Recent development of nanotechnology has reshaped the landscape of modern science and technology, while in the meantime raised concerns about the adverse effects of nanomaterials on biological systems and the environment. [1,2] Owing to their mutual interaction, carbon-based nanomaterials readily aggregate and are not considered potential contaminants in the liquid phase. [3] However, when discharged into the environment, the hydrophobicity of nanomaterials can be averted through their interaction with natural organic matter (NOM), [4] a heterogeneous mixture of decomposed animals and plants and a major pollutant carrier [5] in nature. Consequently, mobile NOM-modified nanomaterials may pose a threat to ecological terrestrial species through further physical, chemical, and biological processes.The impact of nanomaterials on high plants has scantly been examined in the current literature. Among the studies available, [6][7][8][9][10][11][12] none have used major food crops or carbon nanoparticles (a major class of nanomaterials) for their evaluations. Although both enhanced and inhibited growth have been reported for vegetations exposed to nanomaterials at various developmental stages, [6][7][8][9][10][11][12] including seed germina-tion, root growth, and photosynthesis, fundamental questions remain regarding the uptake, accumulation, translocation, and transmission of nanomaterials in plant cells and tissues, and the impact of these processes on plant reproduction. [13] Here, we provide the first evidence on the uptake, accumulation, and generational transmission of NOM-suspended carbon nanoparticles in rice plants, the staple food crops of over half the world's population. The data presented in this Communication suggest the potential impact of nanomaterial exposure on plant development and the food chain, and prompt further investigation into the genetic consequences through plantnanomaterial interactions.NOM in freshwater ecosystems ususally has a concentration between 1-100 mg L À1 . [14] To mimic the natural ecosystems we formed a NOM solution of 100 mg L À1 in Milli-Q water and suspended fullerene C 70 and multiwalled carbon nanotubes (MWNTs) in the NOM. Using a Zetasizer (S90, Malvern Instruments) we identified three hydrodynamic diameters of 1.19 (major), 17.99, and 722.10 nm for C 70 -NOM and one major hydrodynamic diameter of 239.70 nm for MWNT-NOM (see Supporting Information, Sections 1C and 1D). The nonspecific assembly of NOM with C 70 or MWNTs is believed to be a dynamic equilibrium process [4] with the hydrophobic moieties of the NOM interacting and p-stacking with the hydrophobic carbon nanoparticle surfaces.Newly harvested rice seeds were incubated in Petri dishes that contained 15 mL of different concentrations of C 70 -NOM and MWNT-NOM in rice germination buffer. After germination at 25 AE 1 8C for 2 weeks the seedlings were transplanted to soil in big pots and grown in a green house to maturity without addition of nanoparticles. For each sample concentration, 5 pots of plants were maintained f...

MicroRNA319 (miR319) is one of the first characterized and conserved microRNA families in plants and has been demonstrated to target TCP (for TEOSINTE BRANCHED/CYCLOIDEA/PROLIFERATING CELL FACTORS [PCF]) genes encoding plant-specific transcription factors. MiR319 expression is regulated by environmental stimuli, suggesting its involvement in plant stress response, although experimental evidence is lacking and the underlying mechanism remains elusive. This study investigates the role that miR319 plays in the plant response to abiotic stress using transgenic creeping bentgrass (Agrostis stolonifera) overexpressing a rice (Oryza sativa) miR319 gene, Osa-miR319a. We found that transgenic plants overexpressing Osa-miR319a displayed morphological changes and exhibited enhanced drought and salt tolerance associated with increased leaf wax content and water retention but reduced sodium uptake. Gene expression analysis indicated that at least four putative miR319 target genes, AsPCF5, AsPCF6, AsPCF8, and AsTCP14, and a homolog of the rice NAC domain gene AsNAC60 were down-regulated in transgenic plants. Our results demonstrate that miR319 controls plant responses to drought and salinity stress. The enhanced abiotic stress tolerance in transgenic plants is related to significant down-regulation of miR319 target genes, implying their potential for use in the development of novel molecular strategies to genetically engineer crop species for enhanced resistance to environmental stress.

The Arabidopsis vacuolar H + -pyrophosphatase (AVP1), when over-expressed in transgenic (TG) plants, regulates root and shoot development via facilitation of auxin flux, and enhances plant resistance to salt and drought stresses. Here, we report that TG perennial creeping bentgrass plants over-expressing AVP1 exhibited improved resistance to salinity than wild-type (WT) controls. Compared to WT plants, TGs grew well in the presence of 100 mM NaCl, and exhibited higher tolerance and faster recovery from damages from exposure to 200 and 300 mM NaCl. The improved performance of the TG plants was associated with higher relative water content (RWC), higher Na + uptake and lower solute leakage in leaf tissues, and with higher concentrations of Na + , K + , Cl -and total phosphorus in root tissues. Under salt stress, proline content was increased in both WT and TG plants, but more significantly in TGs. Moreover, TG plants exhibited greater biomass production than WT controls under both normal and elevated salinity conditions. When subjected to salt stress, fresh (FW) and dry weights (DW) of both leaves and roots decreased more significantly in WT than in TG plants. Our results demonstrated the great potential of genetic manipulation of vacuolar H + -pyrophosphatase expression in TG perennial species for improvement of plant abiotic stress resistance.

Several types of fibrous stone called asbestos have been an unexpected cause of human cancer in the history. This form of mineral is considered precious in that they are heat-, friction-, and acid-resistant, are obtained easily from mines, and can be modified to any form with many industrial merits. However, it became evident that the inspiration of asbestos causes a rare cancer called malignant mesothelioma. Because of the long incubation period, the peak year for malignant mesothelioma is expected to be 2025 in Japan. Thus, it is necessary to elucidate the mechanisms of asbestos-induced mesothelial carcinogenesis. In this review, we summarize the cutting edge results of our 5-year project funded by a MEXT grant, in which local iron deposition and the characteristics of mesothelial cells are the key issues.

MicroRNA528 (miR528) is a conserved monocot-specific small RNA that has the potential of mediating multiple stress responses. So far, however, experimental functional studies of miR528 are lacking. Here, we report that overexpression of a rice (Oryza sativa) miR528 (Osa-miR528) in transgenic creeping bentgrass (Agrostis stolonifera) alters plant development and improves plant salt stress and nitrogen (N) deficiency tolerance. Morphologically, miR528-overexpressing transgenic plants display shortened internodes, increased tiller number, and upright growth. Improved salt stress resistance is associated with increased water retention, cell membrane integrity, chlorophyll content, capacity for maintaining potassium homeostasis, CATALASE activity, and reduced ASCORBIC ACID OXIDASE (AAO) activity; while enhanced tolerance to N deficiency is associated with increased biomass, total N accumulation and chlorophyll synthesis, nitrite reductase activity, and reduced AAO activity. In addition, AsAAO and COPPER ION BINDING PROTEIN1 are identified as two putative targets of miR528 in creeping bentgrass. Both of them respond to salinity and N starvation and are significantly down-regulated in miR528-overexpressing transgenics. Our data establish a key role that miR528 plays in modulating plant growth and development and in the plant response to salinity and N deficiency and indicate the potential of manipulating miR528 in improving plant abiotic stress resistance.Abiotic stresses, especially drought, salt, and nitrogen (N) deficiency, are limiting factors for plant growth, development, and agricultural productivity. To cope with drought and salt stresses, plants have evolved similar strategies of osmotic adjustment (Munns, 2002;Zhu, 2002). Plants also evolved salinity-specific adjustments against ionic disequilibrium, which encompass excluding salt entry into plants and compartmentalizing ions into vacuoles or old leaves (Munns, 1993;Yeo, 1998). Another worldwide limiting factor for crop yields is N deficiency, which triggers reduced leaf growth rate and photosynthetic rate (Chapin et al., 1988). Due to the sessile nature of plants, abiotic stresses are unavoidable. Therefore, it is critical to develop reliable procedures to genetically modify plants for improved performance under environmental stresses, thereby enhancing agricultural productivity to meet the ever-growing demands in food production.Genetic engineering plays an increasingly important role in agronomic trait modifications in crop species. Currently, many genes encoding functional proteins, transcription factors, and proteins involved in signaling pathways have been identified as abiotic stressresponsive genes (Shinozaki and Yamaguchi-Shinozaki, 2007;Masclaux-Daubresse et al., 2010;Turan et al., 2012). Constitutive expression of some of these genes in transgenic plants has been demonstrated to lead to enhanced salt or drought tolerance (Golldack et al., 2011;Kim et al., 2013;Lu et al., 2013;Li et al., 2014). However, details of the regulatory network in the plant...

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Heat shock proteins (HSPs) are molecular chaperones that accumulate in response to heat and other abiotic stressors. Small HSPs (sHSPs) belong to the most ubiquitous HSP subgroup with molecular weights ranging from 12 to 42 kDa. We have cloned a new sHSP gene, AsHSP17 from creeping bentgrass (Agrostis stolonifera) and studied its role in plant response to environmental stress. AsHSP17 encodes a protein of 17 kDa. Its expression was strongly induced by heat in both leaf and root tissues, and by salt and abscisic acid (ABA) in roots. Transgenic Arabidopsis plants constitutively expressing AsHSP17 exhibited enhanced sensitivity to heat and salt stress accompanied by reduced leaf chlorophyll content and decreased photosynthesis under both normal and stressed conditions compared to wild type. Overexpression of AsHSP17 also led to hypersensitivity to exogenous ABA and salinity during germination and post-germinative growth. Gene expression analysis indicated that AsHSP17 modulates expression of photosynthesis-related genes and regulates ABA biosynthesis, metabolism and ABA signalling as well as ABA-independent stress signalling. Our results suggest that AsHSP17 may function as a protein chaperone to negatively regulate plant responses to adverse environmental stresses through modulating photosynthesis and ABA-dependent and independent signalling pathways.

The excessive use of chemical pesticides brings many environmental problems. Botanical pesticides seem to be a good alternative to control pests, but their slow action and lack of residual action constrain their further application. Here, we developed a star polycation (SPc) as the drug nanocarrier that could combine matrine into a complex to decrease its particle size to the nanoscale. The combination of SPc and matrine increased the zeta potential and the noncovalent molecular interaction, such as hydrogen bonds and hydrophobic interactions playing an important role in the complex formation. The nanosized matrine/SPc complex exhibited a higher cytotoxicity and an enhanced lethal effect on insect pests compared to those of matrine alone. As a botanical pesticide adjuvant, the SPc could increase the control efficacies of matrine, D-limonene, and pyrethrin against insect pests, achieving a great improvement in toxicity and persistence. The construction of SPc provides a powerful tool for delivering pesticides to increase their control efficacies and decrease their application amounts and rates, showing great potential for sustainable pest management.