Identification of the GRAS gene family in the Brassica juncea genome provides insight into its role in stem swelling in stem mustard

GRAS transcription factors are known to play important roles in plant signal transduction and development. A comprehensive study was conducted to explore the GRAS family in the Brassica juncea genome. A total of 88 GRAS genes were identified which were categorized into nine groups according to the phylogenetic analysis. Gene structure analysis showed a high group-specificity, which corroborated the gene grouping results. The chromosome distribution and sequence analysis suggested that gene duplication events are vital for the expansion of GRAS genes in the B. juncea genome. The changes in evolution rates and amino acid properties among groups might be responsible for their functional divergence. Interaction networks and cis-regulatory elements were analyzed including DELLA and eight interaction proteins (including four GID1, two SLY1, and two PIF3 proteins) that are primarily involved in light and hormone signaling. To understand their regulatory role in growth and development, the expression profiles of BjuGRASs and interaction genes were examined based on transcriptome data and qRT-PCR, and selected genes (BjuGRAS3, 5, 7, 8, 10, BjuB006276, BjuB037910, and BjuA021658) had distinct temporal expression patterns during stem swelling, indicating that they possessed diverse regulatory functions during the developmental process. These results contribute to our understanding on the GRAS gene family and provide the basis for further investigations on the evolution and functional characterization of GRAS genes

Hexokinase1: A glucose sensor involved in drought stress response and sugar metabolism depending on its kinase activity in strawberry

Hexokinase1 (HXK1) is a bifunctional enzyme that plays indispensable roles in plant growth, nitrogen utilization, and stress resistance. However, information on the HXK family members of strawberries and their functions in glucose sensing and metabolic regulation is scarce. In the present study, four HXKs were firstly identified in the genome of Fragaria vesca and F. pentaphylla. The conserved domains of the HXK1s were confirmed, and a site-directed mutation (S177A) was introduced into the FpHXK1. FpHXK1, which shares the highest identity with the AtHXK1 was able to restore the glucose sensitivity and developmental defects of the Arabidopsis gin2-1 mutant, but not its kinase-activity-impaired mutant (FpHXK1S177A). The transcription of FpHXK1 was dramatically up-regulated under PEG-simulated drought stress conditions. The inhibition of the HXK kinase activity delayed the strawberry plant’s responses to drought stress. Transient overexpression of the FpHXK1 and its kinase-impaired mutant differentially affected the level of glucose, sucrose, anthocyanins, and total phenols in strawberry fruits. All these results indicated that the FpHXK1, acting as a glucose sensor, was involved in drought stress response and sugar metabolism depending on its kinase activity

An effective method for establishing a regeneration and genetic transformation system for Actinidia arguta

The all-red A. arguta (Actinidia arguta) is an anthocyanin-rich and excellent hardy fruit. Many studies have focused on the green-fleshed A. arguta, and fewer studies have been conducted on the all-red A. arguta. Here we reported a regeneration and Agrobacterium-mediated transformation protocol by using leaves of all-red A. arguta as explants. Aseptic seedling leaves of A. arguta were used as callus-inducing materials. MS medium supplemented with 0.3 mg·L-1 2,4-D and 1.0 mg·L-1 BA was the optimal medium for callus induction of leaves, and medium supplemented with 3 mg·L-1 tZ and 0.5 mg·L-1 IAA was optimal for adventitious shoot regeneration. The best proliferation medium for adventitious buds was MS + 1.0 mg·L-1 BA + 0.3 mg·L-1 NAA. The best rooting medium was 1/2MS + 0.7 mg·L-1 IBA with a 100% rooting rate. For the red flesh hardy kiwi variety ‘Purpurna Saduwa’ (A. arguta var. purpurea), leaves are receptors for Agrobacterium (EHA105)-mediated transformation. The orthogonal experiment was used for the optimization of each genetic transformation parameter and the genetic transformation of the leaves was 21% under optimal conditions. Our study provides technical parameters for applying genetic resources and molecular breeding of kiwifruit with red flesh

FaGAPC2/FaPKc2.2 and FaPEPCK reveal differential citric acid metabolism regulation in late development of strawberry fruit

Citric acid is the primary organic acid that affects the taste of strawberry fruit. Glycolysis supplies key substrates for the tricarboxylic acid cycle (TCA cycle). However, little is known about the regulatory mechanisms of glycolytic genes on citric acid metabolism in strawberry fruits. In this study, the citric acid content of strawberry fruit displayed a trend of rising and decreasing from the initial red stage to the full red stage and then dark red stage. Thus, a difference in citric acid metabolic regulation was suspected during strawberry fruit development. In addition, overexpression of either cytoplasm glyceraldehyde-3-phosphate dehydrogenase (FxaC_14g13400, namely FaGAPC2) or pyruvate kinase (FxaC_15g00080, namely FaPKc2.2) inhibited strawberry fruit ripening and the accumulation of citric acid, leading to a range of maturity stages from partial red to full red stage. The combined transcriptome and metabolome analysis revealed that overexpression of FaGAPC2 and FaPKc2.2 significantly suppressed the expression of phosphoenolpyruvate carboxykinase (FxaC_1g21491, namely FaPEPCK) but enhanced the content of glutamine and aspartic acid. Meanwhile, the activities of PEPCK and glutamate decarboxylase (GAD) were inhibited, but the activities of glutamine synthase (GS) were increased in FaGAPC2/FaPKc2.2-overexpressed fruit. Further, functional verification demonstrated that overexpression of FaPEPCK can promote strawberry fruit ripening, resulting in a range of maturity stage from full red to dark red stage, while the citric acid synthase (CS) activities and citric acid content were significantly decreased. Overall, this study revealed that FaGAPC2/FaPKc2.2 and FaPEPCK perform an important role in reducing citric acid content in strawberry fruit, and FaGAPC2/FaPKc2.2 mainly by promoting the GS degradation pathway and FaPEPCK mainly by inhibiting the CS synthesis pathway

How Do Subway Signs Affect Pedestrians’ Wayfinding Behavior through Visual Short-Term Memory?

Recently, subways have become an important part of public transportation and have developed rapidly in China. In the subway station setting, pedestrians mainly rely on visual short-term memory to obtain information on how to travel. This research aimed to explore the short-term memory capacities and the difference in short-term memory for different information for Chinese passengers regarding subway signs. Previous research has shown that people’s general short-term memory capacity is approximately four objects and that, the more complex the information, the lower people’s memory capacity. However, research on the short-term memory characteristics of pedestrians for subway signs is scarce. Hence, based on the STM theory and using 32 subway signs as stimuli, we recruited 120 subjects to conduct a cognitive test. The results showed that passengers had a different memory accuracy for different types of information in the signs. They were more accurate regarding line number and arrow, followed by location/text information, logos, and orientation. Meanwhile, information type, quantity, and complexity had significant effects on pedestrians’ short-term memory capacity. Finally, according to our results that outline the characteristics of short-term memory for subway signs, we put forward some suggestions for subway signs. The findings will be effective in helping designers and managers improve the quality of subway station services as well as promoting the development of pedestrian traffic in such a setting

Genetic Diversity and Domestication Footprints of Chinese Cherry [Cerasus pseudocerasus (Lindl.) G.Don] as Revealed by Nuclear Microsatellites

Chinese cherry [Cerasus pseudocerasus (Lindl.) G.Don] is a commercially important fruit crop in China, but its structure patterns and domestication history remain imprecise. To address these questions, we estimated the genetic structure and domestication history of Chinese cherry using 19 nuclear microsatellite markers and 650 representative accessions (including 118 Cerasus relatives) selected throughout their natural eco-geographical distributions. Our structure analyses detected no genetic contribution from Cerasus relatives to the evolution history of Chinese cherry. A separate genetic structure was detected in wild Chinese cherries and rough geographical structures were observed in cultivated Chinese cherries. One wild (wild Chinese cherry, WC) and two cultivated (cultivated Chinese cherry, CC1 and CC2) genetic clusters were defined. Our approximate Bayesian computation analyses supported an independent domestication history with two domestication events for CC1 and CC2, happening about 3900 and 2200 years ago, respectively. Moderate loss of genetic diversity, over 1000-year domestication bottlenecks and divergent domestication in fruit traits were also detected in cultivated Chinese cherries, which is highly correlated to long-term clonal propagation and different domestication trends and preferences. Our study is the first to comprehensively and systematically investigate the structure patterns and domestication history for Chinese cherry, providing important references for revealing the evolution and domestication history of perennial woody fruit trees

Negatively Charged Composite Nanofibrous Hydrogel Membranes for High-Performance Protein Adsorption

Nanofibrous materials are considered as promising candidates for fabricating high-efficiency chromatography media, which are urgently needed in protein pharmaceuticals purification and biological research, yet still face several bottlenecks. Herein, novel negatively charged composite nanofibrous hydrogel membranes (NHMs) are obtained by a facile combination of electrospinning and surface coating modification. The resulting NHMs exhibit controllable morphologies and chemical structures. Benefitting from the combined effect of the stable framework of silicon dioxide (SiO2) nanofiber and the function layer of negatively charged hydrogel, as well as good pore connectivity among nanofibers, NHMs exhibit a high protein adsorption capacity of around 1000 mg g−1, and are superior to the commercial cellulose fibrous adsorbent (Sartobind®) and the reported nanofibrous membranous adsorbents. Moreover, due to their relatively stable physicochemical and mechanical properties, NHMs possess comprehensive adsorption performance, favorable resistance to acid and solvents, good selectivity, and excellent regenerability. The designed NHMs composite adsorbents are expected to supply a new protein chromatography platform for effective protein purification in biopharmaceuticals and biochemical reagents

Membrane Effect of Geogrid Reinforcement for Low Highway Piled Embankment under Moving Vehicle Loads

In this paper, the membrane effect of geogrid reinforcement was investigated based on numerical simulation to understand the serviceability and deformation of highway piled embankments under moving vehicle loads. The membrane effect of geogrid reinforcement in low embankments (i.e., the ratio of embankment height to pile spacing is less than 1.5) was clearly emphasized. It has been found that the maximum settlement of geogrid occurs in the central area between the piles, and the maximum tension was concentrated at the corner of the pile cap. Due to the attenuation of the soil arching effect under moving dynamic loads and the punching mechanism, the settlement and tension of the geogrid increased considerably by approximately 35% and 23% compared to those under static loads. A parametric study was also achieved, and the results presented that the geogrid reinforcement tension increased by increasing the pile spacing, embankment height and geogrid stiffness, vehicle wheel load and vehicle velocity. It was also found that the reinforcement tension was most sensitive to the pile spacing among all the parameters considered in this paper, whose magnitude increased by approximately 104% as the pile spacing increased from 2.0 m to 2.5 m under dynamic loads

Membrane Effect of Geogrid Reinforcement for Low Highway Piled Embankment under Moving Vehicle Loads

In this paper, the membrane effect of geogrid reinforcement was investigated based on numerical simulation to understand the serviceability and deformation of highway piled embankments under moving vehicle loads. The membrane effect of geogrid reinforcement in low embankments (i.e., the ratio of embankment height to pile spacing is less than 1.5) was clearly emphasized. It has been found that the maximum settlement of geogrid occurs in the central area between the piles, and the maximum tension was concentrated at the corner of the pile cap. Due to the attenuation of the soil arching effect under moving dynamic loads and the punching mechanism, the settlement and tension of the geogrid increased considerably by approximately 35% and 23% compared to those under static loads. A parametric study was also achieved, and the results presented that the geogrid reinforcement tension increased by increasing the pile spacing, embankment height and geogrid stiffness, vehicle wheel load and vehicle velocity. It was also found that the reinforcement tension was most sensitive to the pile spacing among all the parameters considered in this paper, whose magnitude increased by approximately 104% as the pile spacing increased from 2.0 m to 2.5 m under dynamic loads