Evaluation of combined root exudate and rhizosphere microbiota sampling approaches to elucidate plant-soil-microbe interaction
Authors: Escudero-Martinez, C., Browne, E. Y., Schwalm, H., Santangeli, M., Brown, M., Brown, L., Roberts, D. M., Duff, A. M., Morris, J., Hedley, P. E., Thorpe, P., Abbott, J. C., Brennan, F., Bulgarelli, D., George, T. S., Oburger, E.
The study benchmarked several sampling approaches for simultaneous profiling of root exudates and rhizosphere microbiota in soil-grown barley, revealing consistent exudate chemistry across methods but variation in root morphology and nitrogen exudation. High‑throughput amplicon sequencing and quantitative PCR showed protocol‑specific impacts on microbial composition, yet most rhizosphere-enriched microbes were captured by all approaches. The authors conclude that different protocols provide comparable integrated data, though methodological differences must be aligned with experimental objectives.
Phylogenomic challenges in polyploid-rich lineages: Insights from paralog processing and reticulation methods using the complex genus Packera (Asteraceae: Senecioneae)
Authors: Moore-Pollard, E. R., Ellestad, P., Mandel, J.
The study examined how polyploidy, hybridization, and incomplete lineage sorting affect phylogenetic reconstructions in the genus Packera, evaluating several published paralog‑processing pipelines. Results showed that the choice of orthology and paralog handling methods markedly altered tree topology, time‑calibrated phylogenies, biogeographic histories, and detection of ancient reticulation, underscoring the need for careful methodological selection alongside comprehensive taxon sampling.
Arabidopsis lines with modified ascorbate concentrations reveal a link between ascorbate and auxin biosynthesis
Authors: Fenech, M., Zulian, V., Moya-Cuevas, J., Arnaud, D., Morilla, I., Smirnoff, N., Botella, M. A., Stepanova, A. N., Alonso, J. M., Martin-Pizarro, C., Amorim-Silva, V.
The study used Arabidopsis thaliana mutants with low (vtc2, vtc4) and high (vtc2/OE-VTC2) ascorbate levels to examine how ascorbate concentration affects gene expression and cellular homeostasis. Transcriptomic analysis revealed that altered ascorbate levels modulate defense and stress pathways, and that TAA1/TAR2‑mediated auxin biosynthesis is required for coping with elevated ascorbate in a light‑dependent manner.
The study performed transcriptome profiling of Cryptomeria japonica individuals from different geographic origins grown in three common gardens across Japan, assembling 77,212 transcripts guided by the species' genome. Using SNP-based genetic clustering and weighted gene co‑expression network analysis, they identified gene modules whose expression correlated with genetic differentiation, revealing that defense‑related genes are up‑regulated in Pacific‑side populations while terpenoid metabolism genes are higher in Sea‑of‑Japan populations, indicating local adaptation via regulatory changes.