GA Levels Research Articles

Tomato sprayed monocalcium phosphate had production-phytoremediation dual function with high soil Cd extraction and safer fruit production

In order to make use of the large biomass of tomato plant to fulfill the purpose of remediating-while-producing, two commercial tomato varieties, ‘Baiguoqiangfeng’ (BG) and ‘Ouguan’ (OG) were grown in Cd contaminated acidic soil to compare their performance on Cd phytoextraction, and monocalcium phosphate (Ca) was foliar applied to reduce their fruit Cd concentration. The results showed that the BG was a more Cd tolerant variety, comparing with OG, it suffered lighter tissue peroxidation and photosynthesis obstacle, owning weaker amino acid metabolism, secondary metabolism and stress signal transduction under Cd stress. The Ca application reduced its ABA level but increased the GSH, IAA, ZR and GA3 level, and enhanced its lysine degradation, tyrosine metabolism, alanine, asparagine and glutamate metabolism, plant hormone signal transduction and phenylpropanoid biosynthesis under Cd stress. With these metabolic regulations, the Ca application promoted its leaf biomass accumulation, guaranteeing the total Cd extraction amount (0.88 mg pot−1 as 0.20 mg kg −1), and reduced the fruit Cd partition, decreasing the fruit Cd concentration by 71.4% with higher yield. Meanwhile, the OG had lower Cd phytoextraction capacity than the BG, and Ca spray enhanced its cell energy generation, flavonoids biosynthesis and photosynthetic carbon fixation, but had no effect on fruit Cd concentration. The two tomato varieties had different responses to Ca application under Cd stress in their hormone signaling, energy metabolism, secondary metabolism and amino acids metabolism, which furtherly differed their Cd phytoextraction capacity and production safety. Therefore, the monocalcium phosphate spray combined ‘Baiguoqiangfeng’ tomato realized the dual function of production-phytoremediation, and the mechanism of plant Cd sensitivity adjustment through phenylpropanoid biosynthesis and amino acids metabolism deserved further study.

Alteration in the balance between ABA and GA signaling mediates genetic variation in induction and retention of dormancy during seed maturation in wheat

Induction and retention of dormancy are among the physiological processes that take place during seed maturation; however, the molecular mechanisms underlying these events are poorly understood in wheat. This study revealed that seed maturation in wheat is associated with decreases in abscisic acid (ABA) and gibberellin (GA) levels irrespective of dormancy level exhibited by the seeds mainly via expression of specific ABA (TaCYP707A1) and GA (TaGA3ox2, TaGA2ox3 and TaGA2ox6) metabolism genes. Consistently, ABA to GA level ratio decreased during maturation in both highly dormant and low-dormant seeds with no apparent difference in the ratio of their levels between the two seed samples. Our data, however, showed a close association between the induction and retention of dormancy during seed maturation and modulation of the balance between ABA and GA signaling via expression of specific genes that acts as positive regulators seed response to ABA (TaPYL5 and TaABI5) and GA (TaGAMyb). Consistently, the highly dormant and low-dormant seeds exhibited substantial variation in their sensitivity to ABA and GA during their maturation. The findings of this study highlight that genetic variation in induction and retention of dormancy during wheat seed maturation can be mediated by a shift in balance between seed sensitivity to ABA and GA independent of a shift in balance between their levels.

Glycated albumin levels in the third trimester of women with gestational diabetes mellitus are associated with adverse pregnancy-related outcomes

BackgroundGlycated albumin (GA) levels have been considered as a promising biomarker for estimating glycemic control during pregnancy, but the relationship between GA levels and the incidence of adverse pregnancy outcomes in women with gestational diabetes mellitus (GDM) remains unclear. Our study aimed to investigate the relationship between GA levels during the third trimester and 13 different adverse pregnancy-related outcomes among women with GDM in China.MethodsWe retrospectively extracted clinical data from the medical records of 819 pregnant women with GDM who underwent prenatal examinations and child delivery at the Affiliated Hospital of Qingdao University between January 2022 and October 2022. The cohort was divided into GA-high (GA-H) and GA-low (GA-L) groups based on the median GA level of 10.6%. Then, the incidence rates of 13 specific adverse pregnancy outcomes were compared between the two groups. Furthermore, we estimated the mean GA levels in pregnant GDM women with or without specific adverse outcomes. Multivariate logistic regression analysis was performed to assess whether the GA levels (high or low) were independent risk factors for specific adverse outcomes in pregnant women with GDM. Receiver operating characteristic (ROC) curve analysis was performed to assess the predictive value of GA levels for the adverse pregnant outcomes in women with GDM. E-value for sensitivity analysis was performed to assess the robustness of the findings to unmeasured confoundings.ResultsWe included 819 pregnant women with GDM, whose average age was 33.09 ± 4.47 years, average pre-pregnancy BMI was 23.51 ± 3.67 kg/m2, and the average gestational week in which GDM diagnosed was 24.80 ± 1.79 weeks. The analysis showed that 80.71% (661/819) pregnant women with GDM were associated with adverse pregnancy-related outcomes. Pregnant women in the GA-L group showed higher incidence of the premature rupture of membranes (PROM), whereas those in the GA-H group showed higher incidence of neonatal hypoglycemia. The GA levels showed acceptable clinical performance for predicting neonatal hypoglycemia with an area under the ROC curve (AUC) value of 0.700 (P = 0.010), sensitivity of 71.4%, and specificity of 70.2%. The optimal cut off value for GA was 11.55%.ConclusionsThis study demonstrated that GA levels were significantly associated with specific adverse pregnancy outcomes, especially PROM and neonatal hypoglycemia. Furthermore, GA levels in the third trimester showed acceptable clinical performance for predicting neonatal hypoglycemia among pregnant women with GDM. In the future, the potential role of GA as a predictor of adverse pregnancy outcomes need to be further confirmed and explored in GDM women.

The combined predictive power of the atherogenic index of plasma and serum glycated albumin for cardiovascular events in postmenopausal patients with acute coronary syndrome after percutaneous coronary intervention

BackgroundGlycated Albumin (GA) and atherogenic index of plasma (AIP) are two important biomarkers that respectively reflect lipid and glucose levels. Previous research has revealed their roles in cardiovascular diseases (CVD) and diabetes. However, their combined predictive ability in forecasting cardiovascular events (CVE) after percutaneous coronary intervention (PCI) among postmenopausal acute coronary syndrome (ACS) patients remains insufficiently studied.MethodsBased on the levels of AIP (AIP-L and AIP-H) and GA (GA-L and GA-H), four groups were used to categorize the patients. The CVE assessed included cardiac death, nonfatal myocardial infarction (MI) and nonfatal stroke. To evaluate the relationship between AIP, GA, and CVE, multivariate Cox regression analyses were performed.Results98 patients (7.5%) experienced CVE during follow-up. AIP and GA were revealed as strong independent predictors of CVE through multivariate analysis (AIP: HR 3.324, 95%CI 1.732–6.365, P = 0.004; GA: HR 1.098, 95% CI 1.023–1.177, P = 0.009). In comparison to those in the initial group (AIP-L and GA-L), the fourth group (AIP-H and GA-H) of patients exhibited the greatest CVE risk (HR 2.929, 95% CI 1.206–5.117, P = 0.018). Derived from the model of baseline risk, the combination of AIP + GA significantly enhanced the AUC, meanwhile combining AIP and GA levels maximized prognostic accuracy in the baseline risk model.ConclusionsThis study found that the combined measurement of AIP and GA significantly enhanced the predictive capability for CVE following PCI in postmenopausal ACS patients. By integrating these two biomarkers, it became possible to more accurately identify high-risk individuals and provided clinicians with new predictive tools for postmenopausal ACS patients in risk assessment and management.

Resveratrol and nitric oxide synergistically enhance resistance against B. cinerea in tomato fruit by regulating phytohormones

Resveratrol (RVT), a plant antitoxin, plays an important role in plant resistance against pathogens. While nitric oxide (NO) as an essential signaling factor in disease resistance enhancement is well documented, the potential molecular interplay RVT and NO in postharvest tomato fruit defense against Botrytis cinerea (B.cinerea) still needs exploration. In this study, exogenous RVT reduced gray mold caused by B.cinerea in tomato fruit, with 20 μM being the most effective. Tomato fruit were treated with 20 μM RVT enhanced resistance against B.cinerea, as indicated by reduced symptoms of disease and improved activity of disease resistance related enzymes (PAL, PPO and CHI). In addition, RVT treatment improved the expression of SlPR1, SlLoxd and SlMYC2, and promoted the accumulation of plant hormone IAA and ABA, but reduced the expression of SlNPR1 and the level of GA3. More importantly, the combined treatment of NO donor (SNP) and RVT notably enhanced disease resistance compared to RVT or SNP single treatment. However, the combination of NO inhibitor (L-NNA) and RVT treatment even reduced the positive effect of RVT. Meanwhile, the expression of SlPR1, SlLoxd and SlMYC2 and the accumulation of IAA and ABA in RVT + SNP treated fruit were higher than those in the RVT or SNP single treatment. Thus, our data demonstrate that RVT and NO synergistically enhance resistance against B. cinerea in tomato fruit by regulating phytohormones.

OsNAL11 and OsGASR9 Regulate the Low-Temperature Germination of Rice Seeds by Affecting GA Content

Low temperatures cause serious threat to rice seed emergence, which has become one of the main limiting factors in the production of direct seeding rice. It is of great importance to study the genes controlling low-temperature tolerance during seed germination and to mine the possible regulatory mechanism for developing new rice varieties with immense low-temperature germination ability. In the current research study, two types of mutants of nal11 and gasr9, derived from the WT (wild type) ZH11, were used for the analysis of low-temperature germinability. The results showed that the nal11 and gasr9 mutants displayed no significant difference in germination rate with ZH11 at room temperature, but the mutants showed significantly lower germination rates, germination potential and germination index, and slowed seedling growth in the simulated direct seeding experiments at low temperatures compared to ZH11. Additionally, the activity of POD, SOD, CAT, and anti-superoxide anion radial activity were significantly reduced, but the levels of MDA and H2O2 were significantly higher in the nal11 and gasr9 mutant seeds that were germinated at low temperatures compared to ZH11. Further analysis revealed that the levels of total active GA, especially GA4 and GA7, were significantly lower in the nal11 and gasr9 mutants than that in ZH11 during low-temperature germination. Based on qRT-PCR analysis, the expression levels of some GA synthesis-related genes were higher, whereas some were lower in the nal11 and gasr9 mutants than those in ZH11, however, the GA metabolism-related genes OsGA2ox8 and OsGA2ox10 and the GA signaling negative regulator gene SLR1 were significantly up-regulated in both nal11 and gasr9 mutants at several time points during low-temperature germination. This may explain the lower GA levels in the nal11 and gasr9 mutants. Furthermore, the interaction between the OsNAL11 and OsGASR9 proteins was confirmed by Y2H, LUC, and Co-IP assays. This study provides preliminary insights into the regulatory mechanism of the OsNAL11 and OsGASR9 genes, which control the low-temperature germination of rice seeds by affecting the GA pathway. Our study will provide the basis for further mining the molecular mechanisms of low-temperature germination in rice and valuable theoretical reference for breeding varieties with strong low-temperature germinability.

Exogenous melatonin promoted seed hypocotyl germination of Paeonia ostia 'Fengdan' characterized by regulating hormones and starches.

Seed hypocotyl germination signifies the initiation of the life cycle for plants and represents a critical stage that heavily influences subsequent plant growth and development. While previous studies have established the melatonin (MEL; N-acetyl-5-methoxytrytamine) effect to stimulate seed germination of some plants, its specific role in peony germination and underlying physiological mechanism have yet to be determined. This study aims to evaluate the MEL effect for the hypocotyl germination of peony seeds, further ascertain its physiological regulation factors. In this work, seeds of Paeonia ostia 'Fengdan' were soaked into MEL solution at concentrations of 50, 100, 200, and 400 µM for 48 h and then germinated in darkness in incubators. Seeds immersed in distilled water without MEL for the same time were served as the control group. At concentrations of 100 and 200 µM, MEL treatments improved the rooting rate of peony seeds, while 400 µM inhibited the process. During seed germination, the 100 and 200 µM MEL treatments significantly reduced the starch concentration, and α-amylase was the primary amylase involved in the action of melatonin. Additionally, compared to the control group, 100 µM MEL treatment significantly increased the GA3 concentration and radicle thickness of seeds, but decreased ABA concentration. The promotion effect of 200 µM MEL pretreatment on GA1 and GA7 was the most pronounced, while GA4 concentration was most significantly impacted by 50 µM and 100 µM MEL. Correlation analysis established that 100 µM MEL pretreatment most effectively improved the rooting rate characterized by increasing α-amylase activity to facilitate starch decomposition, boosting GA3 levels, inhibiting ABA production to increase the relative ratio of GA3 to ABA. Moreover, MEL increased radicle thickness of peony seeds correlating with promoting starch decomposition and enhancing the synthesis of GA1 and GA7.

OsMBF1a Facilitates Seed Germination by Regulating Biosynthesis of Gibberellic Acid and Abscisic Acid in Rice.

Seed germination is a pivotal stage in the plant life cycle, orchestrated by a myriad of internal and external factors, notably plant hormones. The underlying molecular mechanisms governing rice seed germination remain largely unelucidated. Herein, we uncover OsMBF1a as a crucial regulatory factor that employs a dual strategy to promote seed germination: positively activating genes involved in gibberellin (GA) biosynthesis pathways, while negatively regulating key genes responsible for abscisic acid (ABA) synthesis. Furthermore, OsMBF1a modulates the endogenous levels of ABA and GA in rice seeds, reinforcing its central role in the germination process. The expression of ZmMBF1a and ZmMBF1b, the homologous genes in maize, in rice seeds similarly affects germination, indicating the conserved functionality of MBF1 family genes in regulating seed germination. This study provides novel insights into the molecular mechanisms underlying rice seed germination and underscores the significance of MBF1 family genes in plant growth and development.

Inflorescence development in female cannabis plants is mediated by photoperiod and gibberellin.

In cannabis seedlings, the initiation of solitary flowers is photoperiod-independent. However, when cannabis reaches the adult stage, short-day photoperiod (SD) triggers branching of the shoot apex and a reduction in internode length, leading to development of a condensed inflorescence. We demonstrate that SD affects cannabis plants in two distinct phases: the first includes rapid elongation of the internodes and main stem, and occurring from Day 5 to Day 10 of plant cultivation under SD; in the second phase, elongation of newly developed internodes ceases, and a condensed inflorescence is formed. Exposure of plants to alternating photoperiods revealed that inflorescence onset requires at least three consecutive days of SD, and SD is consistently required throughout inflorescence maturation to support its typical condensed architecture. This photoperiod-dependent morphogenesis was associated with a decrease in gibberellin (GA4) and auxin levels in the shoot apex. Reverting the plants to a long-day photoperiod (LD) increased GA4 and auxin levels, leading to inflorescence disassembly, internode elongation, and subsequent resumption of LD growth patterns. Similar developmental patterns were observed under SD following the application of exogenous GA (and not auxin), which also impeded inflorescence development. Nevertheless, additional studies will help to further evaluate auxin's role in these developmental changes. We propose a crucial role for GA in sexual reproduction and inflorescence development in female cannabis by mediating photoperiod signaling in the inflorescence tissues.

A LBD transcription factor from moso bamboo, PheLBD12, regulates plant height in transgenic rice.

The regulation mechanism of bamboo height growth has always been one of the hotspots in developmental biology. In the preliminary work of this project, the function of LBD transcription factor regulating height growth was firstly studied. Here, a gene PheLBD12 regulating height growth was screened. PheLBD12-overexpressing transgenic rice had shorter internodes, less bioactive gibberellic acid (GA3), and were more sensitive to GA3 than wild-type (WT) plants, which implied that PheLBD12 involve in gibberellin (GA) pathway. The transcript levels of OsGA2ox3, that encoding GAs deactivated enzyme, was significantly enhanced in PheLBD12-overexpressing transgenic rice. The transcript levels of OsAP2-39, that directly regulating the expression of EUI1 to reduce GA levels, was also significantly enhanced in PheLBD12-overexpressing transgenic rice. Expectedly, yeast one-hybrid assays, Dual-luciferase reporter assay and EMSAs suggested that PheLBD12 directly interacted with the promoter of OsGA2ox3 and OsAP2-39. Together, our results reveal that PheLBD12 regulates plant height growth by modulating GA catabolism. Through the research of this topic, it enriches the research content of LBD transcription factors and it will theoretically enrich the research content of height growth regulation.

Role of auxin and gibberellin under low light in enhancing saffron corm starch degradation during sprouting

The mechanisms by which low light accelerates starch macromolecules degradation by auxin and gibberellin (GA) in geophytes during sprouting remain largely unknown. This study investigated these mechanisms in saffron, grown under low light (50 μmol m−2 s−1) and optimal light (200 μmol m−2 s−1) during the sprouting phase. Low light reduced starch concentration in corms by 34.0 % and increased significantly sucrose levels in corms, leaves, and leaf sheaths by 19.2 %, 9.8 %, and 134.5 %, respectively. This was associated with a 33.3 % increase in GA3 level and enhanced auxin signaling. Leaves synthesized IAA under low light, which was transported to the corms to promote GA synthesis, facilitating starch degradation through a 228.7 % increase in amylase activity. Exogenous applications of GA and IAA, as well as the use of their synthesis or transport inhibitors, confirmed the synergistic role of these phytohormones in starch metabolism. The unigenes associated with GA biosynthesis and auxin signaling were upregulated under low light, highlighting the IAA-GA module role in starch degradation. Moreover, increased respiration rate and invertase activity, crucial for ATP biosynthesis and the tricarboxylic acid cycle, were consistent with the upregulation of related unigenes, suggesting that auxin signaling accelerates starch degradation by promoting energy metabolism. Upregulated of auxin signaling (CsSAUR32) and starch metabolism (CsSnRK1) genes under low light suggests that auxin directly regulate starch degradation in saffron corms. This study elucidates that low light modulates auxin and GA interactions to accelerate starch degradation in saffron corms during sprouting, offering insights for optimizing agricultural practices under suboptimal light conditions.

Soybean plants enhance growth through metabolic regulation under heterogeneous drought stress

Heterogeneous drought stress (HED) is prevalent in drought-resistant practices such as deficit irrigation, root zone irrigation and strip intercropping. The mechanisms and improvement of crop drought resistance under HED are not fully understood. This study used double-root grafted Nandou 12 (ND12) soybean seedlings to simulate HED treatment under controlled conditions. Seedlings were transplanted into root cups with waterproof partitions to establish different soil moisture treatments: sufficient irrigation (SI) with 80 % soil moisture on both sides, HED with 80 % on one side and 40 % on the other, and homogeneous drought stress (HOD) with 60 % on both sides. The results indicated that soybean plants treated with HED exhibited healthier growth compared to those treated with HOD. Photosynthesis rate (Pn), stomatal conductance (cond.), transpiration rate (Tr), and relative water content (RWC) decreased by 10.24 %, 43.90 %, 152.66 %, and 8.69 % in HED-treated plants, respectively, but dry biomass increased by 3.38 %. Conversely, HOD conditions led to a significant decline in these parameters. Metabolomic and transcriptomic analyses revealed significant changes in the biosynthesis and signaling pathways of key phytohormones and metabolites, including abscisic acid (ABA), gibberellin (GA), jasmonic acid (JA), isoflavones, starch, and sugars. In HED-treated plants, GmNCED downregulation resulted in 54.22 % less ABA than HOD. GA levels increased under HED with upregulation of GmGA3OX1 and GmGA3OX2. JA content in HED-treated roots was 90.90 % higher than in HOD-treated roots. Isoflavones concentration including genistein (73.01 %), genistin (63.63 %), malonylgenistin (20.58 %), malonylgenistin (65 %), diadzin (38.15 %), and malonyldiadzin (47.61 %) levels, were significantly higher in HED-treated plants. Antioxidant enzyme activities indicated a 20 % increase in peroxidase (POD) activity under HED, while malondialdehyde (MDA) content was 27 % higher in HOD-treated plants, indicating greater oxidative stress. Chlorophyll content remained stable, and starch concentration increased by 33.33 % in HED-treated plants compared to HOD-treated plants. HED enhances phytohormonal responses and metabolic adjustments in soybean plants, boosting photosynthetic efficiency, antioxidant capabilities, growth, and drought resilience. This regulatory mechanism balances growth promotion and drought resistance, highlighting HED potential in improving crop resilience.

Enrichment Characteristics and Mechanisms of Lithium, Gallium, and Rare Earth Elements (REY) within Late Permian Coal-Bearing Strata in Wanfu Mine, Xian’an Coalfield, Guangxi Province, Southwest China

The study of lithium (Li), gallium (Ga), and rare earth elements (REY) within coal-bearing strata represents a cutting-edge concern in coal geology, ore deposit studies, and metallurgy research. With the rapid advancement of technology and emerging industries, the global demand for Li-Ga-REY has significantly escalated. Several countries worldwide are facing immense pressure due to shortages in Li-Ga-REY resources. Coal-associated Li-Ga-REY depositions have emerged as a pivotal direction for augmenting Li-Ga-REY reserves. To ascertain the enrichment distribution patterns and genetic mechanisms of Li-Ga-REY within the coal-bearing strata of the late Permian Heshan Formation in Wanfu mine, Xian’an Coalfield, Guangxi Province, this study carried out comprehensive testing and analysis on Li-Ga-REY enriched in the mineralized layers within the strata. The Heshan Formation in Wanfu mine presents four layers of Li-Ga-REY-enriched mineralization, labeled from bottom to top as mineralized layers I, II, III, and IV, corresponding to coal seams K5, K4, K3, and K2. These critical metals are predominantly hosted within clay minerals (kaolinite, illite/smectite, and chlorite). The enrichment of critical metals within the Heshan Formation is closely related to terrigenous detrital materials from the Daxin paleocontinent, volcanic detrital materials induced by the Emeishan mantle plume and the Yuenan magmatic arc. The accumulation of Li-Ga-REY and other critical elements within the mineralized layers is the result of inputs from terrestrial and volcanic detrital sources, interactions between peatification and diagenesis stages, and occasionally the input of metal-enriched fluids. In the mineralized layers I, II, and III, the content of lithium oxide (Li2O) surpasses the boundary grade, and the levels of REY, Ga, and (Nb,Ta)2O5 are close to boundary grades, indicating promising exploration prospects. The Wanfu mine in the Xian’an Coalfield can be considered a primary target zone for the exploration and development of coal-associated critical metal resources in Guangxi.

Near-Infrared Fluorescent Carbon Nanotube Sensors for the Plant Hormone Family Gibberellins

Gibberellins (GAs) are a class of phytohormones, important for plant growth, and very difficult to distinguish because of their similarity in chemical structures. Herein, we develop the first nanosensors for GAs by designing and engineering polymer-wrapped single-walled carbon nanotubes (SWNTs) with unique corona phases that selectively bind to bioactive GAs, GA3 and GA4, triggering near-infrared (NIR) fluorescence intensity changes. Using a new coupled Raman/NIR fluorimeter that enables self-referencing of nanosensor NIR fluorescence with its Raman G-band, we demonstrated detection of cellular GA in Arabidopsis, lettuce, and basil roots. The nanosensors reported increased endogenous GA levels in transgenic Arabidopsis mutants that overexpress GA and in emerging lateral roots. Our approach allows rapid spatiotemporal detection of GA across species. The reversible sensor captured the decreasing GA levels in salt-treated lettuce roots, which correlated remarkably with fresh weight changes. This work demonstrates the potential for nanosensors to solve longstanding problems in plant biotechnology.

Genome-Wide Analysis of the Gibberellin-Oxidases Family Members in Four Prunus Species and a Functional Analysis of PmGA2ox8 in Plant Height.

Gibberellins (GAs), enzymes that play a significant role in plant growth and development, and their levels in plants could be regulated by gibberellin-oxidases (GAoxs). As important fruit trees and ornamental plants, the study of the mechanism of plant architecture formation of the Prunus genus is crucial. Here, 85 GAox genes were identified from P. mume, P. armeniaca, P. salicina, and P. persica, and they were classified into six subgroups. Conserved motif and gene structure analysis showed that GAoxs were conserved in the four Prunus species. Collinearity analysis revealed two fragment replication events of PmGAoxs in the P. mume genome. Promoter cis-elements analysis revealed 24 PmGAoxs contained hormone-responsive elements and development regulatory elements. The expression profile indicated that PmGAoxs have tissue expression specificity, and GA levels during the dormancy stage of flower buds were controlled by certain PmGAoxs. After being treated with IAA or GA3, the transcription level of PmGA2ox8 in stems was significantly increased and showed a differential expression level between upright and weeping stems. GUS activity driven by PmGA2ox8 promoter was detected in roots, stems, leaves, and flower organs of Arabidopsis. PmGA2ox8 overexpression in Arabidopsis leads to dwarfing phenotype, increased number of rosette leaves but decreased leaf area, and delayed flowering. Our results showed that GAoxs were conserved in Prunus species, and PmGA2ox8 played an essential role in regulating plant height.

Sorbitol mediates age-dependent changes in apple plant growth strategy through gibberellin signaling.

Plants experience various age-dependent changes during juvenile to adult vegetative phase. However, the regulatory mechanisms orchestrating the changes remain largely unknown in apple (Malus domestica). This study showed that tissue-cultured apple plants at juvenile, transition, and adult phase exhibit age-dependent changes in their plant growth, photosynthetic performance, hormone levels, and carbon distribution. Moreover, this study identified an age-dependent gene, sorbitol dehydrogenase (MdSDH1), a key enzyme for sorbitol catabolism, highly expressed in the juvenile phase in apple. Silencing MdSDH1 in apple significantly decreased the plant growth and GA3 levels. However, exogenous GA3 rescued the reduced plant growth phenotype of TRV-MdSDH1. Biochemical analysis revealed that MdSPL1 interacts with MdWRKY24 and synergistically enhance the repression of MdSPL1 and MdWRKY24 on MdSDH1, thereby promoting sorbitol accumulation during vegetative phase change. Exogenous sorbitol application indicated that sorbitol promotes the transcription of MdSPL1 and MdWRKY24. Notably, MdSPL1-MdWRKY24 module functions as key repressor to regulate GA-responsive gene, Gibberellic Acid-Stimulated Arabidopsis (MdGASA1) expression, thereby leading to a shift from the quick to the slow-growth strategy. These results reveal the pivotal role of sorbitol in controlling apple plant growth, thereby improving our understanding of vegetative phase change in apple.

PpGATA21 Enhances the Expression of PpGA2ox7 to Regulate the Mechanism of Cerasus humilis Rootstock-Mediated Dwarf in Peach Trees.

Dwarfing rootstocks enhance planting density, lower tree height, and reduce both labor in peach production. Cerasus humilis is distinguished by its dwarf stature, rapid growth, and robust fruiting capabilities, presenting substantial potential for further development. In this study, Ruipan 4 was used as the scion and grafted onto Amygdalus persica and Cerasus humilis, respectively. The results indicate that compared to grafting combination R/M (Ruipan 4/Amygdalus persica), grafting combination R/O (Ruipan 4/Cerasus humilis) plants show a significant reduction in height and a significant increase in flower buds. RNA-seq indicates that genes related to gibberellin (GA) and auxin metabolism are involved in the dwarfing process of scions mediated by C. humilis. The expression levels of the GA metabolism-related gene PpGA2ox7 significantly increased in R/O and are strongly correlated with plant height, branch length, and internode length. Furthermore, GA levels were significantly reduced in R/O. The transcription factor PpGATA21 was identified through yeast one-hybrid screening of the PpGA2ox7 promoter. Yeast one-hybrid (Y1H) and dual-luciferase reporter (DLR) demonstrate that PpGATA21 can bind to the promoter of PpGA2ox7 and activate its expression. Overall, PpGATA21 activates the expression of the GA-related gene PpGA2ox7, resulting in reduced GA levels and consequent dwarfing of plants mediated by C. humilis. This study provides new insights into the mechanisms of C. humilis and offers a scientific foundation for the dwarfing and high-density cultivation of peach trees.

Modulation in the ratio of abscisic acid to gibberellin level determines genetic variation of seed dormancy in barley (Hordeum vulgare L.)

Abscisic acid (ABA) and gibberellin (GA) are major regulators of seed dormancy, an adaptive trait closely associated with preharvest sprouting. This study examined transcriptional regulation of ABA and GA metabolism genes and modulation of ABA and GA levels in seeds of barley genotypes exhibiting a range of dormancy phenotype. We observed a very strong negative correlation between genetic variation in seed germination and embryonic ABA level (r = 0.85), which is regulated by transcriptional modulation of HvNCED1 and/or HvCYP707A genes. A strong positive correlation was evident between variation in seed germination and GA level (r = 0.64), mediated via transcriptional regulation of GA biosynthesis genes, HvGA20ox2 and/or HvGA3oxs, and GA catabolism genes, HvGA2ox3 and/or HvGA3ox6. Modulation of the ABA and GA levels in the genotypes led to the prevalence of ABA to GA level ratio that exhibited a very strong negative correlation (r = 0.84) with seed germination, highlighting the importance of a shift in ABA/GA ratio in determining genetic variation of dormancy in barley seeds. Our results overall show that transcriptional regulation of specific ABA and GA metabolism genes underlies genetic variation in ABA/GA ratio and seed dormancy, reflecting the potential use of these genes as molecular tools for enhancing preharvest sprouting resistance in barley.

The BEL1-like homeodomain protein OsBLH4 regulates rice plant height, grain number, and heading date by repressing the expression of OsGA2ox1.

Gibberellins (GAs) play crucial roles in regulating plant architecture and grain yield of crops. In rice, the inactivation of endogenous bioactive GAs and their precursors by GA 2-oxidases (GA2oxs) regulates stem elongation and reproductive development. However, the regulatory mechanisms of GA2ox gene expression, especially in rice reproductive organs, are unknown. The BEL1-like homeodomain protein OsBLH4, a negative regulatory factor for the rice OsGA2ox1 gene, was identified in this study. Loss of OsBLH4 function results in decreased bioactive GA levels and pleiotropic phenotypes, including reduced plant height, decreased grain number per panicle, and delayed heading date, as also observed in OsGA2ox1-overexpressing plants. Consistent with the mutant phenotype, OsBLH4 was predominantly expressed in shoots and young spikelets; its encoded protein was exclusively localized in the nucleus. Molecular analysis demonstrated that OsBLH4 directly bound to the promoter region of OsGA2ox1 to repress its expression. Genetic assays revealed that OsBLH4 acts upstream of OsGA2ox1 to control rice plant height, grain number, and heading date. Taken together, these results indicate a crucial role for OsBLH4 in regulating rice plant architecture and yield potential via regulation of bioactive GA levels, and provide a potential strategy for genetic improvements of rice.

Zinc oxide nanoparticles alleviated vanadium-induced inhibition by regulating plant hormone signal transduction and phenylpropanoid biosynthesis in maize seedlings (Zea may L.)

Our efforts were to identify the role of zinc oxide nanoparticles (ZnO-NPs) on the growth of maize (Zea may L.) under vanadium (V) stress. Transcriptome analysis was performed on maize leaves subjected to CK, V, and V+ZnO treatments. It was found that the application of ZnO-NPs significantly reduces V accumulation and toxicity in maize. A total of 5441 and 3003 differentially expressed genes (DEGs) were identified in the CK vs. V and V+ZnO vs. V comparisons, respectively. Of these detected genes, 3016 DEGs were specific to CV vs. V, and 608 DEGs were specific to V+ZnO vs V, respectively. These genes were primarily involved in plant hormone signal transduction and phenylpropanoid biosynthesis pathways. Under V treatment, ZnO-NPs caused an up-regulation of SAUR, AUX/IAA, ARRs, GID1, and BRIIs, which resulted in high levels of IAA, CTK, GA, BRs, and JAs in maize seedlings compared to those without ZnO-NPs. The addition of ZnO-NPs also leads to a significant decrease in total phenolics and lignin contents in maize seedlings by down-regulating CCR, HCT, CAD, 4CL, and C4H genes compared to those without ZnO-NPs. Overall, the findings suggest that ZnO-NPs can improve V-induced growth suppression by changing the expression of selected genes and constitute a simple and efficient strategy for alleviating V toxicity in high-V soils.