Effects of cadmium stress on the growth and physiological characteristics of sweet potato.

This study evaluated the responses of sweet potatoes to Cadmium (Cd) stress through pot experiments to theoretically substantiate their comprehensive applications in Cd-polluted agricultural land. The experiments included a CK treatment and three Cd stress treatments with 3, 30, and 150 mg/kg concentrations, respectively. We analyzed specified indicators of sweet potato at different growth periods, such as the individual plant growth, photosynthesis, antioxidant capacity, and carbohydrate Cd accumulation distribution. On this basis, the characteristics of the plant carbon metabolism in response to Cd stress throughout the growth cycle were explored. The results showed that T2 and T3 treatments inhibited the vine growth, leaf area expansion, stem diameter elongation, and tuberous root growth of sweet potato; notably, T3 treatment significantly increased the number of sweet potato branches. Under Cd stress, the synthesis of chlorophyll in sweet potato was significantly suppressed, and the Rubisco activity experienced significant reductions. With the increasing Cd concentration, the function of PS II was also affected. The soluble sugar content underwent no significant change in low Cd concentration treatments. In contrast, it decreased significantly under high Cd concentrations. Additionally, the tuberous root starch content decreased significantly with the increase in Cd concentration. Throughout the plant growth, the activity levels of catalase, peroxidase, and superoxide dismutase increased significantly in T2 and T3 treatments. By comparison, the superoxide dismutase activity in T1 treatment was significantly lower than that of CK. With the increasing application of Cd, its accumulation accordingly increased in various sweet potato organs. The the highest bioconcentration factor was detected in absorbing roots, while the tuberous roots had a lower bioconcentration factor and Cd accumulation. Moreover, the transfer factor from stem to petiole was the highest of the potato organs. These results demonstrated that sweet potatoes had a high Cd tolerance and a restoration potential for Cd-contaminated farmland.

Elucidation of the effects of autochthonous starter on nitrogen-containing compounds during fermentation of Yujiangsuan by metabolomics.

To understand the role of microorganisms in nitrogen (N)-containing compound changes during the processing of Yujiangsuan by autochthonous starter cultures, the GC-TOF-MS-based metabolomics method was adopted to investigate the effects of Weissella cibaria and Lactobacillus plantarum. The results demonstrated that inoculation of autochthonous strains led to differential metabolites, such as fatty acids, organic oxygen compounds, and carboxylic acids on day 4 to day 12 of fermentation. The N-containing compounds under the inoculated fermentation group showed a faster relative concentration change. Nucleotide metabolism and arginine and proline metabolism exerted an influence on the formation of N-containing compounds. Apart from that, the effect of W. cibaria and L. plantarum on the hydrolysis of macromolecules was the main factor causing differences in major N-containing compounds.

The complete chloroplast genome sequence of Litsea coreana var. lanuginosa (Lauraceae): genome structure and phylogenetic analysis.

Litsea coreana var. lanuginose is a perennial, indeciduous, and broad-leaved tree used as an essential medicinal and edible plant. In addition, this species is well-known for its leaves are rich in aromatic oil. In this study, we firstly assembled and characterized the complete chloroplast genome of L. coreana var. lanuginose using Illumina pair-end sequencing and performed a phylogenetic analysis with other 13 species in Lauraceae. The results revealed that its chloroplast genome was 152,859 bp in total length with 39% of GC content, containing a pair of inverted repeats of 20,084 bp (IRA and IRB), separated by a large single-copy (LSC) region of 93,795 bp and a small single-copy (SSC) region of 18,896 bp. The plastid genome of L. coreana var. lanuginose encoded 125 genes, including 81 protein-coding genes, 36 transfer RNA (tRNA), and eight ribosomal RNA (rRNA) genes. The phylogenetic analysis suggested that L. coreana var. lanuginose was closely related to the clade of Litsea monopetala, Litsea garrettii, and Litsea elongate in Lauraceae family.

The complete chloroplast genome of Nageia fleuryi (Hickel) de Laub. (Podocarpaceae).

Nageia fleuryi (Hickel) de Laub. 1987 belongs to the genus Nageia in the family Podocarpaceae and is distributed throughout southeast Asia, including China, Vietnam, and Cambodia. It is a plant with high economic beneficial for food and construction industries. Here, we report on the complete chloroplast (cp) genome of N. fleuryi for the first time. The complete cp genome is similar to many gymnosperm plants, however, it lacks inverted repeat regions and does not possess a typical quadripartite structure. The complete cp genome is 133,870 bp in size and the overall guanine-cytosine (GC) content was found to be 37.27%. The total number of genes is 119, including 82 protein-coding genes, 33 tRNA genes, and 4 rRNA genes. Of these, 14 genes contain one intron, two genes contain two introns, and rps12 possessed a trans-splicing mechanism. Finally, the phylogenic tree demonstrated that N. fleuryi is closely related to Nageia nagi (AB830885.1 and LC572156.1).

Cloning and characterization of TaSnRK2.3, a novel SnRK2 gene in common wheat.

Environmental stresses such as drought, salinity, and cold are major adverse factors that significantly affect agricultural productivity. Protein phosphorylation/dephosphorylation is a major signalling event induced by osmotic stress in higher plants. Sucrose non-fermenting 1-related protein kinase 2 (SnRK2) family members play essential roles in the response to hyperosmotic stresses in plants. In this study, the TaSnRK2.3 gene, a novel SnRK2 member was cloned, and three copies located on chromosomes 1A, 1B, and 1D were identified in common wheat. TaSnRK2.3 was strongly expressed in leaves, and responded to polyethylene glycol, NaCl, abscisic acid, and cold stresses. To characterize its function, transgenic Arabidopsis overexpressing TaSnRK2.3-GFP controlled by the cauliflower mosaic virus 35S promoter was generated and subjected to severe abiotic stresses. Overexpression of TaSnRK2.3 resulted in an improved root system and significantly enhanced tolerance to drought, salt, and freezing stresses, simultaneously demonstrated by enhanced expression of abiotic stress-responsive genes and ameliorative physiological indices, including a decreased rate of water loss, enhanced cell membrane stability, improved photosynthetic potential, and significantly increased osmotic potential and free proline content under normal and/or stressed conditions. These results demonstrate that TaSnRK2.3 is a multifunctional regulator, with potential for utilization in transgenic breeding for improved abiotic stress tolerance in crop plants.

Transgenic expression of TaMYB2A confers enhanced tolerance to multiple abiotic stresses in Arabidopsis.

Osmotic stresses such as drought, salinity, and cold are major environmental factors that limit agricultural productivity. Transcription factors play essential roles in abiotic stress signaling in plants. Three TaMYB2 members were identified and designated TaMYB2A, TaMYB2B, and TaMYB2D based on their genomic origins. The cis-regulatory elements in the promoter regions were compared, and their diverse expression patterns under different abiotic stress conditions were identified. TaMYB2A was further characterized because of its earlier response to stresses. Subcellular localization revealed that TaMYB2A localized in the nucleus. To examine the role of TaMYB2A under various environmental stresses, transgenic Arabidopsis plants carrying TaMYB2A controlled by the CaMV 35S promoter were generated and subjected to severe abiotic stress. TaMYB2A transgenics had enhanced tolerance to drought, salt, and freezing stresses, which were confirmed by the enhanced expressions of abiotic stress-responsive genes and several physiological indices, including decreased rate of water loss, enhanced cell membrane stability, improved photosynthetic potential, and reduced osmotic potential. TaMYB2A is a multifunctional regulatory factor. Its overexpression confers enhanced tolerance to multiple abiotic stresses while having no obvious negative effects on phenotype under well-watered and stressed conditions; thus, TaMYB2A has the potential for utilization in transgenic breeding to improve abiotic stress tolerances in crops.

TaSnRK2.4, an SNF1-type serine/threonine protein kinase of wheat (Triticum aestivum L.), confers enhanced multistress tolerance in Arabidopsis.

Osmotic stresses such as drought, salinity, and cold are major environmental factors that limit agricultural productivity worldwide. Protein phosphorylation/dephosphorylation are major signalling events induced by osmotic stress in higher plants. Sucrose non-fermenting 1-related protein kinase2 family members play essential roles in response to hyperosmotic stresses in Arabidopsis, rice, and maize. In this study, the function of TaSnRK2.4 in drought, salt, and freezing stresses in Arabidopsis was characterized. A translational fusion protein of TaSnRK2.4 with green fluorescent protein showed subcellular localization in the cell membrane, cytoplasm, and nucleus. To examine the role of TaSnRK2.4 under various environmental stresses, transgenic Arabidopsis plants overexpressing wheat TaSnRK2.4 under control of the cauliflower mosaic virus 35S promoter were generated. Overexpression of TaSnRK2.4 resulted in delayed seedling establishment, longer primary roots, and higher yield under normal growing conditions. Transgenic Arabidopsis overexpressing TaSnRK2.4 had enhanced tolerance to drought, salt, and freezing stresses, which were simultaneously supported by physiological results, including decreased rate of water loss, enhanced higher relative water content, strengthened cell membrane stability, improved photosynthesis potential, and significantly increased osmotic potential. The results show that TaSnRK2.4 is involved in the regulation of enhanced osmotic potential, growth, and development under both normal and stress conditions, and imply that TaSnRK2.4 is a multifunctional regulatory factor in Arabidopsis. Since the overexpression of TaSnRK2.4 can significantly strengthen tolerance to drought, salt, and freezing stresses and does not retard the growth of transgenic Arabidopsis plants under well-watered conditions, TaSnRK2.4 could be utilized in transgenic breeding to improve abiotic stresses in crops.