Brailey-Jones, P. | Search bioRxiv

bioRxiv2024

Microbial Partner (MiPner) Analysis

Although a few bacteria have been studied in great depth, relatively little is known about the characteristics of microbe-microbe interactions that occur within ecosystems on a daily basis. A simple, robust technique was developed to set up the foundation for investigating pairwise bacterial-bacterial interactions, using cell-cell binding as a self-selective mechanism to identify interesting bacterial species pairs. Using a Serratia marcescens strain (SMC43) isolated from Georgia soil as a "bait", specific bacteria were purified by their specificity in binding SMC43 bacteria that were themselves attached to a wooden applicator stick. The isolated Microbial Partners (MiPners) were greatly enriched for members of the genera Sphingobium and Caulobacter. Two out of 24 streaked MiPners were unable to be separated from, and grow on the plate type tested without, SMC43. This suggests that the MiPner technology will be one strategy for purifying bacteria that were previously recalcitrant to culturing.

microbiology↗

bioRxiv2024

Iron-induced Transcriptional and Microbiome Changes in Host Roots Associated with Drought Tolerance in Sorghum

Drought stress significantly impairs growth, and microbial interactions in sorghum. This study explores the transcriptional and microbial shifts in sorghum under drought, revealing key adaptations to water deficit. LC-MS (Liquid Chromatography-Mass Spectrometry) analyses revealed that drought stress induced abscisic acid while significantly reducing jasmonic acid levels in sorghum roots, likely due to resource conservation strategies during drought. Transcriptional reprogramming highlighted the upregulation of genes in the roots involved in mineral homeostasis (Ferritin 1, Iron dehydrogenase, Nitrate transporter 1), hormone signaling (Ethylene-insensitive protein 3, Gibberellin 2-oxidase), and osmotic regulation (Aquaporin, Dehydrin), underlining key adaptive responses to maintain nutrient uptake, redox status, and cellular turgor. In Fe-supplemented plants, increased Fe in roots correlated with increased Ferritin 1 expression, improved plant health, and reduced Fenton reaction rate and H O levels. This suggests that ferritin helps minimize oxidative stress under drought in sorghum. Drought reduced root-associated bacterial diversity and richness while enriching drought tolerance-associated genera, such as Burkholderia, Caballeronia and Paraburkholderia, known for promoting plant growth through auxin production, phosphate solubilization, and siderophore-mediated iron acquisition. In contrast, fungal diversity and richness remained unchanged, dominated by Talaromyces, which showed a statistically non-significant increase under drought. Random forest models could not identify functional predictors for fungi but revealed a shift in bacterial functional groups under drought, with enrichment in phototrophy, methylotrophy, and nitrate reduction, traits emphasizing microbial roles in nutrient cycling and drought adaptation of sorghum. This study provides insights into the role of ferritin and potential bacterial bioinoculants that could enhance sorghum resilience to drought. Future research should validate these findings to integrate them into breeding programs and biofertilizer formulation for drought-tolerant sorghum and climate-resilient agriculture.

plant biology↗