Project description:Melon is a globally commercialized fruit, and Fusarium rot disease poses a significant threat to post-harvest losses. The conventional use of fungicides raises concerns about chemical residues, prompting exploration into alternative technologies such as Pulsed Light (PL). While PL has been effective in controlling infections in various fruits and vegetables, the precise physiological responses and molecular mechanisms in melon fruits remain incompletely understood. In this study, melon fruits infected with the Fusarium pallidoroseum were treated with different doses of PL (0, 6, 9, and 12 J cm-2), and the impact on both fungal control and fruit shelf life extension was investigated. The 9 J cm-2 dose emerged as the most effective in controlling fungal growth without causing damage, inducing beneficial responses. This optimal PL dose upregulated genes in the lignan biosynthesis pathway and the infection upregulated genes involved with systemic acquired resistance, triggered by the pipecolic acid. In this way, the PL treatment and the infection trigger a double mechanism of resistance in melon fruits. A second and third experiment focused on evaluating the extension of melon fruit shelf life and the safe manipulation window post-PL treatment. The results revealed an average shelf life extension of six days and a safe manipulation period of 24 hours. The extension in shelf life was associated with a deviation in information flux from the ethylene biosynthesis to upregulation of the polyamine biosynthesis pathway, which produces nitric oxide, a product that can inhibit ethylene biosynthesis and its action. Furthermore, the observed 24-hour safety period against fungal infection post-PL treatment was characterized as a memory response resistance caused by the upregulation of lignan biosynthesis, which is a potential and efficient alternative to chemical products like fungicides. Overall, this study provides insights into the transcriptional molecular mechanisms through which PL promotes systemic acquired resistance and extends the shelf life of melon fruits.

Project description:Melon (Cucumis melo L.) is a commercially important fruit crop that is cultivated worldwide. The melon research community has recently benefited from the determination of a complete draft genome sequence and the development of associated genomic tools, which have allowed us to focus on small RNAs (sRNAs). These are short, non-coding RNAs 21â24 nucleotides in length with diverse physiological roles. In plants, they regulate gene expression and heterochromatin assembly, and control protection against virus infection. Much remains to be learned about the role of sRNAs in melon. We constructed 10 sRNA libraries from two stages of developing ovaries, fruits and photosynthetic cotyledons infected with viruses, and carried out high-throughput pyrosequencing. We catalogued and analyzed the melon sRNAs, resulting in the identification of 26 known miRNA families (many conserved with other species), the prediction of 84 melon-specific miRNA candidates, the identification of trans-acting siRNAs, and the identification of chloroplast, mitochondrion and transposon-derived sRNAs. In silico analysis revealed more than 400 potential targets for the conserved and novel miRNAs. This analysis provides insight into the composition and function of the melon small RNAome, and paves the way towards an understanding of sRNA-mediated processes that regulate melon fruit development and melonâvirus interactions. 11 small RNA libraries from several tissues of melon are included en the raw data. 2 samples from ovary, 2 samples from fruit, 1 sample from healthy cotyledons (Cultivar Tendral), 1 samples from healthy cotyledons (genotype TGR-1551), 1 sample from cotyledons (cultivar Tendral) infected with Watermelon mosaic virus (WMV), 1 sample from cotyledons (cultivar TGR-1551) infected with WMV, 1 sample from cotyledons (cultivar Tendral) infected with Melon necrotic spot virus (MNSV, Malfa5 isolate), 1 sample from cotyledons (cultivar Tendral) infected with MNSV (chimeric virus with Malfa5-264 isolates), 1 library from synthetic RNA oligos. Raw reads were obtained from two independent 454 runs, ~22,000 reads each one, to a total of 447,180 reads

Project description:Grafting is widely applied in the cultivation of melon. In this study, 'Qinmi No.1' [Cucumis melo L. (QG)] and 'Ribenxuesong' [Cucurbita maxima Duch. (RG)] were used as rootstocks for 'QingxinYangjiaocui' (Cucumis melo L.). The results showed that grafting with muskmelon rootstocks had no significant effect on fruit aroma, but grafting with pumpkin rootstocks significantly reduced the odor intensity and odor preference scores of melon fruits. Compared with the fruits from self-grafted plants (SG), four new aromatic volatiles with a sweet smell were detected, the alcohol dehydrogenase (ADH) activity was significantly decreased at 30 DAP, but unaffected at 42 DAP in QG fruits. There was no difference for alcohol acetyltransferase (AAT) activity between QG and SG fruits. The expression level of CmADH2 was significantly higher at 30 DAP and 42 DAP, but CmAAT2 was significantly lower at 42 DAP in QG fruits compared with SG fruits. In RG fruits, the main aroma compounds including butanoic acid ethyl ester, 2-methyl-2-butenal and 2-methylheptan-1-al were absent, while the volatile compounds with unpleasant odor characteristics including trans, cis-2,6-nonadien-1-ol, (E,E)-2,4-heptadienal, octanoic acid and styrene were detected. Compared with SG fruits, 1-nonanol and 1-heptanol with green odor characteristics were significantly increased, but eucalyptol and farnesene with fruity aroma characteristics were significantly decreased in RG fruits. The ADH activity of RG fruits was significantly lower than that of SG fruits at 30 DAP and the AAT activity was significantly lower than that of SG fruits at 42 DAP. In addition, the expression levels of CmADH and CmAAT homologs in RG fruits were significantly lower than those in SG or QG fruits. These results show that grafting with pumpkin rootstocks affected the main aroma components, reduced ADH and AAT activities, and down-regulated the expression levels of CmADHs and CmAATs in the melon fruits. This study reveals the mechanism of different rootstocks on melon fruit aroma quality, and lays a theoretical foundation for the selection of rootstocks in melon production. Future studies using overexpression or CRISPR/CAS system to obtain stable transgenic lines of genes encoding key aromatic volatiles, would be promising to effectively improve the flavor quality of melon.

Project description:Viruses are among the most destructive and difficult to control plant pathogens. Melon (Cucumismelo L.) has become the model species for the agriculturally important Cucurbitaceae family. Approaches that take advantage of recently developed genomic tools in melon are being extremely useful for understanding viral pathogenesis and can contribute to the identification of target genes to breed new resistant cultivars. In this work, we have used a recently described melon microarray for transcriptome profiling of two melon cultivars infected with two strains of Melon necrotic spot virus (MNSV) that only differ on their 3´-untranslated regions. Tissues of melon plants from cultivars Out of 7566 and 7074 genes deregulated by MNSV-Mα5 and MNSV-Mα5/3’264, 1851 and 1356, respectively, were strain-specific. Likewise, MNSV-Mα5/3’264 specifically deregulated 2925 and 1618 genes in Planters Jumbo and Tendral, respectively. Thus, significantly affected GO categories were clearly different for the different virus/host combinations. Grouping genes according to their patterns of expression allowed the identification of two groups specifically deregulated by MNSV-Mα5/3’264 with respect to MNSV-Mα5 in Tendral, and one group antagonistically regulated in Planters Jumbo vs. Tendral after MNSV-Mα5/3’264 infection. Genes in these three groups belong to a diversity of functional classes, and no obvious regulatory commonalities were identified. When data on MNSV-Mα5/Tendral infections were compared to equivalent data on cucumber mosaic virus or watermelon mosaic virus infections, cytokinin-O-glucosyltransferase2 was identified as the only gene deregulated by the three viruses, with infections dynamics correlating with the amplitude of transcriptome remodeling. Both common and strain-specific changes, as well as common but also cultivar-specific changes, have been identified by profiling transcriptomes of plants from two melon cultivars infected with two MNSV strains. No obvious regulatory features shared among deregulated genes have been identified, pointing toward regulation through differential functional implications. Viruses are among the most destructive and difficult to control plant pathogens. Melon (Cucumismelo L.) has become the model species for the agriculturally important Cucurbitaceae family. Approaches that take advantage of recently developed genomic tools in melon are being extremely useful for understanding viral pathogenesis and can contribute to the identification of target genes to breed new resistant cultivars. In this work, we have used a recently described melon microarray for transcriptome profiling of two melon cultivars infected with two strains of Melon necrotic spot virus (MNSV) that only differ on their 3´-untranslated regions. Tissues of melon plants from cultivars Out of 7566 and 7074 genes deregulated by MNSV-Mα5 and MNSV-Mα5/3’264, 1851 and 1356, respectively, were strain-specific. Likewise, MNSV-Mα5/3’264 specifically deregulated 2925 and 1618 genes in Planters Jumbo and Tendral, respectively. Thus, significantly affected GO categories were clearly different for the different virus/host combinations. Grouping genes according to their patterns of expression allowed the identification of two groups specifically deregulated by MNSV-Mα5/3’264 with respect to MNSV-Mα5 in Tendral, and one group antagonistically regulated in Planters Jumbo vs. Tendral after MNSV-Mα5/3’264 infection. Genes in these three groups belong to a diversity of functional classes, and no obvious regulatory commonalities were identified. When data on MNSV-Mα5/Tendral infections were compared to equivalent data on cucumber mosaic virus or watermelon mosaic virus infections, cytokinin-O-glucosyltransferase2 was identified as the only gene deregulated by the three viruses, with infections dynamics correlating with the amplitude of transcriptome remodeling. Both common and strain-specific changes, as well as common but also cultivar-specific changes, have been identified by profiling transcriptomes of plants from two melon cultivars infected with two MNSV strains. No obvious regulatory features shared among deregulated genes have been identified, pointing toward regulation through differential functional implications.

Dataset Information

RNA-seq data of melon fruits produced in different locations

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