Search Results (85)

Global crop production faces serious threats from soil salinization. Microbial resources are often exploited to be used as fertilizers or seed coatings to address this issue. Parametarhizium changbaiense, as a novel beneficial microorganism, has been discovered to be capable of assisting limited crops such as mung bean in resisting salt–alkali stress. To investigate the effects of P. changbaiense on sugar beet under salt–alkali stress, the salt (NaCl:Na₂SO₄, molar ratio 9:1) and alkali (NaHCO₃:Na₂CO₃, molar ratio 9:1) stress were set on sugar beet germplasm 780016B. Results demonstrated that P. changbaiense improved the phenotypic characteristics of sugar beet seedlings under salt–alkali stress. The biomass parameters such as plant height and fresh weight significantly increased by growth-promoting effect. The elevated antioxidant enzyme activity could help protect plants from ROS damage induced by stress. Relative electrical conductivity and MDA content decreased with inoculation, thereby mitigating membrane lipid peroxidation and improving membrane system stability. The higher content of soluble sugar could maintain cell turgor pressure and alleviate osmotic stress. Inoculation with P. changbaiense enhanced chlorophyll content, fluorescence, and photosynthetic capacity. The more superior root vitality and architecture were suitable for the functions of metabolism and absorption. P. changbaiense could promote the growth and physiological characteristics under salt–alkali stress, so it has practical application value in agricultural production. Full article

Histone demethylases regulate epigenetic modifications and DNA damage repair in fungal pathogens, yet their specific functions in Magnaporthe oryzae remain poorly understood. This study identifies MoRph1, a JmjC domain-containing histone demethylase that interacts with the COMPASS complex. Targeted deletion of MoRph1 resulted in significantly reduced vegetative growth, impaired conidiation, and defective appressorium formation. The mutant displayed compromised appressorial turgor pressure due to delayed degradation of glycogen and lipid reserves, leading to inefficient host penetration and attenuated virulence on rice and barley. MoRph1 localized to the nucleus, and its absence caused increased nuclear abnormalities under DNA damage stress, suggesting impaired genome stability maintenance. Biochemical analysis confirmed that MoRph1 specifically demethylates histone H3 lysine 36 trimethylation. Transcriptome analysis revealed altered expression of genes associated with DNA replication, mismatch repair, and oxidative stress response. These results establish MoRph1 as a crucial epigenetic regulator coordinating fungal development, infection structure function, energy mobilization, and DNA damage repair. This study underscores the importance of chromatin-level regulation in fungal pathogenicity and provides a foundation for future evaluation of MoRph1 as a potential antifungal target. Full article

Soluble sugars are key determinants of fruit quality, directly influencing sensory attributes such as sweetness and flavor, as well as nutritional value and texture. Their content and composition are precisely regulated by sugar-metabolizing enzymes. Key enzymes, including invertase (INV), sucrose phosphate synthase (SPS), sucrose synthase (SUS), fructokinase (FRK), and hexokinase (HXK), play pivotal roles in these processes. However, a systematic and in-depth analysis of their regulatory mechanisms is currently lacking, which hinders a comprehensive understanding of the regulatory network governing fruit sugar metabolism. This review employs bibliometric analysis to systematically examine research trends in fruit sugar metabolism. Furthermore, it synthesizes recent advances in the coordinated regulatory mechanisms from the perspectives of transcriptional regulation, epigenetic modifications, and signal transduction, aiming to provide a clearer framework for future research. At the transcriptional level, transcription factor families such as MYB, WRKY, NAC, and MADS-box achieve precise regulation of sugar metabolism-related genes by specifically binding to the promoters of their target genes. Regarding epigenetic regulation, mechanisms including histone modifications, non-coding RNAs, and DNA methylation influence the expression of sugar-metabolizing enzymes at the post-transcriptional level by modulating chromatin accessibility or mRNA stability. Signaling pathways integrate hormonal signals (e.g., ABA, ethylene), environmental signals (e.g., temperature, light), and sugar-derived signals into the regulatory network, forming complex feedback mechanisms. These regulatory mechanisms not only directly affect sugar accumulation in fruits but also participate in fruit quality formation by modulating processes such as cell turgor pressure and carbon allocation. By integrating recent findings on transcriptional regulation, epigenetics, and signaling pathways, this review provides a theoretical foundation for fruit quality improvement and targeted breeding. Full article

Veraison represents a pivotal transition point in grape berry ripening, driven by a cascade of temporally coordinated physiological and molecular events. Studies have shown that the onset of veraison is initially triggered by a decline in cell turgor, regulated by osmotic potential and water status, which subsequently leads to fruit softening. This softening process is accompanied by extensive cell wall remodeling, establishing a structural basis for enhanced sugar influx. A rapid accumulation of sugars follows, acting not only as metabolic substrates but also as signaling molecules that synergize with abscisic acid (ABA) to activate transcriptional programs, including the induction of anthocyanin biosynthesis that drives skin color change. ABA accumulates at the early stages of veraison and functions as a key hormonal regulator initiating the ripening process. In contrast, auxin (IAA) and gibberellin (GA) levels decline prior to veraison, thereby releasing their inhibitory effects on ripening. Environmental factors such as water availability, light, and temperature significantly influence the timing and intensity of veraison by modulating hormonal signaling pathways. The initiation of grape berry ripening exemplifies a multilayered regulatory network that progresses through turgor signaling, hormonal regulation, metabolic reprogramming, and transcriptional activation, thereby providing a mechanistic framework for understanding non-climacteric fruit ripening. offering a mechanistic framework for understanding non-climacteric fruit ripening. This review provides an integrated perspective on the initiation mechanism of veraison, offering theoretical insights and practical implications for improving grape quality and vineyard management. Full article

Expansive plant growth during water deficit is common in temperate and extreme climates. Understanding how the turgor pressure, P, behaves during water deficit is essential for a better understanding of expansive growth rate, v. Here, validated biophysical equations together with dimensional analyses are used to simulate water deficit and determine the behavior of P and v. A dimensionless number, Π_pw, helps simplify the biophysical equations and interpret the results. The magnitude of Π_pw increases as water deficit severity increases. Analyses reveal that both P and v decrease curvilinearly as Π_pw increases. Simple mathematical relationships between P, v, and Π_pw, are derived, providing a clear and quantitative understanding of how P and v change as water deficits become more severe. Additionally, it is shown how the results of these analyses can be used to assess P and v of roots growing in water deficit. Full article

Fungal melanin plays a vital role in the survival, reproduction, infection, and environmental adaptation of plant pathogenic fungi. To develop innovative strategies for managing plant fungal diseases, comprehensive investigations into melanin are imperative. Such research is fundamental to elucidating the mechanistic basis of fungal pathogenesis and holds promise for the design of targeted interventions against melanin-mediated virulence determinants. This review systematically elaborates on the classification of fungal melanin in plant pathogens, provides a detailed analysis of the biosynthetic processes of 3,4-dihydroxyphenylalanine (DOPA) and 1,8-dihydroxynaphthalene melanin (DHN melanins), and reveals the catalytic functions and regulatory mechanisms of key enzymes within these pathways. Melanin modulates fungal virulence by influencing appressorial integrity and turgor pressure formation, thereby participating in the host infection process and the formation of overwintering sclerotia. Melanin provides stress resistance by protecting against extreme environmental factors, including UV radiation and high temperatures. It also has the capacity to absorb heavy metals, which increases pathogen survival under adverse conditions. Furthermore, the review also explores the mechanisms of action of melanin inhibitors that target plant pathogenic fungi, providing a theoretical foundation for developing efficient and environmentally friendly antifungal medications. The complex biosynthesis pathways and diverse biological functions of fungal melanin highlight its significant theoretical and practical importance for elucidating pathogenic mechanisms and formulating scientific control strategies. Full article

Poplars and aspens (Populus L. spp.) are undervalued options for use in managed landscapes. The genus comprises a multitude of taxa often negatively associated with disease susceptibility and short lifespans; however, it also hosts a diverse range of abiotic stress tolerances. The objective of this study was to generate a relative scale of the predicted drought tolerance of Populus spp. to inform site and taxon selection in managed settings. Utilizing vapor pressure osmometry, this study examined seasonal osmotic adjustment and predicted leaf water potential at the turgor loss point (Ψ_po) among several Populus taxa. All evaluated taxa demonstrated the ability to osmotically adjust (ΔΨ_π100) throughout the growing season. Bigtooth aspen (P. grandidentata Michx.) exhibited the most osmotic adjustment (−1.1 MPa), whereas black cottonwood (P. trichocarpa Torr. & A. Gray ex Hook.) exhibited the least (−0.44 MPa). Across the taxa, the estimated mean Ψ_po values in spring and summer were −1.8 MPa and −2.8 MPa, respectively. Chinese aspen (P. cathayana Rehder) exhibited the lowest Ψ_po (−3.32 MPa), whereas black cottonwood exhibited the highest (−2.47 MPa). The results indicate that drought tolerance varies widely among these ten Populus species and hybrids; bigtooth aspen and Chinese aspen are the best suited to tolerating drought in managed landscapes. Full article

Elevated temperatures and extended drought periods are driving significant changes in the structure and function of forest ecosystems. High-elevation alpine ash forests (Eucalyptus delegatensis R.T. Baker) in Australia are an example of forests that are already impacted by climate change. These obligate seeder forests can shift to non-forest ecosystems following extreme drought and altered fire regimes, raising concern about their adaptation to a rapidly changing environment and long-term forest persistence. Plant functional traits play a major role in determining adaptive mechanisms to environmental conditions. While alpine ash forests are vulnerable to climate change, it is unclear if different provenances have adapted to the climatic conditions in which they grow. We therefore studied the variation in expression of functional traits related to drought tolerance in 21 provenances of alpine ash distributed across an environmental gradient. We investigated if functional traits varied between the provenances and were related to climate of origin in order to identify provenances that may be better adapted to drought. We measured the following traits in a common garden experiment under well-watered conditions: stomatal density, specific leaf area, minimum stomatal conductance and osmotic potential at full turgor. There was very little variation in trait expression between the 21 provenances for all functional traits related to drought tolerance. All provenances had medium-range stomatal density (170–300 stomata mm²) and specific leaf area (SLA, 50–70 cm² g⁻¹), a very low minimum stomatal conductance (2–4 mmol m² s⁻¹) and a high osmotic potential at full turgor (−0.6–0.7 MPa). There was no statistically significant correlation of trait expression with the climate of origin. Thus, there is very little evidence for genetically controlled differences in trait expression of drought tolerance traits in this species. It is likely that the high elevation and high rainfall environment of the species’ ecological niche has not been subjected to frequent and extensive drought periods that would elicit an evolutionary pressure selecting for drought-tolerant traits. We could not identify provenances that would have different drought-tolerant functional trait responses than others, potentially conferring an adaptive advantage under climate change. This has implications for using climate-adjusted provenancing to improve resilience in alpine ash forests predicted to experience more frequent and severe droughts in the future. Full article

Pyropia haitanensis (T.J. Chang and B.F. Zheng) undergoes periodic dehydration and rehydration cycles, necessitating robust adaptive mechanisms. Despite extensive research on its physiological responses to desiccation stress, the comprehensive metabolic pathways and recovery mechanisms post-rehydration remain poorly understood. This study investigated the metabolic responses of P. haitanensis to varying degrees of desiccation stress using LC-MS and UPLC-MS/MS. Under mild dehydration, the thallus primarily accumulated sugars and proline, while moderate and severe dehydration triggered the accumulation of additional osmoprotectants like alanine betaine and trehalose to maintain turgor pressure and water retention. Concurrently, the alga activated a potent antioxidant system, including enzymes and non-enzymatic antioxidants, to counteract the increased reactive oxygen species levels and prevent oxidative damage. Hormonal regulation also plays a crucial role in stress adaptation, with salicylic acid and jasmonic acid upregulating under mild dehydration and cytokinins and gibberellin GA₁₅ accumulating under severe stress. Rehydration triggered the recovery process, with indole acetic acid, abscisic acid, and jasmonic acid promoting rapid cell recovery. Additionally, arachidonic acid, acting as a signaling molecule, induced general stress resistance, facilitating the adaptation of the thallus to the dynamic intertidal environment. These findings reveal P. haitanensis’ metabolic adaptation strategies in intertidal environments, with implications for enhancing cultivation and stress resistance in this economically important seaweed. Full article

A field experiment was conducted in 2023 and 2024 in Beijing, China, to investigate effects of soil water stress, applied before the fruit ripening stage, on the fruit total soluble solid accumulation and cracking of jujube trees. The experiment consisted of two variation factors: (a) irrigation levels (MDI and SDI, applied 80% and 50% of the irrigation volume, respectively) and (b) growth stages (stage 1, before the fruit enlargement stage, and 2, before the fruit ripening stage). The two irrigation levels were applied at each growth stage in a 2 × 2 factorial arrangement, plus a control treatment receiving 100% irrigation volume, resulting in five treatments per replicate. The findings indicated that pre-enlargement stage water stress enhanced the accumulation of total soluble solid content within fruits, which subsequently promoted faster fruit growth in from the early- to mid-August period. However, by late August, both the total soluble solid content and fruit growth rates had declined, thereby mitigating the risk of fruit cracking. During the fruit enlargement stage, the fruit total soluble solid content in SDI-2 increased by approximately 24% by the end of August compared to the control, leading to lower osmotic potential and higher turgor pressure during the following ripening stage. As skin growth ceased, high turgor pressure caused fruit cracking at the following ripening stage. The SDI-2 treatment demonstrated a fruit cracking rate approximately 1.5 times higher than that of the control. Pearson correlation analysis also indicated that fruit cracking was positively correlated with total soluble solids accumulated in August. Meanwhile, the yield of SDI-2 was reduced about 18%. Therefore, the adequate soil moisture during the fruit enlargement stage was crucial to minimize jujube fruit cracking and economic losses. Meanwhile, the deficit irrigation applied during the pre-enlargement stage could effectively conserve water resources and mitigate the occurrence of extensive jujube fruit cracking. Full article

Rice blast caused by Magnaporthe oryzae pathotype is the worst disease that leads to serious food insecurity globally. Understanding rice blast disease pathogenesis is therefore essential for the development of a blast disease mitigation strategy. Reverse phosphorylation mediated by phosphatases performs a vital function in the activation of diverse biological mechanisms within eukaryotic. However, little has been reported on the roles of PP2Cs in the virulence of blast fungus. In this current work, we deployed functional genomics and biochemical approaches to characterize type 2C protein phosphatase MoPtc6 in blast fungus. Deletion of MoPTC6 led to a drastic reduction in conidiophore development, conidia production, hyphal growth, and stress tolerance. Western blotting assay demonstrated that the phosphorylation level of MoOsm1 was decreased while MoMps1 was increased in the MoPtc6 deletion mutant, and comparative transcriptome assay revealed a higher number of expressed genes between mutant and wild type. Localization assay confirmed that MoPtc6 is sub-localized in the cytoplasm of mycelia, spores, and in the appressoria of M. oryzae. Furthermore, disruption of MoPTC6 impaired appressoria turgor pressure and glycogen utilization; more findings revealed attenuation of hyphal penetration and virulence upon deletion of MoPTC6. Generally, present findings suggested the role of MoPtc6 in the growth and virulence of M. oryzae. Full article

During clathrin-mediated endocytosis in yeast cells, a small patch of flat membrane is deformed into a tubular shape. It is generally believed that the tubulation is powered by actin polymerization. However, studies based on quantitative measurement of the actin molecules suggest that they are not sufficient to produce the forces to overcome the high turgor pressure inside of the cell. In this paper, we model the membrane as a viscous 2D fluid with elasticity and study the dynamic membrane deformation powered by a boundary lipid flow under osmotic pressure. We find that in the absence pressure, the lipid flow drives the membrane into a spherical shape or a parachute shape. The shapes over time exhibit self-similarity. The presence of pressure transforms the membrane into a tubular shape that elongates almost linearly with time and the self-similarity between shapes at different times is lost. Furthermore, the width of the tube is found to scale inversely to the cubic root of the pressure, and the tension across the membrane is negative and scales to the cubic root squared of the pressure. Our results demonstrate that boundary flow powered by myosin motors, as a new way to deform the membrane, could be a supplementary mechanism to actin polymerization to drive endocytosis in yeast cells. Full article

Arid and semiarid ecosystems face significant water scarcity due to high evaporation rates exceeding precipitation. This study examines temporal variations in water relations of two woody species, Vachellia schaffneri (S. Watson) Seigler & Ebinger, and Prosopis laevigata (Humb. & Bonpl. ex Willd.) M.C. Johnst, and one epiphyte, Tillandsia recurvata (L.) L. (Bromeliaceae), to assess their drought tolerance and water storage capacity. We hypothesized that species with greater water storage capacity would exhibit lower drought tolerance due to reduced osmotic adjustments, whereas species with lower storage capacity would maintain turgor through osmotic regulation and cell wall rigidity. Predawn and midday water potentials (Ψ_pd, Ψ_md) were measured, and pressure–volume (P–V) curves were used to derive parameters such as saturated water content (SWC), osmotic potential (π_o), turgor loss point (Ψ_TLP), relative water content at Ψ_TLP (RWC_TLP), bulk modulus of elasticity (ε), and full turgor capacitance (C_FT). Significant correlations were found between C_FT and Ψ_TLP (positive), π_o (positive), and ε (negative). P. laevigata and T. recurvata exhibited higher water storage capacities (41.46 and 26.45 MPa⁻¹, respectively) but had a lower ability to maintain cell turgor under drought conditions. In contrast, V. schaffneri exhibited the lowest water storage capacity (11.88 MPa⁻¹) but demonstrated the highest ability to maintain cell turgor (Ψ_TLP = −1.31 MPa) and superior osmotic adjustments (π_o = −0.59 MPa). Both V. schaffneri and P. laevigata exhibited rigid cell walls, whereas T. recurvata displayed greater elasticity in its cell structures. The lowest moisture content in V. schaffneri suggests increased flammability and fire spread potential. Future studies should focus on live fuel moisture content across more species, explore seasonal variations in hydraulic traits, and integrate these physiological parameters into fire risk models to enhance wildfire prediction and management. Full article

Harvest time is one of the key factors for obtaining high-quality cherry tomatoes. This parameter depends on environmental conditions and tomato variety. In plant factories with artificial lighting (PFALs), it is possible to control environmental conditions to enhance tomato production and quality. Since the ripening status of tomato fruit is correlated with cumulative temperature (CT), and the temperature inside PFALs can be easily controlled, CT could be used as an alternative method to predict tomato harvest time. In this study, three experiments were conducted to determine the optimal CT for harvesting high-quality cherry tomatoes in a PFAL. The experiments aimed to (1) evaluate the yield and quality of cherry tomatoes as affected by different harvest times based on CT (ranging from 900 to 1400 °C), (2) comparatively evaluate the yield and quality of cherry tomatoes that were still on the plant and off the plant (in storage) based on the same CT levels (i.e., 1100, 1200, and 1300 °C), and (3) investigate the fruit-cracking percentage during the ripening stage based on CT levels. The results showed that the fruit harvested at lower CTs exhibited higher hardness values, while those harvested at higher CTs had a higher sugar content. The on-the-plant treatment resulted in a higher yield and sugar content compared with the off-the-plant treatment, indicating that harvesting tomatoes early would come at the expense of a certain yield and sweetness. Moreover, the fruit-cracking percentage tended to increase with increasing CT, possibly due to the fast fruit growth rate and increased internal turgor pressure. These results indicated that producers can use CT as an index to predict the harvest time, thereby optimizing profits in cherry tomato production. Full article

Poplar is an economically and ecologically valuable tree species. Anthracnose, which severely affects poplar tree growth, is mainly caused by Colletotrichum gloeosporioides. In the infestation cycle of poplar anthracnose, the entry of C. gloeosporioides into the host tissue depends on the formation of an appressorium. The subsequent development of the appressorium determines the pathogenesis of poplar anthracnose and the degree of damage. Previous studies have found that the transcription factor CgSte12 affects appressorium formation and development by regulating the expression of a series of genes, including the sterol-synthesis-related gene CgCYP51, which influences appressorium formation and development. In this study, knockout and functional analyses of CgCYP51 revealed decreases in differentiation, darkening rate, and turgor pressure of appressoria in mutants. Additionally, compared with the wild-type appressorium, mutant appressoria secreted less mucus and exhibited abnormal penetration pore formation, ultimately leading to decreased pathogenicity. Moreover, CgCyp51 affected the sensitivity of C. gloeosporioides to sterol biosynthesis inhibitors. Considered together, the study findings indicate CgCYP51 is a key CgSte12-regulated gene that affects C. gloeosporioides appressorium formation and development. Furthermore, the study data provide new insights into the molecular basis of C. gloeosporioides appressorium formation and development. Full article