Manikandan Ariyan

Soil eukaryotes, including fungi, protists, plants, and animals, are central to biosphere functioning and resilience. The Global Standardised Soil Eukaryome Dataset (GloSED) is the first dataset encompassing the entire spectrum of soil eukaryotes, covering 4,063 sampling sites in 121 countries on all continents, revealing nearly one million operational taxonomic units. All samples were collected and analysed using a standardised protocol minimizing technical biases. Long-read sequencing of full-length ITS and 18S-V9 regions provide broad taxonomic coverage and high-resolution identification supported by specialist curation of “dark taxa”. A rigorous bioinformatic processing ensures against homopolymer errors, PCR-mediated chimeras, and index switching providing high data quality. The dataset is supported by raw sequences and an open-source containerised workflow for reproducible analyses. The samples are accompanied by land-cover description and directly measured soil pH, δ ¹³ C, δ ¹⁵ N, as well as P, K, Ca, Mg, and total C and N contents. GloSED is the first database that enables ecological and biogeographic studies of entire soil eukaryotic communities from local to global scales.

Foliar fungal communities are essential components of the plant microbiome, playing a vital role in maintaining plant health and influencing ecosystem dynamics. Despite increasing interest in plant–microbe associations, the drivers shaping foliar fungal community composition remain poorly understood, including the roles of host phylogeny, functional traits, and belowground mycorrhizal symbiosis. We used the MycoPhylo experimental field, in which plant species are planted in a replicated, phylogenetically diverse design, to investigate the influence of host plant identity, mycorrhizal type, and leaf functional traits on foliar fungal assemblages. We examined foliar fungal communities across 158 plots representing 110 distinct plant species using a metabarcoding approach. The resulting operational taxonomic units (OTUs) were dominated by Dothideomycetes (44.5%), Tremellomycetes (12.7%), and Taphrinomycetes (9.0%). Functional guild analysis revealed that plant pathogens and saprotrophs were the most abundant ecological groups. Foliar fungal alpha diversity and community composition were significantly influenced by plant growth form and mycorrhizal association. Although plant deciduousness did not affect fungal richness, it significantly affected fungal community composition. The measured leaf traits (hairiness and thickness) showed the least influence on fungal richness. Mantel tests revealed weak, guild-dependent relationships between host phylogenetic distance and foliar fungal community dissimilarity. Moreover, plant phylogenetic eigenvectors accounted for up to 25.8% of the variation in fungal richness. These findings indicate that host phylogeny and plant traits contribute to—but do not solely determine—the structure of foliar fungal assemblages under field conditions.

High soil pH and excess CaCO₃ are major contributors to calcareous soil limitations on crops’ access to essential nutrients, especially phosphorus (P) and micronutrients, which in turn impact pulses yields and growth. The purpose of this study was to determine the effect of bio sulfur granules (BSG) on the growth of black gram and the availability of nutrients in calcareous vertisols deficient in sulfur. BSG was developed by using sulfur-oxidizing bacteria (SOB) and elemental sulfur (ES) through an incubation study. Developed BSG was tested in a pot and field conditions to evaluate their effectiveness on black gram growth and yield. In the incubation study, soil treated with Methylobacterium thiocyanatum VRI7-A4 and ES (40 kg S/ha) significantly decreased pH and increased available S (SO₄²⁻) in calcareous soils. After 40 days of incubation, the solubility of P, Fe, and Zn was greatly increased by the addition of ES @ 40 kg S/ ha in combination with M. thiocyanatum VRI7-A4 or Pandoraea thiooxydans ATSB16. Black gram in S-deficient calcareous soil was improved by the application of BSG (ES @ 40 kg S/ ha with M. thiocyanatum VRI7-A7) in terms of root and shoot lengths, nodule number, plant biomass, pod yield, and biological yield as compared to control. The same treatment greatly increased plant nutrient intake as well as the concentrations of P, Fe, and Zn in the soil. The results showed that the addition of BSG granules (ES @ 40 kg S/ha + M. thiocyanatum VRI7-A4) to calcareous vertisol deficient in S enhanced the nutrient solubility through S oxidation. The developed bio sulfur granules may be added to the fertilizer schedule of the pulses growers to get improved crop growth and yield of black gram in calcareous soil.

Whitefly Bemisia tabaci, a carrier of cassava mosaic disease (CMD), poses a significant threat to cassava crops. Investigating culturable bacteria and their impact on whiteflies is crucial due to their vital role in whitefly fitness and survival. The whitefly biotype associated with cassava and transmitting CMD in India has been identified as Asia II 5 through partial mitochondrial cytochrome oxidase I gene sequencing. In this study, bacteria associated with adult B. tabaci feeding on cassava were extracted using seven different media. Nutrient Agar (NA), Soyabean Casein Digest Medium (SCDM), Luria Bertani agar (LBA), and Reasoner’s 2A agar (R2A) media resulted in 19, 6, 4, and 4 isolates, respectively, producing a total of 33 distinct bacterial isolates. Species identification through 16SrRNA gene sequencing revealed that all isolates belonged to the Bacillota and Pseudomonadota phyla, encompassing 11 genera: Bacillus, Cytobacillus, Exiguobacterium, Terribacillus, Brevibacillus, Enterococcus, Staphylococcus, Brucella, Novosphingobium, Lysobacter, and Pseudomonas. All bacterial isolates were tested for chitinase, protease, siderophore activity, and antibiotic sensitivity. Nine isolates exhibited chitinase activity, 28 showed protease activity, and 23 displayed siderophore activity. Most isolates were sensitive to antibiotics such as Vancomycin, Streptomycin, Erythromycin, Kanamycin, Doxycycline, Tetracycline, and Ciprofloxacin, while they demonstrated resistance to Bacitracin and Colistin. Understanding the culturable bacteria associated with cassava whitefly and their functional significance could contribute to developing effective cassava whitefly and CMD control in agriculture.

Aim: This study aims to reveal the passenger endophytic bacterium Enterobacter cloacae S23 isolated from groundnut nodules and to underpin the molecular mechanism and genes responsible for abiotic stress tolerance. Background: A variety of microorganisms that contribute to nodulation and encourage plant development activity in addition to the nodulating Rhizobium. Passenger endophytes (PE) are endophytes that accidentally penetrate the plant without any selective pressure keeping them in the interior tissue of the plant. PE possesses characteristics that encourage plant development and boost output while reducing pathogen infection and improving biotic and abiotic stress tolerance. However, there is a lack of molecular evidence on the passenger endophyte-mediated alleviation of abiotic stresses. Objective: This study was formulated to reveal the draft genome sequence of Enterobacter cloacae S23, as well as genes and characteristics involved in plant growth promotion and stress tolerance. Method: The data were submitted to PATRIC and the TORMES-1.0 Unicyclker tools were used to conduct a complete genome study of Enterobacter cloacae S23. The TORMES-1.0 platform was used to process the reads. RAST tool kit (RASTtk) was used to annotate the S23 sequence. The plant growth-promoting traits such as indole acetic acid production, siderophore secretion, production of extracellular polysaccharides, biofilm formation, phosphate solubilization, and accumulation of osmolytes were examined under normal, 7% NaCl and 30% polyethylene glycol amended conditions to determine their ability to withstand salt and moisture stressed conditions, respectively. Result: We report the size of Enterobacter cloacae S23 is 4.82Mb which contains 4511 proteincoding sequences, 71 transfer RNA genes, and 3 ribosomal RNA with a G+C content of DNA is 55.10%. Functional analysis revealed that most of the genes are involved in the metabolism of amino acids, cofactors, vitamins, stress response, nutrient solubilization (kdp, pho, pst), biofilm formation (pga) IAA production (trp), siderophore production (luc, fhu, fep, ent, ybd), defense, and virulence. The result revealed that E. cloacae S23 exhibited multiple plant growth-promoting traits under abiotic stress conditions. Conclusion: Our research suggested that the discovery of anticipated genes and metabolic pathways might characterise this bacterium as an environmentally friendly bioresource to support groundnut growth through several mechanisms of action under multi-stresses.

Sodicity is one of the major salt stresses that impair crop production. Exopolysaccharide-producing sodic tolerant bacteria (EPS-STB) play a significant role in reducing the sodic stress in plants by hampering the uptake of sodium. In this context, this study aims to isolate the EPS-STB for alleviating sodic stress in rice under a sodic environment. Thus, artificial sodicity was created in culture media, and 253 bacteria were isolated from the rice rhizosphere of sodic soils in Trichy and Chinna Salem of Tamil Nadu in India. Fifty bacterial isolates were initially screened based on EPS production, sodic tolerant ability, and plant growth-promoting activities. Further, these bacterial isolates were identified using 16S rDNA sequencing. The results suggested that the isolated bacteria possessed biofilm-forming abilities along with plant growth-promoting activities and osmolyte accumulation under sodic stress conditions. Bacillus rugosus L1C7T, Bacillus paralicheniformis L1C5L, Pseudomonas sp. L5C14T and Franconibacter helveticus L2C1L2 were chosen as better EPS-STB plant growth-promoting bacteria, and their impact on rice under sodic conditions was evaluated. Among the sodic tolerant bacteria, Franconibacter helveticus L2C1L2-inoculated rice plants increased dry matter production compared to the control. Thus, this study showed that the utilization of EPS-STB will become a promising tool to alleviate sodic stress in rice.