Endophytic Bacillus subtilis P10 from Prunus cerasifera as a biocontrol agent against tomato Verticillium wilt

Endophytic bacteria serve key roles in the maintenance of plant health and growth. Few studies to date, however, have explored the antagonistic and plant growth-promoting (PGP) properties of Prunus cerasifera endophytes. To that end, we isolated endophytic bacteria from P. cerasifera tissue samples and used a dual culture plate assay to screen these microbes for antagonistic activity against Verticillium dahliae, Botryosphaeria dothidea, Fusarium oxysporum, F. graminearum, and F. moniliforme. Of the 36 strains of isolated bacteria, four (strains P1, P10, P16, and P20) exhibited antagonistic effects against all five model pathogens, and the P10 strain exhibited the strongest antagonistic to five pathogens. This P10 strain was then characterized in-depth via phenotypic assessments, physiological analyses, and 16s rDNA sequencing, revealing it to be a strain of Bacillus subtilis. Application of a P10 cell suspension (1×108 CFU/mL) significantly enhanced the seed germination and seedling growth of tomato in a greenhouse setting. This P10 strain further significantly suppressed tomato Verticillium wilt with much lower disease incidence and disease index scores being observed following P10 treatment relative to untreated plants in pot-based experiments. Tomato plants that had been treated with strain P10 also enhanced defense-related enzymes, peroxidase, superoxide dismutase, and catalase activity upon V. dahliae challenge relative to plants that had not been treated with this endophytic bacterium. The results revealed that the P10 bacterial strain has potential value as a biocontrol agent for use in the prevention of tomato Verticillium wilt.

​Antagonistic Activity of Panchagavya and Trichoderma spp. against Wilt Complex causing Pathogens of Chickpea (Cicer arietinum L.)

Background: Chickpea wilt complex caused by several soil-borne pathogens is the major yield-reducing malady worldwide. Biological control is one of the best, low-cost and ecologically sustainable method for managing plant diseases caused by soil-borne pathogens. Methods: In this present investigation Panchagavya and Trichoderma spp. were evaluated by following poisoned food technique and dual culture technique against wilt complex causing pathogens i.e. Fusarium oxysporum f. sp. ciceri, Fusarium solani and Macrophomina phaseolina. Result: Among the different isolates of Trichoderma spp. evaluated, Trichoderma viride (AAU isolate) was highly antagonistic to F. oxysporum f. sp. ciceri (52.78%) and F. solani (65.37%) whereas, Trichoderma asperellum (AAU isolate) was highly antagonistic to M. phaseolina (65.93%). Panchagavya at the highest concentration (50%) showed significantly higher efficacy (80.74, 66.62 and 49.67%) in inhibiting the mycelial growth of all three pathogens and at the lowest concentration it was moderately effective.

Biocontrol Potential and Catabolic Profile of Endophytic Diaporthe eres Strain 1420S from Prunus domestica L. in Poland—A Preliminary Study

Recently, Diaporthe has been considered the most frequently isolated genera of endophytic fungi, having a broad spectrum of host plants and a worldwide distribution. The endophytic Diaporthe strain used in the present work came from the Fungal Collection of Phytopathology and Mycology Subdepartment, University of Life Sciences in Lublin (Poland), and was isolated from healthy Prunus domestica shoots during previous studies. Due to the possibility of using the Diaporthe endophytes as a promising option for plant disease management, the main goal of the research was to study the antagonistic effect of endophytic Diaporthe strain against six phytopathogens: Verticillium dahliae, Botrytis cinerea, Fusarium avenaceum, F. sprotrichioides, Alternaria alternata, and Trichothecium roseum based on the dual culture assay and to determine the catabolic profile of the endophyte by using Biolog FF Plates. The dual-culture test assay revealed the ability of the endophytic Diaporthe to limit the growth of all tested pathogens. The growth inhibition percentage ranged from 20% (V. dahliae) to 40% (T. roseum). A distinct zone of inhibition occurred between the endophytic Diaporthe and the pathogens T. roseum, V. dahliae, and B. cinerea in the co-growth combinations. As for the catabolic profile results, the most intensive utilization of carbon substrates was observed after 168 h of incubation. The growth of the analyzed strain was observed on 79 media containing carbohydrates, carboxylic acids, amino acids, amines and amides, polymers, and others. The most effective decomposition was observed in the polymers group, the least in amines and amides. Molecular identification indicated that this strain was closely related to the Diaporthe eres species complex.

Effect of endophytic Bacillus and arbuscular mycorrhiza fungi (AMF) against Fusarium wilt of tomato caused by Fusarium oxysporum f. sp. lycopersici

Background Fusarium wilt of tomato caused by Fusarium oxysporum f. sp. lycopersici (FOL) is a serious disease that causes significant economic losses in tomato production. Seventeen endophytic Bacillus isolates from tomato roots of Meghalaya were tested for antagonistic and plant growth promotion activities. Dominating arbuscular mycorrhiza fungi (AMF) spores were isolated from the rhizosphere soils of tomato grown in Meghalaya. The effect of different combinations of AMF and endophytic Bacillus on Fusarium wilt severity and growth of tomato plant under pot and field conditions was studied. Results The endophytic Bacillus isolates ERBS51 and ERBS10 showed a maximum inhibition against FOL, with 58.43 and 55.68%, respectively, in a dual culture experiment. ERBS51 and ERBS10 were identified as Bacillus velezensis and Bacillus sp., respectively, based on 16s rRNA sequencing. Both isolates were found positive for iturin A, surfactin, bacillomycin D, protease, cellulase, pectinase, alpha-amylase, siderophore, ammonia production and ZnCO3 solubilization. Funneliformis mosseae and Glomus fasciculatum were the dominating AMF species in tomato rhizosphere of Meghalaya. The result of pot and field experiments revealed that out of all the treatments, combination of Funneliformis mosseae + Glomus fasciculatum + Bacillus velezensis + Bacillus sp. was shown to be the best in reducing the severity of Fusarium wilt to 77.44 and 66.74%, respectively. F. mosseae + G. fasciculatum + B. velezensis + Bacillus sp. also recorded the highest in most growth attributes and yield. Conclusions Endophytic Bacillus (B. velezensis and Bacillus sp.) and AMF (F. mosseae and G. fasciculatum) were safe and effective biocontrol agents against Fusarium wilt of tomato.

Antagonistic screening of Trichoderma spp. isolated from patchouli rhizosphere

The objective of this research was to determine the antagonistic activity of Trichoderma spp. isolated from patchouli rhizosphere (Pogostemon cablin Benth.). Another objective was to perform antagonistic screening of these fungi to inhibit the growth of the wilted pathogen Fusarium spp. In vitro research was conducted in the Laboratory of Plant Pathology, Universitas Syiah Kuala, from January to June 2020. The study used a completely randomised design with five treatments and three replications. The antagonistic screening was carried out by using the dual culture method of Trichoderma spp. against Fusarium spp. with the medium of Potato Dextrose Agar (PDA). The result showed that five isolates of Trichoderma have different antagonistic percentages in inhibiting the Fusarium. The highest antagonistic activity was found from isolate 2 and the lowest value was shown by isolate 3.

Potential of Streptomyces sp. in preventing the in vitro growth of Colletotrichum acutatum, the causative agent of infection in Capsicum annum L.

Red chilli plant (Capsicum annum L.) is one of the most popular vegetable crops in Indonesian society. One of them the pathogens attacks is Colletotrichum acutatum, a fungus causing anthracnose on red chilli. This study aims to determine the existence of Streptomyces sp. bacteria in the rhizosphere of the red chilli plant; the ability of Streptomyces sp. in inhibiting C. acutatum; Minimum Inhibitory Concentration (MIC) of Streptomyces isolates extracts in inhibiting C. acutatum; The Streptomyces isolation was carried out by dilution method using selective meida, namely Yeast Malt Agar. The Dual Culture method was used as an inhibition test between Streptomyces sp. and C. acutatum in vitro. A well diffusion method was used to test the effectiveness of the Streptomyces sp. and MIC filtrate concentration in inhibiting C. acutatum. The data obtained in this study were analyzed with Analysis of Varian (ANOVA) then continued with Duncan Multiple Range Test with 5% significance. Five Streptomyces isolates were found, namely Streptomyces sp.1, Streptomyces sp.2, Streptomyces sp.3, Streptomyces sp.4, and Streptomyces sp.5 in the rhizosphere of healthy C. annum L. plants in Daup Village, Kintamani District, Bangli Regency. Streptomyces sp. isolates. can significantly inhibit the growth of the fungus C. acuatum with inhibitory power ranging from 50.30% to 83.76%, Streptomyces sp.5 isolate was able to provide the highest percentage of inhibition in C. acutatum of 83.76 ± 2.91% with MIC 7% (v/v) with a diameter of 6.40 mm.

Potential Rhizopus spp. in control the growth of Aspergillus flavus FNCC6109 in broiler chicken concentrate feed

Aspergillus flavus contamination of agriculture in Indonesia can cause problems to animal health and productivity. Some factors can support the appearance of contamination in feed, especially temperature and humidity. The main objective of this research was to investigate potency of Rhizopus spp. on inhibit A. flavus FNCC6109 in broiler chicken concentrate feed. The experiments were conducted dual culture method and the inhibition test of the Rhizopus spp. filtrate culture was incubated for 3, 4 and 5 days on in vitro. The in vivo test was directly applied in broiler chicken concentrate feed which added Rhizopus spp. filtrate culture concentration at 10% (v/v), 20% (v/v), 30% (v/v), 40% (v/v), dan 50% (v/v). The results showed that the Rhizopus spp. filtrate culture significantly (P?0,05) to inhibit the growth of A. flavus FNCC6109 both in vitro and in vivo. The percentage inhibition of Rhizopus spp. filtrate culture incubated for 5 days showed 67,47±2,10% relatively better results than 3 and 4 days, and therefore was used in the in vivo. Application of 50% (v/v) Rhizopus spp. filtrate culture to the broiler chicken concentrate feed significantly reduced 82% population of A. flavus FNCC6109 after 15 days incubated relative to that of negative control (concentrate feed without addition Rhizopus spp. filtrate culture and A. flavus FNCC6109).

Screening and Identification of Trichoderma Strains isolated from Natural Habitats in China with Potential Agricultural Applications

Trichoderma spp. are widely distributed in natural habitats and have been evaluated as a potential biocontrol agent (BCA) for disease control and plant growth promotion. In this study, 1308 Trichoderma strains were obtained from the plant rhizosphere soil, above-ground plants, and decaying wood from natural habitats in China. Among them, 49 Trichoderma strains showed a good inhibitory effect, especially against Botrytis cinerea, Fusarium oxysporum, and Colletotrichum gloeosporioides with inhibition rate above 85% in the dual culture test. Among these 49 strains, the 13 strains with broad-spectrum inhibitory effects also significantly promoted the seed germination of five crops (rice, cucumber, tomato, melon, and pakchoi) and root growth of four crop seedlings (watermelon, tomato, eggplant, and chili). Furthermore, these strains showed effective colonization in the rhizosphere and root of cucumber. Trichoderma strains SC012 and NX043 showed the highest chitinase and β-1,3-glucanase activity among all strains. Based on the morphological characterization and phylogenetic analysis of the nuclear ribosomal internal transcribed spacer (ITS) and translation elongation factor 1 (tef1), twelve Trichoderma strains were identified as Trichoderma asperellum and one as Trichoderma afroharzianum. This study suggests that the 13 Trichoderma strains are promising BCAs and could be developed as biofertilizers and biological pesticides for agricultural applications.

Fungal Communities in the Native New Zealand Medicinal Plant Pseudowintera colorata (Horopito) Are Determined by Plant Organ Type and Host Maturity with Key Members Promoting Plant Growth

The plant Pseudowintera colorata is well known for its antimicrobial and medicinal properties and is endemic to New Zealand. Using PCR-Denaturing gradient gel electrophoresis (DGGE), we investigated the factors influencing the composition of endophytic fungal communities in P. colorata from ten distinct sites across New Zealand. Our results showed that plant organs of P. colorata influenced the diversity and richness of endophytic fungi (PERMANOVA, p < 0.05). In addition, plant maturity and its interactions revealed that endophytic fungal communities formed discrete clusters in leaves, stems, and roots of mature and immature P. colorata plants (PERMANOVA; p = 0.002, p = 0.001 and p = 0.039, respectively). For identifying isolates with biocontrol potential, dual culture tests were set up against four different phytopathogenic fungi. Isolates with high activity (zone of inhibition >10 mm) were sequenced and identified as Trichoderma harzianum, Pezicula neosporulosa, Fusarium tricinctum, Metarhizium sp., and Chaetomium sp. Applying selected endophytic fungi (n = 7) as soil drenchers significantly increased the growth of P. colorata seedlings and produced more internodes. Seedling shoots treated with Trichoderma sp. PRY2BA21 were 2.2 × longer (8.36 cm) than the untreated controls (3.72 cm). Our results elucidate the main plant factors influencing fungal community composition and demonstrate a role for endophytic fungi in P. colorata growth and further demonstrate that medicinal plants are a rich source of endophytes with potential as biocontrol agents.