Plant Biology最新文献

Grapevine downy mildew, caused by the oomycete Plasmopara viticola, is a destructive disease that causes major economic losses as most elite grapevine cultivars are susceptible to this pathogen. As most crop protection strategies rely on synthetic pesticides that pose a threat to the environment and public health, alternative disease control methods are sought after. One such method involves the use of plant-derived essential oils (EOs). Previous studies on pre-treatment of grapevine with oregano EO vapour reported promising results in downy mildew management. Nevertheless, it remains unclear whether and how specialized metabolism is involved in the observed alleviation of downy mildew susceptibility. Grapevine individuals of a susceptible cultivar were pre-treated with oregano EO vapour for 24 h, after which the plants were inoculated with P. viticola. The effect of this pre-treatment on P. viticola infection in grapevine leaves was analysed by untargeted chemical profiling using LC-MS. Metabolite extracts were prepared from leaves harvested after pre-treatment, and at early (12 h) and late (216 h) timepoints after inoculation with P. viticola. After pre-treatment, monoterpenol disaccharides putatively annotated as dihexosides of (hydroxylated) aromatic (e.g. carvacrol/thymol) and aliphatic (e.g. terpeneol isomers) monoterpenols were detected by LC-MS/MS. These monoterpene(di)ol glycosides positively correlated with reduced disease severity in grapevine leaves 216 h after inoculation. Aromatic monoterpenols are major constituents of oregano EO, and their putative detection as aglycons suggests that monoterpenols emitted from oregano EO are biotransformed and thereafter stored as glycosides in grapevine leaves, which may negatively affect P. viticola proliferation. Overall, our findings highlight the potential of oregano EO as a tool for crop protection in the management of downy mildew proliferation in the susceptible grapevine cultivar 'Müller-Thurgau'.

Understanding the causes of geographic variation in traits is the focus of much research. Prior studies on multiple species of cone-bearing conifers have discovered that geographic variation in cone structure is related to variation in the intensity and form of natural selection exerted by seed predators. Here, we used data on the intensity of pre-dispersal seed predation by common crossbills (Loxia curvirostra) in relation to black pine (Pinus nigra) cone traits, along with seed predation and cone trait data for nine sites in the Iberian Peninsula to determine whether patterns of differential seed predation could account for among-site variation in cone traits. The tree and cone preferences of crossbills within a site were similar to those found in other studies of crossbills and conifers: crossbills preferentially foraged on trees producing many small cones with small scales. In contrast, the variation in the intensity of seed predation among the nine sites appeared to be negatively influenced by the proportion of empty seeds. The preferences for small, thin-scaled cones within a site have the potential to cause the evolution of larger and thicker scaled cones, because such cone traits are often heritable. However, the different intensities of seed predation among sites that we document are unlikely to lead to concordant trait differences among sites because the proportion of empty seeds appears related to environmental factors (e.g., precipitation) affecting pollination success that vary from year to year. Controlling such among-site variation is key for inferring whether selection can account for geographic variation.

Mutualistic plants use non-structural sugar (NSC) to produce carbon-based resources to reward partners. Then, any factor compromising NSC plant supplies should increase the relative costs of these rewards for plants. Drought, for instance, can initially reduce plant growth but not necessarily photosynthesis, which could boost NSC supplies. However, if drought persists and compromises plant water status, photosynthetic rates decline, reducing NSC reserves and potentially impacting the plant's investment in mutualistic rewards. We hypothesized that plants would initially increase extrafloral nectar investment - a sugary solution attractive to ants - at the onset of water shortage, increasing their attractiveness to ants. However, such investment and attractiveness gradually decrease over time as drought lasts and the plant water status is compromised. Here, we experimentally manipulated soil water availability and water potential of Chamaecrista nictitans (Fabaceae) and evaluated the effects of soil water decline over time on patterns of extrafloral nectar secretion and plant visitation by ants. We observed that C. nictitans had more active extrafloral nectaries producing more concentrated nectar at drought onset, while plant water potential was not affected. However, it gradually declined as the water shortage progressed, and plant water potential declined. Ant visitation followed a similar temporal pattern, peaking at the experiment onset and diminishing over time as the drought lasted. These findings emphasize the pivotal role of drought severity in shaping the temporal dynamics of extrafloral nectar secretion and likely other carbohydrate-based mutualistic rewards, shedding light on the physiological mechanisms regulating mutualisms.

Enantiostyly is a floral polymorphism that favours cross-pollination and genetic diversity. It is characterized by flowers with styles curved to the right or to the left. The factors that regulate the proportion and temporal dynamics of enantiostyly in monomorphic species (in which the two floral morphs occur in the same individual) are still poorly understood. This study investigated variation in morph production in four monomorphic species of Chamaecrista. We counted the number of right and left flowers from 40 individuals per species across two flowering seasons to assess daily and long-term variations in morph proportions. The species generally presented a balanced ratio of right and left flowers, regardless of the flowering period. Most individuals also showed a balanced ratio of morphs at the end of the sampling period, but their morph proportions generally changed daily. Individuals of Chamaecrista diphylla, C. rotundifolia, and C. flexuosa showed a greater number of days with unbalanced morph ratios. Chamaecrista ramosa showed no difference in the number of days in which the morphs were in similar or unbalanced proportions. Although populations with monomorphic enantiostyly exhibit a 1:1 ratio, individuals can alternate morph production, generating daily dimorphic individuals. This may hinder geitonogamy and promote intermorph cross-flow. Our results add a temporal factor to the discussion on dimorphic functionality in monomorphic enantiostylous species.

Meloidogyne spp. induce structural changes during the development of root-knot galls, leading to reduced productivity in various crop species, including eggplants (Solanum gilo). In this study, we evaluated the impact of Meloidogyne incognita on the development and structure of root-knot galls in eggplants and assessed the effect of the fungus Purpureocillium lilacinum as nematicide. Three treatments were applied: plants inoculated with M. incognita, plants inoculated with M. incognita + P. lilacinum, and a control. Agronomic impact was assessed 72 days after inoculation (DAI). Histological, morphological, and immunocytochemical analyses were performed at multiple time points after the start of the experiment. There was a reduction in weight as well as in root and shoot growth in the plants inoculated with M. incognita, whereas the plants from the other two treatments presented similar values. Galls and giant cells were observed at 18 DAI. Purpureocillium lilacinum did not interfere with giant cell formation but reduced the number of galls, nematodes, and eggs in the roots. The detection of methyl-esterified homogalacturonans indicated flexible cell walls in young galls, with increased rigidity due to low methyl esterification in mature galls. The growth of the aerial part and mass gain of the eggplants were negatively impacted by M. incognita; however, the use of the P. lilacinum strains reduced crop damage, indicating its efficiency as a biological control agent.

Benzamides have emerged as potent stress inhibitors and growth promoters in plant biotechnology, particularly in the management of crop resilience. This review delves into the mechanisms of action, applications, and potential benefits of benzamides, especially focusing on their role as poly(ADP-ribose) polymerase (PARP) inhibitors. Benzamides modulate stress responses by inhibiting PARP activity, which is crucial for DNA repair and maintaining genomic stability. This inhibition prevents excessive poly(ADP-ribosyl)ation, conserving cellular energy and enhancing stress tolerance. Additionally, benzamides promote alternative DNA repair pathways, contributing to the timely repair of DNA lesions and reducing mutation accumulation. In plant stress management, classical PARP inhibitors like 3-methoxybenzamide (3-MBA) and 3-aminobenzamide (3-AB) have demonstrated efficacy in enhancing resistance to abiotic stresses, improving plant growth, and increasing transformation efficiency. This review also highlights the antimicrobial, herbicidal, and insecticidal properties of benzamides, which enhance plant defence mechanisms against various pests and diseases. In summary, benzamides offer multiple approaches to enhancing crop resilience and stress management, with significant implications for sustainable agriculture.

Application of iron oxide nanoparticles (NP) (Fe₃O₄-NPs) in plant biotechnology presents new opportunities for enhancing metabolic activity of medicinal plants; however, their specific effects on Melissa officinalis subsp. officinalis remain poorly understood. This study examined effects of Fe₃O₄-NPs at 0, 25, 50, 75, and 100 mg L^-1 on morphological traits, phenolic compound accumulation, antioxidant activity, enzyme inhibition, and expression of PAL, TAT and RAS genes under in vitro conditions. Seeds were germinated on Murashige & Skoog medium and cultured for 30 days. Morphological characteristics were measured, total phenolics and flavonoid content were quantified spectrophotometrically, and phenolic profiles determined via HPLC. Antioxidant activity (CUPRAC, DPPH, ABTS), enzyme inhibition (AChE, MAO-A, urease), and gene expression (qRT-PCR) were also assessed. Treatment at 25 mg L^-1 yielded the highest content of total phenolics (41.68 mg GAEg^-1 plant) and rosmarinic acid (22.10 μg mg^-1 DW), together with improved antioxidant, MAO-A (2.95 mg plant mL^-1) and urease (6.71 mg plant mL^-1) inhibition activity. Higher concentrations (75-100 mg L^-1) increased AChE inhibition but reduced antioxidant capacity. PAL, TAT, and RAS expression was upregulated in all treated groups: PAL peaked at 25 mg L^-1, RAS at 100 mg L^-1, and TAT at 75 mg L^-1. There was no direct correlation between gene expression and phenolic levels, suggesting involvement of post-transcriptional or alternative regulatory mechanisms. These results demonstrate that Fe₃O₄-NPs act as dose-dependent modulators of secondary metabolism and bioactivity in M. officinalis, offering promising tools for nanoparticle-based elicitation strategies in medicinal plant biotechnology.

Tropical forests across the globe are facing intensifying droughts, yet their responses are far from uniform. We argue that this variability should be understood in the context of interacting legacies across scales. At the continental scale, evolutionary history and past climatic filters have left distinct imprints on forest composition. At landscape scale, edaphic and hydrological heterogeneity constrain species distributions and functional strategies. These legacies converge in the functional trait space available to tree communities, shaping their resilience or vulnerability to novel drought regimes. By placing drought in this biogeographic, edaphic, and trait-based context, we highlight the importance of integrating historical and environmental filters into predictive models of tropical forest futures.

Soil salinization poses a growing threat to global agriculture, prompting efforts to enhance plant salt tolerance. Recretohalophytes, such as Limonium bicolor, have evolved salt glands – specialized epidermal structures that actively secrete excess salt to survive in saline environments. A recent study identified the importin-β protein LbSAD2 as a key regulator of salt gland development, acting via interaction with Lb2G12567, and repressed by Lb2G12077. Functional studies confirmed that this regulatory module enhances both gland density and salinity tolerance. Comparative insights from Arabidopsis reveal that SAD2-mediated nuclear transport integrates stress and developmental signalling. This reveals the emerging molecular framework linking nuclear transport to epidermal specialization in halophytes, and outlines future directions to explore the evolutionary conservation and biotechnological potential of LbSAD2-mediated salt gland regulation.