Editorial: Rhizosphere conversation among the plant-plant microbiome-soil under consecutive monoculture regimes

[no abstract available

The role of silicon to increase arsenic tolerance in rice (oryza sativa l.) seedlings by reinforcing anti-oxidative defense

Arsenic is a toxic metalloid which can cause severe problems to plants. On the other hand, silicon is a beneficial element, which supports plants to build resistance under stressed conditions. The objective of the present study was to assess the effect of silicon and arsenic on the various enzymatic, and non-enzymatic antioxidants, in shoots and roots of two rice seedlings (Du-WT and DUOE), for one and two weeks. Seedlings were exposed to four different culture media: a) Control; b) 0.70 mM Si+no As; c) 30 μM As+no Si; d) 30 μM As+0.70 mM Si. Culture media and rice genotypes were arranged in a 8-treatment factorial with three replications. Results showed that response to silicon, arsenic and or combination of them in unstressed rice plants followed similar patterns, and varied depending upon the antioxidant. The addition of As always decreased the values, but together with silicon there was a partial recovery of them. The pattern of plant response was similar regardless the plant tissue or time of exposure to As. Transgenic Dullar rice, under As stress conditions, activated the highest level of antioxidants, especially when seedlings were treated with silicon.Rol del silicio en el incremento de la tolerancia al arsénico en plántulas de arroz mediante el refuerzo de la defensa antioxidativa El arsénico es un metaloide tóxico que puede causar graves problemas a las plantas. Por su parte, el silicio es un elemento beneficioso, que ayuda a desarrollar resistencia en condiciones de estrés. El objetivo del presente estudio fue evaluar el efecto del silicio y el arsénico sobre diversos antioxidantes enzimáticos y no enzimáticos, en brotes y raíces de plántulas de dos genotipos de arroz (Du-WT y DU-OE), durante 1 y 2 semanas. Las plántulas fueron expuestas a cuatro medios de cultivo diferentes: a) Control; b) 0,70 mM Si+no As; c) 30 μM As+no Si; d) 30 μM As+0.70 mM Si. Los medios de cultivo y los genotipos de arroz se organizaron en un factorial de 8 tratamientos con three repeticiones. La respuesta al silicio, el arsénico, y la combinación de ellos en plantas sin estrés siguió patrones similares y varió según el antioxidante. La adición de As siempre disminuyó los valores, pero junto con el silicio produjo una recuperación parcial de los mismos. El patrón de respuesta de la planta fue similar, independientemente del tejido o el tiempo de exposición al As. El arroz Dullar transgénico, bajo condiciones de estrés, activó el nivel más alto de antioxidantes, especialmente cuando las plántulas fueron tratadas con silici

Usage of Si, P, Se, and Ca Decrease Arsenic Concentration/Toxicity in Rice, a Review

Rice is one of the most important routes for arsenic to enter the human food chain and threatens more than half of the world’s population. In addition, arsenic-contaminated soils and waters increase the concentration of this element in various tissues of rice plants. Thus, direct or indirect—infecting livestock and poultry—increase diseases such as respiratory diseases, gastrointestinal tract, liver, and cardiovascular diseases, cancer, and ultimately death in the long term. Therefore, finding different ways to reduce the uptake and transfer of arsenic by rice would reduce the contamination of rice plants with this dangerous element and improve animal and human nutrition and ultimately disease and mortality. In this article, we aim to take a small step in improving sustainable life on earth by referring to the various methods that researchers have taken to reduce rice contamination by arsenic in recent years. Adding micronutrients and macronutrients as fertilizer for rice is one way to improve this plant’s growth and health. In this study, by examining two types of macronutrients and two types of micronutrients, their role in reducing arsenic toxicity and absorption was investigated. Therefore, both calcium and phosphorus were selected from the macronutrients, and selenium and silicon were selected from the micronutrients, whose roles in previous studies had been investigated

Molecular physiological mechanism on consecutive monoculture problems of Rehmannia glutinosa

Rehmannia glutinosa, a famous Chinese medicinal plant, is not suitable for consecutive monoculture, because there are autotoxic metabolites excreted by its tuberous roots, which can greatly limit the plant growth and development. In this research, cultivar “Wen 85-5” R. glutinosa under three diTerent cultivation modes, including the newly planted, the two-year and three-year consecutively monocultured, was used in the $eld test. +e diTerential expression of leaf proteins, physiological changes and corresponding medicinal quality of tuberous roots at the early tuberous root enlargement stage were detected and compared in diTerent years of consecutive monoculture. +e results showed that consecutive monoculture resulted in decrement of chlorophyll content, photosynthetic capacity and root activity, but increases in free radicals and lipid peroxidation. Furthermore, the content of catalpol, the main medicinal ingredient in R. glutinosa tuberous roots was analyzed by FTIR and HPLC. +e result showed that consecutive monoculture resulted in declined medicinal ingredients. Comparative proteomics analysis revealed 20 diTerentially expressed protein spots in response to increasing years of monoculture. Among them, ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) kinase, Rubisco, sedoheptulose-1,7-bisphosphatase related to Calvin cycle, and other proteins, i.e. proteasome, malonyl CoA-ACP transferase, antioxidases, pathogenesis-related protein and mRNA-binding protein were down-regulated with increasing years of monoculture. While energy metabolism related proteins (ATP synthase subunit β, ATPase, ATP-binding protein) and stress response related proteins (heat shock proteins) were up-regulated. +erefore it was concluded that consecutive monoculture of R. glutinosa remarkably aTected the physiological reactions and induced the changes in the expression of leaf proteins, this in turn had a negative impact on the biomass and its quality of the medicinal plant

Comparison of Silicon-Evoked Responses on Arsenic Stress between Different Dular Rice Genotypes

Arsenic is one of the most hazardous metalloids in nature, and due to its high water solubility, it is one of the most important causes of pollution. However, silicon reduces the uptake and transport of arsenic in rice. This study investigates the interaction of different arsenic and silicon levels on dry weight, protein content, and concentrations of arsenic and silicon in two different rice shoots and roots of Dular wild-type (DU-WT) and Dular Lsi1-overexpressed (DU-OE) rice. It should be noted that all seedlings were subjected to four different treatments. For RNA-seq and qPCR, the DU-WT genotype was selected as the control and DU-OE as the treatment. With the addition of silicone treatment, dry weight and protein content in the shoots and roots of both rice lines were increased, while the concentration of arsenic in these two organs was decreased. When seedlings were exposed to arsenic treatments, protein content, silicon concentration, and dry weight were decreased in both roots and shoots, while arsenic concentration was increased in both rice genotypes. The RNA-seq in DU-OE showed 5823 differentially expressed genes (DEGs), of which 2604 were up-regulated and 3219 down-regulated. Treatment of rice by arsenic and silicon has changed the expression of genes encoding cytokinin-responsive GATA transcription factor 1, protein IN2-1 homolog B, calcium-binding EGF domain-containing protein, Os01g0369700 protein, probable glutathione S-transferase GSTU1, glutathione S-transferase protein, Os09g0367700 protein, isocitrate dehydrogenase (NADP), and Os08g0522400 protein in the root of DU-OE. The present study’s findings showed that in the presence of silicon, the transgenic genotype is much more resistant to arsenic than the wild genotype of Dular rice

Differential proteomic expressions between superior and inferior spikelets of rice in response to varied nitrogen treatments

Abstract Grain-filling and molecular mechanisms of Indica rice jinhui No.809 (large-panicle type) were investigated. By keeping the total N supply constant and varying the early and late growth stage fertilizer application ratios, changes in the protein expressions of the rice superior and inferior spikelets were determined. The two N fertilization treatments were traditional and modern nitrogen applications (TNA and MNA). Using 2-DE and MALDI-TOF/MS, 38 proteins were identified to show differential expressions in response to the different N treatments. MNA appeared to promote protein up-regulation in the inferior spikelets, including cell respiration related proteins (e.g. fructose-bisphosphate aldolase, phosphoglycerate mutase, glyceraldehyde-3-phosphate dehydrogenase, malic oxidoreductase, succinate dehydrogenase, transketolase, phosphoglucomutase, and some starch synthesis related proteins (e.g., phosphoglucomutase, WRKY, glycolipid transfer and fatty acid hydroxylase) clearly indicating that the increased N supply at the late growth stage was favorable for the grain-filling of inferior spikelets. Moreover, the up-regulated auxin-responsive protein IAA22 and gibberellin response modulator implied that the MNA treatment could increase the content of phytohormones in inferior spikelets. In addition, the proteomic analysis and physiological observations in the present study also elucidated the mechanism underlying the asynchronous grain-fillings between the superior and inferior spikelets of rice

Terminal Restriction Fragment Length Polymorphism Analysis of Soil Bacterial Communities under Different Vegetation Types in Subtropical Area.

Soil microbes are active players in energy flow and material exchange of the forest ecosystems, but the research on the relationship between the microbial diversity and the vegetation types is less conducted, especially in the subtropical area of China. In this present study, the rhizosphere soils of evergreen broad-leaf forest (EBF), coniferous forest (CF), subalpine dwarf forest (SDF) and alpine meadow (AM) were chosen as test sites. Terminal-restriction fragment length polymorphisms (T-RFLP) analysis was used to detect the composition and diversity of soil bacterial communities under different vegetation types in the National Natural Reserve of Wuyi Mountains. Our results revealed distinct differences in soil microbial composition under different vegetation types. Total 73 microbes were identified in soil samples of the four vegetation types, and 56, 49, 46 and 36 clones were obtained from the soils of EBF, CF, SDF and AM, respectively, and subsequently sequenced. The Actinobacteria, Fusobacterium, Bacteroidetes and Proteobacteria were the most predominant in all soil samples. The order of Shannon-Wiener index (H) of all soil samples was in the order of EBF>CF>SDF>AM, whereas bacterial species richness as estimated by four restriction enzymes indicated no significant difference. Principal component analysis (PCA) revealed that the soil bacterial communities' structures of EBF, CF, SDF and AM were clearly separated along the first and second principal components, which explained 62.17% and 31.58% of the total variance, respectively. The soil physical-chemical properties such as total organic carbon (TOC), total nitrogen (TN), total phosphorus (TP) and total potassium (TK) were positively correlated with the diversity of bacterial communities

Principal components analysis (PCA) of T-RFLP data in different vegetation types along an altitude gradient.

<p>The figure describes the variance of bacterial communities in the EBF, CF, SDF and AM sites were clearly different from each other.</p

Schematic representation of bacterial communities in soil samples of different vegetation types.

<p>The figure shows the differences of bacterial communities’ composition among different vegetation types (EBF, CF, SDF and AM).</p

Description of the four vegetation types along an altitude gradient in the Wuyi Mountains.

<p>Description of the four vegetation types along an altitude gradient in the Wuyi Mountains.</p