New Phytologist最新文献

Wind-driven plant movement generates rapid light fluctuations (windflecks), which can impact canopy photosynthesis. Targeting crop photosynthesis in dynamic light provides a potential path towards boosting yield. Here, we quantified how plant architecture and biomechanics modulate such windflecks across 10 high-yielding cultivars of winter wheat (Triticum aestivum). Using synchronized high-frequency measurements of irradiance, wind speed, and canopy motion (quantified by frame differencing from video), we assessed the propensity of wheat cultivars to move (motion sensitivity), and the ability for movement to produce windflecks (light modulation efficiency) in the field. There was up to 10-fold variation in the quantity of motion between cultivars under identical wind speeds. Cultivars also exhibited structural trade-offs and specific in canopy windfleck properties. Some had low motion under wind but produced frequent windflecks when moving, whereas others exhibited high motion under similar wind but varied in windfleck frequency. Overall, windfleck properties were best explained by aerodynamic traits: cultivars with narrower leaves and lower leaf-to-stem mass ratios were associated with more intense windflecks. These findings establish that wheat cultivars actively modulate their light environment through biomechanical traits. By integrating plant motion into crop models, favouring motion-light relationships, which could provide a critical route to yield improvements in turbulent environments.

The root nodule symbiosis between legumes and nitrogen-fixing bacteria (NFB) acts as an important nitrogen source in terrestrial ecosystems. NFB in soil are affected by top-down predation in the food web. However, how protist predation affects abundant and rare sub-communities of NFB remains virtually unknown, limiting the exploitation of soil food webs to promote plant productivity. Here, a 10-yr field experiment combined with a glasshouse experiment was conducted to explore the effects of protist predation on abundant and rare NFB under organic material amendments. Our results revealed that organic material amendments increased the diversity of rare NFB and phagotrophic protists, but decreased the relative abundance of abundant NFB Correlation analysis combined with the glasshouse experiment suggested that protist predation decreased the relative abundance of NFB abundant taxa, but increased the diversity of rare taxa, which further promoted the cytokinin content and decreased the ethylene content in peanut (Arachis hypogaea L.) roots. Subsequent changes in plant hormones regulated the expression of genes involved in rhizobial infection, nodule organogenesis, and bacteroid differentiation, thereby promoting nodulation and increasing peanut yield. Overall, our findings provide unique insights into the interactions between phagotrophic protists and NFB, highlighting their links with plant productivity via predation-stimulated symbiotic nitrogen fixation.

Seed dispersal modes play a crucial role in angiosperm migration, adaptation, and responses to climate change, yet their global spatiotemporal patterns and underlying drivers remain largely unexplored. Here, using a global dataset on seed dispersal modes (zoochory, anemochory, hydrochory, and autochory) of 35 131 angiosperm species, we provide a large-scale assessment of their evolutionary dynamics, diversification impact, and geographic variation. We found that the increase in zoochorous lineages began after c. 105 Ma, and the transition rate from abiotic-to-biotic dispersal strongly correlated with paleotemperature, being positive from 105 to 90 Ma and negative thereafter. However, contrary to previous hypotheses, we found no significant effect of seed dispersal mode on diversification rates across angiosperms. Spatially, the prevalence of zoochory declined, and that of autochory increased with latitude, both closely linked to contemporary temperature. Meanwhile, the frequency of zoochory and anemochory was positively associated with temperature anomalies since the Last Glacial Maximum, suggesting that dispersal modes facilitating long-distance dispersal are favored in climatically unstable regions. These findings highlight the key role of climate fluctuations in shaping the spatiotemporal patterns of angiosperm seed dispersal modes and suggest a more complex relationship between dispersal modes and angiosperm diversification than previously assumed.

Oula Ghannoum, Western Sydney University's Hawkesbury Institute for the Environment (Australia).

Fairy rings in grasslands formed by basidiomycetes fungi are characterized by a green belt with luxuriant plants and soil nutrients. However, the way in which the fairy ring fungi enhance plant-available nutrients and subsequently influence plant growth remains poorly understood. We conducted an observational study involving 30 fairy rings in alpine grasslands to investigate the effects of fairy ring fungi on plant biomass, available nutrients, and soil microbial functions. Furthermore, a glasshouse experiment was performed to test the differential response of five plant species to increased ammonium nitrogen (NH₄ ⁺-N) induced by fairy ring fungi. We found that fairy ring fungi enhanced soil NH₄ ⁺-N accumulation, which might be due to increases in the relative abundance of specific bacteria and N-acquiring enzyme activities. Meanwhile, fairy ring fungi increased the abundance of genes related to N fixation and mineralization, but decreased the abundance of a nitrification gene. Furthermore, the observed 82% greater shoot biomass on the fairy ring as compared to outside it was mainly attributed to grasses and sedges, which were promoted by the increased NH₄ ⁺-N concentration. Our findings reveal a novel mechanism by which fairy ring fungi stimulate the microbial capacity to convert available nutrients, thereby reshaping plant composition in alpine grasslands.

Heat shock proteins (HSPs) are evolutionarily conserved, yet their functions in plant growth and development remain incompletely characterized. Here, we demonstrate that a HSP90 co-chaperone PpNudC6 is essential for directional cell expansion in the moss Physcomitrium patens. We generated ppnudc6 mutants and characterized their phenotypes. Dysregulation of PpNudC6 disrupts cellulose microfibril organization and cell wall stiffness gradients, as shown by scanning electron microscopy and atomic force microscopy, ultimately resulting in shortened and thickened protonemal cells. Mechanistically, this phenotype is mediated by disrupted reactive oxygen species (ROS) homeostasis. Loss of PpNudC6 function induces ectopic activity of the NADPH oxidase PpRbohD in protonemata, leading to abnormal ROS accumulation. Pharmacological inhibition of NADPH oxidases by diphenyleneiodonium rescues mutant phenotypes, confirming ROS overproduction as the primary driver of developmental defects. Furthermore, PpNudC6 interacts with the scaffold protein PpRACK1B and the co-chaperone PpSGT1, suggesting a multisubunit complex that modulates respiratory burst oxidase homolog (Rboh) activity. In summary, our findings reveal a chaperone-mediated regulatory module that mediates the production of ROS, thereby maintaining cell wall mechanical anisotropy required for directional expansion. This work provides insights into a novel role of HSP complexes in regulating directional cell expansion and links redox homeostasis to cell wall mechanics during moss development.

Plant-biotic interactions are driven by the exchange of molecules. Small peptide hormones like CLAVATA3/EMBRYO SURROUNDING REGION (CLE) peptides play central regulatory roles in these interactions. CLEs determine the extent of symbiotic interaction to balance costs and benefits for the host. In parasitic interactions, CLEs regulate the formation of feeding sites by plant pathogenic nematodes and promote the formation of haustoria in parasitic plants. By reviewing recent findings on CLE functions, their receptors, and responses across different biotic interactions, we provide insights into the increasingly complex roles of CLEs in plant development and nutrient signaling.

Phylogenies of long-lived plants often exhibit short molecular branch lengths and high levels of gene-tree conflict. However, the biological mechanisms underlying these patterns remain unclear. We examine this with simulations and through empirical examination of several large seed plant clades. We used an agent-based simulation model varying lifespan, degree of overlapping generations, and somatic mutation. We also compared simulated outcomes to phylogenomic patterns in several datasets of seed plants that include life-history shifts. Lifespan and overlapping generations together can generate both short branches and elevated gene-tree conflict. Somatic mutation can amplify these effects, although available evidence suggests mutation rates are often too low to drive major phylogenetic consequences. Variation across simulation parameterizations can mirror the diversity of phylogenomic patterns observed among lineages with differing life histories. Lifespan and generation overlap are potentially major contributors to characteristic phylogenetic signatures in long-lived plants. Consequently, life history should be considered when interpreting evolutionary patterns, substitution rates, and among-lineage heterogeneity in long-lived plant lineages.

How long do fungal hyphae persist in the environment? And how does this differ between groups and species of fungi? Despite growing knowledge of fungal contributions to decomposition and soil carbon cycles, surprisingly little is known about the turnover of mycelia: What happens to fungal hyphae over time? And how this impacts different fungi's contribution to carbon sequestration? In this study, we compared microscale persistence of fungal hyphae using microfluidic chip technology and visual quantification of hyphal degradation and turnover across six different wood-decay Basidiomycete species. Measured traits included hyphal extension, coverage, turnover rates, and changes in hyphal morphology over time when supplied with two carbon sources of differing recalcitrance. Species clustered into two groups: one with a frugal nutrient strategy (high turnover capacity, active persistence of cytoplasmic hyphae) and one with a wasteful strategy (low turnover of hyphae and large remnants of skeletonized hyphae). Differences matched the ephemeral or long-lasting nature of their fruiting bodies and the substrates they inhabit. Carbon type also influenced hyphal persistence over time. Our results suggest that hyphal turnover has a genetic basis linked to species ecology yet is also shaped by environmental factors such as carbon availability, highlighting the dynamic nature of fungal mycelia.