Phosphate is an essential macro-element for plant growth accumulated in the topsoil. The improvement of phosphate uptake efficiency via manually manipulating root system architecture is of vital ...agronomic importance. This review discusses the molecular mechanisms of root patterning in response to external phosphate availability, which could be applied on the alleviation of phosphate-starvation stress. During the long time evolution, plants have formed sophisticated mechanisms to adapt to environmental phosphate conditions. In terms of root systems, plants would adjust their root system architecture via the regulation of the length of primary root, the length/density of lateral root and root hair and crown root growth angle to cope with different phosphate conditions. Finally, plants develop shallow or deep root system in low or high phosphate conditions, respectively. The plasticity of root system architecture responds to the local phosphate concentrations and this response was regulated by actin filaments, post-translational modification and phytohormones such as auxin, ethylene and cytokinin. This review summarizes the recent progress of adaptive response to external phosphate with focus on integrated physiological, cellular and molecular signaling transduction in rice and
.
The need of jointing aluminum and steel is increasing in automobiles industry. The FSW has advantages over fusion welding in dissimilar welding, and studies about FSW of aluminum and steel has been ...reported widely. However, FSLW of aluminum and steel using Zn as filler metal is few. In this study, sound AlZn-steel “sandwich” joints were achieved. With the tool pin inserted into zinc foil, vast zinc was stirred into aluminum fabricating AlZn mixing layer structure in the upper part of aluminum side. Thin steel-Zn mixing layer structure was discovered at the interface. No intermetallic compound interlayer was discovered at the interface. The lap joints with zinc foil as filler metal showed better strength than joints without filler metal. The microstructure of joints and the effect of Zn foil thickness on the joint strength were discussed.
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•Sandwich structure of AlZn-Steel joints were achieved by FSW.•No IMC interlayer was detected at the interface.•Lap joints showed better strength with the Zn as filler metal.
APETALA2/ETHYLENE RESPONSIVE FACTOR (AP2/ERF) transcription factors play essential roles in plant growth, development, metabolism, and responses to biotic and abiotic stresses. However, few studies ...concerning AP2/ERF genes in sugarcane which are the most critical sugar and energy crops worldwide.
A total of 218 AP2/ERF genes were identified in the Saccharum spontaneum genome. Phylogenetic analysis showed that these genes could be divided into four groups, including 43 AP2s, 160 ERFs and Dehydration-responsive element-binding (DREB) factors, 11 ABI3/VPs (RAV), and four Soloist genes. These genes were unevenly distributed on 32 chromosomes. The structural analysis of SsAP2/ERF genes showed that 91 SsAP2/ERFs lacked introns. Sugarcane and sorghum had a collinear relationship between 168 SsAP2/ERF genes and sorghum AP2/ERF genes that reflected their similarity. Multiple cis-regulatory elements (CREs) present in the SsAP2/ERF promoter were related to abiotic stresses, suggesting that SsAP2/ERF activity could contribute to sugarcane adaptation to environmental changes. The tissue-specific analysis showed spatiotemporal expression of SsAP2/ERF in the stems and leaves of sugarcane at different development stages. In ten sugarcane samples, 39 SsAP2/ERFs were not expressed, whereas 58 SsAP2/ERFs were expressed in all samples. Quantitative PCR experiments showed that SsERF52 expression was up-regulated under salt stress, but suppressed under dehydration stress. SsSoloist4 had the most considerable upregulation in response to treatment with the exogenous hormones ABA and GA. Within 3 h of ABA or PEG6000 treatment, SsSoloist4 expression was up-regulated, indicating that this gene could play a role in the responses to ABA and GA-associated dehydration stress. Analysis of AP2/ERF gene expression patterns under different treatments indicated that SsAP2/ERF genes played an essential role in dehydration and salt stress responses of S. spontaneum.
In this study, a total of 218 members of the AP2 / ERF superfamily were identified in sugarcane, and their genetic structure, evolution characteristics, and expression patterns were studied and analyzed. The results of this study provide a foundation for future analyses to elucidate the importance of AP2/ERF transcription factors in the function and molecular breeding of sugarcane.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
•Intertidal zonation overrided rhizosphere effect on bacterial diversity at a local scale.•Pb and NH4+ content driven the UTZ-LTZ bacterial community variation.•Actinobacteria was significantly ...enriched in the near-root sediments.•Cellulose and hemicelluloses degradation potentials were higher in UTZ than in LTZ.•Higher functional gene in dissimilatory sulfate reduction, nitrate or nitrite reduction occurred in the UTZ.
The combined effects of intertidal zonation and mangrove vegetation on benthic bacterial communities and ecological functions were studied. MiSeq sequencing of the 16S rRNA gene and PICRUSt predictive functional profiles were used to investigate the diversity, community structure and potential metabolic functions of benthic bacteria in surface sediments of a mangrove ecosystem. Compared with the lower intertidal zone, bacterial alpha diversity and richness were significantly higher in the upper intertidal zone and highly associated with sediment organic matter. The upper zone was occupied by higher proportions of heterotrophic bacteria involved in the degradation of organic compounds. These included Desulfobacterales, Anaerolineae and Acidobacteria, while the proportion of Rhodobacterales and Xenococcaceae was greatly increased in the lower zone. No significant difference of either alpha diversity or community composition was found between rhizosphere and bulk sediments, except that higher relative proportions of Rhizobiales and Actinobacteria occurred in rhizosphere sediments. The shift in bacterial community structure was mainly driven by changes in sediment Pb and NH4+ concentrations. Among the major carbon, nitrogen and sulfur cycling processes examined, higher potentials of cellulose and hemicellulose degradation, dissimilatory sulfate reduction, and nitrate or nitrite reduction occurred in the upper intertidal zone. Assimilatory sulfate reduction and sulfur oxidation potentials were higher in the root-associated sediments than in the bulk sediments. This study indicated that intertidal zonation was more important than root effects in modulating benthic bacterial diversity and functional potentials in a mangrove ecosystem.
Soil compaction represents a major challenge for modern agriculture. Compaction is intuitively thought to reduce root growth by limiting the ability of roots to penetrate harder soils. We report that ...root growth in compacted soil is instead actively suppressed by the volatile hormone ethylene. We found that mutant
and rice roots that were insensitive to ethylene penetrated compacted soil more effectively than did wild-type roots. Our results indicate that soil compaction lowers gas diffusion through a reduction in air-filled pores, thereby causing ethylene to accumulate in root tissues and trigger hormone responses that restrict growth. We propose that ethylene acts as an early warning signal for roots to avoid compacted soils, which would be relevant to research into the breeding of crops resilient to soil compaction.
In this paper, submerged friction stir welding (SFSW), capable of significantly weakening the welding thermal cycle compared to conventional FSW, was employed on SAF2507 super duplex stainless steel ...(SDSS). An ultrafine grained (UFG) dual-phase microstructure, characterized by more uniformly distributed and balanced alpha (α) and gamma (γ) phases with average grain sizes of 0.96 and 0.77 µm, respectively, was achieved in the stir zone (SZ). Such unique microstructure leads to a synergistic enhancement of tensile strength and ductility in the longitudinal SZ at room temperature, which increases from 840 MPa to 18% under AFSW condition to 915 MPa - 22%. As well, this UFG dual-phase microstructure plays a crucial role in determining the resultant higher corrosion resistance. Combining with the reduced width of entire joint, a transverse SFSW joint with a remarkable increased total elongation was successfully achieved. In addition, the relatively lower residual stress across the whole joint actually contributed to the increment of ductility in the SFSW joint, as compared to the traditional FSW joint. The aforementioned results demonstrate an effective strategy in achieving a completely balanced UFG microstructure across the whole SZ during SFSW and a concurrent improvement of strength, elongation and corrosion resistance.
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•Submerged FSW is first employed to avoid the undesirable phase transformation in SDSS.•The thermal cycle of stir zone during submerged FSW of SDSS is revealed for the first time.•A superior FSW joint with excellent combination of high strength and ductility is achieved.•The residual stress and anti corrosion behavior of the submerged FSW joint is discussed in detail.
Abstract
Diatom is an important group of marine algae and contributes to around 20% of the global photosynthetic carbon fixation. Photosystem I (PSI) of diatoms is associated with a large number of ...fucoxanthin-chlorophyll
a
/
c
proteins (FCPIs). We report the structure of PSI-FCPI from a diatom
Chaetoceros gracili
s at 2.38 Å resolution by single-particle cryo-electron microscopy. PSI-FCPI is a monomeric supercomplex consisting of 12 core and 24 antenna subunits (FCPIs), and 326 chlorophylls
a
, 34 chlorophylls
c
, 102 fucoxanthins, 35 diadinoxanthins, 18
β
-carotenes and some electron transfer cofactors. Two subunits designated PsaR and PsaS were found in the core, whereas several subunits were lost. The large number of pigments constitute a unique and huge network ensuring efficient energy harvesting, transfer and dissipation. These results provide a firm structural basis for unraveling the mechanisms of light-energy harvesting, transfer and quenching in the diatom PSI-FCPI, and also important clues to evolutionary changes of PSI-LHCI.
Soil compaction represents a major agronomic challenge, inhibiting root elongation and impacting crop yields. Roots use ethylene to sense soil compaction as the restricted air space causes this ...gaseous signal to accumulate around root tips. Ethylene inhibits root elongation and promotes radial expansion in compacted soil, but its mechanistic basis remains unclear. Here, we report that ethylene promotes abscisic acid (ABA) biosynthesis and cortical cell radial expansion. Rice mutants of ABA biosynthetic genes had attenuated cortical cell radial expansion in compacted soil, leading to better penetration. Soil compaction-induced ethylene also up-regulates the auxin biosynthesis gene
OsYUC8
. Mutants lacking OsYUC8 are better able to penetrate compacted soil. The auxin influx transporter OsAUX1 is also required to mobilize auxin from the root tip to the elongation zone during a root compaction response. Moreover,
osaux1
mutants penetrate compacted soil better than the wild-type roots and do not exhibit cortical cell radial expansion. We conclude that ethylene uses auxin and ABA as downstream signals to modify rice root cell elongation and radial expansion, causing root tips to swell and reducing their ability to penetrate compacted soil.
Single-pixel holography (SPH) is capable of generating holographic images with rich spatial information by employing only a single-pixel detector. Thanks to the relatively low dark-noise production, ...high sensitivity, large bandwidth, and cheap price of single-pixel detectors in comparison to pixel-array detectors, SPH is becoming an attractive imaging modality at wavelengths where pixel-array detectors are not available or prohibitively expensive. In this work, we develop a high-throughput single-pixel compressive holography with a space-bandwidth-time product (SBP-T) of 41,667 pixels/s, realized by enabling phase stepping naturally in time and abandoning the need for phase-encoded illumination. This holographic system is scalable to provide either a large field of view (~83 mm
) or a high resolution (5.80 μm × 4.31 μm). In particular, high-resolution holographic images of biological tissues are presented, exhibiting rich contrast in both amplitude and phase. This work is an important step towards multi-spectrum imaging using a single-pixel detector in biophotonics.
Reports about dissimilar joining of aluminum alloy and nickel base alloy are rare. The friction stir welding (FSW) technique reveals advantages over fusion welding in terms of dissimilar jointing. In ...the present research, FSW was employed to produce lap joints of aluminum alloy (2A70) and nickel-base alloy (Inconel 600) with various plunge depths (0–0.5 mm) under a given welding and rotation speed (1200 rpm, 40 mm/min). Macrographs were taken and the microstructure of the cross-section of the lap joints was investigated by optical microscopy and scanning electron microscopy. A fine-grained zone was discovered on both sides of the interface. A thin Al3Ni interlayer was generated at the interface. The plunge depth has a vital influence on the joint strength. The lap joint failed at a very low load when the pin did not reach the nickel alloy surface, while the maximum shear strength of the lap joint was obtained under a plunge depth of 0.3 mm and reached 7.9 KN.
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•Al and Ni alloy was welded by FSW.•Fine grain zone was discovered at both sides of the interface.•A thin Al3Ni interlayer was generated at the interface.
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