Screening of salt tolerant endophytic bacteria with plant growth promoting characters isolated from Acanthus ilicifolius L., a species of mangrove ecosystem located at Corangi wildlife sanctuary, Andhra Pradesh

Mangroves harbour many beneficial microorganisms in their rhizosphere, phyllosphere and endophytically, which forms an ideal ecological habitation for isolating halotolerant endophytic bacteria with unique characteristics. Endophytes can produce numerous bioactive secondary metabolites and phytohormones, which may be directly or in some way beneficial to the host plant.   The present study aimed to identify novel endophytes capable of producing plant growth-promoting substances. The mangrove plants Acanthus ilicifolius L. at Corangi Wildlife Sanctuary were selected, and their leaves and roots were collected for endophyte isolation. Eight isolates from the leaves and roots were collected, purified and preserved. All these isolates were subjected to morphological, phenotypical and biochemical studies. Isolates were grown best at 3% NaCl nutrient agar and could tolerate salinity upto 8%NaCl. Most of them could grow upto 42°C. The majority were gram’s positive, motile, aerobic, rod-shaped and some were gram’s negative, rod-shaped organisms. Many of the endophytic organisms had the ability to synthesize Indole-3-acetic acid(IAA) varied from 0.7 µg/ml (AIL1) to 51.0 µg/ml (AIL2) and the highest phosphate solubilizing ability was recorded with AIR3 (3.71 ppm) followed by AIR4 (3.00 ppm) and lowest was recorded by AIL4 (1.80 ppm). Among total isolates, AIL2 (51µg/ml) showed promising potential in producing IAA and had phosphate solubilization ability. Based on 16S ribosomal RNA molecular method the isolate AIL2 was identified as Bacillus altitudinis. This is the first to report that B.altitudinis strain AIL2 isolated from A.ilicifolius L. could produce IAA, which can be used as a bioinoculant in agriculture and allied sector

Isolation, screening, and characterization of plant growth enhancing endophytic bacteria from halophytic Heliotropium curassavicum L. collected from salt stress areas of Srikakulam, Andhra Pradesh

Farmers use excessive chemical fertilizers to boost crop productivity to meet growing agricultural demands. However, this practice is costly and environmentally hazardous. Sustainable increase in crop yield can be achieved through alternatives like microbial-based fertilizers. In the quest to identify plant growth-promoting endophytic bacteria, the present study was carried out and selected unexplored halophytic plant Heliotropium curassavicum L. Thirteen endophytic bacterial strains were isolated from both aerial and root portions of H.curassavicum. These isolates were tested for salt tolerance, enzyme production, and synthesis of growth-promoting secondary metabolites, like Indole-3-acetic acid (IAA) and phosphate solubilization . Most of the isolates belonged to the Bacillus family, exhibiting varying Gram staining and biochemical reactions. The majority are Gram-positive bacteria, non-motile, spore formers, and exist in two cells or chains. All isolates could tolerate up to 10% NaCl concentration and a temperature of 42°C. Based on phenotypic, bio-chemical characteristics, isolate HCR3 showed promising properties in synthesizing IAA and phosphate solubilization abilities. The isolate HCR3 grew well upto 10% NaCl concentration and also 42°C temperature. Based on molecular characterization by using 16S rRNA gene-based analysis HCR3 isolate was identified and belonged to the Genus Pseudomonas with the highest similarity index with Pseudomonas khazarica sp. HCR3 showed IAA production of 37µg ml-1, had a phosphate solubilization ability of 3.5 ppm, and recorded protease activity on gelatin medium. The findings highlight the potential of HCR3 and other strains from halophytic H. curassavicum L. to enhance plant growth through secondary bioactive metabolites, offering eco-friendly solutions for sustainable agriculture

Isolation and Categorization of Plant Growth Promoting Endophytic Bacteria Isolated from Halophytic Suaeda nigra at Salt Stress Area of Srikakulam, Andhra Pradesh

In search of novel endophytic bacteria capable of producing plant growth promoting phytohormones and providing tolerance against biotic and abiotic stress to the plant, present study was carried out during 2021-22. For this, endophytic bacteria were isolated from halophytic Suaeda nigra at salt stress areas of Srikakulam district, Andhra Pradesh. Total of sixteen endophytic bacteria were isolated from roots and aerial parts of Suaeda nigra. Isolates were enumerated, purified and preserved for subsequent studies. All isolates were analyzed for their phenotypic, biochemical, enzymatic assay and molecular characterization was carried out by 16S rRNA molecular method. Isolates were tested for their ability in producing plant growth promoting phytohormones, siderophores, exo enzymes and ability to solubilize the phosphate molecules. Among total isolates extracted, bacteria which was labeled as “SNA7” isolated from aerial parts of Suaeda nigra showed better characters in producing catalytic enzymes like catalase, amylase, protease, phosphate solubilization ability and Indole-3-acetic acid (IAA) production. Isolate SNA7 was gram negative, motile, aerobic, rod shaped, non-spore forming, and no pigmentation which grows best at 42°C, pH 8.3 with tolerate of 8% NaCl nutrient agar. Based on phenotypic, biochemical, nucleotide homology and phylogenetic analysis isolate SNA7showed higher relationship with Pseudomonas pseudoalcaligenes Pseudomonas spp. was characterized as an effective organism to explore its ability in various research fields. In this current study, isolate SNA7 showed higher potential in producing wide range of enzymes and bioactive secondary metabolites and was first of its kind reported and isolated from halophytic Suaeda nigra

Hearing loss prevalence and years lived with disability, 1990–2019: findings from the Global Burden of Disease Study 2019

Background Hearing loss affects access to spoken language, which can affect cognition and development, and can negatively affect social wellbeing. We present updated estimates from the Global Burden of Disease (GBD) study on the prevalence of hearing loss in 2019, as well as the condition's associated disability. Methods We did systematic reviews of population-representative surveys on hearing loss prevalence from 1990 to 2019. We fitted nested meta-regression models for severity-specific prevalence, accounting for hearing aid coverage, cause, and the presence of tinnitus. We also forecasted the prevalence of hearing loss until 2050. Findings An estimated 1·57 billion (95% uncertainty interval 1·51–1·64) people globally had hearing loss in 2019, accounting for one in five people (20·3% [19·5–21·1]). Of these, 403·3 million (357·3–449·5) people had hearing loss that was moderate or higher in severity after adjusting for hearing aid use, and 430·4 million (381·7–479·6) without adjustment. The largest number of people with moderate-to-complete hearing loss resided in the Western Pacific region (127·1 million people [112·3–142·6]). Of all people with a hearing impairment, 62·1% (60·2–63·9) were older than 50 years. The Healthcare Access and Quality (HAQ) Index explained 65·8% of the variation in national age-standardised rates of years lived with disability, because countries with a low HAQ Index had higher rates of years lived with disability. By 2050, a projected 2·45 billion (2·35–2·56) people will have hearing loss, a 56·1% (47·3–65·2) increase from 2019, despite stable age-standardised prevalence. Interpretation As populations age, the number of people with hearing loss will increase. Interventions such as childhood screening, hearing aids, effective management of otitis media and meningitis, and cochlear implants have the potential to ameliorate this burden. Because the burden of moderate-to-complete hearing loss is concentrated in countries with low health-care quality and access, stronger health-care provision mechanisms are needed to reduce the burden of unaddressed hearing loss in these settings