Search Results (22)

MIKC-type MADS-box transcription factors constitute one of the largest gene families in plants, playing pivotal roles in regulating plant growth and development, hormone signaling transduction, and responses to biotic and abiotic stresses. However, there have been no reports on the systematic identification and characterization of MIKC-type MADS-box proteins in walnuts. In this study, we identified 52 JrMADS genes in the walnut genome and transcriptome, and categorized them into 14 subfamilies through structural domain and phylogenetic tree analysis. It was found that these genes were unevenly distributed across 16 chromosomes. Within the MIKC-type MADS-box gene family, we identified three pairs of tandem-duplicated genes and 40 pairs of segmental duplicated genes, indicating that segmental duplication was the primary mechanism of gene amplification in walnut. Ka/Ks analysis showed that the family genes have undergone purifying selection during evolutionary processes. The promoter was predicted to contain cis-acting elements related to growth, development, plant hormones, and stress response. Expression profile analysis showed that JrMADS genes have different expression patterns in various tissues and developmental stages of male and female flower buds. Notably, an ancient clade of TM8 (JrMADS43) genes was found, which is absent in Arabidopsis but present in other flowering plants. Another gene, TM6 gene (JrMADS4), belongs to the AP3 subfamily and is a clade that has diverged from tomatoes. Through qPCR analysis, we verified the differential expression of JrMADS genes at different developmental stages (MB-1/2/3 and FB-1/2/3), with JrMADS5, JrMADS8, JrMADS14, JrMADS24, JrMADS40, JrMADS46, JrMADS47, JrGA3ox1, and JrGA3ox3 showing significantly higher expression in male than in female flower buds. In summary, our results provide valuable information for further biological functions research on MIKC-type MADS-box genes in walnut, such as flower organ development, and lays a solid foundation for future studies. Full article

Isodon suzhouensis, also known as “Wangzaozi”, is an edible and medicinal plant belonging to the Lamiaceae family. Its main functional constituents are the tetracyclic diterpenoids known as wangzaozins. Wangzaozins have a strong structural similarity to gibberellins (GAs), which are synthesized via the diterpenoid biosynthetic pathway (map00904). The formation of the diterpenoid skeleton is regulated by copalyl diphosphate synthase (CPS) and kaurene synthase (KS). In order to identify and study the KS gene involved in wangzaozins biosynthesis, a transcriptomic and metabolomic analysis of Isodon suzhouensis was performed. The IsKS1 gene, which was highly expressed in leaves, was successfully cloned. The binding mode and sites of IsKS1 with its catalyzed substrate, ent-copalyl diphosphate (ent-CPP), were predicted using AutoDock. The docking results revealed hydrophobic interactions, hydrogen bonds, and salt bridges between them. Furthermore, overexpression of IsKS1 in Arabidopsis thaliana resulted in a significant increase in gibberellin content, as well as the up-regulation of GA2(KS) and GA3OX1 genes. These results suggest that the IsKS1 gene is involved in gibberellin biosynthesis and may potentially contribute to the biosynthesis of wangzaozins. Full article

Environmental temperature significantly affects plant growth and development, particularly flower development. In pepper (Capsicum annuum), the molecular mechanisms underlying temperature-mediated floral organ development remain unclear. Gibberellins (GAs) are key plant hormones regulating growth and development, including flower development, and the CaGA20ox gene family may play a crucial role in this process due to its involvement in GA biosynthesis. In this study, we comprehensively analyzed the CaGA20ox gene family across six pepper genomes (‘Zhangshugang’, ‘Zunla’, ‘Chiltepin’, ‘CM334’, ‘Ca59’, and ‘T2T’) to explore their roles in flower development and temperature stress response, identifying five to six genes per genome. These genes exhibited distinct expression patterns across different tissues and developmental stages, with some members showing higher expression in specific floral organs, particularly pistils. Our results revealed that temperature significantly impacts pepper flower development and GA content, with lower temperatures enhancing antioxidant capacity and increasing GA levels. Specifically, the expression levels of four CazGA20ox genes (CazGA20ox1, CazGA20ox2, CazGA20ox4, and CazGA20ox6) were significantly influenced by temperature changes. Our systematic analysis of the role of the CaGA20ox gene family in temperature-mediated pepper flower development provides a foundation for further studies on the molecular mechanisms as well as the development of improved pepper varieties. Full article

Background: GA 2-oxidases (GA2oxs), a class of enzymes, inhibit the biosynthesis of bioactive gibberellins (GAs) in plants. The GA2 oxidase gene is crucial for regulating the passivation process of active GA and is widely involved in hormone signaling and abiotic stress processes. Objective/Methods: To examine the potential effects of the GA2 oxidase gene on Solanum pennellii, one of the important stress-tolerance wild species of tomato, a systematic analysis was performed to study the structure, phylogenetic tree, genomic locus, and upstream cis-regulatory elements of SpGA2ox genes. The expression patterns of the SpGA2ox family in various tissues were analyzed on the basis of published RNA-seq data, and the changes in SpGA2ox expression in the leaves of seedlings were detected under salinity stress and GA treatment by real-time fluorescence quantitative PCR. Results: We identified nine SpGA2ox genes in S. pennellii. They were located on chromosomes 1, 2, 4, 7, 8, and 10. The SpGA2ox family was clearly divided into three groups through phylogenetic relationship analysis, namely, five in C19-GA2ox class I, one in C19-GA2ox class II, and three in C20-GA2ox class. And cis-element analysis provided the basis for understanding the function of growth, development, hormones, and abiotic stress of GA2ox genes in S. pennellii. The expression patterns of the SpGA2ox family were different in three classes, and SpGA2ox1 exhibited higher expression levels in the stem compared to other tissues. The expression levels of all SpGA2ox genes increased significantly under salt stress and decreased by treatment with GA₃. With the largest changes in relative expression levels, SpGA2ox3 and SpGA2ox8 might exert key effects on the regulation of GA synthesis and the response to salt stress. Conclusions: The present study may be instrumental for further investigation into the impact of SpGA2oxs on responses to abiotic stress and provide potential targets for the genetic improvement of S. pennellii. Full article

The regulation of gibberellic acid 2-oxidase (GA2ox) gene expression represents a critical mechanism in the modulation of endogenous gibberellic acids (GAs) levels, thereby exerting an influence on plant height. In this context, we conducted a comprehensive genome-wide analysis of the GA2ox gene family in mango (Mangifera indica L.), a species of significant economic importance, with the aim of identifying potential candidate genes for mango dwarf breeding. Our findings delineated the presence of at least 14 members within the MiGA2ox gene family in the mango genome, which were further categorized into three subfamilies: C₁₉-GA2ox-I, C₁₉-GA2ox-II, and C₂₀-GA2ox-I. Notably, MiGA2ox12, a member of the C₁₉-GA2ox-II subfamily, exhibited substantial expression across various tissues, including roots, bark, leaves, and flowers. Through overexpression of the MiGA2ox12 gene in tobacco, a distinct dwarf phenotype was observed alongside reduced levels of GA₁ and GA₄, while the knockout line exhibited contrasting traits. This provides evidence suggesting that MiGA2ox12 may exert control over plant height by modulating GA content. Consequently, the MiGA2ox12 gene emerges as a promising candidate for facilitating advancements in mango dwarfing techniques. Full article

Nuclear Factor Y (NF-Y) is a class of heterotrimeric transcription factors composed of three subunits: NF-A, NF-YB, and NF-YC. NF-YC family members play crucial roles in various developmental processes, particularly in the regulation of flowering time. However, their functions in petunia remain poorly understood. In this study, we isolated four PhNF-YC genes from petunia and confirmed their subcellular localization in both the nucleus and cytoplasm. We analyzed the transcript abundance of all four PhNF-YC genes and found that PhNF-YC2 and PhNF-YC4 were highly expressed in apical buds and leaves, with their transcript levels decreasing before flower bud differentiation. Silencing PhNF-YC2 using VIGS resulted in a delayed flowering time and reduced chlorophyll content, while PhNF-YC4-silenced plants only exhibited a delayed flowering time. Furthermore, we detected the transcript abundance of flowering-related genes involved in different signaling pathways and found that PhCO, PhGI, PhFBP21, PhGA20ox4, and PhSPL9b were regulated by both PhNF-YC2 and PhNF-YC4. Additionally, the transcript abundance of PhSPL2, PhSPL3, and PhSPL4 increased only in PhNF-YC2-silenced plants. Overall, these results provide evidence that PhNF-YC2 and PhNF-YC4 negatively regulate flowering time in petunia by modulating a series of flowering-related genes. Full article

Moso bamboo (Phyllostachys edulis) is one of the fastest growing plants. Gibberellin (GA) is a key phytohormone regulating growth, but there are few studies on the growth of Moso bamboo regulated by GA. The gibberellin 20 oxidase (GA20ox) gene family was targeted in this study. Chromosomal distribution and collinearity analysis identified 10 GA20ox genes evenly distributed on chromosomes, and the family genes were relatively conservative in evolution. The genetic relationship of GA20ox genes had been confirmed to be closest in different genera of plants in a phylogenetic and selective pressure analysis between Moso bamboo and rice. About 1/3 GA20ox genes experienced positive selective pressure with segmental duplication being the main driver of gene family expansion. Analysis of expression patterns revealed that only six PheGA20ox genes were expressed in different organs of shoot development and flowers, that there was redundancy in gene function. Underground organs were not the main site of GA synthesis in Moso bamboo, and floral organs are involved in the GA biosynthesis process. The auxin signaling factor PheARF47 was located upstream of PheGA20ox3 and PheGA20ox6 genes, where PheARF47 regulated PheGA20ox3 through cis-P box elements and cis-AuxRR elements, based on the result that promoter analysis combined with yeast one-hybrid and dual luciferase detection analysis identified. Overall, we identified the evolutionary pattern of PheGA20ox genes in Moso bamboo and the possible major synthesis sites of GA, screened for key genes in the crosstalk between auxin and GA, and laid the foundation for further exploration of the synergistic regulation of growth by GA and auxin in Moso bamboo. Full article

Gibberellin (GAs) plays an important regulatory role in the development and growth of pineapple (Ananas comosus (L.) Merr.). Bioinformatics was used to confirm the differential expression of GA2 gibberellin oxidase gene AcGA2oxs in the pineapple genome, which laid the foundation for exploring its role in pineapple. In this study, 42 GA2ox genes (AcGA2oxs) were identified in the pineapple genome, named from AcGA2ox1 to AcGA2ox42, and divided into four groups according to phylogenetic analysis. We also analyzed the gene structure, conserved motifs and chromosome localization of AcGA2oxs. AcGA2oxs within the same group had similar gene structure and motifs composition. Collinear analysis and cis-element analysis provided the basis for understanding the evolution and function of GA2ox genes in pineapple. In addition, we selected different tissue parts to analyze the expression profile of AcGA2oxs, and the results show that 41 genes were expressed, except for AcGA2ox18. AcGA2ox18 may not be expressed in these sites or may be pseudogenes. qRT-PCR (real-time fluorescence quantitative PCR) was used to detect the relative expression levels of the GA2ox gene family under different concentrations of GA3 treatment, and it was found that AcGA2ox gene expression was upregulated in different degrees under GA3 treatment. These results provide useful information for further study on the evolution and function of the GA2ox family in pineapple. Full article

Gibberellins (GAs) are the key regulators controlling plant growth, wood production and the stress responses in perennial woody plants. The role of GA in regulating the above-mentioned processes in Eucalyptus remain largely unclear. There is still a lack of systematic identification and functional characterization of GA-related genes in Eucalyptus. In this study, a total of 59,948 expressed genes were identified from the major vegetative tissues of the E. grandis × E. urophylla using transcriptome sequencing. Then, the key gene families in each step of GA biosynthesis, degradation and signaling were investigated and compared with those of Arabidopsis, rice, and Populus. The expression profile generated using Real-time quantitative PCR showed that most of these genes exhibited diverse expression patterns in different vegetative organs and in response to abiotic stresses. Furthermore, we selectively overexpressed EguGA20ox1, EguGA20ox2 and EguGA2ox1 in both Arabidopsis and Eucalyptus via Agrobacterium tumefaciens or A. rhizogenes-mediated transformation. Though both Arabidopsis EguGA20ox1- and EguGA20ox2-overexpressing (OE) lines exhibited better vegetative growth performance, they were more sensitive to abiotic stress, unlike EguGA2ox1-OE plants, which exhibited enhanced stress resistance. Moreover, overexpression of EguGA20ox in Eucalyptus roots caused significantly accelerated hairy root initiation and elongation and improved root xylem differentiation. Our study provided a comprehensive and systematic study of the genes of the GA metabolism and signaling and identified the role of GA20ox and GA2ox in regulating plant growth, stress tolerance, and xylem development in Eucalyptus; this could benefit molecular breeding for obtaining high-yield and stress-resistant Eucalyptus cultivars. Full article

(1) The phytohormones gibberellins (GAs) play a crucial role in plant growth and development, such as seed germination, flowering, fruiting, and stem elongation. Although many biological roles of GAs have been studied intensively, the molecular mechanisms of GAs in woody plants are still unclear. (2) In this study, we investigated the effects of exogenous application of GAs on Neolamarckia cadamba. (3) The height and biomass of N. cadamba increased after 7 days of GA treatment, especially on the second internode. Transcriptome analysis showed that although the majority of genes involved in the GA signaling pathway were up-regulated, the expression of GA20 oxidase (GA20ox) and GA3 oxidase (GA3ox) was down-regulated in the 3 days GA-treated group compared to the CK group. The expression of the cell elongation-related basic helix-loop-helix genes bHLH74 and bHLH49 was up-regulated in the GA-treated group compared with the CK group. Transcriptional expression levels of transcription factors involved in hormone signaling were changed, mainly including bHLH, ethylene response factor (ERF), and WRKY families. In addition, the transcriptional expression level of the key enzymes engaged in the phenylalanine pathway was downregulated after GA treatment. (4) In brief, our findings reveal the physiological and molecular mechanisms of exogenous GA treatment stimulation in N. cadamba. Full article

Paclobutrazol (PBZ) is a plant-growth regulator (PGR) in the triazole family that enhances plant tolerance to environmental stresses. Low-light (LL) intensity is a critical factor adversely affecting the growth of tall fescue (Festuca arundinacea Schreb.). Therefore, in this study, tall fescue seedlings were treated with PBZ under control and LL conditions to investigate the effects of PBZ on enhancing LL stress resistance by regulating the growth, photosynthesis, oxidative defense, and hormone levels. Our results reveal that LL stress reduced the total biomass, chlorophyll (Chl) content, photosynthetic capacity, and photochemical efficiency of photosystem II (PSII) but increased the membrane lipid peroxidation level and reactive oxygen species (ROS) generation. However, the application of PBZ increased the photosynthetic pigment contents, net photosynthetic rate (P_n), maximum quantum yield of PSII photochemistry (F_v/F_m), ribulose-1,5-bisphosphate carboxylase (RuBisCO) activity, and starch content. In addition, PBZ treatment activated the antioxidant enzyme activities, antioxidants contents, ascorbate acid-glutathione (AsA-GSH) cycle, and related gene expression, lessening the ROS burst (H₂O₂ and O₂∙⁻). However, the gibberellic acid (GA) anabolism was remarkably decreased by PBZ treatment under LL stress, downregulating the transcript levels of kaurene oxidase (KO), kaurenoic acid oxidase (KAO), and GA 20-oxidases (GA20ox). At the same time, PBZ treatment up-regulated 9-cis-epoxycarotenoid dioxygenase (NCED) gene expression, significantly increasing the endogenous abscisic acid (ABA) concentration under LL stress. Thus, our study revealed that PBZ improves the antioxidation and photosynthetic capacity, meanwhile increasing the ABA concentration and decreasing GA concentration, which ultimately enhances the LL stress tolerance in tall fescue. Full article

Plant defense and growth rely on multiple transcriptional factors (TFs). Repression of shoot growth (RSG) is a TF belonging to a bZIP family in tobacco, known to be involved in plant gibberellin feedback regulation by inducing the expression of key genes. The tobacco calcium-dependent protein kinase CDPK1 was reported to interact with RSG and manipulate its intracellular localization by phosphorylating Ser-114 of RSG previously. Here, we identified tobacco mitogen-activated protein kinase 3 (NtMPK3) as an RSG-interacting protein kinase. Moreover, the mutation of the predicted MAPK-associated phosphorylation site of RSG (Thr-30, Ser-74, and Thr-135) significantly altered the intracellular localization of the NtMPK3-RSG interaction complex. Nuclear transport of RSG and its amino acid mutants (T30A and S74A) were observed after being treated with plant defense elicitor peptide flg22 within 5 min, and the two mutated RSG swiftly re-localized in tobacco cytoplasm within 30 min. In addition, triple-point mutation of RSG (T30A/S74A/T135A) mimics constant unphosphorylated status, and is predominantly localized in tobacco cytoplasm. RSG (T30A/S74A/T135A) showed no re-localization effect under the treatments of flg22, B. cereus AR156, or GA₃, and over-expression of this mutant in tobacco resulted in lower expression levels of downstream gene GA20ox1. Our results suggest that MAPK-associated phosphorylation sites of RSG regulate its localization in tobacco, and that constant unphosphorylation of RSG in Thr-30, Ser-74, and Thr-135 keeps RSG predominantly localized in cytoplasm. Full article

Gibberellins (GAs), a pivotal plant hormone, play fundamental roles in plant development, growth, and stress response. In rice, gibberellin-dioxygenases (GAoxes) are involved in the biosynthesis and deactivation of gibberellins. However, a comprehensive genome-wide analysis of GA oxidases in rice was not uncovered. Here, a total of 80 candidate OsGAox genes were identified and 19 OsGAox genes were further analyzed. Studies on those 19 OsGAox genes, including phylogenetic tree construction, analysis of gene structure, exploration of conserved motifs and expression patterns, were conducted. Results showed that the GAox genes in Arabidopsis and rice were divided into four subgroups and shared some common features. Analysis of gene structure and conserved motifs revealed that splicing phase and motifs were well conserved during the evolution of GAox genes in Arabidopsis and rice, but some special conserved motifs possessed unknown functions need to be further studied. Exploration of expression profiles from RNA-seq data indicated that each GAox gene had tissue-specific expression patterns, although they varied greatly. The expression patterns of these genes under GA₃ treatment revealed that some genes, such as OsGA2ox1, OsGA2ox3, OsGA2ox4, OsGA2ox7, OsGA20ox1, and OsGA20ox4, may play a major role in regulating the level of bioactive GA. Taken together, our study provides a comprehensive analysis of the GAox gene family and will facilitate further studies on their roles in rice growth and development so that these genes can be better exploited. Full article

The plant hormones gibberellins (GAs) regulate plant growth and development and are closely related to the yield of cash crops. The GA oxidases (GAoxs), including the GA2ox, GA3ox, and GA20ox subfamilies, play pivotal roles in GAs’ biosynthesis and metabolism, but their classification and evolutionary pattern in Gramineae crops remain unclear. We thus conducted a comparative genomic study of GAox genes in six Gramineae representative crops, namely, Setaria italica (Si), Zea mays (Zm), Sorghum bicolor (Sb), Hordeum vulgare (Hv), Brachypodium distachyon (Bd), and Oryza sativa (Os). A total of 105 GAox genes were identified in these six crop genomes, belonging to the C₁₉-GA2ox, C₂₀-GA2ox, GA3ox, and GA20ox subfamilies. Based on orthogroup (OG) analysis, GAox genes were divided into nine OGs and the number of GAox genes in each of the OGs was similar among all tested crops, which indicated that GAox genes may have completed their family differentiations before the species differentiations of the tested species. The motif composition of GAox proteins showed that motifs 1, 2, 4, and 5, forming the 2OG-FeII_Oxy domain, were conserved in all identified GAox protein sequences, while motifs 11, 14, and 15 existed specifically in the GA20ox, C₁₉-GA2ox, and C₂₀-GA2ox protein sequences. Subsequently, the results of gene duplication events suggested that GAox genes mainly expanded in the form of WGD/SD and underwent purification selection and that maize had more GAox genes than other species due to its recent duplication events. The cis-acting elements analysis indicated that GAox genes may respond to growth and development, stress, hormones, and light signals. Moreover, the expression profiles of rice and maize showed that GAox genes were predominantly expressed in the panicles of the above two plants and the expression of several GAox genes was significantly induced by salt or cold stresses. In conclusion, our results provided further insight into GAox genes’ evolutionary differences among six representative Gramineae and highlighted GAox genes that may play a role in abiotic stress. Full article

The Tiller Angle Control 1 (TAC1) gene belongs to the IGT family, which mainly controls plant branch angle, thereby affecting plant form. Two members of MdTAC1 are identified in apple; the regulation of apple branch angle by MdTAC1 is still unclear. In this study, a subcellular localization analysis detected MdTAC1a in the nucleus and cell membrane, but MdTAC1b was detected in the cell membrane. Transgenic tobacco by overexpression of MdTAC1a or MdTAC1b showed enlarged leaf angles, the upregulation of several genes, such as GA 2-oxidase (GA2ox), and a sensitive response to light and gravity. According to a qRT-PCR analysis, MdTAC1a and MdTAC1b were strongly expressed in shoot tips and vegetative buds of weeping cultivars but were weakly expressed in columnar cultivars. In the MdTAC1a promoter, there were losses of 2 bp in spur cultivars and 6 bp in weeping cultivar compared with standard and columnar cultivars. An InDel marker specific to the MdTAC1a promoter was developed to distinguish apple cultivars and F₁ progeny. We identified a protein, MdSRC2, that interacts with MdTAC1a, whose encoding gene which was highly expressed in trees with large branch angles. Our results indicate that differences in the MdTAC1a promoter are major contributors to branch-angle variation in apple, and the MdTAC1a interacts with MdSRC2 to affect this trait. Full article