Stages Of Bud Development Research Articles

Multi-omics analysis reveals the regulatory mechanism of branching development in Quercus fabri.

The ability of axillary meristems to form axillary buds and subsequently develop into branches is influenced by phytohormones, environmental conditions, and genetic factors. The main trunk of Quercus fabri is prone to branching, which not only impacts the appearance and density of the wood and significantly reduces the yield rate. This study conducted transcriptomic, proteomic, and metabolomic analyses on three stages of axillary bud development in Q. fabri. A total of 12,888 differentially expressed genes (DEGs), 8193 differentially accumulated proteins (DAPs), and 1788 differentially accumulated metabolites (DAMs) were identified through comparisons among the stages and subjected to multi-omics joint analysis. Conduct interaction network analysis on DEGs and DAPs to identify the significant transcription factor family (AP2/ERF) involved in the regulation of axillary bud development. Furthermore, KEGG enrichment analysis of DEGs, DAPs and DAMs indicated significant enrichment in plant hormone signaling pathways. The analysis of endogenous hormone levels and qRT-PCR results for pathway genes demonstrated that the expression levels of IAA and tZ significantly increased during late developmental stages, whereas the expression levels of ABA, ACC and JA significantly decreased. In summary, these findings contribute to a comprehensive understanding of the regulatory networks underlying the branching development of Q. fabri. SIGNIFICANCE: Q. fabri exhibits robust vegetative growth, and its primary trunk is prone to branching, significantly influencing the wood yield rate. Through a joint analysis of transcriptomics, proteomics, and metabolomics, we comprehensively examined the regulatory network governing the axillary bud development of Q. fabri. Our findings revealed the crucial roles of the AP2/ERF transcription factor family and plant hormone signal transduction pathways in branch development. These insights contribute to a deeper understanding of the mechanisms regulating branch development.

Metabolites of blueberry roots at different developmental stages strongly shape microbial community structure and intra-kingdom interactions at the root-soil interface

The rhizosphere microorganisms of blueberry plants have long coexisted with their hosts under distinctively acidic soil conditions, exerting a profound influence on host performance through mutualistic symbiotic interactions. Meanwhile, plants can regulate rhizosphere microorganisms by exerting host effects to meet the functional requirements of plant growth and development. However, it remains unknown how the developmental stages of blueberry plants affect the structure, function, and interactions of the rhizosphere microbial communities. Here, we examined bacterial communities and root metabolites at three developmental stages (flower and leaf bud development stage, fruit growth and development stage, and fruit maturation stage) of blueberry plants. The results revealed that the Shannon and Chao 1 indices as well as community composition varied significantly across all three developmental stages. The relative abundance of Actinobacteria significantly increased by 10 % (p < 0.05) from stage 1 to stage 2, whereas that of Proteobacteria decreased significantly. The co-occurrence network analysis revealed a relatively complex network with 1179 edges and 365 nodes in the stage 2. Niche breadth was highest at stage 2, while niche overlap tended to increase as the plant developed. Furthermore, the untargeted metabolome analysis revealed that the number of differential metabolites of vitamins, nucleic acids, steroids, and lipids increased between stage 1 to stage2 and stage 2 to stage 3, while those for differential metabolites of carbohydrates and peptides decreased. Significant changes in expression levels of levan, L-glutamic acid, indoleacrylic acid, oleoside 11-methyl ester, threo-syringoylglycerol, gingerglycolipid B, and bovinic acid were highly correlated with the bacterial community structure. Collectively, our study reveals that significant alterations in dominant bacterial taxa are strongly correlated with the dynamics of root metabolites. These findings lay the groundwork for developing prebiotic products to enhance the beneficial effects of root microorganisms and boosting blueberry productivity via a sustainable approach.

Regulated Deficit Irrigation Perspectives for Water Efficiency in Apricot Cultivation: A Review

Addressing agricultural water scarcity poses a current challenge of growing concern, exacerbated by climate change. This is particularly relevant for stone fruit trees, such as apricot, cultivated in semi-arid zones, where regulated deficit irrigation (RDI) strategies are gaining attention to tackle the challenge. The RDI method involves optimizing various factors based on how the plant responds physiologically to indicators of its water needs. Among these indicators, water potential is considered the most reliable and influential measure. For numerous apricot varieties and diverse geographic locations, research consistently shows that implementing water reduction strategies during non-critical developmental stages of floral bud development or fruit growth does not significantly impact crop yield. However, it does lead to reduced vegetative growth, which could offer additional benefits in crop management. Furthermore, the implementation of RDI strategies leads to advantageous improvements in fruit quality, particularly storage capacity and morphometric and chemical fruit characteristics, such as total soluble solids content. This scoping review study suggests that RDI is a feasible strategy to address water scarcity in apricot cultivation; however, further studies focused on continuous water monitoring alternatives are necessary to optimize RDI techniques. Future research should prioritize optimizing RDI for different growth stages, exploring advanced technologies for precise implementation, and assessing environmental impacts, while addressing research gaps including the influence of climate variability and the interaction with other agronomic practices, to refine RDI strategies and enhance apricot orchard sustainability and productivity.

Integrative Metabolomic and Transcriptomic Analysis Elucidates That the Mechanism of Phytohormones Regulates Floral Bud Development in Alfalfa.

Floral bud growth influences seed yield and quality; however, the molecular mechanism underlying the development of floral buds in alfalfa (Medicago sativa) is still unclear. Here, we comprehensively analyzed the transcriptome and targeted metabolome across the early, mid, and late bud developmental stages (D1, D2, and D3) in alfalfa. The metabolomic results revealed that gibberellin (GA), auxin (IAA), cytokinin (CK), and jasmonic acid (JA) might play an essential role in the developmental stages of floral bud in alfalfa. Moreover, we identified some key genes associated with GA, IAA, CK, and JA biosynthesis, including CPS, KS, GA20ox, GA3ox, GA2ox, YUCCA6, amid, ALDH, IPT, CYP735A, LOX, AOC, OPR, MFP2, and JMT. Additionally, many candidate genes were detected in the GA, IAA, CK, and JA signaling pathways, including GID1, DELLA, TF, AUX1, AUX/IAA, ARF, GH3, SAUR, AHP, B-ARR, A-ARR, JAR1, JAZ, and MYC2. Furthermore, some TFs related to flower growth were screened in three groups, such as AP2/ERF-ERF, MYB, MADS-M-type, bHLH, NAC, WRKY, HSF, and LFY. The findings of this study revealed the potential mechanism of floral bud differentiation and development in alfalfa and established a theoretical foundation for improving the seed yield of alfalfa.

Two key enzyme genes associated with ethylene bio-synthesis, LbACS and LbACO, are involved in the regulation of lily flower senescence

Ethylene plays an important role in regulating the growth and development of flowers and determines the flower life span of ornamental plants. In this study, the lily variety 'Manissa' was used to elucidate the mechanism associated with the regulation of lily senescence by the genes for 1-aminocyclopropane-1-carboxylic acid synthetase (ACS) and 1-aminocyclopropane-1-carboxylic acid oxidase (ACO), which are key enzymes in the ethylene biosynthesis pathway. The results showed that ethylene release increased, the relative water content first increased and then decreased, and relative conductivity continuously increased as lily bud development progressed. LbACS1 transcription was highest at the blooming stage, LbACS7 transcription was highest at the green bud stage, and LbAC03 and LbAC04 levels both peaked at the yellow bud stage and the blooming stage. After treating cut lily flowers with ethephon and ethylene inhibitor 1-methylcyclopropene (1-MCP), the results showed that ethephon promoted the senescence of cut flowers, ethylene release, and the transcription levels of the four Lb genes. 1-MCP treatment also delayed the aging of cut flowers, but reduced ethylene release and inhibited the transcription of LbAC03 and LbAC04 when the treatment was applied during the later stages of bud development. This study provided evidence for the role of ethylene and the functions of LbACS and LbAC0 in the aging process associated with cut lily flowers.

Genome-Wide Identification and Characterization of LIM Gene Family in Grapevine (Vitis vinifera L.) and Their Expression Analysis at Early Bud Developmental Stages

Genome-Wide Identification and Characterization of LIM Gene Family in Grapevine (Vitis vinifera L.) and Their Expression Analysis at Early Bud Developmental Stages

Comparative transcriptome analysis reveals the involvement of an MYB transcriptional activator, SmMYB108, in anther dehiscence in eggplant.

Male sterility is a highly attractive agronomic trait as it effectively prevents self-fertilization and facilitates the production of high-quality hybrid seeds in plants. Timely release of mature pollen following anther dehiscence is essential for stamen development in flowering plants. Although several theories have been proposed regarding this, the specific mechanism of anther development in eggplant remains elusive. In this study, we selected an R2R3-MYB transcription factor gene, SmMYB108, that encodes a protein localized primarily in the nucleus by comparing the transcriptomics of different floral bud developmental stages of the eggplant fertile line, F142. Quantitative reverse transcription polymerase chain reaction revealed that SmMYB108 was preferentially expressed in flowers, and its expression increased significantly on the day of flowering. Overexpression of SmMYB108 in tobacco caused anther dehiscence. In addition, we found that SmMYB108 primarily functions as a transcriptional activator via C-terminal activation (amino acid 262-317). Yeast one-hybrid and dual-luciferase reporter assays revealed that genes (SmMYB21, SmARF6, and SmARF8) related to anther development targeted the SmMYB108 promoter. Overall, our results provide insights into the molecular mechanisms involved in the regulation of anther development by SmMYB108.

A global view of transcriptome dynamics during flower development in Capsicum annuum L.

An analysis of genome-wide gene expression profiles during floral organ development can provide important clues about the molecular basis of gene functions and developmental processes. In this study, we analyzed the transcriptome data of 36 samples obtained during floral organ development from pepper ‘6421’ and detected 30 016 genes that were expressed in at least one sample. K-means clustering analysis was used to classify the data into 16 clusters based on the similarities between the dynamic expression profiles of genes. Of these, 15 clusters exhibited notable up-regulation or down-regulation trends in different developmental stages or tissues of floral organs. We identified transcription factors expressed at the early, medium, and late stages of bud development (F1, F5, F9). Transcription factor families such as AP2-ERF, MADS-box, MYB, bHLH, and NAC showed significant levels of enrichment. In comparison with genes expressed in vegetative tissues at different stages, certain genes were specifically up-regulated during flower development; among these, the number of genes specifically up-regulated during the stamen (Sta10) and bud tetrad development (F4) stages was the highest. Through extensive studies of the ABCDE model of flower development in Arabidopsis, we identified 17 ABCDE model candidate genes in pepper, most of which were up-regulated at specific stages of flower bud development. The expression data provided in this study is the most comprehensive dataset available for pepper to date and will serve as a resource for identifying the functions of many specific genes involved in flower development in pepper and other Solanaceae plants.

Effects of different phosphorus levels on tiller bud development in hydroponic Phyllostachys edulis seedlings.

An appropriate amount of phosphate fertilizer can improve the germination rate of bamboo buds and increase the bamboo shoot output. However, the underlying biological mechanisms of phosphate fertilizer in bamboo shoot development have not been systematically reported. Herein, the effects of low (LP, 1μM), normal (NP, 50μM) and high (HP, 1000μM) phosphorus (P) on the growth and development of moso bamboo (Phyllostachys edulis) tiller buds were first investigated. Phenotypically, the seedling biomass, average number of tiller buds and bud height growth rate under the LP and HP treatments were significantly lower than those under the NP treatment. Next, the microstructure difference of tiller buds in the late development stage (S4) at three P levels was analyzed. The number of internode cells and vascular bundles were significantly lower in the LP treatments than in the NP treatments. The relative expression levels of eight P transport genes, eight hormone-related genes and four bud development genes at the tiller bud developmental stage (S2-S4) and the tiller bud re-tillering stage were analyzed with real-time polymerase chain reaction. The results showed that the expression trends for most P transport genes, hormone-related genes and bud development genes from S2 to S4 were diversified at different P levels, and the expression levels were also different at different P levels. In the tiller bud re-tillering stage, the expression levels of seven P transport genes and six hormone-related genes showed a downward trend with increasing P level. REV expression level decreased under LP and HP conditions. TB1 expression level increased under HP condition. Therefore, we conclude that P deficiency inhibits tiller bud development and re-tillering, and that P depends on the expression of REV and TB1 genes and auxin, cytokinin and strigolactones synthesis and transporter genes to mediate tiller bud development and re-tillering.

Gene coexpression analysis reveals key pathways and hub genes related to late-acting self-incompatibility in Camellia oleifera.

Self-incompatibility (SI) is an important strategy for plants to maintain abundant variation to enhance their adaptability to the environment. Camellia oleifera is one of the most important woody oil plants and is widely cultivated in China. Late acting self-incompatibility (LSI) in C. oleifera results in a relatively poor fruit yield in the natural state, and understanding of the LSI mechanism remains limited. To better understand the molecular expression and gene coexpression network in the LSI reaction in C. oleifera, we conducted self- and cross-pollination experiments at two different flower bud developmental stages (3-4 d before flowering and 1 d before flowering), and cytological observation, fruit setting rate (FSR) investigation and RNA-Seq analysis were performed to investigate the mechanism of the male -female interaction and identify hub genes responsible for the LSI in C. oleifera. Based on the 21 ovary transcriptomes, a total of 7669 DEGs were identified after filtering out low-expression genes. Weighted gene coexpression network analysis (WGCNA) divided the DEGs into 15 modules. Genes in the blue module (1163 genes) were positively correlated with FSR, and genes in the pink module (339 genes) were negatively correlated with FSR. KEGG analysis indicated that flavonoid biosynthesis, plant MAPK signaling pathways, ubiquitin-mediated proteolysis, and plant-pathogen interaction were the crucial pathways for the LSI reaction. Fifty four transcription factors (TFs) were obtained in the two key modules, and WRKY and MYB were potentially involved in the LSI reaction in C. oleifera. Network establishment indicated that genes encoding G-type lectin S-receptor-like serine (lecRLK), isoflavone 3'-hydroxylase-like (CYP81Q32), cytochrome P450 87A3-like (CYP87A3), and probable calcium-binding protein (CML41) were the hub genes that positively responded to the LSI reaction. The other DEGs inside the two modules, including protein RALF-like 10 (RALF), F-box and pectin acetylesterase (MTERF5), might also play vital roles in the LSI reaction in C. oleifera. Overall, our study provides a meaningful resource for gene network studies of the LSI reaction process and subsequent analyses of pollen-pistil interactions and TF roles in the LSI reaction, and it also provides new insights for exploring the mechanisms of the LSI response.

Identification of Phenological Growth Stages of Four Morus Species Based on the Extended BBCH-Scale and Its Application in Fruit Development with Morphological Profiles and Color Characteristics

Mulberry (Morus L.; Moraceae; Rosales) is an economically important tree with a long history in China and valued for its rich nutrient, flavor content, medicinal value and useful ecological functions. Morus species are widely distributed in Asia, Europe, North and South America and Africa and exhibit obvious differences in morphological characteristics and phenological stages due to being distributed in diverse climate zones. The morphological description of the phenological stages of black mulberry (Morus nigra L.) has been established in Mediterranean climates and this study extended the BBCH scale for application in different Morus species, especially for mulberry trees grown in subtropical monsoon climates. In this study, we used the BBCH (Biologische Bundesanstalt, Bundessortenamt and CHemische Industrie) scale to describe in detail the phenological growth stages for Morus species in Wuhan, China (a subtropical monsoon climate). Based on this general scale, eight principal stages, i.e., bud, leaf and shoot development stage, inflorescence emergence stage, flowering stage, fruit development stage, fruit maturation stage, senescence and beginning of dormancy stage, were described. We provide photographic images of some primary and secondary developmental stages to better define and standardize morphological characteristics and phenological descriptions of these mulberries (Morus spp.). In addition, because the color of mulberry fruit varies from white, purple, black, or pink to red at maturity, with mostly monosexual flowers, we have also presented detailed descriptions of morphological traits of flower sexuality and fruit color among these four species. In addition, two late phenological germplasms (late bud sprouting associated with late blooming and late fruit ripening) were screened out according to the BBCH scale. Overall, this study will contribute to advance the field of mulberry breeding and implementation of agronomic practices and facilitate convenient communication between mulberry cultivators and researchers in different areas.

How light pollution can affect spring development of urban trees and shrubs

While artificial light at night (ALAN) is gaining more attention in view of its proven negative effect on animals, including humans, it remains a little-known matter when it comes to plants. Street lamps emit light that can be perceived by plants, and therefore disturb their natural photoperiod. In the present work we examine two different light treatments considered as low intensity (L-LP) and medium intensity (M-LP) light pollution (1 μmol·m−2·s−1 and 30 μmol·m−2·s−1 during the night, respectively) both comparable to different street lamps parameters (based on own field measurements). We have studied the influence of those LP treatments on the spring phenology and physiology of 4 tree species and 4 shrub species. The experiment involved species commonly used in European urban areas: Tilia tomentosa, Betula pendula, Fagus sylvatica, Acer campestre, Cornus alba, Lonicera pileata, Kerria japonica and Spiraea ×cinerea. All the investigated species were influenced by ALAN and developed buds faster than the control group. However, the changes were visible at different stages of bud development depending on species. The light pollution treatments resulted in a reduction of soluble sugars, measured in apical twigs of T. tomentosa, S. ×cinerea, K. japonica and A. campestre. In contrast, the soluble sugar content increased in branches of light-polluted L. pileata and C. alba when compared to the control group. These results prove, that light pollution affects the spring phenology and physiology of deciduous species. Long-term consequences of such reactions require more detailed studies.

Study on exogenous application of thidiazuron on seed size of Brassica napus L.

Thidiazuron (TDZ) is a novel and efficient cytokinin commonly used in tissue culture, and numerous studies have demonstrated that TDZ can increase berry size. However, no study to date has explored the effect of TDZ on seed size of Brassica napus and the mechanism. To shed light on the effect of TDZ on the seed size of B. napus, four different concentrations of TDZ were applied to B. napus. Results indicated that TDZ treatment could increase the seed diameter and silique length of B. napus to varying degrees and 100 and 200 μmol/L TDZ treatments were the most effective with a 3.6 and 4.6% increase in seed diameter, respectively. In addition, the yield of B. napus was also substantially increased under TDZ treatment. On the other hand, confocal micrographs of embryos and cotyledon cells suggested that embryos and their cotyledon epidermal cells treated with 200 μmol/L TDZ were obviously larger in size than the control. Furthermore, TDZ promoted the upregulation of some key maternal tissue growth-related genes, including two G-protein signaling genes (AGG3 and RGA1) and two transcriptional regulators (ANT and GS2). The expression analysis of genes related to the auxin metabolic pathways, G-protein signaling, endosperm growth and transcriptional regulators confirmed that treatment with TDZ negatively regulated the key genes ABI5, AGB1, AP2, ARF2, and ARF18 during bud development stage and florescence. The results strongly suggested that TDZ might regulate the transcriptional levels of key genes involved in auxin metabolic pathways, G-protein signaling, endosperm growth and transcriptional regulators, which resulted in bigger cotyledon epidermal cells and seed size in B. napus. This study explored the mechanism of TDZ treatment on the seed size of B. napus and provided an important reference for improving rapeseed yield.

Transcriptome analysis of flower bud identified genes associated with pistil abortions between long branches and spur twigs in apricots (Prunus armeniaca L.).

Pistil abortions of flower buds occur frequently in many apricot cultivars, especially in long branches. However, the molecular mechanism underlying pistil abortion in apricots remains unclear. To better understand the molecular mechanism of pistil abortions between long branches and spur twigs, paraffin sections and high-throughput sequencing technology were employed to analyze the expression patterns of genes associated with pistil abortions during later flower bud development stage in ‘Shajinhong’ apricot. The result of stage III (separation of bud scales) was the critical stage of pistil abortion in apricots. A total of 163 differentially expressed genes were identified as candidate genes related to pistil abortion in long branches. These genes are implicated in programmed cell death, hormone signaling, cell wall degeneration, and the carbohydrate metabolism pathway. The results showed that the up-regulation of gene expression of Xyloglucan endotransglucosylase/hydrolase and β-glucosidase in flower buds might be the direct cause of cell wall breakdown and pistil necrosis in long branches. We hypothesize that there is a molecular relationship between pistil abortion before blooming and cellulose degradation, and then carbohydrate transport in the case of carbon deficiency in long branches. Our work provides new insights into cellulose degradation in abortion pistils and valuable information on flower development in apricots, and also provides a useful reference for cultivation regulation in apricot or other fruit crops.

Research on spring frost damage in cherries

A frost occurred in spring following high temperatures in Michigan in 2007. It caused important crop losses. In this study, the damage the frost had on the flower buds of some cherry cultivars on ‘Gisela 5’ at the Southwest Michigan Research and Extension Center (SWMREC) and different cherry scion/rootstock combinations at the Clarksville Horticultural Experiment Station (CHES) were determined. In cherries, the frost damage at SWMREC varied from 26.7% to 99.3% depending on the cherry cultivar while it varied from 41.9 to 99.3% at CHES depending on the cherry combinations. ‘Rainier/Gisela 6’ at CHES and ‘NY119’ at SWMREC were promising. The bud development stage during the freeze, the cultivar, the rootstock, the ages of the trees and the low temperature level were effective in the spring frost resistance.

Phenological growth stages of shea tree (Vitellaria paradoxa subsp. paradoxa) according to the BBCH scale

AbstractThe shea tree is among the socio‐economically and environmentally most important plants in the Sudano‐Sahelian region of Africa. Shea butter is internationally valued for use in pharmaceutical, cosmetic and confectionary industries. Scaling and describing phenological growth stages is of great importance in crops management. However, such phenological scale is still lacking for shea tree. To fill this gap, we documented the different growth stages of shea tree by referencing to the Biologische Bundesantalt, Bundessortenamt und Chemische Industrie (BBCH) scale. Eight of the ten principal growth stages (0–9) and 43 secondary growth stages (0–9) were described in shea tree. Among the eight principal stages, four were related to reproductive phenophases: inflorescence emergence stage (5), flowering stage (6), fruit development stage (7), and fruit maturity stage (8). The remaining four principal stages concerned vegetative phenophases and contained: bud development stage (0), leaf development stage (1), shoot development stage (3), and senescence stage (9). Observations of shea tree phenophases depicted asynchronous growth patterns with overlapping secondary growth stages of different principal stages within an individual tree canopy at the same time. The proposed phenological growth scale specific to shea tree but compatible with other crops is a valuable contribution for the implementation of crops management protocols and the standardisation of research between different laboratories.

Corema album (L.) D. Don Phenological Growth Stages according to Extended BBCH Scale

ABSTRACT The wild dioecious plant Corema album, endemic to the Atlantic coast of the Iberian Peninsula, has potential to become a new crop and to integrate the berry fruit market. Due to its potential, the aim of this study was to propose a BBCH (Biologische Bundesanstalt, Bundessortenamt and CHemical Industry) scale for the species. Based on field observation, the principal growth stages were described and sequentially established. Photographs and stereomicroscope acquisition software were used to illustrate the phenological stages of male and female plants. The scale includes seven principal stages starting with bud development (stage 0), followed by leaf development (Stage 1), main stem elongation (Stage 3), inflorescence emergence (Stage 5), flowering (Stage 6), fruit development (Stage 7) and ending with fruit maturation (stage 8), with mesostages for male and female inflorescence (stage 5) and flower development (stage 6). Through field observations carried out in plants in different growth conditions, the proposition of this extended BBCH scale was made, to have a standardized system for Corema album phenological stages. This study will have an application especially in fields of agronomy and plant breeding and will also be a stepping stone for the inclusion of this species as a novelty crop in a nearby future.

A systematic review and meta-analysis of vineyard techniques used to delay ripening.

Several vineyard techniques have been proposed to delay grape maturity in light of the advanced maturation driven by increasingly frequent water and heat stress events that are detrimental to grape quality. These studies differ in terms of their experimental conditions, and in the present work we have attempted to summarize previous observations in a quantitative, data-driven systematic review. A meta-analysis of quantitative data gathered across 43 relevant studies revealed the overall significance of the proposed treatments and evaluated the impact of different experimental conditions on the outcome of antitranspirants, delayed pruning and late source limitation. Antitranspirants were most effective when applied twice and closer to veraison, while di-1-p-menthene increased the ripening delay by about 1 °Brix compared to kaolin. Larger ripening delays were achieved with delayed pruning of low-yielding vines or by pruning at later stages of apical bud development. Late defoliation or shoot trimming delayed ripening in high-yielding vines and represent suitable solutions for late-harvested varieties, but became ineffective where the treatment decreased yield. This quantitative meta-analysis of 242 primary observations uncovers factors affecting the efficacy of vineyard practices to delay ripening, which should be carefully considered by grape growers attempting to achieve this outcome.

Integrated analysis of mRNA-seq and miRNA-seq reveals the advantage of polyploid Solidago canadensis in sexual reproduction

BackgroundThe invasion of Solidago canadensis probably related to polyploidy, which may promotes its potential of sexual reproductive. S. canadensis as an invasive species which rapidly widespread through yield huge numbers of seed, but the mechanism remains unknown. To better understand the advantages of sexual reproduction in hexaploid S. canadensis, transcriptome and small RNA sequencing of diploid and hexaploid cytotypes in flower bud and fruit development stages were performed in this study.ResultsThe transcriptome analysis showed that in the flower bud stage, 29 DEGs were MADS-box related genes with 14 up-regulated and 15 down-regulated in hexaploid S. canadensis; 12 SPL genes were detected differentially expressed with 5 up-regulated and 7 down-regulated. In the fruit development stage, 26 MADS-box related genes with 20 up-regulated and 6 down-regulated in hexaploid S. canadensis; 5 SPL genes were all up-regulated; 28 seed storage protein related genes with 18 were up-regulated and 10 down-regulated. The weighted gene co-expression network analysis (WGCNA) identified 19 modules which consisted of co-expressed DEGs with functions such as sexual reproduction, secondary metabolism and transcription factors. Furthermore, we discovered 326 miRNAs with 67 known miRNAs and 259 novel miRNAs. Some of miRNAs, such as miR156, miR156a and miR156f, which target the sexual reproduction related genes.ConclusionOur study provides a global view of the advantages of sexual reproduction in hexaploid S. canadensis based on the molecular mechanisms, which may promote hexaploid S. canadensis owing higher yield and fruit quality in the process of sexual reproduction and higher germination rate of seeds, and finally conductive to diffusion, faster propagation process and enhanced invasiveness.

Morphological characteristics and transcriptome analysis at different anther development stages of the male sterile mutant MS7\u20132 in Wucai (Brassica campestris L.)

BackgroundThe discovery of male sterile materials is of great significance for the development of plant fertility research. Wucai (Brassica campestris L. ssp. chinensis var. rosularis Tsen) is a variety of non-heading Chinese cabbage. There are few studies on the male sterility of wucai, and the mechanism of male sterility is not clear. In this study, the male sterile mutant MS7–2 and the wild-type fertile plant MF7–2 were studied.ResultsPhenotypic characteristics and cytological analysis showed that MS7–2 abortion occurred at the tetrad period. The content of related sugars in the flower buds of MS7–2 was significantly lower than that of MF7–2, and a large amount of reactive oxygen species (ROS) was accumulated. Through transcriptome sequencing of MS7–2 and MF7–2 flower buds at three different developmental stages (a–c), 2865, 3847, and 4981 differentially expressed genes were identified in MS7–2 at the flower bud development stage, stage c, and stage e, respectively, compared with MF7–2. Many of these genes were enriched in carbohydrate metabolism, phenylpropanoid metabolism, and oxidative phosphorylation, and most of them were down-regulated in MS7–2. The down-regulation of genes involved in carbohydrate and secondary metabolite synthesis as well as the accumulation of ROS in MS7–2 led to pollen abortion in MS7–2.ConclusionsThis study helps elucidate the mechanism of anther abortion in wucai, providing a basis for further research on the molecular regulatory mechanisms of male sterility and the screening and cloning of key genes in wucai.