Effects of Bacillus subtilis on Cucumber Seedling Growth and Photosynthetic System under Different Potassium Ion Levels.

Potassium deficiency is one of the important factors restricting cucumber growth and development. This experiment mainly explored the effect of Bacillus subtilis (B. subtilis) on cucumber seedling growth and the photosynthetic system under different potassium levels, and the rhizosphere bacteria (PGPR) that promote plant growth were used to solubilize potassium in soil, providing theoretical support for a further investigation of the effect of biological bacteria fertilizer on cucumber growth and potassium absorption. "Xinjin No. 4" was used as the test material for the pot experiment, and a two-factor experiment was designed. The first factor was potassium application treatment, and the second factor was bacterial application treatment. The effects of different treatments on cucumber seedling growth, photosynthetic characteristics, root morphology, and chlorophyll fluorescence parameters were studied. The results showed that potassium and B. subtilis had obvious promotion effects on the cucumber seedling growth and the photosynthesis of leaves. Compared with the blank control, the B. subtilis treatment had obvious effects on the cucumber seedling height, stem diameter, leaf area, total root length, total root surface area, total root volume, branch number, crossing number, gs, WUE, Ci, and A; the dry weight of the shoot and root increased significantly (p ≤ 0.05). Potassium application could significantly promote cucumber growth, and the effect of B. subtilis and potassium application was greater than that of potassium application alone, and the best effect was when 0.2 g/pot and B. subtilis were applied. In conclusion, potassium combined with B. subtilis could enhance the photosynthesis of cucumber leaves and promote the growth of cucumber.

The Anti-Microbial Peptide Citrocin Controls Pseudomonas aeruginosa Biofilms by Breaking Down Extracellular Polysaccharide.

Citrocin is an anti-microbial peptide that holds great potential in animal feed. This study evaluates the anti-microbial and anti-biofilm properties of Citrocin and explores the mechanism of action of Citrocin on the biofilm of P. aeruginosa. The results showed that Citrocin had a significant inhibitory effect on the growth of P. aeruginosa with a minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of 0.3 mg/mL. All five concentrations (1/4MIC, 1/2MIC, MIC, 2MIC, and 4MIC) of Citrocin inhibited P. aeruginosa biofilm formation. Citrocin at the MIC, 2MIC and 4MIC removed 42.7%, 76.0% and 83.2% of mature biofilms, respectively, and suppressed the swarming motility, biofilm metabolic activity and extracellular polysaccharide production of P. aeruginosa. Metabolomics analysis indicated that 0.3 mg/mL of Citrocin up- regulated 26 and down-regulated 83 metabolites, mainly comprising amino acids, fatty acids, organic acids and sugars. Glucose and amino acid metabolic pathways, including starch and sucrose metabolism as well as arginine and proline metabolism, were highly enriched by Citrocin. In summary, our research reveals the anti-biofilm mechanism of Citrocin at the metabolic level, which provides theoretical support for the development of novel anti-biofilm strategies for combatting P. aeruginosa.

Leaf Spot of Hedychium coronarium Caused by Colletotrichum gloeosporioides in China.

Hedychium coronarium (white ginger) is widely cultivated for garden decoration and folk medicine. Since 2020, symptomatic leaves showed brown necrosis and yellow borders on H. coronarium in the field (approximately 200 m2) at Southwest University, Rongchang District, Chongqing City. Small brown-yellow spots gradually enlarged and caused withering in severe cases with a mortality rate of around 10%. Disease incidence and severity varied from 55 to 65% and from 30 to 40%, respectively. Infected tissues (5 mm in diameter) were cut from lesion margins, surface sterilized in 70% ethanol for 10 s and 0.1% acidic mercuric chloride for 3 min, followed by rinsing in sterile water three times, and then were cultured onto potato dextrose agar (PDA) at 25 °C. Five isolates were transferred onto fresh PDA and purified by single-spore culturing. The colonies were initially white and turned hoary, and the diameter reached 32.95 to 38.37 mm × 32.42 to 38.61 mm after 3 days of incubation. Pale gray abundant fluffy aerial mycelia were arranged irregularly and densely. Hyphae were septate and branched, 2 to 5 µm in width. Conidiophores were pale brown, septate, branched, cylindrical to ampulliform. Conidia were hyaline, smooth-walled, cylindrical with obtuse ends, and 8.1 to 13.3 µm × 2.4 to 5.8 µm (n = 50) in size. Appressoria were medium brown to dark brown, aseptate, in irregular shape, solitary or in groups, and measured 1.5 to 12.5 µm × 2.1 to 13.3 µm. Morphological characteristics of isolates agreed with the description of Colletotrichum (Liu et al. 2015). Genomic DNA was extracted from fungal colonies incubated on PDA for 7 days following the instructions from the PlantGen DNA Kit (CWBIO, China). The internal transcribed spacer (ITS) region, and fragments of glyceraldehyde-3-phosphate dehydrogenase (GAPDH), actin (ACT), beta-tubulin (TUB2) and large subunit ribosomal DNA (LSU rDNA) genes were amplified by primer pairs ITS1/ ITS4, GDF1/GDR1, ACT512F/ACT783R (Naz et al. 2017), T1/Bt2b (Glass et al. 1995) and LROR/LR7 (Castlebury et al. 2002), respectively. The sequence of representative isolate CG-H (GenBank accession nos. OM010355, OM238213, OM238214, OM045778 and OM010358 for ITS, GAPDH, ACT, TUB2 and LSU rDNA, respectively) exhibited 99 to 100% identity to Colletotrichum gloeosporioides. A multi-locus phylogenetic tree with concatenated sequences of ITS, GAPDH, ACT and TUB regions was constructed using the maximum likelihood method by MEGA7, which revealed that strain CG-H was grouped with C. gloeosporioides. To confirm the pathogenicity, six healthy H. coronarium plants were surface sterilized, and conidial suspension (1 × 106 conidia/mL) was sprayed onto the leaves. Six plants were inoculated with sterile distilled water as controls. All the plants grew in a greenhouse at 25 °C under 12 h/12 h photoperiod. The experiment was repeated four times. Yellow lesions appeared after 7 days of inoculation, irregular-shaped brown spots were formed and slightly sunken within 14 days, and the whole leaf gradually became withered in 50 days. All inoculated plants exhibited leaf spot symptoms while the control plants remained asymptomatic. C. gloeosporioides was re-isolated from lesions of leaves and identified by morphology and sequence analysis, fully confirming Koch's postulates. This is the first report of C. gloeosporioides associated with H. coronarium leaf spot in China and worldwide. Further studies will be conducted on the sensitivity of C. gloeosporioides to various fungicides.

Antifungal Peptide P852 Effectively Controls Fusarium oxysporum, a Wilt-Causing Fungus, by Affecting the Glucose Metabolism and Amino Acid Metabolism as well as Damaging Mitochondrial Function.

Fusarium oxysporum causes wilt disease, which causes huge economic losses to a wide range of agricultural cash crops. Antifungal peptide P852 is an effective biocide. However, the mechanism of direct inhibition of pathogenic fungus needs to be explored. The proteomics and transcriptomics results showed that P852 mainly affected intracellular pathways such as glucose metabolism, amino acid metabolism, and oxidoreductase activity in F. oxysporum. P852 disrupts the intracellular oxidative equilibrium in F. oxysporum, and transmission electron microscopy observed mitochondrial swelling, disruption of membrane structure, and leakage of contents. Decreased mitochondrial membrane potential, mitochondrial cytochrome c leakage, and reduced ATP production were also detected. These results suggest that P852 is able to simultaneously inhibit intracellular metabolism and disrupt the mitochondrial function of F. oxysporum, exerting its inhibitory effects in multiple pathways together. The present study provides some insights into the multitargeted mechanism of fungus inhibition of antifungal lipopeptide substances produced by Bacillus spp.

First Report of Leaf Blight of Hedychium coronarium Caused by Alternaria alternata in China.

Hedychium coronarium is an economically significant crop that is widely cultivated for its ornamental, aromatic, and medicinal value (Abbas et al. 2021). From 2020 to 2023, a leaf blight was observed in about 85% of H. coronarium growing in a production field (approximately 500 m2) at Southwest University, Chongqing, China (29° 150'-29° 41' N, 105° 17'-105° 44' E). Symptoms included dark brown necrotic tissue with a clear yellow border. When the disease became severe, affected leaves became dry and abscised. Symptomatic pieces (2 to 5 mm2) between necrotic and healthy tissues were collected from 20 leaf samples, then were immersed in 70% ethanol for 10 s, 0.1% mercury bichloride for 3 min, rinsed in sterile water three times, and placed onto potato dextrose agar (PDA). Four Alternaria isolates were obtained by transferring hyphal tips to new plates. All isolates had identical morphological traits. Cultures on PDA were initially white mycelium on the rim with a light brown center. At around the fourth day, the colony margin changed into light gray and the central part turned sooty black. Conidiophores were branched. Conidia were dark brown, ovoid or ellipsoid in shape, 3.4 to 13.2 µm × 4.1 to 23.5 µm (n = 50) with zero to four transverse and longitudinal septa. For molecular identification, DNA was extracted using the PlantGen DNA Kit CW0553A (Cwbio, Taizhou, China) for PCR amplification of internal transcribed spacer (ITS) region, and 28S large subunit ribosomal RNA (LSU), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), Alternaria major allergen (Alt a 1) and actin (ACT) genes (Choi et al. 2022; Xie et al. 2022; Zhang et al. 2021). BLASTn searches showed that ITS, LSU, GAPDH, Alt a 1 and ACT of four isolates had 100% homology with the corresponding sequences of A. alternata strains MZ578214, KP940477, MK903028, MN655781 and MF564199, respectively. Representative sequences of one strain (AH1) with accession numbers of OK639009, OK639186, OK664976, OK664977 and OK664978 for ITS, LSU, GAPDH, Alt a 1 and ACT regions were deposited in GenBank. The maximum-likelihood tree generated by MEGA 5.10 demonstrated that the pathogenic isolate AH1 obtained from H. coronarium leaf was grouped in the same clade with A. alternata strain CBS121348, which was supported by 100% bootstrap values. To fulfill Koch's postulates, conidia were collected from a 7-day-old culture, suspended in sterile distilled water, and adjusted to 1 × 106 conidia/mL. Leaves on 6-month-old H. coronarium were surface disinfected with 1% sodium hypochlorite solution for 1 min, rinsed twice in water, and then inoculated with AH1 using a sprayer, while leaves treated with sterile water served as negative controls. The experiment was conducted four times, and each repeat contained 10 plants. Pathogenicity tests were performed in the greenhouse at 25°C with a 12 h photoperiod. Partial yellow lesions were observed 3 days of post-inoculation. As the disease progressed, the tawny color gradually spread across the leaf and the tip became dark brown within 7 days. The necrosis expanded and some small leaves were completely affected within 2 weeks. The pathogen was re-isolated from the lesions and re-identified through morphological traits and sequence analysis. A. alternata have been reported to cause leaf diseases in a variety of cereal crops, vegetables, and fruits across China (Sun et al. 2021; Zheng et al. 2015), which cause significant crop loss. To our knowledge, this is the first report of A. alternata causing leaf blight of H. coronarium in the world. More surveys are needed to explore the epidemiology and management strategies for disease caused by A. alternata in Southwest China.

First Report of Fungal Pathogens Causing Leaf Spot on Sorghum-Sudangrass Hybrids and Their Interactions with Plants.

The sorghum-sudangrass hybrid is the main high-quality forage grass in Southwest China, but, in recent years, it has suffered from leaf spot disease, with a prevalence of 88% in Bazhong, Sichuan, China, seriously affecting yield and quality. The causal agents were obtained from symptomatic leaves by tissue isolation and verified by pathogenicity assays. A combination of morphological characterization and sequence analysis revealed that strains SCBZSL1, SCBZSX5, and SCBZSW6 were Nigrospora sphaerica, Colletotrichum boninense, and Didymella corylicola, respectively, and the latter two were the first instance to be reported on sorghum-sudangrass hybrids in the world. SCBZSX5 significantly affected the growth of the plants, which can reduce plant height by 25%. The biological characteristics of SCBZSX5 were found to be less sensitive to the change in light and pH, and its most suitable culture medium was Potato Dextrose Agar (PDA), with the optimal temperature of 25 °C and lethal temperature of 35 °C. To clarify the interactions between the pathogen SCBZSX5 and plants, metabolomics analyses revealed that 211 differential metabolites were mainly enriched in amino acid metabolism and flavonoid metabolism. C. boninense disrupted the osmotic balance of the plant by decreasing the content of acetyl proline and caffeic acid in the plant, resulting in disease occurrence, whereas the sorghum-sudangrass hybrids improved tolerance and antioxidant properties through the accumulation of tyrosine, tryptophan, glutamic acid, leucine, glycitein, naringenin, and apigetrin to resist the damage caused by C. boninense. This study revealed the mutualistic relationship between sorghum-sudangrass hybrids and C. boninense, which provided a reference for the control of the disease.

Effects of Lactobacillus plantarum and its fermentation products on growth performance, immune function, intestinal pH, and cecal microorganisms of Lingnan yellow chicken.

The present research was conducted to investigate the effects of dietary supplementation of Lactobacillus plantarum and its fermentation products on growth performance, specific immune function, intestinal pH, and cecal microorganisms in yellow-feather broilers. A total of 1,200 yellow-feather broilers of similar weight and good health condition at 1 d of age were selected and randomly divided into 5 groups. The CK group was fed the basal diet, and the experimental group (I, II, III, IV) were supplemented with 0.1, 0.15% L. plantarum and 3, 4% L. plantarum fermentation products. The results showed that each treatment could improve the growth performance (P < 0.05) and feed conversion rate of yellow-feather broilers. Besides, the pH value of the gastrointestinal tract of yellow-feather broilers (P < 0.05) was significantly reduced through the use of L. plantarum and its fermentation products as additives, which also facilitated the animals to regulate the balance of cecal microorganisms. The immune function assay showed that the bursal index (P < 0.05), spleen index (P < 0.05), and the content of serum immunoglobulins IgA and IgG (P < 0.05) were significantly increased in yellow-finned broilers aged 1 to 21 d by supplementing the diet with L. plantarum. In conclusion, adding L. plantarum or its fermentation products to the diet can improve the growth performance of yellow-feather broilers, and the direct addition of L. plantarum is better than adding fermentation products.

Mercury biomagnification at higher rates than the global average in aquatic ecosystems of the Qinghai-Tibet Plateau.

Mercury biomagnification in aquatic ecosystems is a global issue. Biomagnification patterns and drivers in alpine regions remain poorly understood. Hg biomagnification in the aquatic food web of the Qinghai-Tibetan Plateau (Q-T Plateau) was investigated. A total of 302 fish and macroinvertebrate tissue samples were analysed for total mercury (THg) and nitrogen (δ15N) stable isotope ratios. Overall, 26.75% of fish individuals exceeded the USFWS consumption guidelines. A total of 52.17% of the sampling sites covering different habitats exhibited a significantly positive THg-δ15N relationship, which confirmed the Hg biomagnification potential of Q-T Plateau aquatic ecosystems. The Q-T Plateau Hg biomagnification rates were generally far higher than global averages regardless of the habitat type. Hg in sediments, elevation and population density were positively related to the Hg biomagnification magnitude on the Q-T Plateau, which could be attributed to the disproportionate response of Hg concentrations in macroinvertebrates and fishes along environmental gradients. Our findings offer empirical evidence that fish consumption on the Q-T Plateau poses a substantial Hg exposure risk to people living along river and lake shores. Higher biomagnification rates could further disproportionately accelerate Hg pollution in Q-T Plateau aquatic ecosystems under future anthropogenic activities and climate warming trajectories.

Antimicrobial Peptides Mediate Apoptosis by Changing Mitochondrial Membrane Permeability.

Changes in mitochondrial membrane permeability are closely associated with mitochondria-mediated apoptosis. Antimicrobial peptides (AMPs), which have been found to enter cells to exert physiological effects, cause damage to the mitochondria. This paper reviews the molecular mechanisms of AMP-mediated apoptosis by changing the permeability of the mitochondrial membrane through three pathways: the outer mitochondrial membrane (OMM), inner mitochondrial membrane (IMM), and mitochondrial permeability transition pore (MPTP). The roles of AMPs in inducing changes in membrane permeability and apoptosis are also discussed. Combined with recent research results, the possible application prospects of AMPs are proposed to provide a theoretical reference for the development of AMPs as therapeutic agents for human diseases.

Screening of differentially expressed microRNAs and target genes in two potato varieties under nitrogen stress.

BACKGROUND: A reasonable supply of nitrogen (N) fertilizer is essential for obtaining high-quality, high-level, and stable potato yields, and an improvement in the N utilization efficiency can effectively reduce N fertilizer use. It is important to use accurate, straightforward, and efficient transgenic breeding techniques for the identification of genes that can improve nitrogen use efficiency, thus enabling us to achieve the ultimate goal of breeding N-efficient potato varieties. In recent years, some of the mechanisms of miRNAs have been elucidated via the analysis of the correlation between the expression levels of potato miRNA target genes and regulated genes under conditions of stress, but the role of miRNAs in the inhibition/expression of key genes regulating N metabolism under N stress is still unclear. Our study aimed to identify the role played by specific enzymes and miRNAs in the responses of plants to N stress. RESULTS: The roots and leaves of the N-efficient potato variety, Yanshu4 ("Y"), and N-inefficient potato variety, Atlantic ("D"), were collected at the seedling and budding stages after they were exposed to different N fertilizer treatments. The miRNAs expressed differentially under the two types of N stress and their corresponding target genes were first predicted using miRNA and degradome analysis. Then, quantitative polymerase chain reaction (qRT-PCR) was performed to verify the expression of differential miRNAs that were closely related to N metabolism. Finally, the shearing relationship between stu-miR396-5p and its target gene StNiR was determined by analyzing luciferase activity levels. The results showed that NiR activity increased significantly with an increase in the applied N levels from the seedling stage to the budding stage, and NiR responded significantly to different N treatments. miRNA sequencing enabled us to predict 48 families with conserved miRNAs that were mainly involved in N metabolism, carbon metabolism, and amino acid biosynthesis. The differences in the expression of the following miRNAs were identified via screening (high expression levels and P < 0.05): stu-miR396-5p, stu-miR408b-3p_R-1, stu-miR3627-3p, stu-miR482a-3p, stu-miR8036-3p, stu-miR482a-5p, stu-miR827-5p, stu-miR156a_L-1, stu-miR827-3p, stu-miR172b-5p, stu-miR6022-p3_7, stu-miR398a-5p, and stu-miR166c-5p_L-3. Degradome analysis showed that most miRNAs had many-to-many relationships with target genes. The main target genes involved in N metabolism were NiR, NiR1, NRT2.5, and NRT2.7. qRT-PCR analysis showed that there were significant differences in the expression levels of stu-miR396-5p, stu-miR8036-3p, and stu-miR482a-3p in the leaves and roots of the Yanshu4 and Atlantic varieties at the seedling and budding stages under conditions that involved no N and excessive N application; the expression of these miRNAs was induced in response to N stress. The correlation between the differential expression of stu-miR396-5p and its corresponding target gene NiR was further verified by determining the luciferase activity level and was found to be strongly negative. CONCLUSION: The activity of NiR was significantly positively correlated with N application from the seedling to the budding stage. Differential miRNAs and target genes showed a many-to-many relationship with each other. The expression of stu-miR396-5p, stu-miR482a-3p, and stu-miR8036-3p in the roots and leaves of the Yanshu4 and Atlantic varieties at the seedling and budding stages was notably different under two types of N stress. Under two types of N stress, stu-miR396-5p was down-regulated in Yanshu4 in the seedling-stage and shoot-stage roots, and up-regulated in seedling-stage roots and shoot-stage leaves; stu-miR482a-3p was up-regulated in the seedling and shoot stages. The expression of stu-miR8036-3p was up-regulated in the leaves and roots at the seedling and budding stages, and down-regulated in roots under both types of N stress. The gene expressing the key enzyme involved in N metabolism, StNiR, and the stu-miR396-5p luciferase assay reporter gene had a strong regulatory relationship with each other. This study provides candidate miRNAs related to nitrogen metabolism and highlights that differential miRNAs play a key role in nitrogen stress in potato, providing insights for future research on miRNAs and their target genes in nitrogen metabolic pathways and breeding nitrogen-efficient potatoes.

Antifungal Peptide P852 Controls Fusarium Wilt in Faba Bean (Viciafaba L.) by Promoting Antioxidant Defense and Isoquinoline Alkaloid, Betaine, and Arginine Biosyntheses.

Green pesticides are highly desirable, as they are environmentally friendly and efficient. In this study, the antifungal peptide P852 was employed to suppress Fusarium wilt in the Faba bean. The disease index and a range of physiological and metabolomic analyses were performed to explore the interactions between P852 and the fungal disease. The incidence and disease index of Fusarium wilt were substantially decreased in diseased Faba beans that were treated with two different concentrations of P852 in both the climate chamber and field trial. For the first time, P852 exhibited potent antifungal effects on Fusarium in an open field condition. To explore the mechanisms that underlie P852's antifungal effects, P852 treatment was found to significantly enhance antioxidant enzyme capacities including guaiacol peroxidase (POD), superoxide dismutase (SOD), catalase (CAT), and the activities of antifungal enzymes including chitinase and ß-1,3-glucanase, as well as plant dry and fresh weights, and chlorophyll content compared to the control group (p ≤ 0.05). Metabolomics analysis of the diseased Faba bean treated with P852 showed changes in the TCA cycle, biological pathways, and many primary and secondary metabolites. The Faba bean treated with a low concentration of P852 (1 µg/mL, IC50) led to upregulated arginine and isoquinoline alkaloid biosynthesis, whereas those treated with a high concentration of P852 (10 µg/mL, MFC) exhibited enhanced betaine and arginine accumulation. Taken together, these findings suggest that P852 induces plant tolerance under Fusarium attack by enhancing the activities of antioxidant and antifungal enzymes, and restoring plant growth and development.

Fusarium oxysporum Associated with Fusarium Wilt on Pennisetum sinese in China.

Pennisetum sinese, a versatile and adaptable plant, plays an essential role in phytoremediation, soil reclamation, and fodder production. From 2018 to 2021, the occurrence of Fusarium wilt, with symptoms of foliar blight and internal discoloration of the stem, was observed in Chongqing, China. Pathogens were isolated from the symptomatic leaves. Based on morphological characteristics as well as DNA sequences of the 18S ribosomal RNA (SSU), translation elongation factor 1-α (EF1-α), RNA polymerase II subunit 1 (rpb1), and RNA polymerase II second largest subunit (rpb2) genes, the causal agents were identified as Fusarium oxysporum. Phylogenetic analysis of the combined dataset of EF1-α, rpb1 and rpb2 showed that pathogenic isolates clustered with F. oxysporum strains. The pathogen was reisolated from inoculated and diseased tissues; thus, Koch's postulates were fulfilled. This is the first report of F. oxysporum causing Fusarium wilt on P. sinese in China and worldwide.

Plant-Growth-Promoting Potential of PGPE Isolated from Dactylis glomerata L.

Plant-growth-promoting endophytes (PGPE) are a kind of beneficial microorganisms which could inhabit plant tissues to antagonize certain plant pathogens and promote the host plant's growth and development. At present, many studies have confirmed the mutualistic effect of endophytes with plants, but there are few systematic studies on beneficial roles between endophytes and Dactylis glomerata, especially on the PGPE characteristics of the forage and environmental restoration plant. This study aimed to isolate PGPE from D. glomerata, evaluate their effects on plant growth, and ultimately acquire desirable microbial inoculants for agricultural use. First, endophytes were isolated from D. glomerata by plant re-inoculation experiment, and identified by morphological and molecular analyses. Fixation medium and methods were carried out to assess the nitrogen fixation ability of the strains. Then, the ability to dissolve phosphorus was determined by the Olsen and silicate medium methods; secretory IAA was measured by Salkowski colorimetric method; and the inhibitive effects on phytopathogen were observed by confrontation culture. Twenty-one strains were isolated from four varieties of D. glomerata, among which 14 strains with plant-growth-promoting characteristics were obtained by re-inoculation experiments, including seven endophytic bacteria and seven endophytic fungi. Further evaluation of three selected strains with the most significant PGP attributes were performed by using the pot re-inoculation experiment which revealed that TG2-B derived from Myroides odoratimimus was the most effective plant-growth-promoting agent due to its ability to produce high levels of IAA; the strain Bacillus cereus exhibited the most robust ability in dissolving inorganic phosphorus; and Trichoderma harzianum manifested a conspicuously antagonistic effect against a variety of plant pathogens. For the first time, this study reports the identification of D. glomerata endophytes that were able to promote plant growth and have a considerable antagonistic effects on plant pathogens, which could be considered as microbial inoculants for using in improving crop production and plant disease control.

Anti-cancer Substances and Safety of Lactic Acid Bacteria in Clinical Treatment.

Lactic acid bacteria (LAB) are a kind of Gram-positive bacteria which can colonize in the biological gastrointestinal tract and play a variety of probiotic roles. LAB have a wide range of applications in industry, animal husbandry, planting, food safety, and medical science fields. Previous studies on LAB have typically concentrated on their effects on improving the digestion and absorption of the gastrointestinal tract, regulating the balance of the microflora, and inhibiting the production and accumulation of toxic substances. The resistance of LAB to cancer is a topic of growing interest and relevance. This paper provided a summary of bio-active substances of LAB when they act against cancer, as well as the safety of LAB in clinical cancer treatment. Moreover, this paper further discussed several possible directions for future research and the potential application of LAB as anti-cancer therapy.

Correction: Transcriptome analysis reveals Nitrogen deficiency induced alterations in leaf and root of three cultivars of potato (Solanum tuberosum L.).

[This corrects the article DOI: 10.1371/journal.pone.0240662.].

Characterization of the complete chloroplast genome of the Solanum tuberosum L. cv. Favorita (Solanaceae).

Potato (Solanum tuberosum L.), a species of the family Solanaceae, is the fourth most important food crop worldwide. Solanum tuberosum L. cv. Favorita is a long oval, smooth, yellowish-skinned potato variety with green and plump leaves. It has a dry matter content of 17.7% and starch content of 12.4-14.01% in the tuber. In order to support more genetic data for the taxonomy of S. tuberosum, the complete chloroplast (cp) genome sequence of S. tuberosum L. cv. Favorita was determined using next-generation sequencing. In leaves, the chloroplast genome accounts for 5.17% of the total genome. The entire cp genome was determined to be 155,296 bp in length. It contained large single-copy (LSC) and small single-copy (SSC) regions of 85,737 and 18,373 bp, respectively, which were separated by a pair of 25,593 bp inverted repeat (IR) regions. The genome contained 132 total genes, including 87 protein-coding genes, 37 tRNA genes, and eight rRNA genes. The overall GC content of the genome is 37.9%. A phylogenetic tree reconstructed by 60 chloroplast genomes reveals that S. tuberosum L. cv. Favorita is most closely related to S. tuberosum L. cv. Desiree and S. tuberosum L. cv. Atlantic.

Characterization of the complete chloroplast genome of the Solanum tuberosum L. cv. Atlantic (Solanaceae).

Potato (Solanum tuberosum L.), a species of the family Solanaceae, is the fourth most important food crop worldwide. Solanum tuberosum L. cv. Atlantic, a main fried special potato, has a dry matter content of 19%-23% and a starch content of 16.26% in the tuber. In order to support more molecular data for the taxony of S. tuberosum, the complete chloroplast (cp) genome sequence of S. tuberosum L. cv. Atlantic was determined using next-generation sequencing. In leaves, the chloroplast genome accounts for 5.49% of the total genome. The entire cp genome was determined to be 155,296 bp in length. It contained large single-copy (LSC) and small single-copy (SSC) regions of 85,737 and 18,373 bp, respectively, which were separated by a pair of 25,593 bp inverted repeat (IR) regions. The genome contained 132 genes, including 87 protein-coding genes, 37 tRNA genes, and eight rRNA genes. The overall GC content of the genome is 37.9%. A phylogenetic tree reconstructed by 64 chloroplast genomes reveals that S. tuberosum L. cv. Atlantic is most closely related to Solanum tuberosum L. cv. Desiree.

Transcriptome analysis reveals Nitrogen deficiency induced alterations in leaf and root of three cultivars of potato (Solanum tuberosum L.).

Nitrogen (N) is a key element for the production of potato. The N uptake efficiency, N use efficiency and increased N utilization efficiency can be decreased by N deficiency treatment. We performed this study to investigate the association between transcriptomic profiles and the efficiencies of N in potato. Potato cultivars "Yanshu 4" (short for Y), "Xiabodi" (cv. Shepody, short for X) and "Chunshu 4" (short for C) were treated with sufficient N fertilizer and deficient N fertilizer. Then, the growth parameters and tuber yield were recorded; the contents of soluble sugar and protein were measured; and the activities of enzymes were detected. Leaf and root transcriptomes were analyzed and differentially expressed genes (DEGs) in response to N deficiency were identified. The results showed that N deficiency decreased the nitrate reductase (NR), glutamine synthetase (GS) and root activity. Most of the DEGs between N-treated and N-deficiency participate the processes of transport, nitrate transport, nitrogen compound transport and N metabolism in C and Y, not in X, indicating the cultivar-dependent response to N deficiency. DEGs like glutamate dehydrogenase (StGDH), glutamine synthetase (StGS) and carbonic anhydrase (StCA) play key roles in these processes mentioned above. DEGs related to N metabolism showed a close relationship with the N utilization efficiency (UTE), but not with N use efficiency (NUE). The Major Facilitator Superfamily (MFS) members, like nitrate transporter 2.4 (StNRT2.4), 2.5 (StNRT2.5) and 2.7 (StNRT2.7), were mainly enriched in the processes associated with response to stresses and defense, indicating that N deficiency induced stresses in all cultivars.

First report of Leaf Spot Associated with Boeremia exigua on White Clover in China.

White clover (Trifolium repens L.) is an important perennial legume forage widely cultivated in China (Zhang et al. 2016). In April 2018, severe necrotic lesions on leaves were observed in a cultivated white clover field in Chongqing, China. Approximately 90% of plants in the field were affected. Leaf spots were amphigenous, dark-brown, elliptic to subcircular, with diameter ranging between 1 to 12 mm, well defined by brown margins and yellow halos. Severely infected leaves became withered and abscised. Stems and flowers were not affected by the disease. Symptomatic leaves were surface sterilized with 70% ethanol for 30 s followed by 0.1% HgCl2 treatment for 3 min, and rinsed in sterile water three times. Thereafter, tissue samples from margins of individual lesions were placed on potato dextrose agar (PDA) amended with 50 mg/L of chloramphenicol and incubated at 25℃ in the dark. An olivaceous gray fungal colony was consistently isolated (90.5% isolation frequency). After 15 days of incubation, subglobose, black pycnidia developed in the cultural medium. Conidia were hyaline, ellipsoid to oblong, nonseptate(n = 50), ranging from 4.0 to 7.5 µm long (5.6 ± 2.3µm) × 2.0 to 3.8 µm wide(2.8 ± 1.0 µm). On the basis of its morphological characteristics, the fungus was identified as Boeremia sp. (Aveskamp et al. 2010). To confirm the identity, the internal transcribed spacer region (ITS), large subunit ribosomal RNA (LSU), partial actin (ACT), RNA polymerase II second largest subunit (rpb2) and beta-tubulin (tub2) genes were amplified with primers ITS1/ITS4, LR0R/LR7, ACT-512F/ACT-783R, RPB2-5F2/fRPB2-7cR, and Btub2Fd/Btub4Rd, respectively, in eight representative isolates and sequenced(Aveskamp et al. 2009; Chen et al. 2015). BLAST results showed 100% identity of the ITS (506/506 nucleotides), LSU (966/966 nucleotides), ACT (244/244 nucleotides) and tub2 (297/297 nucleotides) sequences with those of B. exigua (KY419536, MK398746, EU880878, and MK514090) and 99.83% identity of those of the rpb2 (593/594 nucleotides) sequence with B. exigua (KT389572).Based on morphology and DNA sequence analysis, the associated fungus was identified as B. exigua. Representative sequences of one isolate (BT2-1) were deposited in GenBank (MN826339, MN836592, MT265217, MT265218 and MT265219). In a pathogenicity test, ten 2-month-old potted white clover plants were spray-inoculated with a spore and mycelial suspension (approximately 105 CFU/mL) and the control plants were inoculated with sterile distilled water. Plants were incubated in a greenhouse at 20 to 24°C under natural light and enclosed in plastic bags for the first 3 days to maintain high humidity. After 10 days, typical dark-brown lesions similar to those seen in naturally infected leaves developed on the inoculated leaves and not on the control plants. B. exigua was reisolated from the lesions, thus completing Koch's postulates. There is some evidence that B exigua is capable of invading seedling root tissue of white clover and causing necrotic lesions on roots (Skipp and Christensen,1982). However, to our knowledge, this is the first report of leaf spot on T. repens caused by B. exigua. This disease severely reduces forage quality and yield. Proper identification of the causal organism is essential in formulating management strategies.

Androgen aggravates liver fibrosis by activation of NLRP3 inflammasome in CCl4-induced liver injury mouse model.

Studies have shown that there are differences between the sexes regarding to the occurrence and development of liver diseases, which may be associated with sex hormones. However, the mechanisms behind it are largely unknown. In this study, we first investigated the differences of liver injury between male and female mice, using the CCl4-induced liver injury mouse model. It showed that the liver damage of male mice was much more severe than that of female mice. Both the acute injury and fibrosis of the liver were reduced when androgens were depleted by castration of male mice. The vulnerability of male liver was associated with testis endocrine and excessive activation of inflammatory response in the liver. Castrated male mice with testosterone supplementation showed aggravated liver inflammatory response and fibrosis. The activity of NOD-like receptor protein 3 (NLRP3) inflammasome was increased when testosterone supplementation was provided. However, the enhanced inflammatory response and fibrosis due to testosterone supplementation were negated by inhibiting the activation of NLRP3 using the specific small molecule inhibitor MCC950. It suggests that testosterone is a key factor that influences liver injury by regulating the NLRP3 inflammasome activation-mediated inflammatory response.