Complex phase behavior of dihydroxyl-functionalized ionic liquids at low temperature.

Here, we have synthesized six dihydroxyl-functionalized ionic liquids for phase behavior studies at low temperature via crystallographic methods, Raman spectroscopy, differential scanning calorimetry (DSC), and density functional theory (DFT) calculations. Phase varieties are observed depending on the direction and strength of hydrogen bonding. Our studies also show that the ILs could be potentially excellent phase-change thermal storage materials with nearly no change of the phase transition enthalpy.

Screening and optimisation of in vitro pollen germination medium for sweetpotato (Ipomoea batatas).

BACKGROUND: Sweetpotato is an important vegetable and food crop that is bred through sexual crosses and systematic selection. The use of in vitro germination of sweetpotato pollen to test its viability has important theoretical and practical implications for improving the efficiency of sweetpotato crossbreeding by controlling pollination and conducting research on sweetpotato pollen biology. RESULTS: In this study, we observed the morphological structure of sweetpotato pollen under a scanning electron microscope (SEM), developed an effective method for the in vitro germination of sweetpotato pollen, and examined the viability of sweetpotato pollen after treating plants at different temperatures before blossoming. Sweetpotato pollen grains are spherical, with an average diameter of 87.07 ± 3.27 µm (excluding spines), with multiple germination pores and reticulate pollen surface sculpture. We applied numerous media to sweetpotato pollen germination in vitro to screen the initial medium and optimised the medium components through single-factor design. The most effective liquid medium for in vitro sweetpotato pollen germination contained 50 g/L Sucrose, 50 g/L Polyethylene glycol 4000 (PEG4000), 100 mg/L Boric acid and 300 mg/L Calcium nitrate, with a pH = 6.0. The optimum growth temperature for pollen development in sweetpotato was from 25 to 30 °C. Neither staining nor in situ germination could accurately determine the viability of sweetpotato pollen. CONCLUSIONS: In vitro germination can be used to effectively determine sweetpotato pollen viability. The best liquid medium for in vitro germination of sweetpotato pollen contained 50 g/L Sucrose, 50 g/L Polyethylene glycol 4000 (PEG4000), 100 mg/L Boric acid and 300 mg/L Calcium nitrate, with the pH adjusted to 6.0. This study provides a reliable medium for the detection of sweetpotato pollen viability, which can provide a theoretical reference for sweetpotato genetics and breeding.

Isolation, characterization, and functional verification of salt stress response genes of NAC transcription factors in Ipomoea pes-caprae.

Adverse environmental stress is a major environmental factor threatening food security, which is why improving plant stress resistance is essential for agricultural productivity and environmental sustainability. The NAC (NAM, ATAF, and CUC) transcription factors (TFs) play a dominant role in plant responses to abiotic and biotic stresses, but they have been poorly studied in Ipomoea pes-caprae. In this research, 12 NAC TFs, named IpNAC1-IpNAC12, were selected from transcriptome data. The homologous evolution tree divided IpNACs into four major categories, and six IpNACs were linearly associated with Arabidopsis ANAC genes. From the gene structures, protein domains, and promoter upstream regulatory elements, IpNACs were shown to contain complete NAC-specific subdomains (A-E) and cis-acting elements corresponding to different stress stimuli. We measured the expression levels of the 12 IpNACs under abiotic stress (salt, heat, and drought) and hormone treatment (abscisic acid, methyl jasmonate, and salicylic acid), and their transcription levels differed. IpNAC5/8/10/12 were located in the nucleus through subcellular localization, and the overexpressing transgenic Arabidopsis plants showed high tolerance to salt stress. The cellular Na+ homeostasis content in the mature and elongation zones of the four IpNAC transgenic sweetpotato roots showed an obvious efflux phenomenon. These conclusions demonstrate that IpNAC5/8/10/12 actively respond to abiotic stress, have significant roles in improving plant salt tolerance, and are important salt tolerance candidate genes in I. pes-caprae and sweetpotato. This study laid the foundation for further studies on the function of IpNACs in response to abiotic stress. It provides options for improving the stress resistance of sweetpotato using gene introgression from I. pes-caprae.

Comparative Metabolomic and Transcriptomic Analyses of Phytochemicals in Two Elite Sweet Potato Cultivars for Table Use.

To elucidate nutritional components in sweet potato cultivars for table use and to compare the phytochemicals of cultivars from different countries, 'Kokei No. 14' and 'Xinxiang' were selected. The physiological parameters and metabolites were determined using the colorimetric method and widely targeted metabolomics, respectively. Transcriptomic analysis was performed to explain the mechanism that resulted in phytochemical differences. 'Xinxiang' showed higher flavonoid and carotenoid contents. Metabolomics showed five upregulated flavonoids. Two essential amino acids (EAAs) and one conditionally essential amino acid (CEAA) were upregulated, whereas four EAAs and two CEAAs were downregulated. Unlike lipids, in which only one of thirty-nine was upregulated, nine of twenty-seven differentially accumulated phenolic acids were upregulated. Three of the eleven different alkaloids were upregulated. Similarly, eight organic acids were downregulated, with two upregulated. In addition, three of the seventeen different saccharides and alcohols were upregulated. In 'other metabolites,' unlike vitamin C, 6'-O-Glucosylaucubin and pantetheine were downregulated. The differentially accumulated metabolites were enriched to pathways of the biosynthesis of secondary metabolites, ABC transporters, and tyrosine metabolism, whereas the differentially expressed genes were mainly concentrated in the metabolic pathway, secondary metabolite biosynthesis, and transmembrane transport functions. These results will optimize the sweet potato market structure and enable a healthier diet for East Asian residents.

Comparative analysis of chloroplast genomes of cultivars and wild species of sweetpotato (Ipomoea batatas [L.] Lam).

BACKGROUND: Sweetpotato (Ipomoea batatas [L.] Lam.) is an important food crop. However, the genetic information of the nuclear genome of this species is difficult to determine accurately because of its large genome and complex genetic background. This drawback has limited studies on the origin, evolution, genetic diversity and other relevant studies on sweetpotato. RESULTS: The chloroplast genomes of 107 sweetpotato cultivars were sequenced, assembled and annotated. The resulting chloroplast genomes were comparatively analysed with the published chloroplast genomes of wild species of sweetpotato. High similarity and certain specificity were found among the chloroplast genomes of Ipomoea spp. Phylogenetic analysis could clearly distinguish wild species from cultivars. Ipomoea trifida and Ipomoea tabascana showed the closest relationship with the cultivars, and different haplotypes of ycf1 could be used to distinguish the cultivars from their wild relatives. The genetic structure was analyzed using variations in the chloroplast genome. Compared with traditional nuclear markers, the chloroplast markers designed based on the InDels on the chloroplast genome showed significant advantages. CONCLUSIONS: Comparative analysis of chloroplast genomes of 107 cultivars and several wild species of sweetpotato was performed to help analyze the evolution, genetic structure and the development of chloroplast DNA markers of sweetpotato.