Sculpting the maturation, softening and ethylene pathway: The influences of microRNAs on tomato fruits

<p>Abstract</p> <p>Background</p> <p>MicroRNAs (miRNAs), a ubiquitous class of short RNAs, play vital roles in physiological and biochemical processes in plants by mediating gene silencing at post-transcriptional (PTGS) level. Tomato is a model system to study molecular basis of fleshy fruit ripening and senescence, ethylene biosynthesis and signal transduction owing to its genetic and molecular tractability. To study the functions of miRNAs in tomato fruit ripening and senescence, and their possible roles in ethylene response, the next generation sequencing method was employed to identify miRNAs in tomato fruit. Bioinformatics and molecular biology approaches were combined to profile the miRNAs expression patterns at three different fruit ripening stages and by exogenous ethylene treatment.</p> <p>Results</p> <p>In addition to 7 novel miRNA families, 103 conserved miRNAs belonging to 24 families and 10 non-conserved miRNAs matching 9 families were identified in our libraries. The targets of many these miRNAs were predicted to be transcriptional factors. Other targets are known to play roles in the regulation of metabolic processes. Interestingly, some targets were predicted to be involved in fruit ripening and softening, such as Pectate Lyase, beta-galactosidase, while a few others were predicted to be involved in ethylene biosynthesis and signaling pathway, such as ACS, EIN2 and CTR1. The expression patterns of a number of such miRNAs at three ripening stages were confirmed by stem-loop RT-PCR, which showed a strong negative correlation with that of their targets. The regulation of exogenous ethylene on miRNAs expression profiles were analyzed simultaneously, and 3 down-regulated, 5 up-regulated miRNAs were found in this study.</p> <p>Conclusions</p> <p>A combination of high throughput sequencing and molecular biology approaches was used to explore the involvement of miRNAs during fruit ripening. Several miRNAs showed differential expression profiles during fruit ripening, and a number of miRNAs were influenced by ethylene treatment. The results suggest the importance of miRNAs in fruit ripening and ethylene response.</p

BnaMPK3 Is a Key Regulator of Defense Responses to the Devastating Plant Pathogen Sclerotinia sclerotiorum in Oilseed Rape

The disease caused by Sclerotinia sclerotiorum has traditionally been difficult to control, resulting in tremendous economic losses in oilseed rape (Brassica napus). Identification of important genes in the defense responses is critical for molecular breeding, an important strategy for controlling the disease. Here, we report that a B. napus mitogen-activated protein kinase gene, BnaMPK3, plays an important role in the defense against S. sclerotiorum in oilseed rape. BnaMPK3 is highly expressed in the stems, flowers and leaves, and its product is localized in the nucleus. Furthermore, BnaMPK3 is highly responsive to infection by S. sclerotiorum and treatment with jasmonic acid (JA) or the biosynthesis precursor of ethylene (ET), but not to treatment with salicylic acid (SA) or abscisic acid. Moreover, overexpression (OE) of BnaMPK3 in B. napus and Nicotiana benthamiana results in significantly enhanced resistance to S. sclerotiorum, whereas resistance is diminished in RNAi transgenic plants. After S. sclerotiorum infection, defense responses associated with ET, JA, and SA signaling are intensified in the BnaMPK3-OE plants but weakened in the BnaMPK3-RNAi plants when compared to those in the wild type plants; by contrast the level of both H2O2 accumulation and cell death exhibits a reverse pattern. The candidate gene association analyses show that the BnaMPK3-encoding BnaA06g18440D locus is a cause of variation in the resistance to S. sclerotiorum in natural B. napus population. These results suggest that BnaMPK3 is a key regulator of multiple defense responses to S. sclerotiorum, which may guide the resistance improvement of oilseed rape and related economic crops

Existence of solution to transpiration control problem

Transpiration control can avoid change of the shape of a high-speed vehicle resulting from ablation of the nose, therefore also can avoid the change of the performance of Aerodynamics. Hence it is of practical importance. A set of mathematical equations and their boundary conditions are founded and justified by an example of non-ablation calculation in reference [1]. In [2], the ablation model is studied by the method of finite differences, the applicable margin of the equations is estimated through numerical calculation, and the dynamic responses of control parameters are analyzed numerically. In this paper we prove that the solution to transpiration control problem given in [1] exists uniquely under the assumption that the given conditions (i.e. given functions) are continuous

Genesis and hydrocarbon significance of vesicular welded tuffs: A case study from the Fengcheng Formation, Wu-Xia area, Junggar Basin, NW China

On the basis of a large number of core and thin-section observations, the petrologic and pore evolution characteristics of welded tuffs in the Fengcheng Formation in the Wu-Xia area, Junggar Basin, are evaluated, and the genesis of vesicular welded tuffs and the formation mechanism of vesicles are analyzed. Volcanic activity in the Fengcheng Formation is characterized by welded pyroclastic rocks. There are predominant plastic shards with rounded edges and obvious devitrification in the rocks. Plastic debris (fiamme) is commonly deformed and wrinkled, and crystal fragments are usually corroded. A lot of lithophysae occur in the welded tuffs, and the welded texture is obscured due to the occurrence of these lithophysae features. Vesicles are the cavities of lithophysae, which are formed by solidification contraction. They have little or no late filling cement because the volatile constituent and water vapour in the bubbles have escaped with the help of devitrification. Lithophysae distribution within a cooling unit are characterized by vertical zonation: increasing upwards but decreasing gradually later. The cavities of lithophysae have greatly improved the reservoir quality of welded tuffs. Influenced by the intensive welding process, lithophysae are not subject to collapse or damage. In the study area, deeply buried vesicular welded tuffs are important hydrocarbon reservoir rocks, and the vesicular welded tuff has good petroliferous properties. Key words: welded tuffs, vesicle, lithophysa, pyroclastic flow, Fengcheng Formation, Wu-Xia area, Junggar Basi

Functional Analysis and RNA Sequencing Indicate the Regulatory Role of Argonaute1 in Tomato Compound Leaf Development.

Regardless of whether a leaf is simple or compound, the mechanism underlying its development will give rise to a full comprehension of plant morphogenesis. The role of Argonaute1 (AGO1) in the development of simple leaves has been established, but its role in the development of compound leaves remains to be characterized. In this paper, a virus-induced gene silencing (VIGS) strategy was used to dramatically down-regulate the expression of AGO1 ortholog in tomatoes, a model plant for research into compound leaves. AGO1-silenced tomato compound leaves exhibited morphological defects of leaf adaxial-abaxial and trichome development. Analysis of global gene expression profiles indicated that the silencing of AGO1 in tomato compound leaf caused significant changes in the expression of several critical genes, including Auxin Response Factor 4 (ARF4) and Non-expressor of PR5 (NPR5), which were involved in adaxial-abaxial formation and IAA15 that was found to contribute to growth of trichomes as well as Gibberellic Acid Insensitive (GAI) which participated in hormone regulation. Collectively, these results shed light on the complicated mechanism by which AGO1 regulates compound leaf development

Synthesis and optical properties of three novel functional polyurethanes bearing nonlinear optical chromophoric pendants with different pi electron conjugation bridge structure

High molecular weight functional polyurethanes bearing large pi electron conjugated chromophoric pendants with different conjugation bridge structure, poly(1a), poly(1b), and poly(1e), were synthesized and characterized by FTIR, H-1 NMR and UV-vis absorption spectra. Their optical properties were evaluated by optical limiting and nonlinear optical analyses. The results show that these polymers possess good optical limiting and large nonlinear optical properties, which are attributed to the long D-pi-A conjugated pi electron structure of the NLO-chromophoric segment. Poly(la) with C=C double bond as pi electron conjugation bridge shows better optical limiting property than poly(1b) and poly(1c) with C=N or N=N double bond as conjugation bridge structure under the same linear transmittance, while poly(le) with N=N double bond as pi electron conjugation bridge of the NLO-chromophoric segment is superior on nonlinear optical properties to poly(la) and poly(1b) with C=C and C=N double bonds as pi electron conjugation bridge structure, respectively. (c) 2006 Elsevier Ltd. All rights reserved

Lycopene Is Enriched in Tomato Fruit by CRISPR/Cas9-Mediated Multiplex Genome Editing

Numerous studies have been focusing on breeding tomato plants with enhanced lycopene accumulation, considering its positive effects of fruits on the visual and functional properties. In this study, we used a bidirectional strategy: promoting the biosynthesis of lycopene, while inhibiting the conversion from lycopene to β- and α-carotene. The accumulation of lycopene was promoted by knocking down some genes associated with the carotenoid metabolic pathway. Finally, five genes were selected to be edited in genome by CRISPR/Cas9 system using Agrobacterium tumefaciens-mediated transformation. Our findings indicated that CRISPR/Cas9 is a site-specific genome editing technology that allows highly efficient target mutagenesis in multiple genes of interest. Surprisingly, the lycopene content in tomato fruit subjected to genome editing was successfully increased to about 5.1-fold. The homozygous mutations were stably transmitted to subsequent generations. Taken together, our results suggest that CRISPR/Cas9 system can be used for significantly improving lycopene content in tomato fruit with advantages such as high efficiency, rare off-target mutations, and stable heredity

Analysis of the Coding and Non-Coding RNA Transcriptomes in Response to Bell Pepper Chilling

Increasing evidence suggests that long non-coding RNAs (lncRNAs), circular RNAs (circRNAs), and microRNAs (miRNAs) have roles during biotic and abiotic stress, though their exact contributions remain unclear. To explore their biological functions in response to chilling in bell pepper, we examined their accumulation profiles by deep sequencing and identified 380 lncRNAs, 36 circRNAs, 18 miRNAs, and 4128 differentially expressed mRNAs in the chilled versus the non-chilled fruit. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses revealed differentially expressed genes and putative ncRNA targets, including transcription factors of multiple classes, such as myeloblastosis (MYB), basic helix-loop-helix (bHLH), and ethylene response factor (ERF) transcription factors (TFs), enzymes involved in bio-oxidation and oxidative phosphorylation (serine/threonine-protein kinase, polyphenol oxidase, catalase, peroxidase, lipoxygenase, and ATPase), and cell wall metabolism-related enzymes (beta-galactosidase, pectate lyase, pectinesterase, and polygalacturonase). On the basis of the accumulation profiles, a network of putatively interacting RNAs associated with bell pepper chilling was developed, which pointed to ncRNAs that could provide the foundation for further developing a more refined understanding of the molecular response to chilling injury