Search Results (972)

Thidiazuron, 6-benzylaminopurine riboside, and meta-topolin are cytokinins often used in apple tissue cultures. Three different CK-containing Murashige and Skoog media were used during the experiments: medium without CK or media containing 4.5 μM thidiazuron, 4.5 μM 6-benzylaminopurine riboside, or 4.5 μM meta-topolin, respectively. Comparative ultrastructural studies across cytokinin types and apple cultivars were lacking. We studied the changes in photosynthetic pigment content of the leaves with absorption spectroscopy and chloroplast structure with light and transmission electron microscopy. At the light microscopy level, large changes were detected in the length and length-to-width ratios of the chloroplasts in the spongy and palisade mesophyll cell sections in 6-benzylaminopurine riboside- and meta-topolin-treated leaves of the McIntosh scion. In the chloroplasts of the McIntosh plants treated with 6-benzylaminopurine riboside and meta-topolin, and Húsvéti rozmaring leaves treated with meta-topolin, the diameter of grana increased. In both cultivars, thidiazuron caused the height of grana to increase. Thidiazuron and 6-benzylaminopurine riboside influenced leaf anatomy both in the Húsvéti rozmaring and McIntosh cultivars. 6-benzylaminopurine riboside and thidiazuron treatments reduced the content of photosynthetic pigments in the in vitro leaves of both cultivars. In contrast, meta-topolin treatment had no significant effect on the chlorophyll content as compared to the control. Differences were observed not only among the effects of cytokinins, but even between the two apple scions examined. In in vitro apple shoot cultures, TOP maintained chloroplast integrity and pigment content, whereas TDZ exerted stress-like effects. Full article

Fusarium spp. cause devastating crop diseases and produce carcinogenic mycotoxins such as fumonisins, threatening global food safety and human health. In this study, Trichoderma longibrachiatum A25011, isolated from apples in Aksu, Xinjiang, exhibited significant antagonistic activity with mycelial growth inhibition rates of 54.52% against F. verticillioides 48.62% against F. proliferatum, and 58.22% against F. oxysporum in confrontation assays. Enzyme activity detection revealed high chitinase (583.21 U/mg protein) and moderate cellulase (43.92 U/mg protein) production, which may have the capacity to degrade fungal cell walls. High-Performance Liquid Chromatography–Mass Spectrometry (HPLC-MS/MS) analyses enabled the quantification of fungal hormones including gibberellin A3 (GA3, 2.44 mg/L), cytokinins (cis-zeatin riboside (CZR): 0.69 mg/L; trans-zeatin riboside (TZR) : 0.004 mg/L; kinetin: 0.006 mg/L), and auxins (indole-3-acetic acid (IAA) : 0.35 mg/L; abscisic acid: 0.06 mg/L). Application of a T. longibrachiatum A25011 spore suspension around the roots of peanut plants enhanced growth by 13.20% (height), 5.65% (stem and leaf biomass), and 39.13% (root biomass). Notably, A25011 reduced F. proliferatum-derived fumonisin accumulation in rice-based cultures by 93.58% (6 d) and 99.35% (10 d), suggesting biosynthetic suppression. The results demonstrated that T. longibrachiatum strain A25011 exhibited excellent biocontrol capability against Fusarium spp., proving its dual role in simultaneously suppressing fungal growth and fumonisin accumulation while promoting plant growth. T. longibrachiatum A25011 could be applied as a multifunctional biocontrol agent in sustainable agriculture in the future. Full article

Grafting is a pivotal horticultural technique for enhancing vegetable crop productivity; however, the specific molecular mechanisms governing rootstock-induced vigor remain insufficiently elucidated. This study deciphers how bottle gourd rootstock augments growth in melon scions through an integrated approach combining physiology, transcriptomics, phytohormone profiling, and functional genetics. Phenotypic analysis confirmed a significant increase in plant height, fresh weight, and stem diameter in heterografted scions compared to controls. Transcriptome sequencing of scion apices identified 663 core differentially expressed genes (DEGs) specifically modulated by the bottle gourd rootstock. These DEGs were prominently enriched in carbohydrate metabolism and plant hormone signal transduction pathways. Consistent with this, hormonal assays revealed a specific elevation in cytokinin and ethylene levels in the scion, accompanied by the upregulation of key pathway genes, including MELO3C016881 (LOG) and MELO3C007769 (ERF060). Crucially, virus-induced gene silencing of either gene completely abolished the rootstock-conferred growth advantage. Our findings preliminarily unveil the secret behind scion vigor, providing a foundational mechanistic framework for how rootstocks reprogram scion development. The identified genes, MELO3C016881 and MELO3C007769, offer direct molecular targets for the precision breeding of superior scions in melon. Full article

Microbial volatile metabolites can enhance plant growth, yet the mechanisms by which plants perceive and transduce these signals are unknown. Growth of Arabidopsis thaliana Col-0 seedlings was found to be stimulated by volatiles from the soil bacterium Streptomyces coelicolor. To investigate volatile-responding candidate signaling molecules and genes, cultivation of seedlings in gas-phase contact with S. coelicolor genotypes was combined with GC-MS and plant transcriptomics. Components potentially involved were further studied using pure compounds and A. thaliana T-DNA mutants. Application of volatiles from S. coelicolor enhanced the growth of A. thaliana seedlings primarily by stimulating lateral root growth rate and inhibiting primary root extension. Concurrently, a family-wide induction of the Kelch-repeat F-box gene family KISS ME DEADLY (KMD) was observed. A. thaliana genotypes with a loss of function for the KMD family or other alterations of auxin/cytokinin signaling homeostasis suppressed the root response to both S. coelicolor total volatiles and the common microbial volatile 3-octanone. The results reveal a novel function of KMDs in mediating plant growth stimulation in response to volatile stimulation that alters auxin/cytokinin signaling and emphasize rhizospheric microbials as potential indicators of soil status to plants. Full article

Using the cotyledonary node method, four traits related to callus induction rate were identified in 185 soybean germplasm resources. Cultivation of callus tissue is crucial for soybean (Glycine max (L.) Merr.) genetic transformation and functional genomics studies. Identifying genes associated with the induction rate of soybean callus tissue is therefore essential for biotechnological breeding and for understanding the molecular genetic mechanisms of soybean regeneration. The efficiency of genetic transformation impacts the breeding rate of soybeans, with its success rate dependent on the soybean regeneration system. Subsequently, whole genome association analysis (GWAS) and multidimensional functional validation were conducted. GWAS identified 66 significantly associated SNP loci corresponding to the four traits. Expression analysis in extreme phenotypes highlighted four candidate genes: Glyma.12G164100 (GmARF1), Glyma.12G164700 (GmPPR), Glyma.02G006200 (GmERF1), and Glyma.19G128800 (GmAECC1), which positively regulate callus formation. Overexpression and gene-editing assays in hairy roots confirmed that these genes significantly enhanced callus formation rate and density, with GmARF1 exerting the most prominent effect. Hormone profiling revealed elevated levels of gibberellin (GA), auxin (IAA), cytokinin (CTK), and other phytohormones in transgenic lines, consistent with enhanced responsiveness to exogenous GA. Overall, the results suggest that these four candidate genes may promote soybean regeneration, with GmARF1 showing the most pronounced effect. These results provide valuable genetic resources for improving soybean regeneration efficiency and accelerating genetic transformation-based breeding. Full article

The Dendrobium genus originates from tropical and subtropical regions of Asia, extending to northern Australia. Species and hybrids of this genus, including Dendrobium phalaenopsis Sa-Nook ‘Thailand Black’, are the second most popular cultivars worldwide. To meet this demand, it is necessary to implement techniques such as micropropagation, which allows the mass production of plants. The objective of this study was to evaluate the effect of plant growth regulators (NAA, BA, and TDZ) on the in vitro regeneration of D. phalaenopsis Sa-Nook ‘Thailand Black’ plants, their acclimatization, and production costs. Rootless shoots of 1–1.5 cm in height were grown on 50% MS medium supplemented with BA (0, 2.22, 4.44, or 8.88 µM), TDZ (0, 2.27, 4.54, or 9.08 µM), and NAA (0 or 2.69 µM), individually or in combination. After the second phase of in vitro shoot growth, the highest number of shoots per explant (8.5) was observed with 9.08 µM of TDZ. Plants regenerated with this concentration of TDZ showed the highest survival rate (96%) at 90 days of greenhouse cultivation, as well as the formation of new shoots (0.9), and the lowest production cost per plant (0.49 USD). Full article

Secondary somatic embryogenesis (SSE) represents a powerful tool for clonal propagation, efficient genetic modification, and plant conservation, enabling the continuous production of secondary somatic embryos (SSEs) from previously formed embryogenic tissues. The efficiency of SSE is determined both by external factors such as exogenous hormonal and environmental conditions and internal cues such as explant type and genotype. Auxins, particularly synthetic 2,4-dichlorophenoxyacetic acid (2,4-D), represent key factors in inducing and maintaining embryogenic competence, while cytokinins often modulate the differentiation and proliferation of SSEs. The interplay of plant growth regulators (PGRs) not only affects the frequency of SSE induction, but also the morphology and proper development of the resulting embryos. Here, we provide a comprehensive review on hormonal treatments, especially the role of auxins and cytokinins and environmental factors such as temperature, light, and culture medium composition, that shape the embryogenic potential in SSE, with species-specific responses frequently being observed. The importance of primary explant selection, as well as the liquid phase and potential scale-up with bioreactors, are also discussed. Other challenges related to genotype recalcitrance, limited efficiency, maturation and conversion rates, and the lack of an advanced molecular approach are further addressed, providing a framework for improved regeneration and reliability across diverse species. Full article

A new class of plant phosphotransfer proteins belonging to the multistep phosphorelay (MSP) system implicated in phytohormone cytokinin signaling was discovered based on large-scale bioinformatics methods. Unlike the canonical soluble nucleo-cytosolic forms, these proteins were predicted to have transmembrane (TM) domains and, apparently, should be localized on some kind of cell membrane. To date, 94 predicted TM-containing phosphotransmitter (TM-HPt) homologs were found in 62 plant species belonging to different clades, taxa, and groups of embryophytes: bryophytes, gymnosperms, and mono- and dicotyledons. The conserved HPt motif with phosphorylatable histidine was preserved in most of the TM-HPts under study, which allowed us to consider these proteins potentially active in MSP signaling. For the identified TM-HPts, a Bayesian analysis at the DNA level was performed, and a relevant phylogenetic tree was constructed. According to evolutionary relationships, plant TM-HPts were divided into two main groups corresponding to Arabidopsis AHP1-3,5,6, and AHP4 orthologs. Transcriptomic analysis confirmed the expression of most of the investigated TM-HPt-encoding genes. Their moderate-to-low overall transcription rate may be a consequence of inducible and/or tissue-specific expression. Using molecular modeling methods, a variety of potential spatial organizations of several such proteins are demonstrated. The ability of the uncovered TM domains to tether HPts to membranes was supported by molecular dynamic simulation. Possible roles of TM-HPts as modulators of the MSP signaling pathway and corresponding putative mechanisms of their action are suggested. Full article

The grain-filling stage is crucial for determining yield and quality in rice. This process, and the pronounced disparity in development between superior and inferior grains, is orchestrated by a dynamic network of endogenous phytohormones. However, an integrated synthesis of their synthesis, transport, signaling, and crosstalk—particularly in the context of modern high-yield cultivation—is lacking. This review comprehensively analyzes the roles of auxin, cytokinin, gibberellin, abscisic acid, ethylene, brassinosteroids, and polyamines, with emphasis on their spatiotemporal dynamics and interactions in shaping grain fate. We explicitly link these hormonal mechanisms to agronomic and chemical regulation practices, such as nitrogen management and alternate wetting-drying irrigation. By synthesizing this knowledge, we aim to propose a unified model of grain filling regulation. This framework provides an actionable theoretical foundation for designing precise strategies to manipulate hormonal balances, thereby improving grain filling uniformity, yield, and quality in rice. Full article

Citrus species develop fruits through both sexual reproduction and parthenocarpy, following a growth pattern with an initial exponential phase dominated by cell division in the ovary wall, followed by a linear phase driven by cell expansion in juice vesicles. Sustained carbohydrate supply is essential to support the metabolic energy required for these processes, which are tightly regulated by hormonal signaling pathways involving gibberellins (GAs), auxins (IAA), cytokinins, and abscisic acid (ABA). Recent studies across cultivars have identified genes associated with hormone biosynthesis, carbohydrate metabolism, cell cycle regulation, and abscission in ovule and pericarp tissues. Manipulation of these hormones through targeted treatments and cultural practices has shown potential to enhance fruit set and growth. Notably, exogenous GA₃ application promotes fruit set in parthenocarpic cultivars by upregulating GA20ox2/GA3ox and CYCA1.1, whereas synthetic auxins enhance fruit enlargement by improving assimilate partitioning and water uptake. Optimizing such treatments, however, requires a comprehensive understanding of physiological, environmental, and agronomic factors influencing fruit development. This review summarizes recent advances in hormonal and molecular regulation of citrus fruit set and developments, assesses applied strategies to improve productivity, and identifies current knowledge gaps needed to refine biotechnological and management aimed at enhancing both yield and fruit quality. Full article

Mustard (Brassica juncea), an essential leaf and oil crop in China, exhibits notable yield potential and adaptability, both of which are influenced by the morphology of the leaf margin. Despite its agronomic importance, the genetic regulatory mechanisms governing this trait remain poorly understood, posing a challenge to molecular breeding efforts. In this study, mustard varieties with lobed and non-lobed leaf margins were used to systematically investigate the genetic basis of leaf margin differentiation through BSA-seq, RNA-seq, and bioinformatics analyses. BSA-seq screening identified four LMI1 homologous genes, including BjuOA10G33260, which may fissure the leaf margin by suppressing cytokinin signaling. RNA-seq analysis revealed significant enrichment of ethylene and growth hormone pathways during key stages of leaf development (at 12 days post-sowing). Integrated analysis of BSA-seq and RNA-seq data identified 15 genes involved in leaf morphogenesis, including BjuOB05G34700 (ADF4, an actin depolymerization factor), BjuOA08G35830 (GATA transcription factor 11), BjuOA09G42060 (ERF transcription factor), and BjuOA07G29650 (GATA transcription factor). Notably, BjuOA10G30380 (TGA2) and BjuOA10G34680 (LAX1) may regulate cytoskeletal dynamics and hormonal signaling, contributing to the development of leaf morphology. This study presents the first molecular network regulating the morphogenesis of the leaf edge in mustard, offering a theoretical foundation and valuable genetic resources for breeding new varieties with optimized leaf architecture. Full article

Branching traits play a critical role in shaping the tree structure of fruit crops and directly influence both yield and fruit quality. Effective and well-managed branching is crucial for maximizing productivity. However, loquat trees typically exhibit weak branching ability, characterized by fewer and longer bearing shoots, along with terminal flower buds, which collectively result in lower yields per unit area. Despite their significance, research on branching characteristics in loquat remains limited. To clarify the factors influencing branching and to provide a rational and effective direction for improving the inherently weak branching performance of current loquat cultivars, we selected the loquat varieties ‘Dawuxing’ and ‘Chunhua 1’, which exhibit significant differences in leaf and branch growth. Compared to ‘Dawuxing’, ‘Chunhua 1’ has longer branches, wider stem and leaf angles, fewer lateral branches, and a looser leaf cell structure. Transcriptome analysis of terminal buds at different developmental stages revealed that differentially expressed genes in the terminal buds of central branches from the spring and summer shoots of the two cultivars were enriched in the plant hormone signal transduction pathway. Hormone-targeted metabolomics identified significant differences in the levels of abscisic acid, auxins, cytokinins, gibberellins, jasmonic acid, and strigolactones in the terminal buds of both cultivars. Through integrated analysis, two candidate genes were identified as potential regulators of branching differences between the two cultivars: EVM0025028 (EjSAPK1), SnRK2 gene a core component of the abscisic acid signaling pathway, and EVM0040331 (EjRMS3), a D14 gene involved in encoding a strigolactone receptor. These findings provide valuable genetic resources for future research on branching regulation in Eriobotrya species and offer a theoretical foundation for enhancing branching management in loquat cultivation. Full article

The inhibition of low-position tillering in machine-transplanted seedlings affects rice yields. Paclobutrazol (PBZ) is a plant growth regulator that can improve seedling quality and promote low-position tillering in machine-transplanted seedlings. However, the physiological mechanisms underlying the promotion of tiller bud formation induced by exogenous PBZ via sucrose transport remain unclear. Thus, rice cultivar ‘Yongyou 12’ was used to analyze the effects of different seeding rates and the application of exogenous PBZ, gibberellin (GA₃), and water (control) on sucrose transport and metabolism as well as tiller bud development. Exogenous PBZ application combined with a low seeding rate significantly increased the number of tillers as well as seedling fullness (by 42.35%). Increases were also detected for the seedling cytokinin content, chlorophyll content (by 10.55%), and sucrose transport from leaves to the stem base. These changes were associated with the upregulated expression of sucrose transporter genes in leaves and the stem base, as well as increased activities of key sucrose-metabolizing enzymes in the stem base. Notably, the opposite trend was observed after exogenous GA₃ was applied or a high seeding rate was used. Hence, a low seeding rate combined with exogenous PBZ application is useful for controlling seedling height, promoting the formation of low-position tillering, facilitate sucrose translocation from leaves to the stem base, and increasing sucrose metabolism in the basal part of rice plants. These findings provide a theoretical basis for optimizing low-position tillering in machine-transplanted seedlings. Full article

Root pruning affects the ability of roots of Quercus variabilis Blume to absorb water and nutrients. Suillus grevillea can form a mutualistic symbiosis with Quercus variabilis Blume. A pot experiment in three compartments with two inoculation treatments (inoculation with Suillus grevillea and noninoculation control) and four different root pruning treatments (0, 1/4, 1/3, and 1/2 of the main root length pruned) was conducted. The shoot dry weight, root dry weight, shoot and root N, P and K contents, root morphological and physiological parameters of Quercus variabilis Blume seedlings, and soil properties were measured. The results showed that root pruning affected root endogenous hormone levels, root morphology, shoot and root nutrient absorption, and biomass accumulation. Compared with those without inoculation, the shoot dry weight, root dry weights, shoot and root N, and P and K contents of inoculated plants were greater, regardless of the degree of root pruning. The root length, root projection area, root surface area, root average diameter, root density, root volume, and root tip number increased in response to Suillus grevillea. The root auxin (IAA), cytokinin (CTK), gibberellin (GA), zeatin riboside (ZR), and salicylic acid (SA) contents were greater in inoculated Quercus variabilis Blume seedlings than in noninoculated plants. Inoculation with Suillus grevillea improved the soil microenvironment around the seedlings. Suillus grevillea can compensate for the adverse effects of root pruning on nutrient absorption, root morphological and physiological growth and the soil properties of Quercus variabilis Blume seedlings. Full article

Fruit cracking in jujube is a major constraint on the sustainable development of the jujube industry. In this study, 60 mg L⁻¹ of 6-Benzylaminopurine (6-BA) was foliar-sprayed at the early fruit stage. Fruit cracking incidence was recorded during the green and white fruit periods, and these observations were integrated with transcriptomic and metabolomic analyses to explore the potential mechanisms by which 6-BA influences fruit cracking. The results showed that the fruit cracking in the treatment groups was 53% and 18% of that in the control group during the green period and the white period, respectively. In jujube peel, catalase (CAT) activity was significantly increased in the treated peel during both periods. In the peel metabolites, compounds belonging to the cytokinin (CTK) category exhibited significant accumulation in both periods. Transcriptomic analysis showed that differentially expressed genes (DEGs) were enriched in pathways related to starch and sucrose metabolism, plant hormone signal transduction, and cellular polysaccharide metabolism. These findings suggest that 6-BA treatment may alleviate jujube fruit cracking by enhancing antioxidant capacity, modulating hormone homeostasis, and upregulating genes associated with carbohydrate and cell wall metabolism. Full article