Mediterranean temporary ponds (MTPs) are dynamic habitats where low levels of dissolved oxygen can significantly impact plant life. This study investigated the effect of hypoxia and near-anoxia on seed germination and the induction of secondary dormancy in 14 plant species, characteristic of this habitat. Imbibed seeds were subjected to various oxygen concentrations (0.1, 5, 10, or 21% O), in both light and darkness. We also tested seed ability to recover germination by moving them to aerobic conditions. We measured embryo growth after hypoxic treatments and during recovery in three species with morpho-physiological dormancy, a rarely investigated response in this dormancy class. Our findings revealed a wide range of species-specific responses. Hypoxia did not inhibit germination in half of the tested species in the light, while near-anoxia completely inhibited germination in all species. However, most seeds fully recovered germination ability once aerobic conditions were restored. Interestingly, hypoxia in darkness reduced or prevented germination in some species and specifically induced secondary dormancy in Juncus bufonius. Surprisingly, seeds of Bulliarda vaillantii lost their light requirement for germination under hypoxia. In three Ranunculus species with morpho-physiological dormancy, hypoxia slowed embryo growth, which delayed germination recovery. This study reveals that MTPs species have evolved adaptations, ranging from tolerance to hypoxic conditions, to the ability to trigger secondary dormancy, which are crucial to surviving and reproducing in these unique environments. The results offer new insights into the germination ecophysiology of MTPs species and their regeneration niche in temporary wetlands.

Space is considered one of the harshest environments for living organisms, where ionizing radiation poses a significant threat to biological systems. Although plants exhibit higher resistance to radiation than animals, their photosynthetic machinery remains highly vulnerable. Given the role of plants in Controlled Ecological Life Support Systems (CELSSs), understanding how environment influences plant performance is critical for space missions. This study investigated the combined effects of X-ray irradiation (0.3, 10, or 20 Gy) and light quality (white, red, or red-blue LEDs) on young Vigna radiata L. plants. To assess plant potential acclimation strategies to radiation, we evaluated key functional traits, focusing on growth and photosynthetic performance. Specifically, we quantified in vivo chlorophyll fluorescence, photosynthetic pigments (chlorophylls, carotenoids), and expression of two major photosynthetic proteins: D1 (PSII core) and Rubisco. To our knowledge, no previous studies have explored how specific light wavelengths modulate plant responses to ionizing radiation during early development stages. Our results showed that red light enhances biomass allocation to shoots, promotes pigment accumulation, specifically at 0.3 and 10 Gy, and maintains higher photochemical efficiency and protein expression even at the highest radiation dose, compared to other light wavelengths. Maintaining an appropriate light environment during initial phases of growth enhances photosynthetic performance, reducing the harmful effects of X-rays, thus enabling plants to fulfil their ecological role in CELSSs.

Soybean (Glycine max), is an important oilseed crop that plays a vital role in ensuring global food security. However, it is susceptible to multiple abiotic stresses that can reduce yield. The ubiquitination-proteasome pathway is a crucial regulatory mechanism that controls a broad range of processes in plants. We investigated the function of Glycine max drought-induced SINA (GmDIS1), an E3 ligase gene, in soybean abiotic stress tolerance using Agrobacterium-mediated transformation to develop soybean GmDIS1-RNAi transgenic lines. GmDIS1 was significantly induced under drought and heat stress. Several physiological traits revealed resilience of GmDIS1-RNAi lines under drought and heat stress. The functions of stress-related genes, such as AOS and GmPAL were investigated to dissect the pathways that contribute to drought and heat tolerance in GmDIS1-RNAi lines. The results suggest that decreasing expression of GmDIS1 can enhance soybean tolerance to drought and heat, and also provide a significant target for developing more drought- and heat-tolerant soybean varieties and other crops.

Cyphomandra betacea, a valuable understory crop in southwestern China, exhibits high sensitivity to water availability. Under global climate change with increasingly erratic precipitation, understanding how Cyphomandra betacea, seedlings respond to rainfall variations is crucial for sustaining this distinctive industry. Through controlled experiments, this work systematically investigates how different rainfall patterns affect seedling growth and physiology, providing a theoretical basis for science-based management under future climate scenarios. Seedlings were subjected to a four-month simulated rainfall experiment with two rainfall intervals (T: 3-day; T: 6-day) and three rainfall amounts (W: control; W: +40%; W: -40%). Biomass, non-structural carbohydrates (NSC), and carbon, nitrogen, phosphorus stoichiometric characteristics were analysed. Seedling growth is more sensitive to variations in rainfall amount, and appropriate increases in rainfall can promote seedling growth and development. Under changes in rainfall patterns, seedlings prioritize the storage of NSC in stems, followed by leaves, with the lowest allocation to roots. Nitrogen content within organs is pivotal for the composition of NSC and can regulate the sugar-starch conversion process. The July WT treatment resulted in optimal performance for the majority of growth indicators and demonstrated the highest nutrient accumulation efficiency. We identified a stem-preferential carbon allocation strategy and systemic N limitation, offering key insights for conservation and cultivation under changing climates.

Caves present unique ecological conditions that influence the distribution and adaptation of species, yet studies on cave-associated vegetation remain limited. This study investigated how cave conditions affect the functional traits of Miconia sellowiana Naudin (Melastomataceae), comparing individuals from the cave interior with those from the adjacent understory. Our objective was to understand how these environments influence the species' morpho-functional characteristics and ecological relevance, aiming to identify physiological responses to the constraints of each habitat. Based on this, we hypothesize that caves act as distinct environmental filters compared to the understory, selecting for unique morphological and physiological variations. Leaf morpho-functional traits were evaluated, including macroscopic dimensions (length, width, and leaf area) and microscopic characteristics, such as the anatomy of the central vein, mesophyll, and epidermis. Samples were fixed, processed for histological sections, and analysed by optical and electron microscopy. Statistical analysis included PCA to identify morpho-functional patterns and Student's t-tests/Wilcoxon tests to compare variables between habitats. Cave individuals had thinner leaves, with fewer layers of photosynthetic parenchyma, smaller relative phloem area in the central vein, lower stomatal density, and reduced leaf area and length compared to understory individuals. Low light availability, high humidity, shallow soils, and nutrient scarcity in caves likely limit the development of thicker leaves and affect stomatal density, vascular tissue, and leaf size. These results suggest that cave environments drive morpho-functional and physiological variations in surrounding plants. This study fills gaps in the literature and highlights ecological mechanisms that sustain life in subterranean ecosystems.

Floral colour is a key trait mediating plant-pollinator interactions, with UV reflection hypothesized to evolve in response to the effectiveness of pollinators. The bee-avoidance hypothesis predicts higher UV reflection in white flowers and lower reflection in red and yellow flowers of bird-pollinated plants, with opposite patterns in bee-pollinated flowers. However, the macroevolutionary role of this process remains unclear. We analysed 245 angiosperm species using ancestral state reconstruction and comparative evolutionary models to assess UV reflection patterns in relation to flower colour and pollinator type. Ancestral reconstructions revealed frequent transitions in both hue and UV reflection states. Higher UV reflection optima were found in red and bee-pollinated flowers compared to red bird-pollinated flowers, supporting the role of UV in bee attraction. White and yellow bee-pollinated lineages showed elevated evolutionary rates and selective strength compared to bird-pollinated lineages of the same hue. Unexpectedly, yellow bird-pollinated flowers displayed higher UV reflection optima than yellow bee-pollinated flowers. Our results suggest that both attraction and exclusion mechanisms contribute to the macroevolution of UV reflection in flowers. We found strong support for the bee-avoidance hypothesis in red flowers. However, while white flowers generally followed predicted patterns, yellow flowers showed a reverse pattern, with higher UV reflection in bird-pollinated lineages, providing contrasting evidence across colour categories. These findings highlight complex and colour-dependent selection dynamics in pollinator-mediated floral evolution.

In many plants, pollinators are attracted to the flowers by scent. Among plants, Banksia (Proteaceae) is exceptional in being pollinated by several functional groups of vertebrates, including honeyeater birds, members of two marsupial orders, and rodents. Here, we test the hypothesis that in Banksia interspecific variation in the frequency of floral visitation by functionally different vertebrate pollinators can be explained by floral scent traits. We used GC-MS to analyse floral volatiles of nine co-occurring Banksia species and tested for correlations between floral visitation by vertebrate pollinators quantified through camera trapping and (i) the abundance in floral headspace of three candidate mammal-attracting compounds, and (ii) overall scent richness (number of volatiles detected). Visitation by non-flying mammals, but not birds, was positively correlated with scent richness, aligning with general trends for other functional groups of pollinators that use olfaction when foraging for nectar. Visitation by native and introduced mice, but not by Honey possums, was correlated with median abundance of 3-methyl-1-nitrobutane and 2-methyl-1-nitrobutane - structural isomers of 1-nitropentane, a known semiochemical in Black rat that is attractive to both sexes. Further, the known rodent semiochemicals, sulcatone (6-methyl-5-hepten-2-one) and 2-methylbutanoic acid were detected in species frequently visited by mice. Our results demonstrate that within mixed-vertebrate pollination systems, the frequency of visitation by functionally different vertebrate pollinators can be partially explained by interspecific variation in floral scent chemistry. While behavioural tests are needed to confirm attractiveness of specific compounds, our results provide the first evidence for chemical adaptation to pollination by rodents in Australian flora.

Natural light conditions are inherently dynamic, yet their effects on plant light acclimation remain ambiguous. We established two light regimes with the same daily quantum input [constant light (CL) and fluctuating light (FL)] with cotton (Gossypium hirsutum L.) cultivar Xinkang4 as the object, and measured leaf anatomy, chlorophyll fluorescence, photosynthetic gas exchange, and light induction kinetics. (1) Compared with CL, FL induced more shade-acclimated leaf morphology, with total leaf thickness reduced by 8.2%, palisade layer thickness by 11.3%, and total stomatal density by 16.7%. (2) Compared with CL, FL induced more sun-acclimated photochemistry, evidenced by 12.0% lower chlorophyll content, 29.6%-32.3% higher PSI (and CEF) electron transport rates, 24.0%-28.2% improved photochemical quantum yield, and 42.3% higher carboxylation capacity, collectively leading to an increase in maximum photosynthesis of 11.8%. (3) Light induction kinetics showed that despite superior photosynthesis rates under FL, slower rate of stomatal responses to light fluctuations constrained CO uptake, negating the differences in photoassimilate accumulation between treatments. This study demonstrates the unique structure-function decoupling strategy for light acclimation in the cotton cultivar Xinkang4, providing a novel framework for improving crop light management.

While carpels in Orchidaceae are predominantly unilocular, trilocular carpels can also occur, mainly in branches separated during the early diversification of the family. Variation in septa structure in the trilocular ovaries of the anthetic flower of orchids suggests distinct ontogenetic processes. In general, Orchidaceae fruits are capsules dehiscent by longitudinal slits, however, the number of valves, the pericarp composition, and the form of dehiscence can vary. To date, little is known about the development of unilocular capsules in Orchidaceae, and even less is understood about the development of trilocular fruits and the potential mechanisms of seed dispersal. Our aim was, therefore, to evaluate development of the ovary of the trilocular fruit and the form of dehiscence in fruits of Phragmipedium longifolium (Warsz. & Rchb.f.) Rolfe, a terrestrial species with dehiscent trilocular capsules. Using light microscopy and scanning electron microscopy, we discovered that septum formation in ovaries occurs in the flower bud stage, after differentiation of the floral parts. Septum is formed mainly by the installation of an intercalary meristem at the apex of each placenta. After pollination and during fruit development, there are few structural changes in the ovary, besides lignification process of the pericarp. The rupture and lysis of cells of the dehiscence line and dehydration of the mesocarp result in fruit dehiscence. The ovary of P. longifolium therefore has post-genital septum formation. Fruit dehiscence occurs by a mixed mechanism of cell rupture and lysis and fruit dehydration, evidenced for the first time in Orchidaceae.

Crassulacean acid metabolism (CAM) is a photosynthetic adaptation enabling higher CO concentration close to Rubisco and increased water use efficiency. It evolved in at least 38 plant families, none reported to be carnivorous. Here, we investigate CAM activity in the carnivorous genus Pinguicula, so far reported as C, with succulent leaves and distributed mainly in Central America. Eight species of Pinguicula, most with seasonal heterophylly, were cultivated under controlled conditions and monitored for changes in diel acidification (ΔH) when grown with abundant or limited water availability. Additionally, leaf anatomy and gas exchange were studied in representative species. In the winter trial, five species had positive and significant ΔH 1 week after withholding water (P. agnata, P. esseriana, P. gigantea, P. laxifolia and P. moranensis). ΔH levels were in the range previously reported in weak, facultative CAM plants (15-30 μmol H g FW). The summer trial revealed positive ΔH for most species tested, regardless of water availability. Three of the homophyllous species had an unclear pattern of CAM induction (P. emarginata, P. martinezii) or no CAM induction (P. grandiflora). Gas exchange in P. agnata found no dark CO assimilation, suggesting CAM cycling. We present the first report of CAM in a carnivorous plant, reinforcing the need to search for CAM in other families. Future work should assess reversibility of the C-CAM transition, explore the interplay between nutrient and carbon balance, and the contribution of weak CAM to plant fitness.

Understanding the physiological and molecular mechanisms by which plants adapt to environmental factors is essential for improving crop production and protecting biodiversity amid rapid anthropogenic climate change. The Cleomaceae is a family that stands out for its potential to study areas including floral diversity, species richness, and C photosynthesis. Its close relationship to the Brassicaceae allows for comparisons with Arabidopsis thaliana, which will lead to new knowledge that can be transferred to other species, including crops. This proximity paves the way for the investigation of monosymmetric and polysymmetric differences in flowers of the Brassicaceae. The rich variety of Cleomaceae floral forms represents a little studied but highly promising resource for understanding the evolution of key features that influence pollination. Additionally, Cleomaceae contain high concentrations of flavonoids, terpenoids, tannins, alkaloids, saponins, and anthocyanins, which could contribute to pharmaceutical discoveries and new health treatments. They also have significant potential in elucidating tolerance mechanisms to biotic and abiotic stresses, and can be consumed as food, although not traditionally cultivated. This review describes and discusses opportunities to advance research in various areas using Cleomaceae. Despite promising prospects, effective functional techniques to elucidate the diversity within this group are lacking.

Little is known about seed dormancy and germination of Circaeasteraceae, an early-diverging eudicot family. This study investigated the seed dormancy-breaking and germination requirements of Circaeaster agrestis, an annual herb in subalpine and alpine regions of the Himalaya-Hengduan Mountains and neighbouring ranges in China. Temperature requirements for embryo growth and dormancy-break were investigated using a move-along experiment. We examined effects of dry after-ripening (DAR) and GA on dormancy release, and ability to form a soil seed bank in the field. Germination responses to various light and water potentials at 5/1°C, 15/5°C, and 25/15°C were determined after 6 months of DAR. At seed dispersal in autumn, the embryo length:seed length (E:S) ratio was 0.29, increasing to 0.61 just before germination. Fresh seeds failed to germinate within 4 weeks under any temperature regime in light or dark. Thus, seeds possess morphophysiological dormancy (MPD). After 16 weeks of incubation at 1°C, embryo growth and germination occurred at 5/1°C or higher temperatures, confirming simple MPD. Based on fresh seed responses to GA, DAR and the move-along experiment, buried photoblastic seeds may form a small persistent seed bank. Low winter temperatures alleviate the PD component of MPD, enabling rapid embryo growth and germination with increased temperatures in early spring. However, embryo growth and germination are also influenced by soil moisture and light in spring. We conclude that C. agrestis seeds have nondeep simple MPD. This ensures that seed germination occurs at the optimal time-immediately after snowmelt-thereby maximizing length of the growing period and enhancing probability of seedling survival and reproductive success.

Thlaspi arvense (field pennycress; Brassicaceae) is a competitive and invasive weed which causes significant yield reductions in crops. It is also a target for domestication as an oil seed crop. Here we investigate its dormancy cycling and seedling emergence behaviour to understand how it will adapt to climate change. Seed dormancy cycling was monitored in the field. Germination at alternating temperatures was modelled to understand the field response. Seedling emergence timing in response to increasing soil temperature was studied in field experiments and in a thermogradient tunnel to evaluate the impact of global warming. Thlaspi arvense displays winter annual dormancy cycling. However, the thermal germination window (TGW) of this species does not close during winter, resulting in a small opportunistic spring emergence window, in contrast to the dominant autumn window which coincides with falling soil temperatures. Thermal alternations >8°C contribute to dormancy release, consistent with increasing germination in seeds recovered from field soils in late summer. Soil temperatures >10°C promote emergence in both windows, which correlates with accumulated thermal time. Because of TGW, T. arvense has evolved independent high-risk spring and low-risk autumn seedling emergence windows. The opportunistic spring window exploits temperate summers, while the low-risk autumn window exploits falling soil temperature to maximize seedling emergence success by avoiding hot dry conditions. This indicates T. arvense is highly adapted to survive in soils disturbed in spring and autumn by agricultural practices.

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.

The continuous fragmentation of tropical forests is a major threat to biodiversity and ecosystem functioning. This process creates extensive forest edges, alters microclimates, and promotes shifts in species composition. Functional traits are key to understanding how species respond to these disturbances and to predicting future vegetation dynamics. This study investigates the ecological strategies of species located at the edges and interiors of forest fragments in the Eastern Amazon. We sampled abundant tree species in seven forest fragments distributed across three municipalities in Pará, Brazil. We analysed 16 morphological and anatomical traits related to leaf economics and xylem function. Comparisons were made between edge and interior environments, and traits were correlated with edaphic variables. Species at forest edges had traits associated with hydraulic efficiency, including higher hydraulic conductivity and a greater fiber fraction. In contrast, interior species displayed a range of strategies, from resource-acquisitive to conservative. We found evidence of a decoupling between leaf and wood trait axes, with wood traits varying independently from leaf traits. Soil conditions influenced trait patterns only at fragment edges. Our study enhances understanding of the mechanisms regulating species survival, as evidenced by the different strategies adopted by plants in the interior and at the edges of forest fragments, reflecting contrasting responses to resource availability. These findings also provide support for conservation and forest management strategies and contribute to policy development aimed at mitigating the impacts of fragmentation on Amazonian biodiversity.

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 FW, with Brazilian samples having the highest levels. Putrescine, the most abundant polyamine, varied significantly (0.02-1.9 μg g 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.

Non-structural carbohydrates (NSC), including soluble sugars (SS) and starch (ST), are vital for plant metabolism and stress resilience. However, how the allocation of NSC and their components varies diurnally between C3 trees and shrubs in arid regions, and their respective roles in drought response, has received limited attention. This study examines the diurnal dynamics of NSC in leaves of woody species to elucidate growth-form-specific carbon storage strategies. In August 2023, we measured SS and ST concentrations in leaves of 16 C3 common species (11 trees, 5 shrubs) in Xinjiang, comparing daytime and nighttime levels. We used a two-way ANOVA to assess the effects of life form (tree/shrub) and time (day/night) on NSC, SS, ST, and SS:ST. Trees had significantly higher NSC and SS concentrations than shrubs. Life form and time jointly influenced NSC, ST, and SS:ST ratios, while SS concentration varied only with life form. Starch accumulates during the day and decreases at night, indicating it is a temporary carbon reserve that is converted to sugars for nighttime metabolism. The findings highlight divergent carbon allocation strategies between the studied C3 trees and shrubs, with trees maintaining higher NSC pools. Diurnal starch turnover underscores its importance in balancing carbon supply under arid conditions. These insights advance our understanding of growth-form-specific adaptations in carbon allocation within water-limited ecosystems.

This study explores the role of α-AtCAH1, a carbonic anhydrase gene, in enhancing drought tolerance and tuber yield in potato plants. While carbonic anhydrases are known for their role in photosynthesis, their function in plant stress adaptation - particularly in regulating stomatal behaviour and abscisic acid (ABA) signalling - remains insufficiently explored. Transgenic potato plants were generated to constitutively express α-AtCAH1 under control of the 35S promoter. Drought stress was simulated under controlled laboratory conditions. Analyses included subcellular localization, stomatal aperture measurement, water loss assays, and quantification of ABA levels and expression of ABA-responsive genes, such as StRD29A and StOST1. Transgenic plants showed enhanced tolerance to simulated drought and increased tuber yield compared to the controls. α-AtCAH1 was mainly localized to chloroplasts in guard cells. These plants had reduced stomatal aperture and transpiration rates. Additionally, there was significant upregulation of ABA content and ABA-response genes, indicating an enhanced drought-responsive signalling mechanism. Heterologous expression of α-AtCAH1 improves drought tolerance in potato plants by promoting stomatal closure and reducing water loss, likely through activation of ABA signalling pathways. These findings suggest α-AtCAH1 is a promising genetic target for engineering drought-resistant crops with improved yield under water-limited conditions.

Fires dramatically reduce both floral resources and pollinator abundance, potentially compromising flowering plant reproduction in post-fire landscapes through low pollination rates. Yet, some plant species flower shortly after fires (fire-stimulated flowering (FSF)), which seems a risky strategy given low pollinator abundance after fire. We investigated whether bird-pollinated plants with FSF have low pollinator dependence and generalized pollination systems to ensure reproduction in post-fire landscapes. This study was conducted in three nature reserves in fynbos within the Cape Floristic Region that experienced fires between 6 and 15 months previously. One bird-pollinated species (Watsonia pillansii, Satyrium carneum, or W. fourcadei) dominated at each site, where flower visitor counts were conducted in 15 plots (20 × 20 m), floral traits measured, and pollinator specialization for each species verified using hand pollination and exclusion experiments. The exclusion of bird pollinators from flowers highly reduced fruit set (>70%) for all three species, as well as seed set for the two Watsonia species. Although W. pillansii and S. carneum demonstrated partial self-compatibility, the fruit and seed set of self-pollinated inflorescences was reduced compared to cross- and naturally pollinated inflorescences, highlighting the importance of pollinators in the reproductive success of these species. Furthermore, all three species lack autogamy. Nevertheless, our results suggest that bird pollination, because of reduced competition for pollinator attention, remains the primary reproductive strategy. While these plants demonstrate partial self-compatibility and non-bird pollination, these mechanisms appear to complement rather than replace bird pollination, and may explain the persistence of these mutualisms despite recurring fire disturbances.

SlHDA1, a histone deacetylase gene, plays essential roles in plant growth, development, and fruit ripening. However, little is known about how SlHDA1 affects the response to abiotic stress. We constructed a SlHDA1-RNAi vector to generate SlHDA1-RNAi transgenic lines and assessed effects of silencing of SlHDA1 in tomato on tolerance to multiple abiotic stresses: low temperature, high temperature, and waterlogging. There were severe growth impairments in SlHDA1-RNAi transgenic tomato plants under low and high temperature stress or waterlogging compared with WT plants, with significant reductions in ABA, chlorophyll, proline, and CAT activity, and elevated MDA and histone H3 acetylation. RNA-seq analysis of transgenic plants found that transcripts of genes encoding defence proteins related to responses to abiotic stress (e.g., protein detoxification and oxidase) and biotic stress (e.g., pathogenesis-related proteins) were upregulated or downregulated in SlHDA1-RNAi lines, indicating the importance of SlHDA1 in mediating stress-related gene expression. In summary, SlHDA1 functions as a stress-response gene that positively regulates both temperature and waterlogging tolerance in tomato. These findings highlight its potential as a novel target for molecular breeding to improve tomato tolerance to these stresses.

Grasses and Epichloë endophytes often form mutualistic symbiotic defence systems. Studies have shown Epichloë endophytes improve resistance of host plants to airborne diseases. However, whether endophytes affect soil-borne disease resistance of host or neighbouring non-host plants remains unclear. We used endophyte-infected (EI) and endophyte-free (EF) Achnatherum sibiricum as host grass, Leymus chinensis as non-host grass, and Rhizoctonia solani as pathogen to explore the effects of endophyte infection on disease resistance of host and neighbouring non-host grasses. To clarify the contribution of root exudates to disease resistance of the non-host grass, three different root separation methods were employed between host and non-host plants: plastic barrier (PB), nylon mesh barrier (NL, allowing root exudates to pass through), or no barrier (NB). Epichloë endophytes decreased the disease index (DI) of the host A. sibiricum and reduced pathogen abundance in both host roots and soil. The DI of L. chinensis was affected by the interaction between root separation and endophyte infection. Under NL and NB treatments, the DI of L. chinensis with an EI neighbour was significantly lower than that with an EF neighbour, indicating that endophytic fungi can alleviate disease in non-host plants by influencing root exudates. Additionally, endophytic fungi increased the content of total phenolic compounds and salicylic acid in L. chinensis through activation of host root exudates, which could be one reason for the reduced DI of L. chinensis. Upon analysing root exudate components of the host, we found 2,4-di-tert-butylphenol (DTBP) and dibutyl phthalate (DBP) were the main antifungal compounds mediated by endophyte infection. Epichloë endophytes improved soil-borne disease resistance of the host and enhanced resistance of the neighbouring non-host grass through host root exudates; overall, host and non-host plants showed "associational resistance" to soil-borne diseases. This study highlights that Epichloë endophytes could potentially serve as efficient biological control agents against R. solani-associated diseases in grassland communities.