad fungitoxic spectrum and was recorded to be more efficient than some synthetic fungicides. The oil also showed an inhibitory effect on pectinase and cellulase enzymes. The oil enhanced the shelf life of mango fruits by protecting from fungal rotting when tested as a fumigant. The LD₅₀ of Eupatorium oil was found to be 22.01 ml/kg body weight on mammalian mice.     

Isolation and characterization of the gene encoding a chitin synthase with a myosin motor-like domain from the edible basidiomycetous mushroom, <Emphasis Type="Italic">Lentinula edodes</Emphasis>, and its expression in the course of fruit-body formation

We isolated and characterized the genomic and complementary DNAs encoding a chitin synthase from an edible basidiomycetous mushroom, Lentinula edodes. The gene (which we designated Lechs1) contains a large open reading frame encoding a polypeptide of 1937 amino acid residues. The open reading frame is interrupted by 14 small introns (49–116 bp). The gene product (LeChs1) consists of a myosin motor-like domain in its N-terminal half and a chitin synthase domain in its C-terminal half, analogous to the class V and VI chitin synthases of other filamentous fungi. Phylogenetic analysis demonstrated that LeChs1 is classified into class VI chitin synthases. Southern blot analysis indicated that Lechs1 is a single-copy gene per haploid genome and that L. edodes has no other highly homologous chitin synthase genes. Northern blot analysis revealed that Lechs1 is expressed throughout the whole stages of fruit-body formation of L. edodes, but its expression level gradually declines in a fruit body-maturation-dependent manner with highest expression in vegetative mycelia and fruit body at the early stage of maturation (immature fruit body). This is the first report on the isolation and characterization of the gene encoding a chitin synthase with a myosin motor-like domain from basidiomycetes.     

Expression of phytoene synthase gene (Psy) is enhanced during fruit ripening of Cara Cara navel orange (Citrus sinensis Osbeck)

Citrus is an important fruit crop as regards accumulation of carotenoids. In plant carotenoid biosynthesis, phytoene synthase gene (Psy) plays a key role in catalyzing the head-to-head condensation of geranylgeranyl diphosphate molecules to produce colorless phytoene. In the present paper, we reported the phytoene contents determination and characterization of Psy during fruit ripening of “Washington” navel orange and its red-fleshed mutant “Cara Cara”. Results showed that phytoene was exclusively accumulated in peel and pulp of “Cara Cara”. Although phytoene was observed accumulating with fruit ripening of “Cara Cara”, the contents in pulp were 10 times higher than those in peel. The isolated two Psy cDNAs were both 1520 bp in full length, containing 436 deduced amino acid residues, with a different amino acid at 412th. Genomic hybridization results showed that one or two copies might be present in “Cara Cara” and “Washington” genomes. During “Cara Cara” and “Washington” fruit coloration, expression of Psy was observed to be up-regulated, as revealed by tissue specific profiles in the flavedo, albedo, segment membrane and juice sacs. However, Psy expression in albedo of “Cara Cara” was higher than that in “Washington”, as evidenced by phytoene accumulation in the peel.     

Fruit removal efficiency and success: influence of crop size in a neotropical treelet

The reproductive success of animal-dispersed plants is closely linked to the number of seeds that they are able to disperse. The fruit crop size hypothesis states that a plant with large fruit crop size will attract more dispersers than a plant with a smaller fruit crop, which may result in more seeds being dispersed from the foremost. In this study, we experimentally examined the effect of crop size and other factors on primary seed dispersal in a neotropical shrub/tree, Casearia corymbosa (Flacourtiaceae). We used two predictive variables of reproductive success, which produce an accurate picture of seed dispersal ratio: fruit removal efficiency (proportion of a fruit crop removed by frugivores) and fruit removal success (relative contribution of each individual tree to the number of fruits removed in the population). We established two levels of fruit crop size at the C. corymbosa individuals, using plants with large (150 fruits) and small crops (50 fruits). We found that individual plants with larger crops had significantly higher values of fruit removal efficiency (92.6%) and success (5%) than plants with smaller crops (69.3% and 1.3%, respectively). Fruit removal efficiency was related to vegetation type, plant height and fruit width, but the variance explained by these variables was low ( < 8%). Fruit removal success was significantly related to crop size ( > 90% of the variance explained). These results suggest that fruit removal efficiency and success are strongly related to fruit crop size of C. corymbosa plants.     

Biohydrogen from thermophilic co-fermentation of swine manure with fruit and vegetable waste: maximizing stable production without pH control

Hydrogen production by dark fermentation may suffer of inhibition or instability due to pH deviations from optimality. The co-fermentation of promptly degradable feedstock with alkali-rich materials, such as livestock wastes, may represent a feasible and easy to implement approach to avoid external adjustments of pH.Experiments were designed to investigate the effect of the mixing ratio of fruit-vegetable waste with swine manure with the aim of maximizing biohydrogen production while obtaining process stability through the endogenous alkalinity of manure.Fruit-vegetable/swine manure ratio of 35/65 and HRT of 2 d resulted to give the highest production rate of 3.27 ± 0.51 L_H2 L⁻¹ d⁻¹, with a corresponding hydrogen yield of 126 ± 22 mL_H2 g⁻¹_VS-added and H₂ content in the biogas of 42 ± 5%. At these operating conditions the process exhibited also one of the highest measured stability, with daily productions deviating for less than 14% from the average.     

Alleviation of frost damage to pear flowers by application of gibberellin

Adverse effects of gibberellin applications on pear trees after frost such as small fruit size, abnormal fruit shape and poor return bloom are often attributed both to the sole use of GA₃ and its overdose. It is unclear whether protection against spring frosts before flower opening is more efficient when GA is applied directly after frost, i.e. before flower opening, or at full bloom or both. In April 2003, early spring frosts at Klein-Altendorf near Bonn, Germany damaged ca. 88% flowers of the early flowering cv. Alexander Lucas, 64% of cv. Conference and ca. 25% of flowers of the later flowering cv. Comice pears. Hence, the objective of the present work was to investigate the optimum timing of the application of low doses of the combined GA₃ and GA_{4 + 7} to improve parthenocarpic fruit set in pears, while maximising fruit quality and size for trees affected by a severe spring frost before full bloom. Return bloom was also considered and quantified. Frost-affected pear trees were treated with gibberellin GA₃+GA_{4 + 7}, either immediately after the frost, at the white bud stage, or at full bloom or both to improve parthenocarpic set. Early flowering cv. Alexander Lucas pear was most affected by the early spring frost, but lost only 25% of fruitlets at June drop, irrespective of GA treatment. June drop was, however, severe in the two other cultivars least affected by frost, i.e. by 33% in cv. Conference and 55% in cv. Comice. Both initial and final fruit set were significantly increased by a combined application of GA₃+GA_{4 + 7} at full bloom, without affecting return bloom, but June drop was also enhanced by GA application. The largest positive effect of GA application on fruit yield, an additional 2 kg of fruit per tree equivalent to €1200/ha, was apparent with the cv. Alexander Lucas, i.e. the cultivar most affected by frost. There was no loss in fruit quality viz fruit size after any of the GA applications with any of the pear cultivars examined and no increase in abnormally-shaped, elongated fruit.