Differences in ethylene sensitivity, expression of ethylene biosynthetic genes and vase life among carnation varieties

Carnation (Dianthus caryophyllus L.) is a typical ethylene-sensitive cut flower. Variations in carnation vase life and sensitivity to ethylene have been reported, but no detailed analysis has been performed to date. In order to investigate the ethylene sensitivity of different cut carnation varieties and study the effect of ethylene on postharvest physiological changes of different carnation varieties, 14 varieties were used to explore ethylene sensitivity, and six varieties were used to analyze the release pattern of endogenous ethylene and the expression pattern of related genes. The results showed that among the 14 carnation varieties, 'Master' had the strongest ethylene sensitivity and 'Snow White' had the weakest ethylene sensitivity. Ethylene release changes of 'Master' are the terminal ascending type, and 'Cloud Shium', 'Little Pink', 'Seashell', 'Freedom' and 'Snow White' are the similar ethylene leap type. Ethylene biosynthesis genes DcACS1 and DcACO1 of 'Master' were up-regulated the most, and DcACO1 of 'Snow White' was the least up-regulated. The transient silencing and overexpression of DcACS1 and DcACO1 were performed and it was found that transient silencing can significantly delay aging, and overexpression significantly accelerates aging. This study laid the foundation for further research on the molecular mechanism of ethylene regulation of postharvest senescence of cut flowers of carnation, and also indicated the direction for further breeding and artificial screening of new storage tolerant carnation species by gene editing technology

Comparative transcriptomics and proteomics analysis of citrus fruit, to improve understanding of the effect of low temperature on maintaining fruit quality during lengthy post-harvest storage

Fruit quality is a very complex trait that is affected by both genetic and non-genetic factors. Generally, low temperature (LT) is used to delay fruit senescence and maintain fruit quality during post-harvest storage but the molecular mechanisms involved are poorly understood. Hirado Buntan Pummelo (HBP; Citrus grandis × C. paradis) fruit were chosen to explore the mechanisms that maintain citrus fruit quality during lengthy LT storage using transcriptome and proteome studies based on digital gene expression (DGE) profiling and two-dimensional gel electrophoresis (2-DE), respectively. Results showed that LT up-regulated stress-responsive genes, arrested signal transduction, and inhibited primary metabolism, secondary metabolism and the transportation of metabolites. Calcineurin B-like protein (CBL)–CBL-interacting protein kinase complexes might be involved in the signal transduction of LT stress, and fruit quality is likely to be regulated by sugar-mediated auxin and abscisic acid (ABA) signalling. Furthermore, ABA was specific to the regulation of citrus fruit senescence and was not involved in the LT stress response. In addition, the accumulation of limonin, nomilin, methanol, and aldehyde, together with the up-regulated heat shock proteins, COR15, and cold response-related genes, provided a comprehensive proteomics and transcriptomics view on the coordination of fruit LT stress responses

Physicochemical, Morphological, and Functional Properties of Starches Isolated from Avocado Seeds, a Potential Source for Resistant Starch

This study compared the physicochemical and functional properties of starches from eight cultivars of avocado seeds. Amylose content, morphology, crystalline structure, swelling power, solubility, thermal and pasting properties, and in vitro digestibility were investigated. The results revealed that the apparent amylose content of starches from avocado seeds varied with different varieties. Light microscopic and scanning electron microscopic examination demonstrated that the eight starches differed slightly in terms of morphology and granule size. The X-ray diffraction and Fourier transform infrared spectroscopy analyses showed that the crystal structure and chemical linkage of the avocado seed starches were similar. However, the pasting, water solubility, and thermal properties of the eight avocado seed starches differed. Importantly, all the starches had high resistant starch content (>60%), with the highest found in Hass seeds (77.83%). To conclude, starch from avocado seeds has a high potential for use in the production of resistant starch

Chemotaxonomic Study of Citrus, Poncirus and Fortunella Genotypes Based on Peel Oil Volatile Compounds - Deciphering the Genetic Origin of Mangshanyegan (Citrus nobilis Lauriro)

Volatile profiles yielded from gas chromatography-mass spectrometry (GC-MS) analysis provide abundant information not only for metabolism-related research, but also for chemotaxonomy. To study the chemotaxonomy of Mangshanyegan, its volatile profiles of fruit and leaf and those of 29 other genotypes of Citrus, Poncirus, and Fortunella were subjected to phylogenetic analyses. Results showed that 145 identified (including 64 tentatively identified) and 15 unidentified volatile compounds were detected from their peel oils. The phylogenetic analysis of peel oils based on hierarchical cluster analysis (HCA) demonstrated a good agreement with the Swingle taxonomy system, in which the three genera of Citrus, Poncirus, and Fortunella were almost completely separated. As to Citrus, HCA indicated that Citrophorum, Cephalocitrus, and Sinocitrus fell into three subgroups, respectively. Also, it revealed that Mangshanyegan contain volatile compounds similar to those from pummelo, though it is genetically believed to be a mandarin. These results were further supported by the principal component analysis of the peel oils and the HCA results of volatile profiles of leaves in the study

Spatial and temporal distribution characteristics and source apportionment of VOCs in Lianyungang City in 2018

International audienceFrom April to September 2018, five sampling sites were selected in Lianyungang City for volatile organic compounds (VOCs) analysis, including two sampling sites in the urban area (Lianyungang City Environmental Monitoring Supersite and Mine Design Institute), one sampling site in the industrial area (Deyuan Pharmaceutical Factory), and two sampling sites from the suburb (Hugou Management Office and YuehaiLou). The results showed that the mean VOCs concentration followed this pattern: industrial area (36.06 ± 12.2 µg m$^{-3}$ ) > urban area (33.47 ± 13.0 µg m$^{-3}$) > suburban area (27.68 ± 9.8 µg m$^{-3}$). The seasonal variation of the VOCs trend in the urban and suburban areas was relatively consistent, which was different from that in industrial areas. The concentration levels of VOCs components in urban and industrial areas were relatively close, which were significantly higher than that in suburban areas. The possible sources and relative importance of VOCs in Lianyungang City atmosphere were measured by the characteristic ratio of toluene/benzene (T/B), ethane/acetylene (E/E) and isopentane/TVOCs. The contribution of traffic sources to the VOCs in Lianyungang City was significant (T/B ~ 2), and there were obvious aging phenomena in the five sampling sites (E/E > 4). The ratio of isopentane/TVOCs in the contribution of gasoline volatilization sources in urban and suburban areas was significantly bigger than that in industrial areas. According to the maximum incremental reactivity (MIR) method, aromatics (40.32–58.09%) contributed the most to ozone formation potential (OFP) at the five sampling sites. The top 10 OFP species showedthat controlling n-hexane and aromatics, such as benzene, toluene, xylene, and trimethylbenzene in Lianyungang City can effectively control ozone generation. Nineteen typical VOCs components were selected and the sources of VOCs from five sampling points were analyzed by the principal component analysis (PCA) model. The sources of VOCs in different areas in Lianyungang were relatively consistent. Five sources were analyzed at the two sampling sites in the urban area: industrial emission + plants, vehicle exhaust, fuel evaporation, combustion and industrial raw materials. Four sources were analyzed in the industrial area: industrial emission + plants, vehicle exhaust, fuel evaporation and combustion. Five sources were analyzed at the two sampling sites in the suburban area: industrial emission + plants, vehicle exhaust, fuel evaporation, combustion and solvent usag

The GRAS Salts of Na₂SiO₃ and EDTA-Na₂ Control Citrus Postharvest Pathogens by Disrupting the Cell Membrane

Sodium silicate (Na2SiO3) and ethylenediaminetetraacetic acid disodium salt (EDTA-Na2) are inorganic salts classified as ‘Generally Recognized as Safe’ (GRAS) compounds with great advantages in controlling various pathogens of postharvest fruits and vegetables. Here, we determined the median effective concentration (EC50) of Na2SiO3 (0.06%, 0.05%, 0.07% and 0.08%) and EDTA-Na2 (0.11%, 0.08%, 0.5%, and 0.07%) against common pathogens affecting postharvest citrus fruit, including Penicillium digitatum, Penicillium italicum, Geotrichum citri-aurantii, and Colletotrichum gloeosporioides. Na2SiO3 and EDTA-Na2 treatments at the EC50 decreased the spore germination rate, visibly disrupted the spore cell membrane integrity, and significantly increased the lipid droplets (LDs) of the four postharvest pathogens. Moreover, both treatments at EC50 significantly reduced the disease incidence of P. italicum (by 60% and 93.335, respectively) and G. citri-aurantii (by 50% and 76.67%, respectively) relative to the control. Furthermore, Na2SiO3 and EDTA-Na2 treatment resulted in dramatically lower disease severity of the four pathogens, while also demonstrating no significant change in citrus fruit quality compared with the control. Therefore, Na2SiO3 and EDTA-Na2 present a promising approach to control the postharvest diseases of citrus fruit