Search Results (112)

Dense planting and intercropping are the main ways to improve soybean production. However, both confront inter- and intra-crop shading stress. This leads to stem elongation, resulting in lodging and yield losses. Most previous studies have focused on the later growth stages for shade tolerance. However, it has been found that the seedling stage is crucial, and understanding the genetic basis of shade tolerance at this stage is pivotal for yield improvement. In this study, 310 soybean accessions were used to evaluate shade tolerance under greenhouse conditions. Plant height (PH), main stem length (MSL), and hypocotyl length (HL) were examined at seedling stage, and their treatment/control ratios (PH_r, MSL_r, HL_r) were used for genetic dissection of shade tolerance. Their overall phenotypic variation and heritability (H²) ranged 22.97–36.85% and 31.66–83.81%, respectively. RTM-GWAS identified 12, 10, and 6 QTLs associated with PH_r, MSL_r, and HL_r, respectively. Among these, Block_17_11907536_11926235 was associated with both PH_r and MSL_r, and Block_1_55630414_55715065 associated with the HL_r trait showed the highest contribution (R² = 10.38%). Additionally, seven promising candidate genes, primarily linked to ethylene-responsive transcription factors, were proposed, supported by their established roles in plant development and stress responses, as evidenced in prior studies. The germplasm, QTLs, and candidate genes identified in this study improve our understanding of shade tolerance and have the potential to accelerate the breeding of shade-resilient soybeans. Full article

Root-knot nematodes (RKNs), specifically Meloidogyne incognita, are notoriously difficult to eliminate as endophytic nematodes, and cause severe damage to various plants. Cucumber (Cucumis sativus), which is a cash crop widely grown across the world, is often infected by RKNs. ELONGATED HYPOCOTYL5 (HY5), a member of the bZIP transcription factor family, plays a vital role in hormone, nutrient, abiotic stress, biotic stress, and oxygen species (ROS) signaling pathways. However, the involvement of HY5 in the defense against RKNs has rarely been reported. The present study initially explored the response of CsHY5 to RKNs. The results indicated that the hy5 mutant had a higher number of nematodes and galls in the root system and exhibited a higher susceptibility to RKNs compared with the wild type (WT). Particularly, the root-knot nematodes in hy5 plants completed their life cycle more quickly and produced more eggs. The activities of defense-related hormones and antioxidant enzymes were measured, and the results indicated that JA, jasmonoyl-isoleucine (JA-Ile), abscisic acid (ABA), peroxidase (POD), and ascorbate peroxidase (APX) were significantly elevated in the wild type, but were not induced or decreased in the mutant. Through transcriptome sequencing analysis and quantitative real-time PCR (qRT-PCR), it was found that when RKNs infect plants, the key genes of jasmonic acid (JA) synthesis, CsAOC and CsAOS, as well as the key gene of the antioxidant system, CsPOD, were all significantly induced. Nevertheless, this induction effect disappeared in the hy5 mutant. Generally, CsHY5 plays a role in the response of cucumber to RKNs, and its deletion increases the sensitivity of cucumber to RKNs. These results suggest that CsHY5 may affect the resistance of cucumber to RKNs by affecting antioxidant enzyme activities and hormone content. Full article

Blue light serves as a critical environmental cue regulating Glycine max (soybean) stem morphology, yet the hormonal mechanisms underlying varietal differences remain unclear. Previous studies have highlighted the role of blue light in modulating plant architecture, but the specific hormone interactions driving morphological divergence between soybean varieties remain underexplored. Two soybean varieties with contrasting stem phenotypes—Henong 60 (HN60, tall) and Heinong 48 (HN48, dwarf)—were subjected to 0% (full light) and 30% (shade) transmittance conditions, supplemented with blue light (450 nm, 45.07 ± 0.03 μmol·m⁻²·s⁻¹). Stem anatomical traits (xylem area, cell length), hormone profiles, and proteomic changes were analyzed. Grey correlation analysis quantified relationships between hormone ratios and plant height. Blue light increased soybean stem xylem area and diameter while reducing plant height and cell longitudinal length. This treatment concurrently reduced growth-promoting hormones (gibberellin A₃ (GA₃), indole-3-acetic acid (IAA), brassinolide (BR)) and increased growth-inhibiting hormones (salicylic acid (SA), jasmonic acid (JA), strigolactones (SLs)), thereby inhibiting stem elongation. Although exogenous GA₃ promoted hypocotyl elongation, it failed to counteract blue-light-induced inhibition. Proteomic analysis identified 16 differentially expressed proteins involved in hormone signal transduction pathways. Grey correlation analysis highlighted cultivar-specific hormone ratio impacts: GA₃/JA, GA₃/SA, and BR/SLs significantly influenced HN60 plant height, while GA₃/SLs, IAA/SLs, and BR/SLs were critical for HN48, demonstrating highly significant positive correlations. The differential sensitivity of growth-promoting/inhibiting hormone ratios to blue light drives varietal morphological divergence in soybean stems. This study establishes a hormonal regulatory framework for blue-light-mediated stem architecture, offering insights for crop improvement under light-limited environments. Full article

Coumarins are natural products commonly found in plants and are typical allelopathic substances that strongly affect the growth of plants after being exudated from the root and help plants absorb Fe in cases of iron deficiency. Although coumarins have been found to have multiple effects, this understanding is still relatively limited. Here, we show that coumarin significantly promotes the elongation of the hypocotyl by enhancing cell elongation. Further research has found that coumarin increases the content of BR in plants by enhancing the expression of brassinosteroid (BR) synthesis genes. The effect of coumarin on promoting hypocotyl elongation is completely blocked by the mutation of the BR synthesis gene DEETIOLATED 2 (DET2) or the co-addition of the BR synthesis inhibitor brassinazole (BRZ). Genetic analysis using Arabidopsis mutants showed that coumarin promoting hypocotyl elongation depends on the signaling pathway of the BRs. Overall, coumarin promotes elongation of the hypocotyl by increasing the synthesis of BRs in plants. These results provide us with new insights into the role of coumarins and offer strong theoretical support for the mechanisms of interactions between plants. Full article

Hypocotyl length is closely related to quality in seedlings and is an important component of plant height vital for plant-type breeding in cucumber. However, the underlying molecular mechanisms of hypocotyl elongation are poorly understood. In this study, the endogenous hormone content of indole acetic acid (IAA) and gibberellin (GA₃) showed an increase in the long hypocotyl Csphyb (phytochrome B) mutant AM274M compared with its wild-type AM274W. An RNA-sequencing analysis identified 1130 differentially expressed genes (DEGs), of which 476 and 654 were up- and downregulated in the mutant AM274M, respectively. A KEGG enrichment analysis exhibited that these DEGs were mainly enriched in the plant hormone signal transduction pathway. The expression levels of the pivotal genes CsGA20ox-2, in the gibberellin biosynthesis pathway, and CsYUCCA8, in the auxin biosynthesis pathway, were notably elevated in the hypocotyl of the mutant AM274M, in contrast to the wild-type AM274W. Additionally, GUS staining and a dual-luciferase reporter assay corroborated that the phytochrome-interacting factors CsPIF3/4 can bind to the E(G)-box motifs present in the promoters of the CsGA20ox-2 and CsYUCCA8 genes, thereby modulating their expression and subsequently influencing hypocotyl elongation. Consequently, this research offers profound insights into the regulation of hypocotyl elongation by auxin and gibberellin in response to light signals and establishes a crucial theoretical groundwork for cultivating robust cucumber seedlings in agricultural practice. Full article

Sunflower is a crop species well adapted for cultivation in open fields under full sunlight. Young plantlets can be grown in growth chambers under low irradiance, where different aspects of light can be easily tracked. Using time-lapse imaging, we have shown how monochromatic red, blue, and far-red light and their combinations interacted, affecting the rhythmicity and elongation of sunflower hypocotyls. Monochromatic light of any color, applied individually, canceled all manifestations of diurnal rhythmicity and anticipation of imminent light transitions present in diurnal photoperiods established by white LED light panels. Monochromatic light also significantly increased the rate of hypocotyl elongation, which became uniform (arrhythmic) and often triggered the appearance of guttation. The rate of hypocotyl elongation was highest with the blue light and lowest with red light. In double light combinations, red light suppressed the stimulative effect of blue light, but it promoted the elongation rate when used together with far-red light. A triple light combination of red, blue, and far-red light stimulated hypocotyl elongation to a high degree and increased the elongation rate more than twofold compared with red and fourfold compared with white LED light. Full article

Arabidopsis thaliana LEAFY COTYLEDON1 (LEC1) gene is shown to have numerous diverse functions in plant development, including the regulation of embryo morphogenesis and maturation, hypocotyl elongation, flowering transition, etc. However, the functions of LEC1 orthologs in different plant species have not been extensively studied. In this study, we obtained a line of Medicago truncatula, a model leguminous plant, carrying the loss-of-function mutation in the MtLEC1 (MtNF-YB10) gene, orthologous to LEC1, using the Clustered Regularly Interspaced Short Palindromic Repeats/CRISPR-associated proteins (CRISPR/Cas9) genome editing system. Edited plants with loss of MtNF-YB10 function did not demonstrate any severe abnormalities during their normal growth and gave viable seeds, but their capability for somatic embryogenesis in vitro was dramatically reduced. The T1 progeny of unedited plants with a Cas9-gRNA cassette insertion was also analyzed based on the suggestion that editing could occur during seed formation. However, no edited plants were found in the T1 generation. These results suggest divergent functions of LEC1 orthologs and make it possible to investigate potential specific MtNF-YB10 functions. Full article

Plants of several species, including crops, change their volatilome when exposed to a low ratio of red to far-red light (low R/FR) that informs about the presence of nearby plants (i.e., proximity shade). In particular, the volatile hormone ethylene was shown to be produced at higher levels in response to the low R/FR signal in shade-avoider plants. Here, we show that the shade-tolerant species Cardamine hirsuta produces more ethylene than shade avoiders such as Arabidopsis thaliana (a close relative of C. hirsuta) and tomato (Solanum lycopersicum) under white light (W). However, exposure to low R/FR (specifically to FR-supplemented W, referred to as W+FR or simulated shade) resulted in only a slight increase in ethylene emission in C. hirsuta compared to shade avoiders. Stimulation of ethylene production by growing plants in media supplemented with 1-aminocyclopropane-1-carboxylate (ACC) resulted in reduced hypocotyl growth under W+FR in both A. thaliana and C. hirsuta. ACC-dependent ethylene production also repressed hypocotyl elongation under low W and in the dark in C. hirsuta. By contrast, in A. thaliana, ACC supplementation inhibited hypocotyl elongation in the dark but stimulated it under W. Most interestingly, elongation of dark-grown A. thaliana seedlings was also repressed by exposure to the volatiles released by ACC-grown A. thaliana or tomato plants. This observation suggests that increased ethylene levels in the headspace can indeed impact the development of nearby plants. Although the amount of ethylene released by ACC-grown plants to their headspace was much higher than that released by exposure to low R/FR, our results support a contribution of this volatile hormone on the communication of proximity shade conditions to neighboring plants. Full article

Genes involved in iron deficiency responses have been well characterized in Arabidopsis thaliana, but their roles in crop species have not been well explored. Reliance on model species may fail to identify novel iron stress mechanisms present within crop species, likely selected by hundreds of years of selection. Fiskeby III (PI 438471) is a soybean line from Sweden that demonstrates high levels of resilience to numerous stresses. Earlier Fiskeby III studies have identified a suite of genes responding to iron deficiency stress in Fiskeby III that are also associated with Arabidopsis iron deficiency responses. We were interested in determining how canonical iron genes function in Fiskeby III under normal and iron stress conditions. To investigate this, we used virus-induced gene silencing to knock down gene expression of three iron deficiency response genes (FER-like iron deficiency induced transcription factor (FIT), elongated hypocotyl 5 (HY5) and popeye (PYE)) in Fiskeby III. Analyses of RNAseq data generated from silenced plants in iron-sufficient and -deficient conditions found silencing FIT and HY5 altered general stress responses but did not impact iron deficiency tolerance, confirming Fiskeby III utilizes novel mechanisms to tolerate iron deficiency stress. Full article

The uniformity of growth and mechanical properties of grafted seedlings affect the quality of mechanical grafting operations. The growth uniformity of grafted seedlings in a greenhouse will be poor due to the uneven and unstable light and temperature conditions. Plant factories can cultivate grafted seedlings in the most suitable environment by regulating environmental parameters such as light and temperature. The aim of this study was to investigate the impact of the light conditions on tomato seedlings in plant factory and to develop an optimal cultivation light formula. The effects of light intensity (50, 100, 150, 200, and 250 μmol m⁻² s⁻²) and photoperiod (10, 12, 14, 16, and 18 h a day(h/d)) on the morphological and mechanical properties of tomato seedlings were experimentally investigated. Orthogonal experiments were conducted involving light quality (R:B = 75:25, R:B = 50:50, and R:B = 25:75), light intensity (150 μmol m⁻² s⁻², 200 μmol m⁻² s⁻², and 250 μmol m⁻² s⁻²), and photoperiod (14, 16, and 18 h/d) as independent variables to determine the optimal combination. Finally, a comparative grafting experiment was conducted between the seedlings cultivated using the optimal light formula and commercially available seedlings. The result showed that increasing light intensity inhibited hypocotyl length and promoted seedling stem growth, and excessive light intensity decreased seedling mechanical properties. The optimal light intensity for rootstocks is 200 μmol m⁻² s⁻², and the optimal light intensity for scions is 250 μmol m⁻² s⁻². Shortening the photoperiod would promote hypocotyl growth and inhibit seedling stem elongation. Different photoperiods had a significant impact on the mechanical properties of tomato seedlings. The most suitable photoperiod for rootstocks was 18 h/d and for scions was 16 h/d. The most suitable light formula was R:B = 50:50, 250 μmol m⁻² s⁻², 18 h/d. By analyzing the experimental results, the mechanical properties of seedlings grown by the regulated light environment were better than those of commercially available seedlings, and the success rate of mechanical grafting was 7% higher. Overall, in plant factories compared to commercially available tomato seedlings, tomato seedlings cultivated by the regulated light environment were more suitable for mechanical grafting. This research result provides theoretical support for subsequent research on grafting machinery. Full article

Deep sowing, as a method to mitigate drought and preserve soil moisture and seedlings, can effectively mitigate the adverse effects of drought stress on seedling growth. The elongation of the hypocotyl plays an important role in the emergence of maize seeds from deep-sowing stress. This study was designed to explore the function of exogenous methyl jasmonate (MeJA) in the growth of the maize mesocotyl and to examine its regulatory network. The results showed that the addition of a 1.5 μ mol L⁻¹ MeJA treatment significantly increased the mesocotyl length (MES), mesocotyl and coleoptile length (MESCOL), and seedling length (SDL) of maize seedlings. Transcriptome analysis showed that exogenous MeJA can alleviate maize deep-sowing stress, and the differentially expressed genes (DEGs) mainly include ornithine decarboxylase, terpene synthase 7, ethylene responsive transcription factor 11, and so on. In addition, candidate genes that may regulate the length of maize hypocotyls were screened by Weighted Gene Co-expression Network Analysis (WGCNA). These genes may be involved in the growth of maize hypocotyls through transcriptional regulation, histones, ubiquitin protease, protein binding, and chlorophyll biosynthesis and play an important role in maize deep-sowing tolerance. Our research findings may provide a theoretical basis for determining the tolerance of maize to deep-sowing stress and the mechanism of exogenous hormone regulation of deep-sowing stress. Full article

Much work has been dedicated to the quest to determine the structure–activity relationship in synthetic brassinosteroid (BR) analogs. Recently, it has been reported that analogs with phenyl or benzoate groups in the alkyl chain present activities comparable to those shown by natural BRs, depending on the nature of the substituent in the aromatic ring. However, as it is well known that the activity depends on the structure of the whole molecule, in this work, we have synthesized a series of compounds with the same substituted benzoate in the alkyl chain and a hydroxyl group at C3. The main goal was to compare the activities with analogs with -OH at C2 and C3. Additionally, a molecular-docking study and molecular dynamics simulations were performed to establish a correlation between the experimental and theoretical results. The synthesis of eight new BR analogs was described. All the analogs were fully characterized by spectroscopical methods. The bioactivity of these analogs was assessed using the rice lamina inclination test (RLIT) and the inhibition of the root and hypocotyl elongation of Arabidopsis thaliana. The results of the RLIT indicate that at the lowest tested concentration (1 × 10⁻⁸ M), in the BR analogs in which the aromatic ring was substituted at the para position with methoxy, the I and CN substituents were more active than brassinolide (50–72%) and 2–3 times more active than those analogs in which the substituent group was F, Cl or Br atoms. However, at the highest concentrations, brassinolide was the most active compound, and the structure–activity relationship changed. On the other hand, the results of the A. thaliana root sensitivity assay show that brassinolide and the analogs with I and CN as substituents on the benzoyl group were the most active compounds. These results are in line with those obtained via the RLIT. A comparison of these results with those obtained for similar analogs that had a hydroxyl group at C2 indicates the importance of considering the whole structure. The molecular-docking results indicate that all the analogs adopted a brassinolide-like orientation, while the stabilizing effect of the benzoate group on the interactions with the receptor complex provided energy binding values ranging between −10.17 and −13.17 kcal mol⁻¹, where the analog with a nitrile group was the compound that achieved better contact with the amino acids present in the active site. Full article

Paeonia peregrina Mill. is a protected, herbaceous species native to Southeastern Europe and Turkey. Due to its vulnerability, it has to be protected both in its natural habitats and through cultivation. Peonies are known to have a low potential for natural regeneration due to their seed dormancy, low germination rate, and long germination period. In this study, treatments with gibberellic acid (GA₃ 150, 200, 250, 300, and 350 mg L⁻¹ GA₃) and warm (at 20/16 °C day/night regime) and cold stratification (at 4 °C) were used to accelerate dormancy release and increase the germination rate. The seeds of P. peregrina from four natural habitats in Serbia and the Institute’s collection were collected and analyzed. They showed an underdeveloped embryo that needs to grow inside the seed before it can germinate. The application of GA₃ accelerated each stage of germination (seed coat rapturing, hypocotyl dormancy release, and epicotyl dormancy release) for approximately 10 days compared to the control. It was also found that two-day imbibition with 200 mg L⁻¹ GA₃ significantly accelerated and equalized germination. Higher GA₃ concentrations had a more pronounced impact on each stage but also resulted in greater seed infection after the seed coat rupture, elongated and weak seedlings, while lower concentrations did not result in obtaining uniform seedlings. There were no significant differences observed between localities. Restoring P. peregrina through seeds and nursery-produced plants is crucial for conserving the genetic diversity of the tested species. Full article

Anthocyanin is one important nutrition composition in Tartary buckwheat (Fagopyrum tataricum) sprouts, a component missing in its seeds. Although anthocyanin biosynthesis requires light, the mechanism of light-induced anthocyanin accumulation in Tartary buckwheat is unclear. Here, comparative transcriptome analysis of Tartary buckwheat sprouts under light and dark treatments and biochemical approaches were performed to identify the roles of one B-box protein BBX22 and ELONGATED HYPOCOTYL 5 (HY5). The overexpression assay showed that FtHY5 and FtBBX22 could both promote anthocyanin synthesis in red-flower tobacco. Additionally, FtBBX22 associated with FtHY5 to form a complex that activates the transcription of MYB transcription factor genes FtMYB42 and FtDFR, leading to anthocyanin accumulation. These findings revealed the regulation mechanism of light-induced anthocyanin synthesis and provide excellent gene resources for breeding high-quality Tartary buckwheat. Full article

The ethylene-regulated hypocotyl elongation of Arabidopsis thaliana involves many transcription factors. The specific role of MYC transcription factors in ethylene signal transduction is not completely understood. The results here revealed that two MYCs, MYC2 and MYC3, act as negative regulators in ethylene-suppressed hypocotyl elongation. Etiolated seedlings of the loss-of-function mutant of MYC2 or MYC3 were significantly longer than wild-type seedlings. Single- or double-null mutants of MYC2 and MYC3 displayed remarkably enhanced response to ACC(1-aminocyclopropane-1-carboxylate), the ethylene precursor, compared to wild-type seedlings. MYC2 and MYC3 directly bind to the promoter zone of ERF1, strongly suppressing its expression. Additionally, EIN3, a key component in ethylene signaling, interacts with MYC2 or MYC3 and significantly suppresses their binding to ERF1’s promoter. MYC2 and MYC3 play crucial roles in the ethylene-regulated expression of functional genes. The results revealed the novel role and functional mechanism of these transcription factors in ethylene signal transduction. The findings provide valuable information for deepening our understanding of their role in regulating plant growth and responding to stress. Full article