Morphological and metabolomics profiling of intraspecific Arabidopsis hybrids in relation to biomass heterosis

Heterosis contributes greatly to the worldwide agricultural yield. However, the molecular mechanism underlying heterosis remains unclear. This study took advantage of Arabidopsis intraspecific hybrids to identify heterosis-related metabolites. Forty-six intraspecific hybrids were used to examine parental effects on seed area and germination time. The degree of heterosis was evaluated based on biomass: combinations showing high heterosis of F₁ hybrids exhibited a biomass increase from 6.1 to 44% over the better parent value (BPV), whereas that of the low- and no-heterosis hybrids ranged from - 19.8 to 9.8% over the BPV. Metabolomics analyses of F₁ hybrids with high heterosis and those with low one suggested that changes in TCA cycle intermediates are key factors that control growth. Notably, higher fumarate/malate ratios were observed in the high heterosis F₁ hybrids, suggesting they provide metabolic support associated with the increased biomass. These hybrids may produce more energy-intensive biomass by speeding up the efficiency of TCA fluxes. However, the expression levels of TCA-process-related genes in F₁ hybrids were not associated with the intensity of heterosis, suggesting that the post-transcriptional or post-translational regulation of these genes may affect the productivity of the intermediates in the TCA cycle.

Evaluation of the use of biochar to stabilize polycyclic aromatic hydrocarbons and phthalates in sediment

Three types of biochar (BC) (mulberry biochar (MB), wheat straw biochar, and pine tree sawdust biochar) were prepared and used to stabilize hydrophobic organic compounds (HOCs) in contaminated sediment. The kinetics of HOC adsorption to the BCs had two distinct stages. The second stage adsorption process was longer for MB than the other BCs, presumably because MB contained large pores, mesopores, and micropores. The adsorption isotherms for the three BCs were described well by the Freundlich model. The adsorption capacities of MB, WS and PT for HOCs ranged between 106.7 and 1202 μg/g, 135.1 and 1002 μg/g, and 255.6 and 909 μg/g, respectively. The apparent HOC adsorption coefficients (K_BC-w) for the three BCs were determined from the isotherm data and were similar. The HOC logK_OW values correlated well with the logK_BC-w values. In sediment slurry experiments, HOCs were much more effectively stabilized by MB than wheat straw and pine tree sawdust biochar. This was probably because of the MB pore characteristics that favored adsorption of HOCs of various molecular sizes. The Fourier-transform infrared and Raman spectra indicated that the main binding mechanisms were hydrogen boding, hydrophobic interactions, and π-π interactions. MB was found to be a possible agent for stabilizing HOCs in contaminated sediment. HOCs in sediment slurry continued to become adsorbed to MB for a long time, indicating that relatively long reaction times should be allowed for in situ remediation using MB.

Insights into the gene and protein structures of the CaSWEET family members in chickpea (Cicer arietinum), and their gene expression patterns in different organs under various stress and abscisic acid treatments

'Sugars Will Eventually be Exported Transporters' (SWEETs) are a group of sugar transporters that play crucial roles in various biological processes, particularly plant stress responses. However, no information is available yet for the CaSWEET family in chickpea. Here, we identified all putative CaSWEET members in chickpea, and obtained their major characteristics, including physicochemical patterns, chromosomal distribution, subcellular localization, gene organization, conserved motifs and three-dimensional protein structures. Subsequently, we explored available transcriptome data to compare spatiotemporal transcript abundance of CaSWEET genes in various major organs. Finally, we studied the changes in their transcript levels in leaves and/or roots following dehydration and exogenous abscisic acid treatments using RT-qPCR to obtain valuable information underlying their potential roles in chickpea responses to water-stress conditions. Our results provide the first insights into the characteristics of the CaSWEET family members and a foundation for further functional characterizations of selected candidate genes for genetic engineering of chickpea.

SWEET Gene Family in Sugar Beet (Beta vulgaris): Genome-Wide Survey, Phylogeny and Expression Analysis

<b>Background and Objective:</b> The SWEET (Sugars Will Eventually be Exported Transporter) proteins play important roles in modulating the growth and development processes in plants. However, little information is available on the SWEET family in sugar beet (<i>Beta vulgaris</i>). The objectives of this present study were to genome-wide identify and characterize the BvSWEET family in sugar beet. <b>Materials and Methods:</b> Based on the available genome, proteome and transcriptome databases of sugar beet, various computational tools have been used to analyze the nucleotide and full-length protein sequences of members of the BvSWEET family. <b>Results:</b> A total of 16 members of the BvSWEET family has been identified in sugar beet at the genome-wide scale. Structural analysis indicated that the BvSWEET family exhibited variable characteristics. Furthermore, the BvSWEET family in sugar beet could be categorized into four distinct groups like in other plant species. Of our interest, we found that some <i>BvSWEET</i> genes exhibited strongly preferential expression in major organs/tissues under adverse environmental stimuli. <b>Conclusion:</b> The results provided a comprehensive foundation for further functional characterization of the <i>BvSWEET </i>gene family.

Genome-Wide Identification and Analysis of Genes Encoding Putative Heat Shock Protein 70 in Papaya (Carica papaya)

<b>Background and Objective:</b> In high plants, the 70 kDa heat stress proteins (Hsp70-s) have been regarded as one of the vital components of the cellular network of chaperones and folding catalysts that play important roles in numerous biological processes during growth and development. The Hsp70 families have been reported in many plant species, unfortunately, no information on this important protein family in papaya (<i>Carica papaya</i>). The objective of this study was to provide comprehensive information on the CpHsp70 family in papaya. <b>Materials and Methods:</b> The <i>CpHsp70</i> genes in the papaya genome were identified by a basic local alignment search tool against the papaya genome database by using well-known <i>Arabidopsis</i> Hsp70-s. Sequences were then analyzed by various bioinformatics tools to investigate the characteristics of the CpHsp70 family. <b>Results:</b> A total of 12 members of the CpHsp70 family has been identified and characterized in papaya. By using various computational tools, these results revealed that all general characteristics of the CpHsp70 family, like physic-chemical parameters, gene structure, phylogenetic tree and subcellular localization were provided. The transcriptome atlas was applied to re-analyze the expression patterns of genes encoding the CpHsp70 family in major tissues/organs during the growth and development of papaya plants. <b>Conclusion:</b> Results from this work exhibited the characteristics and expression analysis of the <i>CpHsp70</i> genes of this important tropical fruit crop. Taken together, this study could provide a solid foundation of the CpHsp70 family, which will be helpful in the construction of stress tolerance in papaya plants.

Integrated transcript and metabolite profiling reveals coordination between biomass size and nitrogen metabolism in Arabidopsis F1 hybrids

Heterosis refers to the improved agronomic performance of F₁ hybrids relative to their parents. Although this phenomenon is widely employed to increase biomass, yield, and stress tolerance of plants, the underlying molecular mechanisms remain unclear. To dissect the metabolic fluctuations derived from genomic and/or environmental differences contributing to the improved biomass of F₁ hybrids relative to their parents, we optimized the growth condition for Arabidopsis thaliana F₁ hybrids and their parents. Modest but statistically significant increase in the biomass of F₁ hybrids was observed. Plant samples grown under the optimized condition were also utilized for integrated omics analysis to capture specific changes in the F₁ hybrids. Metabolite profiling of F₁ hybrids and parent plants was performed using gas chromatography-mass spectrometry. Among the detected 237 metabolites, 2-oxoglutarate (2-OG) and malate levels were lower and the level of aspartate was higher in the F₁ hybrids than in each parent. In addition, microarray analysis revealed that there were 44 up-regulated and 12 down-regulated genes with more than 1.5-fold changes in expression levels in the F₁ hybrid compared to each parent. Gene ontology (GO) analyses indicated that genes up-regulated in the F₁ hybrids were largely related to organic nitrogen (N) process. Quantitative PCR verified that glutamine synthetase 2 (AtGLN2) was upregulated in the F₁ hybrids, while other genes encoding enzymes in the GS-GOGAT cycle showed no significant differences between the hybrid and parent lines. These results suggested the existence of metabolic regulation that coordinates biomass and N metabolism involving AtGLN2 in F₁ hybrids.

Caesium adsorption on a zeolitic imidazolate framework (ZIF-8) functionalized by ferrocyanide

¹³⁷Cs is one of the most hazardous radionuclides in nuclear waste owing to its toxicity. Developing an adsorbent for Cs⁺ with a high capacity and selectivity is a challenging task. A metal-organic framework (MOF) is a material with a high surface area that has been widely applied in wastewater treatment. Exploiting the affinity between ferrocyanide (FC) and Cs⁺, zeolitic imidazolate framework-8 (ZIF-8) was chemically functionalized with FC, ZIF-8-FC to selectively capture Cs⁺. After functionalization, ZIF-8-FC has a hollow morphology and small FC related crystals, which might result in better migration of Cs⁺ inside ZIF-8-FC. This synergistic effect was proven by the Q_max of ZIF-8-FC, 422.42 mg g^-1, which is 15.9 times higher than that of ZIF-8. Additionally, ZIF-8-FC retained its good adsorption performance within a pH range of 3-11 and an excellent Cs⁺ selectivity even in artificial seawater conditions. The structure of ZIF-8-FC after adsorption proves its stability. Furthermore, the thermodynamic adsorption implied that higher temperatures are more favorable for Cs⁺ uptake. This work demonstrates the remarkable adsorption and selectivity of ZIF-8-FC, which make it a promising candidate for remediation of radioactive Cs⁺.

Association analysis of phenotypic and metabolomic changes in Arabidopsis accessions and their F1 hybrids affected by different photoperiod and sucrose supply

Photoperiod and sucrose (Suc) assimilation play important roles in the regulation of plant growth and development. However, it remains unclear how natural variation of plants could contribute to metabolic changes under various growth conditions. Here, we investigated the developmental and metabolomic responses of two natural accessions of Arabidopsis thaliana, Columbia (Col) and C24, and their reciprocal F₁ hybrids grown under four carbon source regimens, i.e., two different photoperiods and the presence or absence of exogenous Suc supply. The effect of exogenous Suc clearly appeared in the growth of Col and the F₁ hybrid but not in C24, whereas long-day conditions had significant positive effects on the growth of all lines. Comparative metabolite profiling of Col, C24, and the F₁ hybrid revealed that changes in metabolite levels, particularly sugars, were highly dependent on genotype-specific responses rather than growth conditions. The presence of Suc led to over-accumulation of seven metabolites, including four sugars, a polyamine, and two amino acids in C24, whereas no such accumulation was observed in the profiles of Col and the F₁ hybrid. Thus, the comparative metabolite profiling revealed that the two parental lines of the hybrid show a distinct difference in sugar metabolism.