The circadian clock gates lateral root development
Authors: Nomoto, S., Mamerto, A., Ueno, S., Maeda, A. E., Kimura, S., Mase, K., Kato, A., Suzuki, T., Inagaki, S., Sakaoka, S., Nakamichi, N., Michael, T. P., Tsukagoshi, H.
The study identifies the circadian clock component ELF3 as a temporal gatekeeper that limits hormone‑induced pericycle proliferation and lateral root development in Arabidopsis thaliana. Time‑resolved transcriptomics, imaging, and genetic analyses show that ELF3 maintains rhythmic expression of key regulators via LNK1 and MADS‑box genes, and that loss of ELF3 disrupts this rhythm, enhancing callus growth and accelerating root organogenesis.
The study reveals that the thermosensor and circadian regulator ELF3 interacts with the PLT3 transcription factor in Arabidopsis root stem cell niches, forming subcellular condensates that sustain quiescent centre and columella stem cell fate. ELF3’s intrinsically disordered prion‑like domains drive condensate formation with PLT3, and PIF3/4 act as nuclear shuttles recruiting ELF3 to nuclear condensates, linking environmental cues to stem cell maintenance.
The authors used a bottom‑up thermodynamic modelling framework to investigate how plants decode calcium signals, starting from Ca2+ binding to EF‑hand proteins and extending to higher‑order decoding modules. They identified six universal Ca2+-decoding modules that can explain variations in calcium sensitivity among kinases and provide a theoretical basis for interpreting calcium signal amplitude and frequency in plant cells.
The study demonstrates that ELF4 is essential for recruiting ELF3 into hypocotyl nuclei at dusk, a process that enhances ELF3’s ability to repress target gene expression and limit hypocotyl elongation, especially under short‑day conditions. Subnuclear localization patterns of ELF3 differ between hypocotyl and root tissues, indicating tissue‑specific temporal regulation by ELF4.
The study examined how Turnip mosaic virus (TuMV) infection reshapes root-associated bacterial and fungal communities in two Arabidopsis thaliana genotypes. TuMV markedly reduced bacterial diversity and altered community composition in a genotype‑specific manner, while fungal communities stayed stable; bacterial co‑occurrence networks later recovered and even increased in complexity, highlighting microbial resilience. These findings underscore virus‑driven selective filtering of bacterial root microbiota and the role of host genotype in mediating microbiome responses to viral stress.
Trichoderma afroharzianum behaves differently with respect to the host transcriptome and microbial communities under varying iron availability in pea plants
Authors: Kabir, A. H., Thapa, A., Ara Saiful, S. A., Talukder, S. K.
The study examined how the bioinoculant Trichoderma afroharzianum T22 influences Pisum sativum growth under iron-sufficient versus iron-deficient conditions, finding pronounced benefits—enhanced photosynthesis, Fe/N accumulation, and stress‑related gene expression—only during iron deficiency. RNA‑seq revealed distinct gene expression patterns tied to symbiosis, iron transport, and redox pathways, and microbiome profiling showed T22 reshapes the root bacterial community under deficiency, suggesting context‑dependent mutualism.
The study genotyped 1,013 hard red spring wheat lines using SNP arrays and targeted KASP markers to track changes in genetic diversity and the distribution of dwarfing Rht alleles over a century of North American breeding. It found shifts from Rht‑D1b to Rht‑B1b dominance, identified low‑frequency dwarf alleles at Rht24 and Rht25 that have increased recently, and revealed gene interactions that can fine‑tune plant height, along with evidence of recent selection for photoperiod sensitivity.
Seed treatment with melatonin markedly improved root biomass, nodulation, nitrogen balance, and yield in three peanut genotypes, particularly Kainong 308. 16S rRNA amplicon sequencing revealed genotype‑ and compartment‑specific reshaping of bacterial communities, with enrichment of key Proteobacteria and more complex co‑occurrence networks that correlated with enhanced plant traits. These results highlight melatonin’s dual function as a plant bio‑stimulant and microbiome modulator.
The study examined how plant‑derived benzoxazinoid metabolites influence interactions among root‑associated bacterial strains and between these bacteria and their plant host. Using both simple pairwise assays and more complex multi‑organism setups, the authors found that these chemicals modulate bacterial‑bacterial and bacterial‑plant interactions, altering plant defense, immunity, and sugar transport especially when bacterial inocula are present. The work highlights the role of the soil chemical legacy in shaping holobiont dynamics and demonstrates the utility of combining reductionist and holistic experimental approaches.
A forward genetic screen in light-grown Arabidopsis seedlings identified the Evening Complex component ELF3 as a key inhibitor of phototropic hypocotyl bending under high red:far-red and blue light, acting upstream of PIF4/PIF5. ELF3 and its partner LUX also mediate circadian regulation of phototropism, and the orthologous ELF3 in Brachypodium distachyon influences phototropism in the opposite direction.