Search Results (29)

Double-petal ornamental pomegranate presents for its enhanced ornamental value. Thus, cultivation techniques that promote petaloidy while modulating related gene expression are desired. To screen out the efficient treatments of plant growth regulator and key genes that enhance petaloidy, this study treated the flower buds of double- and single-petal ornamental pomegranate varieties with different concentrations of plant growth regulators naphthaleneacetic acid (NAA), methyl jasmonate (MeJA), abscisic acid (ABA), and ethephon (ETH) and quantified the number of petalized stamens (NOPSs) and the number of petals (NOPs) in both varieties. Furthermore, we investigated the expression levels of the genes flavin-containing monooxygenase (YUC), IAA-amino acid hydrolase (ILR1),indole-3-acetic acid-amido synthetase (GH3.17), auxin transporter (LAX2), auxin response factor (ARF), auxin-induced in root cultures protein (AIR12), jasmonic acid-amido synthetase (JAR1), and ABA stress ripening-induced protein (ASR) under the different treatments and analyzed their role in regulating relevant phenotypic traits. Plant growth regulator experiments demonstrated that NAA (10 mg/L) significantly increased the number of petalized stamens (NOPSs) and petals (NOPs), MeJA (100 mg/L) significantly increased the number of petalized stamens, while neither ABA nor ETH induced this morphological shift. qRT-PCR analysis confirmed that NAA upregulated ILR1, LAX2, ARF, and JAR1 in the stamens of single-petal flowers (StSi) and double-petal flowers (StDo) and petals of single-petal flowers (PeSi) and double-petal flowers (PeDo), with their expression levels strongly positively correlated with NOPS in both single- and double-petal flowers and NOP in double-petal flowers. MeJA upregulated ILR1, GH3.17, LAX2, ARF, and JAR1 in StDo and PeDo and was strongly positively correlated with NOPS and NOP in double-petal flowers. Consequently, NAA (10 mg/L) and MeJA (100 mg/L) were efficient treatments, and ILR1, GH3.17, LAX2, ARF, and JAR1 were identified as key genes in NAA- and MeJA-mediated petaloidy in ornamental pomegranates. Our results provide theoretical support for identifying the formation mechanism and improving industrial cultivation techniques for double-petal pomegranates. Full article

Cytoplasmic male sterility (CMS) is a crucial tool for exploiting plant heterosis, though its underlying mechanisms in tobacco remain incompletely understood. In this study, Tobacco CMSK326, derived from a naturally occurring variant of Nicotiana tabacum, exhibited a range of stamen abnormalities, including stamen degeneration, stamen absence, and carpelloid, petaloid, and sepaloid traits. Histological and electron microscopy showed that CMS K326 and its maintainer differentiated at the early bud stage. Analysis of differentially expressed genes (DEGs) revealed abnormal expressions of several key genes, including WUSCHEL (WUS), GLOBOSA (GLO), SUPERMAN (SUP), and auxin-related genes such as AUX22, during bud development. Weighted gene correlation network analysis (WGCNA) identified a module highly correlated with flower development, the tricarboxylic acid cycle (TCA), auxin, and the mitochondrial retrograde regulation signal molecules CDKE1 and KIN10. The promoter regions of 19 out of the 42 hub genes in this module possess auxin cis-response elements. These results point to a correlation between auxin irregularities and stamen development in CMS K326. Full article

Background: The Actinidia deliciosa cultivar ‘Guichang’ is a remarkable kiwifruit variety. The phenotypic traits of this variety are influenced by the climatic conditions in Guizhou. The flowering time, which is shaped by multiple environmental factors, has a substantial impact on both the fruit yield and quality. Objectives and Methods: This study was designed to explore the molecular mechanisms underlying the transition from bud to flowering in ‘Guichang’ through transcriptomic and proteomic analyses. Results: The transcriptomic results revealed that 6201 genes were up-regulated, while 5849 genes were down-regulated during this transition. Key genes related to hormone signaling, such as AdPIF4, AdBSK, AdBRI1, and AdCYCD3, were recognized as crucial regulators. The proteomic analysis detected a total of 10,488 proteins. Among them, AdBSK1 was regulated, while AdPIF4, AdBRI1, and AdCYCD3 showed stable expressions. A moderate positive correlation (with a Pearson correlation coefficient of 0.445) was found between the expression levels of transcriptomics and proteomics. When AdBSK1 was over-expressed in Arabidopsis, it promoted earlier flowering. This was achieved by down-regulating FLC and up-regulating FT and SOC1. Conclusions: This study clarifies the molecular mechanisms involved in the bud-to-flowering transition in ‘Guichang’. It emphasizes the intricate interactions among hormonal pathways, key genes, and proteins, which are consistent with the broader understanding of plant flowering regulation in recent research. These findings are significant for deepening our understanding of, and potentially controlling, the flowering mechanisms. Full article

Camellia’s ornamental value is constrained by its natural winter–spring flowering period. Although the discovery of Camellia azalea provides important germplasm resources for developing cultivars with year-round flowering, the molecular mechanisms underlying flowering time variation remain unclear. Here, we investigated three germplasms with distinct flowering patterns: winter–spring flowering Camellia japonica ‘Tieke Baozhu’, summer–autumn flowering Camellia azalea, and their hybrid Camellia ‘Lingnan Yuanbao’ inheriting the latter’s flowering traits. Integrated transcriptomic and metabolomic analyses revealed that differentially expressed genes (DEGs) and metabolites (DAMs) were mainly enriched in the pathways related to photoperiod regulation, plant hormone synthesis and signal transduction and flavonoid synthesis. The transcription factor (TF) analysis revealed that the bHLH and MYB TF families were significantly differentially expressed in different Camellia germplasm, suggesting their potential involvement in the regulation of flowering time through the plant hormone signal transduction and photoperiod pathway. Meanwhile, photoperiod regulation related genes, including Cryptochrome circadian regulator (CRY), Timing of CAB expression 1 (TOC1), and phytochrome interacting factor 3 (PIF3), showed significant expression differences, further confirming the photoperiod pathway’s crucial regulatory function. In terms of plant hormone levels, there were significant differences in the levels of gibberellin (GA), abscisic acid (ABA), and jasmonic acid (JA) among Camellia germplasm. The differential expression characteristics of DELLA (Asp-Glu-Leu-Leu-Ala) proteins indicated that the GA signal transduction pathway was one of the key factors regulating flowering time in Camellia. Additionally, metabolomics analyses showed significant differences in flavonoid metabolite content among Camellia germplasm, which was significantly correlated with the different developmental stages of the buds. Our findings provide a theoretical basis for the molecular breeding of everblooming Camellia cultivars, advancing the understanding of flowering regulation mechanism in ornamental species. Full article

Cotton is regarded as one of the significant economic crops in China, and its earliness is defined as one of the crucial traits influencing fiber quality and yield. To study the physiological and biochemical mechanisms related to early-maturing traits of cotton, cotton shoot apexes at the one-leaf, three-leaf, and five-leaf stages of the early-maturing cotton CCRI50 and late-maturing cotton Guoxinmian11 were collected for transcriptome sequencing and metabolomics, respectively. A total of 616, 782, and 842 differentially expressed genes (DEGs) at the one-leaf stage, three-leaf stage, and five-leaf stage were obtained through transcriptome sequencing, respectively. The metabolic detection results showed that 68, 56, and 62 differential metabolites (DMs) were obtained in the three periods, respectively. A total of 10 DMs were detected simultaneously from the one-leaf to five-leaf stage, 4 of which were phenolic acids and down-regulated in the early maturing variety CCRI50. A combined transcriptomic and metabolomic analysis revealed that phenylpropanoid biosynthesis, tyrosine metabolism, and phenylalanine metabolism might be important metabolic pathways in cotton bud differentiation. GhTYDC-A01 was identified in both the tyrosine metabolism and phenylalanine metabolism pathways, and it was highly expressed in pistils. To investigate the function of this gene in flowering, we overexpressed it in Arabidopsis thaliana. Compared to the wild type, the flowering time of the overexpression of GhTYDC-A01 in Arabidopsis was delayed. This study provides valuable resources and new insights into the relationship between metabolites and early-maturing cotton. Full article

Transposable elements (TEs) are crucial for genome evolution and ecological adaptation, but their dynamics in non-model plants are poorly understood. Using genomic, transcriptomic, and population genomic approaches, we analyzed the TE landscape of Barthea barthei (Melastomataceae), a species distributed across tropical and subtropical southern China. We identified 64,866 TE copies (16.76% of a 235 Mb genome), dominated by Ty3/Gypsy retrotransposons (8.82%) and DNA/Mutator elements (2.7%). A genome-wide analysis revealed 13 TE islands enriched in genes related to photosynthesis, tryptophan metabolism, and stress response. We identified 3859 high-confidence TE insertion polymorphisms (TIPs), including 29 fixed insertions between red and white flower ecotypes, affecting genes involved in cell wall modification, stress response, and secondary metabolism. A transcriptome analysis of the flower buds identified 343 differentially expressed TEs between the ecotypes, 30 of which were near or within differentially expressed genes. The non-random distribution (primarily within 5 kb of genes) and association with adaptive traits suggest a significant role in B. barthei’s successful colonization of diverse habitats. Our findings provide insights into how TEs contribute to plant genome evolution and ecological adaptation in tropical forests, particularly through their influence on regulatory networks governing stress response and development. Full article

Nightlily (Hemerocallis citrina Baroni) is an important vegetable with edible floral organs. It possesses considerable economic value due to its edibility, ornamental, and medicinal properties. However, the genetic linkage map construction and quantitative trait locus (QTL) mapping of nightlily have not been performed. This study used two varieties ‘Dongzhuanghuanghua’ and ‘Chonglihua’ of nightlily as cross parents to establish an intraspecific hybridization population of 120 F₁ progenies. The ‘Datonghuanghua’ (female) variety of nightlily and ‘Lullaby Baby’ (male) variety of daylily were selected to construct an interspecific hybridization population of 55 F₁ progenies. A total of 965 expressed sequence tag–simple sequence repeats (EST-SSRs), along with 20 SSR markers from various sources, were used for genetic mapping. Among these markers, CT/TC (9.24%) of the dinucleotide and GGA/GAG/AGG (4.67%) of the trinucleotide repeat motifs were most abundant. In the intraspecific hybridization genetic map, a total of 124 markers were resolved into 11 linkage groups, with a total map length of 1535.07 cM and an average interval of 12.38 cM. Similarly, the interspecific hybridization map contained 11 linkage groups but with 164 markers, a total map length of 2517.06 cM, and an average interval of 15.35 cM. The two constructed maps had 48 identical markers and demonstrated good collinearity. The collinearity analysis showed that 161 markers hit the genomic sequence of the published H. citrina genome, indicating that the two constructed genetic maps had high accuracy. Phenotypic data were investigated over two consecutive years (2018 and 2019) for flower bud fresh weight, dry weight, and bud length in two hybridization populations. A total of nine QTLs associated with flower bud-related traits were identified, among which those located on linkage group 8 of the intraspecific genetic map and linkage group 4 of the interspecific genetic map showed good stability. All nine QTLs had LOD values of not less than 4 and PVE values of not less than 15% over two years. This is the first report about the intra- and interspecific genetic map construction and QTL mapping of the flower bud-related traits in nightlily based on a genetic map. The results promote marker-assisted breeding and offer insights into the mechanisms underlying important traits of the genus Hemerocallis. Full article

Methylation plays an important role in regulating crop development, but little is known about how methylation regulates plant architecture in rapeseed (Brassica napus L.). Here, we examined how methylation affects the thickness-of-pod-canopy (TPC) trait in rapeseed by performing genome-wide methylation analysis of two extreme TPC lines. In flower buds, 26 genes had significantly higher methylation levels in the high-TPC samples compared to the low-TPC samples, resulting in significantly reduced gene expression. By contrast, in the stem apex samples, the promoter regions of 22 genes were hypermethylated in the high- vs. low-TPC samples. The promoters of 19 and 21 genes had significantly reduced methylation levels in the flower bud and stem apex, respectively, of the high- vs. low-TPC samples, resulting in significantly higher expression levels. Some of these differentially expressed genes are associated with TPC-related traits, such as BnaC01g12960D (NRT1.8). In addition, 14 important genes related to growth and development were differentially regulated between the two groups due to miRNA-mediated differences in methylation levels in their promoters. For example, hypermethylation in the promoter region of BnaCnng64040D (Lipase family protein), mediated by miR159, led to significantly reduced gene expression in flower buds of high-TPC vs. low-TPC lines. These results, together with our previously generated RNA-seq and miRNA profiling data, indicate that both methylation and miRNAs are perhaps involved in regulating the expression of genes, thereby affecting the TPC trait in B. napus, providing a reference for uncovering the molecular mechanism regulating this crucial trait. Full article

Ogura cytoplasmic male sterility (CMS) lines play a crucial role in the utilization of heterosis. However, valuable traits, such as disease resistance genes from Ogura CMS hybrids, are challenging to incorporate for germplasm innovation, particularly in cabbage and broccoli. To date, the Rfo-mediated network regulating fertility restoration remains largely unexplored. In this study, we conducted a transcriptomic analysis of broccoli flower buds from Ogura CMS SFB45 and its Rfo-transgenic fertility restoration line, pRfo, at different stages of pollen development. Gene Ontology (GO) terms such as “pollen exine formation”, “flavonoid metabolic and biosynthetic processes”, and “pollen wall assembly”, along with Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways including “flavonoid biosynthesis”, “MAPK signaling pathway-plant”, and “ABC transporters”, were significantly enriched. We identified five differentially expressed genes (DEGs) involved in tapetum-mediated callose metabolism, thirty-four DEGs related to tapetum-mediated pollen wall formation, three DEGs regulating tapetum programmed cell death (PCD), five MPKs encoding DEGs, and twelve DEGs associated with oxidative phosphorylation. Additionally, yeast two-hybrid and bimolecular fluorescence complementation (BiFC) assays demonstrated that RFO directly interacts with ORF138 at the protein level. These findings provide valuable insights into the fertility recovery mechanisms regulated by Rfo in broccoli and offer important clues for breeders aiming to enhance Ogura CMS hybrids in Brassica oleracea. Full article

Two important traits of Chinese cabbage, internode length and budding time, destroy the maintenance of rosette leaves in the vegetative growth stage and affect flowering in the reproductive growth stage. Internodes have received much attention and research in rice due to their effect on lodging resistance, but they are rarely studied in Chinese cabbage. In Chinese cabbage, internode elongation affects not only the maintenance of rosette leaves but also bolting and yield. Budding is also an important characteristic of Chinese cabbage entering reproductive growth. Although many studies have reported on flowering and bolting, studies on bud emergence and the timing of budding are scarce. In this study, the mutant lcc induced by EMS (Ethyl Methane Sulfonate) was used to study internode elongation in the seedling stage and late budding in the budding stage. By comparing the gene expression patterns of mutant lcc and wild-type A03, 2280 differentially expressed genes were identified in the seedling stage, 714 differentially expressed genes were identified in the early budding stage, and 1052 differentially expressed genes were identified in the budding stage. Here, the transcript expression patterns of genes in the plant hormone signaling and clock rhythm pathways were investigated in relation to the regulation of internode elongation and budding in Chinese cabbage. In addition, an F₂ population was constructed with the mutants lcc and R500. A high-density genetic map with 1602 marker loci was created, and QTLs for internode length and budding time were identified. Specifically, five QTLs for internode length and five QTLs for budding time were obtained. According to transcriptome data analysis, the internode length candidate gene BraA02g005840.3C (PIN8) and budding time candidate genes BraA02g003870.3C (HY5-1) and BraA02g005190.3C (CHS-1) were identified. These findings provide insight into the regulation of internode length and budding time in Chinese cabbage. Full article

The oil sunflower is an important oil crop and ornamental plant. Flowering time affects the environmental adaptability and final yield of oil sunflowers. Floral induction is one of the important events that determines subsequent reproductive growth and seed setting, but there has been no systematic study on the regulation of gene expression during the transition from vegetative growth to reproductive growth in oil sunflowers. In this study, an oil sunflower mutant displaying early flowering (ef) was obtained by heavy ion beam irradiation. This mutant had a stable genetic trait, and its flowering time was 15 days earlier than the wild type (WT) in the field. The histology result showed that the ef mutant induced floral meristem at 6-leaf stage earlier than WT. The shoot apical meristems (SAMs) of the ef mutant and WT at 4-leaf, 6-leaf, 8-leaf, 10-leaf and budding periods were collected for RNA sequencing. The results showed that the transition from the leaf meristem to the floral meristem resulted in significant changes in the transcriptional landscape. Overall, 632, 1825, 4549, 5407 and 2164 differentially expressed genes (DEGs) were identified at 4-leaf, 6-leaf, 8-leaf, 10-leaf and budding periods, respectively. These DEGs were mainly enriched in biological pathways, including plant hormone signal transduction, carbon metabolism, protein processing in endoplasmic reticulum, secondary metabolism, and photosynthesis. We also found significant differences in the expression levels of starch and sucrose metabolism-related genes in the ef mutant and WT, indicating that sugar signaling plays an important role in the early flowering of oil sunflowers, especially SUC9 and sugar synthesis and degradation enzyme genes. In addition to hormone and sugar signals, flowering integration genes SOC1, AP1, FUL and LFY were upregulated in the ef mutant, and genes in photoperiod, aging, autonomous and temperature pathways were also involved in the regulation of floral transition. The results showed that plant hormones, sucrose metabolism, and flowering genes synergistically cause the early flowering of oil sunflowers. Our study provided important information for understanding flowering and is helpful for the genetic improvement of sunflowers. Full article

Plant height plays an important role in crop yield, product quality, and cultivation management. However, the physiological mechanisms that regulate the establishment of plant height in alfalfa plants remain unclear. Herein, we measured plant height traits, leaf characteristics, photosynthetic physiology, cell wall composition, and endogenous hormone contents of tall- and short-stalked alfalfa materials at different reproductive periods. We analyzed the physiology responsible for differences in plant height. The results demonstrated that the number of internodes in tall- and short-stalked alfalfa materials tended to converge with the advancement of the fertility period. Meanwhile, the average internode length (IL) of tall-stalked materials was significantly higher than that of short-stalked materials at different fertility periods, with internode length identified as the main trait determining the differences in alfalfa plant height. Leaf characteristics, which are closely related to photosynthetic capacity, are crucial energy sources supporting the expression of plant height traits, and we found that an increase in the number of leaves contributed to a proportional increase in plant height. Additionally, a significant positive correlation was observed between plant height and leaf dry weight per plant during the branching and early flowering stages of alfalfa. The leaves of alfalfa affect plant height through photosynthesis, with the budding stage identified as the key period for efficient light energy utilization. Plant height at the budding stage showed a significant positive correlation with soluble sugar (SS) content and a significant negative correlation with intercellular CO₂ concentration. Moreover, we found that alfalfa plant height was significantly correlated with the contents of indole-3-acetic acid in stem tips (SIAA), gibberellin A₃ in leaves (LGA₃), zeatin in stem tips (SZT), and abscisic acid in leaves (LABA). Further investigation revealed that SS, SIAA, and LGA₃ contents were important physiological indicators affecting alfalfa plant height. This study provides a theoretical basis for understanding the formation of alfalfa plant height traits and for genetic improvement studies. Full article

Broccoli (Brassica oleracea L. var. italica) has a large, edible green flower head, which is one of its critical economic traits. A prerequisite of broccoli flower head formation is flower bud differentiation (FBD). Low-temperature treatment is an effective way to induce FBD in broccoli. However, the molecular mechanism underlying low-temperature-induced broccoli FBD remains largely unclear. In this study, using broccoli cultivar Zhongqing 10 as the experimental material, we investigated the effects of low-temperature treatment on FBD by comparing the plants grown at low temperatures (17 °C/9 °C, 16 h/8 h) with the control plants grown under normal temperature conditions (25 °C/17 °C, 16 h/8 h). After 15 days of different temperature treatments, the flower buds of the plants growing under the low-temperature condition started to differentiate. However, the control plants remained in the vegetative growth stage, indicating that low temperature successfully induced flower bud formation. Subsequently, a global transcriptomic analysis was conducted to detect the differentially expressed genes (DEGs) during low-temperature-induced FBD in broccoli. A total of 14 DEGs in five phytohormone signaling pathways, 42 DEGs in nine transcription factor families, and 16 DEGs associated with the floral development pathways were identified. More DEGs were present in the auxin signaling pathway than in other phytohormone signaling pathways, which indicated that the auxin signaling pathway played a critical role in modulating low-temperature-induced FBD in broccoli. Furthermore, four TF classes, including bZIP, GCM domain factors, MADS-box factors, and C2H2 zinc finger factors, possessed enriched motifs, indicating that their closely related DETFs ABI5, HY5L, WRKY11, WRKY15, WRKY22, SOC1, AGL8, FLC, SPL8, and SPL15 may be directly involved in the transcription regulation of broccoli FBD. This study provides an important basis for further investigation of the molecular regulatory mechanism of broccoli flower development under low temperatures. Full article

In Fraxinus mandshurica Rupr. (F. mandshurica), the mature seeds exhibit a deep dormancy trait, and the seedlings are vulnerable to external environmental factors, such as low temperature and drought, leading to ecological dormancy. In order to investigate the role of FmDELLA in growth and development, the variation in FmDELLA transcriptional level, the endogenous hormone content in seed germination and bud dormancy release, and the effects of the month, organs, and exogenous hormones on FmDELLA were determined. The results showed that FmDELLA genes had a synergistic impact with the XERICO, PP2C, and DOG genes on regulating hypocotyl elongation during seed germination. Unlike growing buds, the dormant buds had much higher levels of FmDELLA transcripts. Still, these transcript levels were lowered by using 100 mg/L exogenous gibberellin acid (GA), which could promote bud dormancy release. Exogenous hormones regulated the transcription of FmDELLA, which primarily occurred in the stems, leaves, buds, and flowers and reached its lowest level in September. The transition from dormancy to germination for buds and seeds was related to increased GA, auxin, and cytokinin and decreased abscisic acid. In conclusion, our study revealed the role of FmDELLA in the seed germination and release of bud dormancy and provided a solid basis for F. mandshurica tissue culture and micropropagation. Full article

Shea tree (Vitellaria paradoxa) is an important fruit tree crop because of its oil used for cooking and the industrial manufacture of cosmetics. Despite its essential benefits, quantitative trait loci linked to the economic traits have not yet been studied. In this study, we performed association mapping on a panel of 374 shea tree accessions using 7530 Single-Nucleotide Polymorphisms (SNPs) markers for oil yield and seed-related traits. Twenty-three SNP markers significantly (−log10 (p) = 4.87) associated with kernel oil content, kernel length, width, and weight were identified. The kernel oil content and kernel width had the most significant marker–trait associations (MTAs) on chromosomes 1 and 8, respectively. Sixteen candidate genes identified were linked to early induction of flower buds and somatic embryos, seed growth and development, substrate binding, transport, lipid biosynthesis, metabolic processes during seed germination, and disease resistance and abiotic stress adaptation. The presence of these genes suggests their role in promoting bioactive functions that condition high oil synthesis in shea seeds. This study provides insights into the important marker-linked seed traits and the genes controlling them, useful for molecular breeding for improving oil yield in the species. Full article