Bacillus velezensis Yao Suppresses Fusarium Solani-Induced Pepper Root Rot via Fengycin and Induces Systemic Resistance.

The plant-growth-promoting rhizobacteria (PGPR) B. subtilis PTS-394 has been utilized as a biocontrol agent (in a wettable powder form) due to its excellent ability to suppress tomato soil-borne diseases caused by Fusarium oxysporum and Ralstonia solanacearum. In this study, we evaluated the biocontrol efficiency of Bacillus subtilis PTS-394 wettable powder on pepper root rot in pot experiments and field trials. B. subtilis PTS-394 and its lipopeptide crude extract possessed excellent inhibition activity against Fusarium solani, causing pepper root rot; in an antifungal activity test B. subtilis PTS-394 wettable powder exhibited a good ability to promote pepper seed germination and plant height. The experiments in pots and the field indicated that B. subtilis PTS-394 wettable powder had an excellent control effect at 100-fold dilution, and its biocontrol efficacy reached 69.63% and 74.43%, respectively. In this study, the biocontrol properties of B. subtilis PTS-394 wettable powder on pepper root rot were evaluated and its application method was established. It was concluded that B. subtilis PTS-394 wettable powder is a potential biocontrol agent with an excellent efficiency against pepper root rot.

The pepper rhizospheric soil-derived Bacillus velezensis Yao from the Shangqiu region of the Henan province in China possesses antagonistic activity against Fusarium solani, which causes pepper root rot. In this report, we introduced the entire genomic sequence of B.velezensis Yao, which is 3,951,864 bp long, with 46.61% G+C content, and 4,097 genes. Using antiSMASH analysis, we predicted 12 gene clusters that encode for secondary antimicrobial metabolites and multiple genes that regulate plant bacterial interactions. The B.velezensis Yao genome data may be a valuable resource as this strain may serve as an effective biocontrol agent against pepper root rot.

Plant growth-promoting bacteria modulate gene expression and induce antioxidant tolerance to alleviate synergistic toxicity from combined microplastic and Cd pollution in sorghum

Breeding for polyploidy in Brassica campestris L. has been employed to enhance agronomic traits. Polyploid plants exhibit improved productivity due to the 'gigas' effect driven by chromosome doubling. In our previous study, autotetraploids were induced in Pakchoi (Brassica campestris L. ssp. chinensis) via colchicine, resulting in two distinct autotetraploid genotypes: gigantic genotype 'P4x-3' with high-yield potential and dwarf genotype 'P4x-7' with low-yield traits in comparison to their diploid progenitor, 'P2x'. However, the molecular mechanisms underlying this phenotypic divergence between the two Pakchoi autotetraploids and their diploid progenitor remain poorly understood. Significant phenotypic differences were observed between the two autotetraploid genotypes and their diploid progenitor. The per plant fresh weight of 'P4x-3' was significantly higher than that of 'P2x' due to its higher leaf area, leaf width, leaf thickness, petiole width, and petiole thickness. 'P4x-7' showed a significantly lower per plant fresh weight than 'P2x' due to its lower plant height, number of leaves, leaf length, and petiole length. The most differentially expressed genes (DEGs) were identified in 'P4x-7 vs. P2x' with 2337 upregulated and 2067 downregulated DEGs. Gene Ontology enrichment analysis showed that DEGs in all three comparisons ('P4x-3 vs. P2x', 'P4x-7 vs. P2x', and 'P4x-3 vs. P4x-7') were primarily enriched in 'response to stimuli' and 'primary metabolic processes'. Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis identified three significantly enriched pathways: 'plant hormone signal transduction', 'MAPK signaling pathway - plant', and 'plant - pathogen interaction'. Therefore, we hypothesized that crosstalk between auxin and ethylene signaling regulates plant growth, directly influencing phenotypic traits and the formation of the gigantic 'P4x-3' and dwarf 'P4x-7' genotypes. DEGs, including those from the AUX/IAA, SAUR, ETS/ERS, and CaM/CML families, were identified as critical regulators of growth and stimulus responses in Pakchoi autotetraploids and potentially caused morphological variation. Additionally, 638, 655, and 704 differentially accumulated metabolites were identified in 'P4x-3 vs. P2x', 'P4x-7 vs. P2x', and 'P4x-3 vs. P4x-7', respectively. Enrichment analysis of indole-type metabolites among plant hormones revealed that 'tryptophan metabolism' was associated with the most enriched metabolites. L-tryptophan abundance followed the order of 'P4x-3' > 'P2x' > 'P4x-7'. This finding was consistent with the endogenous indole-3-acetic acid (IAA) content. The endogenous ethylene content exhibited an opposite trend to that of IAA. Chromosome doubling modulates phenotypic variation in Pakchoi by integrating gene expression across signaling and regulatory pathways, with a focus on those governing plant growth and stimulus responses. Auxin and ethylene signaling transduction and metabolism may act as key determinants of morphological divergence in autotetraploid Pakchoi. This study provides novel insights into the mechanisms underlying phenotypic variation in autotetraploid, with implications for optimizing polyploid breeding strategies.

Arbuscular mycorrhizal fungi (AMF) can stimulate root development in plants and enhance their ability to adapt to stress conditions. This study investigated the effects of arbuscular mycorrhizal fungi (AMF) inoculation on the growth, hormone dynamics, and phosphorus (P) metabolism of two wheat cultivars with differing phosphorus utilization efficiencies under both normal and low phosphorus concentration conditions. The research focused on the symbiotic interaction between AMF and these wheat varieties to elucidate their responses to varying phosphorus availability. The experiment showed that phosphorus inefficient wheat SW14 inoculated with AMF for 30 days under low phosphorus stress showed significant enhancement in plant height, biomass, leaf width, stem thickness, root surface area, and vegetative phosphorus content, while total root length and primary root length were reduced, This change in root length was attributed to the fact that the root system undergoes elongation and growth to adapt to the adversity under low phosphorus stress in crops, and inoculation with AMF effectively alleviated the extent of this low phosphorus stress. while IAA, SL, cellulose and lignin hormone levels and APC enzyme activities were significantly elevated, and stem structure was significantly optimized; whereas, the phosphorus-efficient variety, SW2, did not show significant improvement due to its own unique tolerance to low phosphorus stress (Table2). Transcriptomic profiling identified 2,500 differentially expressed genes (DEGs: 983↑/1,517↓), enriched in ABC transporters (ko02010), Plant hormone signal transduction (ko04075), and MAPK signaling pathway - plant (ko04016), Cutin, suberin and wax biosynthesis(ko00073). WGCNA further resolved that AMF responded to low phosphorus stress by up-regulating the expression of cellulose, lignin, APC synthesis, and IAA/SL-related genes in SW14, with the most relevant phenotypes shown to correlate to primary root length, total root length, root dry weight and stem diameter. AMF inoculation significantly enhanced growth and dry matter accumulation in the low-phosphorus-use-efficiency wheat variety SW14 under phosphorus-deficient stress. This treatment concurrently stimulated IAA, SL, and APC activities, resulting in increased phosphorus uptake/accumulation, notable accumulation of cellulose and lignin, and consequently significantly improved stem strength. Although AMF inoculation improved growth in the high-phosphorus-use-efficiency wheat variety SW2, these enhancements failed to reach statistical significance.

Pepper (Piper nigrum L.) root rot caused by Fusarium solani f. sp. piperis (FSP; teleomorph: Nectria haematococca f. sp. piperis) includes two symptom types called root rot (RR) type and stem rot (SR) type. In this study, the temporal and spatial associations between perithecial formation of FSP and development of SR were investigated in naturally infested fields to verify the hypothesis that ascospores from the perithecia are the major inoculum source of the SR type on vines in the field. In surveys of all vines in two neighboring pepper fields every month from December 2005 to November 2006, I mapped the locations of all vines with perithecia and all vines the SR type. The frequency of vines with perithecia increased during April and May, the late rainy season. In June, the early dry season, the number of vines with SR type greatly increased. The vertical range of perithecial formation on the vines extended to 200 cm in height, but was restricted to 30 cm in the dry season in both fields. The join-count statistics showed a significant spatial association between vines with perithecia and vines with SR type in one field (P = 0.042), while no significant spatial association was recognized in another field. The results suggested that ascospores from perithecia of FSP on pepper vines are likely to be one of the main inoculum sources of the SR type of the disease on adjacent vines, but they may not be the exclusive source.

Plant growth-promoting bacteria (PGPB) have been reported to promote plant growth and protect against plant diseases effectively. PGPB can control plant diseases through direct and indirect mechanisms. The direct mechanism involves the ability to provide nutrients and phytohormones. In contrast, the indirect mechanism refers to the ability to suppress the activity of pathogens through the production of various compounds and metabolites. The purpose of this study is to evaluate the plant health-promoting potential of Bacillus species. Several genetic determinants in 18 isolates of PGPB were investigated via polymerase chain reaction based on the genes fenD, sfp, bamC, ituA, aiiA, ipdC and nifH. Plant-beneficial traits were confirmed through seedling growth tests and in vitro antagonistic assays in the laboratory, followed by a field experiment that used selected Bacillus isolates to improve plant growth and control twisted disease in shallots. Results revealed that two Bacillus isolates, B-27 and RC76, have potential as PGPB. Isolates B-27 and RC76 were identified as Bacillus velezensis and B. tropicus, respectively, based on gyrB sequence analysis. The application of B. velezensis B-27 by spraying resulted in the lowest intensity of twisted disease in shallots. In addition, combined treatment with B. velezensis B-27 and B. tropicus RC76 increased plant height and leaf number.

Cassava mosaic disease (CMD) is a major disease affecting cassava production in Southeast Asia. This study aimed to perform an integrated proteomics and metabolomics analysis of cassava cv. Kasetsart 50 infected with Sri Lankan cassava mosaic virus (SLCMV). Proteomics analyses revealed that 359 proteins were enriched in the plant–pathogen interaction, plant hormone signal transduction, and MAPK signaling pathways. A total of 79 compounds were identified by metabolomics analysis of the healthy and SLCMV-infected cassava plants. Integrated omics analysis revealed that 9 proteins and 5 metabolites were enriched in 11 KEGG pathways. The metabolic pathways, plant hormone signal transduction, and plant–pathogen interaction pathway terms were specifically investigated. The findings revealed that caffeic acid and chlorogenic acid were associated with the plant–pathogen interaction pathway, histidine (HK3) was involved in plant hormone signal transduction, while citric acid and D-serine were associated with the metabolic pathways. KEGG functional enrichment analysis revealed that plant–pathogen interaction, plant hormone signal transduction, and metabolic pathways were linked via the enriched protein (protein phosphatase 2C) and metabolites (cyclic nucleotide-binding (AT2G20050) and D-serine). The available information and resources for proteomics and metabolomics analyses of cassava can elucidate the mechanism of disease resistance and aid in cassava crop improvement programs.

SUMMARY Cultural practices such as tillage and crop rotation can be used as components of pest-management programs. The appropriate combination of tillage systems and crops may favor the development of beneficial microorganisms, preventing the spread of fungal pathogens. A long-term field study was carried out to analyze the effect of crop management on the abundance of actinomycetes, Trichoderma spp., and Gliocladium spp., as potential biocontrol agents (PBAs), and their relationship with the incidence of peanut root rot caused by Fusarium solani. Soil samples were taken at sowing and harvest, and root rot incidence was evaluated at harvest. There was an inverse relationship between root rot incidence peanut PBA populations under no-till suggesting a possible role of PBAs in the control of F. solani, the incidence of root rot being low under no-till and disc harrow, associated with a high concentration of potential antagonists. However, this correlation was not observed when soybean preceded peanut, when the incidence of root rot was low despite relatively lower populations of biocontrol agents present in the soil, in comparison with maize as previous crop.

A description is provided for Aphanomyces cladogamus . Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Capsicum sp., Lactuca saliva, Linum sp., Lycopersicon esculenteum, Raphanus sativus, Solanum melongena, Spinacea oleracea, Viola tricolor . DISEASE: Root rot of pepper, spinach, pansy, tomato and several other crop and garden plants. The fungus, a facultatively necrotrophic plant pathogen, attacks seeds (pre-emergence disease) and/or seedlings (post-emergence damping off). Affected plants develop a generalized wilt which becomes progressively more severe. In pepper, seeds are attacked and black lesions develop on hypocotyls of the surviving seedlings, often extending to the bases of the cotyledons (32, 360). In spinach, roots become covered in yellow to orange spots their tissues becoming soft and water-soaked. In pansies, the vascular cylinder develops a deep orange-reddish discoloration in which, in the early stages of infection, numerous oospores can be seen. Stem bases become extensively rotted and eventually the aerial organs collapse and shrivel (13, 379; 34, 370). In tomato plants, rootlet tips become discoloured and die back (6, 517). GEOGRAPHICAL DISTRIBUTION: Europe: Sweden. North America: Canada (Ontario), USA (MD, NC, NJ, VA, WA, WI). See CMI Distribution Maps of Plants Diseases 601. TRANSMISSION: Not reported. Presumably by zoospores and oogonia remaining in infected tissues. As the fungus appears to infect a wide range of plants, it may persist in the roots of weeds.

Planting aromatic plant might be a promising strategy for safely utilizing heavy metal (HM)-contaminated soils, as HMs in essential oil could be completely excluded using some special technologies with ease. Clove basil (Ocimum gratissimum L.) is an important aromatic plant used in essential oil production. Improving cadmium (Cd) tolerance in clove basil can increase its production and improve the utilization efficiency of Cd-contaminated soils. However, the lack of genomic information on clove basil greatly restricts molecular studies and applications in phytoremediation. In this study, we demonstrated that high levels of Cd treatments (0.8, 1.6 and 6.5mg/L) significantly impacted the growth and physiological attributes of clove basil. Cd contents in clove basil tissues increased with treatment concentrations. To identify Cd stress-responsive genes, we conducted a comparative transcriptomic analysis using seedlings cultured in the Hoagland's solution without Cd ion (control) or containing 1.6mg/L CdCl2 (a moderate concentration of Cd stress for clove basil seedlings). A total of 104.38Gb clean data with high-quality were generated in clove basil under Cd stress through Illumina sequencing. More than 1,800 differential expressed genes (DEGs) were identified after Cd treatment. The reliability and reproducibility of the transcriptomic data were validated through qRT-PCR analysis and Sanger sequencing. KEGG classification analysis identified the "MAPK signaling pathway," "plant hormone signal transduction" and "plant-pathogen interaction" as the top three pathways. DEGs were divided into five clusters based on their expression patterns during Cd stress. The functional annotation of DEGs indicated that downregulated DEGs were mainly involved in the "photosynthesis system," whereas upregulated DEGs were significantly assigned to the "MAPK signaling pathway" and "plant-pathogen interaction pathway." Furthermore, we identified a total of 78 transcription factors (TFs), including members of bHLH, WRKY, AP2/ERF, and MYB family. The expression of six bHLH genes, one WRKY and one ERF genes were significantly induced by Cd stress, suggesting that these TFs might play essential roles in regulating Cd stress responses. Overall, our study provides key genetic resources and new insights into Cd adaption mechanisms in clove basil.

<b>Background and Objective:</b> Anthracnose in shallot contributes to significant losses. To solve this issue, silica nanoparticles, in combination with <i>Bacillus velezensis</i> and <i>Bacillus thuringiensis</i> were used together. <b>Materials and Methods:</b> <i>In vitro</i> antagonistic test of <i>Bacillus velezensis</i> B-27 with <i>Colletotrichum gloeosporioides</i> was carried out using dual culture and co-culture methods. Treatment in greenhouse experiments was carried out using single application of silica, <i>B. thuringiensis</i>, <i>B. velezensis</i>, a combination of <i>B. thuringiensis</i> and <i>B. velezensis</i> and a combination of <i>B. thuringiensis</i>, <i>B. velezensis</i> and silica. Detection of <i>B. velezensis</i> in the roots of shallot plants was carried out by PCR using a pair of specific primers. <b>Results:</b> <i>Bacillus velezensis</i> was able to inhibit the growth of <i>C. gloeosporioides</i> mycelium <i>in vitro</i>, both in the dual culture and co-culture methods, by 62.8 and 77.17%, respectively. Treatment of <i>B. thuringiensis</i> and <i>B. velezensis</i>, either individually or in combination with silica, could reduce the intensity of anthracnose disease by 20% each and stimulate the growth of shallot plants. The PCR detection using specific primers on the roots of shallot plants showed that <i>B. velezensis</i> was detected with a DNA band length of ±576 bp. <b>Conclusion:</b> <i>Bacillus velezensis</i> can inhibit the growth of <i>C. gloeosporioides</i> mycelium <i>in vitro</i>. Applying <i>B. velezensis</i>, <i>B. thuringiensis</i> and silica can reduce the intensity of anthracnose disease, promote plant growth and increase plant productivity. Furthermore, <i>B. velezensis</i> was detected in the roots of shallot plants, revealing that the bacteria are well-established.

The aim of this study was isolating and diagnosing the causative agent of root rot of pepper in Karbala province and control it using some biological applications. The results showed that the main pathogenic fungus of root rot and damping-off pepper in Karbala Province was Fusarium solani. This fungus was highly pathogenic by inhibition germination of all pepper seeds on the culture medium and in plastic pots. The treatment of integration between among Bacillus velesensis + Biohealth + Beltanol displayed the highest effectiveness in control of the pathogenic F.solani, as it reduced the disease incidence and severity to 9.00, 6.66%, respectively, compared to the pathogenic fungus alone, which amounted to 100%, 86.6%, respectively.

Soilless crops have become an important alternative for large-scale vegetable production because of the quality of their products and optimization of resources. Brassinosteroids (Brs) and Plant Growth-Promoting Bacteria (PGPB), has been reported to promote growth and physiological parameters in soil crops, but there are few reports on the application of these compounds in soilless crops. The effects of Brs ((25R)-3β 5α-dihydroxy-spirostan-6-one) and three strains of PGPB (Bacillus velezensis, Pseudomona sp., and Azospirillum brasilense) on the growth and yield of lettuce under hydroponic conditions were evaluated. Two separate experiments were carried out: one using a substrate in pots under greenhouse conditions and the other using a deep-flow hydroponic system in a growth room with artificial LED lighting. Plant physiological parameters (yield, dry weight, root surface area, and leaf area) and PGPB attributes under in vitro tests (phosphate solubilization and indole-3-acetic acid (IAA) synthesis) were determined using in vitro tests. A completely randomized design was used in all experiments. The results showed that in in vitro tests Azospirillum brasilense and Pseudomonas sp. were the strains that synthesized the highest amounts of IAA (36 mg mL−1 and 34 mg mL−1, respectively). Phosphorus solubilization was significantly higher in the Pseudomonas sp. strain (110.35 µg mL−1). Regarding physiological and quality parameters, the application of Brs (0.5 ppm), Bacillus velezensis, and Azospirillum brasilense (1 × 106 CFU mL−1) caused an increase between 20% and 40% on variables such as plant yield, leaf area, root surface area, and colorimetry of lettuce for substrate or hydroponic conditions, respectively.

To investigate the effect of plant growth-promoting bacteria (PGPR) and arbuscular mycorrhizal fungi (AMF) on phytoremediation in saline-alkali soil contaminated by petroleum, saline-alkali soil samples were artificially mixed with different amount of oil, 5 and 10 g/kg, respectively. Pot experiments with oat plants (Avena sativa) were conducted under greenhouse condition for 60 days. Plant biomass, physiological parameters in leaves, soil enzymes, and degradation rate of total petroleum hydrocarbon were measured. The result demonstrated that petroleum inhibited the growth of the plant; however, inoculation with PGPR in combination with AMF resulted in an increase in dry weight and stem height compared with noninoculated controls. Petroleum stress increased the accumulation of malondialdehyde (MDA) and free proline and the activities of the antioxidant enzyme such as superoxide dismutase, catalase, and peroxidase. Application of PGPR and AMF augmented the activities of three enzymes compared to their respective uninoculated controls, but decreased the MDA and free proline contents, indicating that PGPR and AMF could make the plants more tolerant to harmful hydrocarbon contaminants. It also improved the soil quality by increasing the activities of soil enzyme such as urease, sucrase, and dehydrogenase. In addition, the degradation rate of total petroleum hydrocarbon during treatment with PGPR and AMF in moderately contaminated soil reached a maximum of 49.73%. Therefore, we concluded the plants treated with a combination of PGPR and AMF had a high potential to contribute to remediation of saline-alkali soil contaminated with petroleum.