Plant Biology最新文献

This study explores how bioactive compounds in green coffee beans (Coffea arabica L.) vary across different geographic regions, addressing the key question of how environmental factors shape coffee biochemistry and adaptation mechanisms to diverse conditions. Identifying these variations provides insight into how environmental and processing factors influence coffee's sensory quality. Samples from six major coffee-producing regions were analysed for key bioactive compounds, including biogenic amines, caffeine, trigonelline, sucrose, free amino acids, and phenolics. Total polyphenol content and polyamine concentrations were measured, and PCA was used to differentiate samples based on chemical composition. A correlation analysis was specifically conducted for Brazilian samples, using meteorological and environmental data. Total polyphenol content ranged from 44.8 to 70.7 mg GAeq g^-1 FW, with Brazilian samples having the highest levels. Putrescine, the most abundant polyamine, varied significantly (0.02-1.9 μg g^-1 FW). PCA highlighted Ethiopian samples with high sucrose and low caffeine. Brazilian samples showed distinct separation based on key compounds, including putrescine, trigonelline, and amino acids. Environmental factors in Brazil correlated with polyamine and amino acid composition, suggesting associations with heat and drought tolerance. Environmental factors, particularly heat and drought, influence the biochemical profile of coffee beans. Polyamine levels correlate with stress tolerance, while amino acid composition reflects adaptations for osmotic protection. These findings enhance our understanding of coffee's biochemical adaptation to diverse climates and offer valuable insights for optimizing cultivation strategies in the face of climate change.

Trans-acting small interfering RNA (tasiRNAs) are a special type of endogenous small RNAs (sRNAs) found only in plants. Their biogenesis requires an initial miRNA-mediated cleavage of RNA precursors transcribed from TAS genes. TasiRNAs act in trans to silence gene expression by cleaving mRNAs with sequences partially complementary to their own. While Arabidopsis thaliana contains several TAS genes not found in other plants, the miR390-TAS3-ARF pathway is highly conserved among land plant lineages. This pathway exerts its function by silencing a subgroup of Auxin Response Factor (ARF) genes; these tasiRNAs are termed tasiR-ARFs. Many downstream auxin signals are mediated by ARFs acting as transcription factors to confer sensitivity and robustness to the hormone responses in diverse development contexts. These pathway functions are critical for plant growth, developmental timing, and correct organ patterning, such as leaf morphology and polarity, lateral root architecture, and flowering, as well as coping with stress. The phenotypes caused by mutations affecting tasiR-ARF production vary across plant species, showing pleiotropic effects, suggesting a co-opted process where the tasiR-ARF pathway evolution occurred to serve different functions, depending on plant developmental cues. One way to unify the diverse roles of this pathway would be through auxin response integration, possibly by exploring the evolution of ARF3 transcription factors and downstream genes. In this review, we discuss versatility of the tasiR-ARF pathway in land plants according to known developmental and environmental responses where the phytohormone auxin plays an essential role.

Iron deficiency is a common nutritional disorder observed in calcareous soils, where its resolution by classical methods has shown its failure. However, the exploitation of certain potentialities possessed by crops (rhizosphere acidification, H-ATPase; Fe chelate reductase, FeCR, etc.), and the use of some biostimulants remains most efficient and sustainable approach. A greenhouse experiment was conducted on common bean plants subjected (FeD), or not (control, C) to Fe deficiency, or subjected to Fe deficiency and sprayed with 1 mM indole-3-acetic acid (FeD-IAA). The key physio-biochemical traits developed by plants in the different treatments, and their interrelationships were analysed. Iron deficiency induced specific Fe chlorosis, reduced chlorophyll and disrupted photosystem II performance. Plant growth and Fe concentration also significantly decreased, despite the stimulation of H-ATPase and FeCR activities. However, exogenous IAA application alleviated the adverse effects of FeD, particularly through promoted H-ATPase and FeCR activities, and Fe²⁺ concentration. The polar transport of IAA promoted root growth, H-ATPase and FeCR activities under FeD. The resulted Fe promotes chlorophyll biosynthesis and photosynthetic functioning. The calculated rhizosphere acidification capacity (RAC) and Fe chelate reductase capacity (FeCRC) are two useful traits for tolerant plant screening. The exogenous IAA application is a useful, efficient and eco-friendly approach for Fe-chlorosis alleviation. It promotes soil quality through the improvement of the soluble, plant-available form of iron.

European grassland plants are frequently attacked by root hemiparasites. However, little is known about host defence responses to parasitism. We investigated whether prior parasitization by a root hemiparasite makes hosts more susceptible to parasitism or, on the contrary, stimulates host defence against a future attack by hemiparasites. We grew three host species (Lolium perenne, Trifolium repens and Sanguisorba minor) in phase 1 for 3 months with the hemiparasite Rhinanthus alectorolophus, removed the parasite and grew the same host individuals in phase 2 with the hemiparasites R. alectorolophus or Melampyrum arvense. Previous infection by a parasite reduced the survival of the seedlings of Rhinanthus and Melampyrum with all host species but increased the biomass of the surviving parasites. A previous infection reduced the biomass of the hosts in most treatment combinations, but variation in initial host biomass at the start of phase 2 only partly explained this effect. Some of these interactions were specific to particular parasite-host species combinations. The results indicate that infection by root hemiparasites induces in the hosts defence mechanisms against future infection by the parasites (increased pre-attachment resistance), but parasite individuals that overcome this defence may then also be particularly good at exploiting the hosts (no increased post-attachment resistance). Thus, infection by root hemiparasites may activate host defence pathways that can influence future interactions with herbivores and pathogens and thus community dynamics.

Vessel length in xylem of woody species is a key functional trait for understanding water transport mechanisms, directly influencing xylem hydraulic efficiency and safety. However, the accurate measurements of vessel length are susceptible to methodological variations. This study employed silicone injection, air injection and pneumatic method on eight subtropical woody branches to compare their applicability, accuracy and limitations for measuring vessel length and its distribution pattern. The results demonstrated that the vessel length distribution curves in three methods all showed an asymmetric unimodal right-skewed distribution. Both mean and mode vessel lengths of eight species obtained from the pneumatic and air injection methods showed no significant differences and were all higher than that from the silicone injection method. Besides, across all vessel diameter ranges in eight species, both mean and mode vessel lengths showed significant positive correlations among the three methods. However, the correlations became weakened in wide vessel species, especially for the silicone injection data. Moreover, vessel lengths were significantly positively related to the vessel diameter in eight species. This study provides empirical evidence for selecting appropriate methods to measure vessel length, which has a crucial role in determining water transport functions in the xylem of plants.

Photoreceptors perceive light to assist plants to adapt to diurnal changes under varying environmental conditions. Among them, phytochromes act as photoreceptors for red or far-red light, regulating numerous developmental processes in plants; however, their roles in nutrient ion uptake remain largely unexplored. In this study, we investigated the effect of phytochrome A (phyA) deficiency on nutrient ion uptake and photosynthetic activity in wild-type (WT) plants and phyA-deficient mutants (phyA mutants) grown hydroponically, and productivity of mature plants in paddy fields in rice (Oryza sativa L.). We found that the uptake of various nutrient ions and photosynthetic CO₂ assimilation increased in phyA mutants grown hydroponically with abundant nutrients. Moreover, grain and shoot dry weights were improved in phyA mutants grown in a paddy field under doubled fertilizer amounts in comparison with the recommended doses for WT plants. Quantification of mineral nutrients in grains revealed no difference in mineral nutrient content between WT plants and phyA mutants, despite phyA mutants showing increased grain weight per plant. Taken together, these results indicate that phyA mutants possess favourable agronomic traits that enhance productivity through improved nutrient utilization.

Magnesium (Mg) leaching in acidic soils poses a significant challenge to sustainable agriculture. While nanotechnology offers potential solutions, the efficacy of magnesium oxide nanoparticles (MgO-NPs) in mitigating Mg loss remains poorly understood. This study investigated the effects of MgO-NPs on tomato growth and Mg migration in acidic soil using a soil column experiment, comparing them with conventional bulk MgO and MgSO₄. Our results demonstrated that MgO-NPs were the most effective treatment in reducing Mg leaching, showing a significantly lower Mg migration flux than MgSO₄ in tomatoes. Concurrently, MgO-NPs substantially increased exchangeable Mg content in the topsoil (0-20 cm) by over 113% and improved soil pH, thereby enhancing the retention of other key nutrients such as potassium and calcium. These improvements in the soil environment translated into enhanced plant performance: MgO-NPs significantly boosted chlorophyll content, photosynthetic efficiency, and mineral nutrient accumulation, which collectively led to increased plant growth and superior fruit yield and quality. In conclusion, MgO-NPs present a highly promising sustainable amendment for acidic soils, outperforming traditional Mg fertilizers by simultaneously minimizing nutrient leaching and promoting tomato productivity.

Distylous species have populations with two floral morphs bearing stigmas and anthers positioned reciprocally. This arrangement, assisted by the flower-pollinator fit, facilitates pollen deposition in different parts of pollinators' bodies, promoting outcrossing between morphs (i.e., legitimate pollen deposition - LPD). Typically, distyly occurs in one dimension (i.e., in height; 1D-heterostyly) but it can also appear as 3D-heterostyly, with stamens and styles bent and twisted. It is hypothesized that 3D-heterostyly improves reciprocity and LPD, reducing pollen loss compared to 1D-heterostyly. Variations in pollinator assemblages may lead to divergent selective pressures, resulting in different degrees of reciprocity and pollen flow patterns among populations of 1D- and 3D-heterostylous species. We tested these hypotheses in Linum tenue (1D-heterostyly) and L. suffruticosum (3D-heterostyly) using data on pollen deposition on stigmas, pollinators and reciprocity from six natural populations occupying contrasting environmental conditions in Spain. LPD was higher in L. suffruticosum than in L. tenue only when specialized pollinators predominated (Usia bee flies; Bombyliidae). Both pollinator frequency and the reciprocity of sex organs were associated with LPD in L. suffruticosum. In contrast, L. tenue showed consistently moderate LPD and high reciprocity across populations, despite variation in pollinator assemblages. However, frequent spontaneous self-pollination in L. tenue might reduce LPD on its stigmas. 3D-heterostyly appears more effective in specific pollination contexts but may be vulnerable to shifts in pollinator availability. In 1D-heterostylous populations, the independence of LPD from pollinator assemblage composition may explain the prevalence of 1D-heterostyly, although persistent spontaneous self-pollination in L. tenue could threaten the long-term maintenance of polymorphism.

Global change affects plant performance, both directly through warming and indirectly through changes in their biotic and abiotic surroundings. Soil microbes can critically influence plant performance, but are vulnerable to warming themselves. Disentangling direct effects of warming on plants from those intermediated by changes in microbial populations is complex under field conditions. To distinguish those effects, we monitored the performance of Agrostis capillaris and Anthoxanthum odoratum grown under uniform and controlled glasshouse conditions in soils inoculated with soil microbiomes conditioned by ambient, medium (14 years; MTW) or long-term (>55 years; LTW) geothermal warming. This was replicated under normal watering or drought conditions to additionally assess stress resistance. Furthermore, we analysed the microbiome of the inocula through metabarcoding to identify root-associated fungi and compare their relative abundance under different warming conditions. We found a decreased belowground biomass of both plant species when grown with LTW-conditioned microbiomes, with an exacerbated effect under drought for Ag. capillaris. We did not observe an associated increase in aboveground biomass, resulting in an increased aboveground biomass:belowground biomass ratio. These changes coincided with concurrent increases in the relative abundance of putative plant pathogens and arbuscular mycorrhizal fungi. We therefore conclude that soil microbes can mediate warming effects on plant performance through reduced belowground biomass.

Plants are multicellular organisms composed of diverse cell types, each with its own distinct mRNA, protein and metabolite profile. In addition, each cell type exhibits developmental gradients that require fine-tuned balancing with neighbouring cells in terms of cell geometry and chromatin status. These factors highlight the need for precise knowledge of gene expression and chromatin dynamics during stress responses at the single-cell level in planta, linked to cell position and fate. In this viewpoint, we discuss the importance of spatial cell biology in situ methods in modern plant research and briefly compare it with the methods currently available for studying single-cell resolution.