Rhizobia, the root-nodule endosymbionts of leguminous plants, also form natural endophytic associations with roots of important cereal plants. Despite its widespread occurrence, much remains unknown about colonization of cereals by rhizobia. We examined the infection, dissemination, and colonization of healthy rice plant tissues by four species of gfp-tagged rhizobia and their influence on the growth physiology of rice. The results indicated a dynamic infection process beginning with surface colonization of the rhizoplane (especially at lateral root emergence), followed by endophytic colonization within roots, and then ascending endophytic migration into the stem base, leaf sheath, and leaves where they developed high populations. In situ CMEIAS image analysis indicated local endophytic population densities reaching as high as 9 ؋ 10 10 rhizobia per cm 3 of infected host tissues, whereas plating experiments indicated rapid, transient or persistent growth depending on the rhizobial strain and rice tissue examined. Rice plants inoculated with certain test strains of gfp-tagged rhizobia produced significantly higher root and shoot biomass; increased their photosynthetic rate, stomatal conductance, transpiration velocity, water utilization efficiency, and flag leaf area (considered to possess the highest photosynthetic activity); and accumulated higher levels of indoleacetic acid and gibberellin growthregulating phytohormones. Considered collectively, the results indicate that this endophytic plant-bacterium association is far more inclusive, invasive, and dynamic than previously thought, including dissemination in both below-ground and above-ground tissues and enhancement of growth physiology by several rhizobial species, therefore heightening its interest and potential value as a biofertilizer strategy for sustainable agriculture to produce the world's most important cereal crops.
Wearable thermoelectric devices show promises to generate electricity in a ubiquitous, unintermittent and noiseless way for on-body applications. Threedimensional thermoelectric textiles (TETs) outperform other types in smart textiles owing to their out-of-plane thermoelectric generation and good structural conformability with fabrics. Yet, there has been lack of efficient strategies in scalable manufacture of TETs for sustainably powering electronics. Here, we fabricate organic spacer fabric shaped TETs by knitting carbon nanotube yarn based segmented thermoelectric yarn in large scale. Combing finite element analysis with experimental evaluation, we elucidate that the fabric structure significantly influences the power generation. The optimally designed TET with good wearability and stability shows high output power density of 51.5 mW/m 2 and high specific power of 173.3 µW/(g·K) at ∆T= 47.5 K. The promising on-body applications of the TET in directly and continuously powering electronics for healthcare and environmental monitoring is fully demonstrated. This work will broaden the research vision and provide new routines for developing high-performance and large-scale TETs toward practical applications.
In order to avoid the complex conditions of the intact plant for simple analysis of proteins in wound-response stress, we used the detached rice leaf sheath which is a very active part of the rice seedling. Proteins were extracted from rice leaf sheath at 0, 12, 24, 48 h after cutting and separated by two-dimensional (2-D) polyacrylamide gel electrophoresis. Changes in differentially displayed proteins were found in leaf sheaths after cutting in the 0-48 h time course. Ten proteins were up-regulated, while 19 proteins were down-regulated compared with those on the four 2-D gels. Among them, 14 proteins were analyzed by N-terminal, or internal amino acid sequence. The clear functions of nine proteins could be identified. Six proteins did not yield amino acid sequence information due to their blocked N-termini. Furthermore, 11 proteins were determined by matrix-assisted laser desorption/ionization-time of flight mass spectrometry, and identified protein database matching. It was shown that the down-regulated proteins were calreticulin (nos. 5, 6), histone H1 (no. 15) and hemoglobin (no. 17), putative peroxidase (no. 19); the up-regulated proteins were Bowman-Birk trypsin inhibitor (no. 23), putative receptor-like protein kinase (nos. 24, 25), calmodulin-related protein (no. 26), small subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase (no. 27), mannose-binding rice lectin (nos. 28, 29). Among all the above proteins, four (nos. 23, 24, 25, 26) have been confirmed to be wound-response proteins. The others cannot be excluded as also being related to wound-responses, such as the signal transduction-related proteins (nos. 5, 6), photosynthesis-related protein (no. 27), and stress-response proteins (nos. 19, 28, 29). This is the first time protein changes in response to wounding in rice leaf sheath have been shown.
Rhizobial endophytes infect and colonize not only leguminous plants, but several non-leguminous species as well. Using green fluorescent protein tagging technique, it has been shown that Rhizobia infect different varieties of rice species and migrate from plant roots to aerial tissues such as leaf sheaths and leaves. The interaction between them was found to promote the growth of rice. The growth promotion is the cumulative result of enhanced photosynthesis and stress resistance. In addition, indole-3-acetic acid also contributes to the promotion. Gel-based comparative proteomic approaches were applied to analyze the protein profiles of three different tissues (root, leaf sheath and leaf) of Sinorhizobium meliloti 1021 inoculated rice in order to get an understanding about the molecular mechanism. Upon the inoculation of rhizobia, proteins involved in nine different functional categories were either up-regulated or down-regulated. Photosynthesis related proteins were up-regulated only in leaf sheath and leaf, while the up-regulated proteins in root were exclusively defense related. The results implied that there might have been an increase in the import and transport of proteins involved in light and dark reactions to the chloroplast as well as more efficient distribution of nutrients, hence enhanced photosynthesis. Although the initiation of defensive reactions mainly occurred in roots, some different defense mechanisms were also evoked in the aerial tissues.
Wearable inorganic semiconductors (ISCs) based thermoelectric (TE) devices, especially fiber-based thermoelectric textiles (TETs), show promises in electrical power generation and solid-state cooling compared with bulk ISCs-based TE generators (TEGs). However,...
A rotating sample method has been developed to study the slip planes of succinic acid by atomic force microscopy (AFM) nanoindentation. A nonaxisymmetric cube corner indenter was utilized to generate an inhomogeneous stress field, which selectively activates different slip systems simply by rotating the sample. The slip planes identified were repeatable and frequently observed for different indentations of the single crystals using four sample rotations. By applying this rotating sample method to both (001) and (010) crystal faces, the repeatedly observed major slip planes were identified as (010) and (111) planes; these agree with the theoretical prediction. Many higher index operative slip planes were identified that were not reported previously. The rotating sample method presented herein is pragmatic and suggests that the anisotropic slip properties of single pharmaceutical crystals can be studied in a systematic manner.
Plant growth, contents of photosynthetic pigments, photosynthetic gas exchange, and chlorophyll (Chl) fluorescence in soybean [Glycine max (L.) Merr. cv. Heinong37] were investigated after it was inoculated with Sinorhizobium fredii USDA191 or treated with 5 mM (NH 4 ) 2 SO 4 (N5) and 30 mM (NH 4 ) 2 SO 4 (N30), respectively. In the plants following N5 fertilization, not only plant biomass, leaf area, and Chl content, but also net photosynthetic rate (P N ), stomatal conductance (g s ), carboxylation efficiency (CE), maximum photochemical efficiency (F v /F m ) of photosystem 2 (PS2), and quantum yield of PS2 (Φ PS2 ) were markedly improved as compared with the control plants. There were also positive effects on plant growth and plant photosynthesis after rhizobia inoculation, but the effects were much less than those of N5 fertilization. For N30 plants there were no significant positive effects on plant growth and photosynthetic capacity. Plant biomass, P N , and g s were similar to those of N-limited (control) plants. Φ PS2 and photochemical quenching (q P ) were obviously declined while content of carotenoids and non-photochemical quenching (q N ) were significantly enhanced in N30 treated plants. This indicated that excess N supply may cause some negative effects on soybean plants.
The growth-promotion of rice seedling following inoculation with Sinorhizobium meliloti 1021 was a cumulative outcome of elevated expression of genes that function in accelerating cell division and enhancing cell expansion. Various endophytic rhizobacteria promote the growth of cereal crops. To achieve a better understanding of the cellular and molecular bases of beneficial cereal-rhizobia interactions, we performed computer-assisted microscopy and transcriptomic analyses of rice seedling shoots (Oryza sativa) during early stages of endophytic colonization by the plant growth-promoting Sinorhizobium meliloti 1021. Phenotypic analyses revealed that plants inoculated with live rhizobia had increased shoot height and dry weight compared to control plants inoculated with heat-killed cells of the same microbe. At 6 days after inoculation (DAI) with live cells, the fourth-leaf sheaths showed significant cytological differences including their enlargement of parenchyma cells and reduction in shape complexity. Transcriptomic analysis of shoots identified 2,414 differentially-expressed genes (DEGs) at 1, 2, 5 and 8 DAI: 195, 1390, 1025 and 533, respectively. Among these, 46 DEGs encoding cell-cycle functions were up-regulated at least 3 days before the rhizobia ascended from the roots to the shoots, suggesting that rhizobia are engaged in long-distance signaling events during early stages of this plant-microbe interaction. DEGs involved in phytohormone production, photosynthetic efficiency, carbohydrate metabolism, cell division and wall expansion were significantly elevated at 5 and 8 DAI, consistent with the observed phenotypic changes in rice cell morphology and shoot growth-promotion. Correlation analysis identified 104 height-related DEGs and 120 dry-weight-related DEGs that represent known quantitative-trait loci for seedling vigor and increased plant height. These findings provide multiple evidences of plant-microbe interplay that give insight into the growth-promotion processes associated with this rhizobia-rice beneficial association.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.