No abstract

Domain of unknown function 4228 (DUF4228) proteins are a class of proteins widely found in plants, playing an important role in response to abiotic stresses. However, studies on the DUF4228 family in soybean (Glycine max L.) are sparse. In this study, we identified a total of 81 DUF4228 genes in soybean genome, named systematically based on their chromosome distributions. Results showed that these genes were unevenly distributed on the 20 chromosomes of soybean. The predicted soybean DUF4228 proteins were identified in three groups (Groups I–III) based on a maximum likelihood phylogenetic tree. Genetic structure analysis showed that most of the GmDUF4228 genes contained no introns. Expression profiling showed that GmDUF4228 genes were widely expressed in different organs and tissues in soybean. RNA-seq data were used to characterize the expression profiles of GmDUF4228 genes under the treatments of drought and salt stresses, with nine genes showing significant up-regulation under both drought and salt stress further functionally verified by promoter (cis-acting elements) analysis and quantitative real-time PCR (qRT-PCR). Due to its upregulation under drought and salt stresses based on both RNA-seq and qRT-PCR analyses, GmDUF4228-70 was selected for further functional analysis in transgenic plants. Under drought stress, the degree of leaf curling and wilting of the GmDUF4228-70-overexpressing (GmDUF4228-70-OE) line was lower than that of the empty vector (EV) line. GmDUF4228-70-OE lines also showed increased proline content, relative water content (RWC), and chlorophyll content, and decreased contents of malondialdehyde (MDA), H2O2, and O2–. Under salt stress, the changes in phenotypic and physiological indicators of transgenic plants were the same as those under drought stress. In addition, overexpression of the GmDUF4228-70 gene promoted the expression of marker genes under both drought and salt stresses. Taken together, the results indicated that GmDUF4228 genes play important roles in response to abiotic stresses in soybean.

Soybean (Glycine max) is one of the important oil crops worldwide. In recent years, environmental stresses such as drought and soil salinization have severely deteriorated soybean yield and quality. We investigated the overexpression of the transcription factor GmTGA15 in response to drought stress in transgenic soybean hairy roots and Arabidopsis plants. The results of quantitative real time polymerase chain reaction (qRT-PCR) analyses showed that GmTGA15 was greatly induced by salt, PEG6000, salicylic acid (SA), gibberellic acid (GA), abscisic acid (ABA), and methyl jasmonate (MeJA) in soybean. In response to drought stress, the contents of both chlorophyll and proline were significantly increased, while the content of malondialdehyde (MDA) was significantly decreased in the soybean hairy roots with the overexpression of GmTGA15 in comparison to wild type (WT). Under the simulated drought conditions, the transgenic Arabidopsis plants showed significantly longer roots and lower mortality than that of the wild type. These results suggest that GmTGA15 promotes tolerance to drought stress in both soybean and Arabidopsis plants. This study provides the scientific evidence for further functional analysis of soybean TGA transcription factors in drought stress and the breeding of drought-resistance crops.

A periodic patterned graphene-based terahertz metamaterial comprised of three transverse graphene strips and one longitudinal continuous graphene ribbon is proposed to achieve a dynamically tunable quadruple plasmon-induced transparency (PIT) effect....

Roots are generally the critical drought sensors, but little is known about their molecular response to drought stress. We used the drought-tolerant soybean variety ‘Jiyu 47’ to investigate the differentially expressed proteins (DEPs) in soybean roots during the seedling stage based on the tandem mass tag (TMT) proteomics analysis. Various expression patterns were observed in a total of six physiological parameters. A total of 468 DEPs (144 up-regulated and 324 down-regulated) among a total of 8687 proteins were identified in response to drought stress in 24 h. The expression of DEPs was further validated based on quantitative real-time PCR of a total of five genes (i.e., GmGSH, GmGST1, GmGST2 k GmCAT, and Gm6PGD) involved in the glutathione biosynthesis. Results of enrichment analyses revealed a coordinated expression pattern of proteins involved in various cellular metabolisms responding to drought stress in soybean roots. Our results showed that drought stress caused significant alterations in the expression of proteins involved in several metabolic pathways in soybean roots, including carbohydrate metabolism, metabolism of the osmotic regulation substances, and antioxidant defense system (i.e., the glutathione metabolism). Increased production of reduced glutathione (GSH) enhanced the prevention of the damage caused by reactive oxygen species and the tolerance of the abiotic stress. The glutathione metabolism played a key role in modifying the antioxidant defense system in response to drought stress in soybean roots. Our proteomic study suggested that the soybean plants responded to drought stress by coordinating their protein expression during the vegetative stage, providing novel insights into the molecular mechanisms regulating the response to abiotic stress in plants.

The amino acid permease (AAP) is an important transmembrane protein that is involved in the absorption and transport of amino acids in plants. We investigated the expression patterns of AtAAP genes in Arabidopsis thaliana, based on quantitative real-time PCR. The results revealed differential expression patterns of eight AtAAP genes in different tissues, with five genes (AtAAP1, AtAAP2, AtAAP6, AtAAP7, and AtAAP8) expressed at relatively high levels in both flowers and siliques, suggesting their shared functions in the accumulation of amino acids. In transgenic plants, with endosperm-specific overexpression of AtAAP1, both AtAAP1 and AtAAP6 were up-regulated in both the roots and siliques, while AtAAP2, AtAAP3, AtAAP4, and AtAAP5 showed similar expression levels in the stems and siliques, whereas AtAAP7 and AtAAP8 were expressed at their highest levels in the stems and roots. The results of the amino acid affinity experiments revealed varied absorption capacities for different amino acids, by AtAAP1, and increased acid amino contents in the reproductive organs. These results were verified in transgenic maize plants, with the overexpression of AtAAP1, revealing higher amino acid contents in the reproductive organs than those of the vegetative organs. Our study clearly demonstrated that the endosperm-specific promoter increased the amino acid contents in the reproductive organs and improved the effective utilization of organic nitrogen in plants.

A monolayer graphene metamaterial composed of a graphene block and four graphene strips, which has the metal-like properties in terahertz frequency range, is proposed to generate an outstanding quadruple plasmon-induced transparency (PIT). Additional analyses show that the forming physical mechanism of the PIT with four transparency windows can be explained by strong destructive interference between the bright mode and the dark mode, and the distributions of electric field intensity and electric field vectors under the irradiation of the incident light. Coupled mode theory (CMT) and finite-difference time-domain (FDTD) method are employed to study the spectral response characteristics of the proposed structure, and the theoretical and simulated results are in good agreement. It is found that a tunable multi-frequency switch and excellent optical storage can be achieved in the wide PIT window. The maximum modulation depth is up to 99.7%, which corresponds to the maximum extinction ratio of 25.04 dB and the minimum insertion loss of 0.19 dB. In addition, the time delay is as high as 0.919 ps, the corresponding group refractive index is up to 2755. Thus, the proposed structure provides a new method for the design of terahertz multi-frequency switches and slow light devices.

Feeding with a suitable level of milk replacer (MR) can improve the survival rate and stimulate the growth potential of early lambs. However, feeding excessive MR might be detrimental to rumen development and microbial colonization. Herein, we investigated the effects of feeding different levels of MR on rumen digestive function and ruminal microorganisms. Fourteen healthy male Hu lambs with similar birth weights and detailed pedigree records were divided into two groups to receive low (2% of average body weight per day) and high (4% of average body weight per day) levels of MR. We analyzed the effects of the MR feeding level on growth performance, fiber degradation rates, rumen fermentation parameters, enzyme activities and rumen histomorphology. We found that feeding with a high level of MR improved the average daily gain of early lambs, but decreased the starter intake, rumen weight and papillae length. We also analyzed the effects of the MR feeding level on the rumen microbiota using 16S-rRNA amplicon sequencing data. The results showed that high a MR feeding level increased the rumen microbial diversity but decreased the abundance of many carbohydrate degrading bacteria. Several bacterial genera with significant differences correlated positively with rumen cellulase activity and the acid detergent fiber degradation rate. Our results suggested that a high level of MR could improve the growth performance of early lambs in the short term; however, in the long term, it would be detrimental to rumen development and have adverse effects on the adaptation process of the microbiota to solid feed.