Biology subjects

Pavagadhi, S.

Publications and source records attributed to Pavagadhi, S..

3 recordsLinked to original sources

bioRxiv2025

Live-Exudation Assisted Phytobiome Cultromics System (LEAP-CS): A High-Throughput Cultromics System for Studying Plant-Microbiome Interactions through Non-Contact Metabolic Exchange.

This study introduces an innovative methodology for co-cultivating plants and microbes, employing a membrane-based structure to facilitate their physical separation. The Live-Exudation Assisted Phytobiome Cultromics System (LEAP-CS) has the capability to investigate the complex interaction of plant and soil microbiome under in vitro conditions, offering potential benefits. Subsequent validation and testing can be performed through pot, greenhouse, and field trials. The system can efficiently function as a high-throughput screening tool for assessing plant-microbiome interactions and their associated metabolic signatures. Our phytobiome culturing technique harnesses root exudation from live plants, capitalizing on the membranes selective separation to prevent direct physical interaction between plant and microbiome components. Consequently, the interaction is solely through chemical-mediated signalling. By employing this method, we can intricately dissect complex plant-microbiome interactions while faithfully maintaining and emulating the contact independent inherent associations prevalent within these phytobiomes. In conclusion, this user-friendly and reproducible in-vitro model holds immense potential for shedding light on the intricate community and metabolic exchange dynamics of plant-microbiome interactions, thus significantly advancing our understanding in this area.

plant biology↗

bioRxiv2019

Host developmental stage is associated with shifts in the exosphere microbiome of urban-farmed Asian green leafy vegetables

Green leafy vegetables (GLVs) comprise a significant part of urban South-East Asian (SEA) diets and are intensively farmed in SEA cities, including Singapore. Urban farming practices and urban-adapted vegetable cultivars likely select for specific above- and below-ground microbial communities - microbiomes - that assemble in close proximity to the plant tissues - the exosphere. A healthy exosphere microbiome is important for plant growth and safe human consumption. Using 16S rDNA gene amplicon sequencing compositional analyses, we show here that the exosphere microbiome of two commonly-consumed GLVs - Choy Sum (Brassica oleracea Alboglabra Group) and Gai Lan (Brassica chinensis var. parachinensis) - dominated by Gammaproteobacteria, Alphaproteobacteria, Bacteroidia and Actinobacteria. Shifts in exosphere microbiome composition were strongly associated with plant developmental stage. Finally, microbial taxa consistently detected in the exosphere comprise a small subset, which are predicted to harbour plant-beneficial traits.\n\nSignificanceAmong plant crops, GLVs form an integral part of the Asian diet, especially so in Southeast Asia. Some of these GLVs have short life-cycles ({bsim}30-45 days), which makes them suitable for urban farms in terms of cost advantage as short cycle crops are preferred in urban farms. From a food-security perspective, GLVs forms an important target food group and efforts are being made to increase its productivity to meet the increasing food demands. Current farming practices often place lot of importance on chemical fertilizers and nutrient inputs to improve the fertility of non-arable urban lands to increase the crop productivity. Furthermore, farms in urban settings are also associated with anthropogenic inputs and eutrophic conditions. These together, contribute to negative environmental externalities questioning the sustainability and eco-sustenance of urban farming. Microbial based management systems can not only resolve these challenging issues, but can also enhance plant growth, nutrient use efficiency and disease tolerance. However, their use as microbial adjuncts to agricultural practices is currently limited in urban environments, which could possibly be due to the restricted knowledge-base on these urban phytobiomes.

systems biology↗

bioRxiv2017

Extracellular Electron Transfer Powers Enterococcus faecalis Biofilm Metabolism

Enterococci are important human commensals and significant opportunistic pathogens associated with endocarditis, urinary tract infections, wound and surgical site infections, and medical device associated infections. These infections often become chronic upon the formation of biofilm. The biofilm matrix establishes properties that distinguish this state from free-living bacterial cells and increase tolerance to antimicrobial interventions. The metabolic versatility of the Enterococci is reflected in the diversity and complexity of environments and communities in which they thrive. Understanding metabolic factors governing colonization and persistence in different host niches can reveal factors influencing the transition from commensal to opportunistic pathogen. Here, we report a new form of iron-dependent metabolism for Enterococcus faecalis where, in the absence of heme, respiration components can be utilised for extracellular electron transfer (EET). Iron augments E. faecalis biofilm growth and generates alterations in biofilm matrix, cell spatial distribution, and biofilm matrix properties. We identify the genes involved in iron-augmented biofilm growth and show that it occurs by promoting EET to iron within biofilm.\n\nSignificanceBacterial metabolic versatility is often key in dictating the outcome of host-pathogen interactions, yet determinants of metabolic shifts are difficult to resolve. The bacterial biofilm matrix provides the structural and functional support that distinguishes this state from free-living bacterial cells. Here, we show that the biofilm matrix provides access to resources necessary for metabolism and growth which are otherwise inaccessible in the planktonic state. Our data shows that in the absence of heme, components of Enterococcus faecalis respiration (l-lactate dehydrogenase and acetaldehyde dehydrogenase) may function as initiators of EET through the cytoplasmic membrane quinone pool and utilize matrix-associated iron to carry out EET. The presence of iron resources within the biofilm matrix leads to enhanced biofilm growth.

microbiology↗