Stages Of Floral Development Research Articles

De novo Assembly and Characterization of the Floral Transcriptomes of Two Varieties of Melastoma malabathricum.

Melastoma malabathricum is an important medicinal and landscape plant that is globally distributed in temperate and subtropical regions. However, available genomic information for the entire Melastomataceae family is notably limited. In view of the application potential of floral parts in secondary metabolite extraction, we characterized for the first time the floral transcriptomes of two key M. malabathricum varieties, purple variety and white variety. Our transcriptome assembly generated 52,498 and 49,380 unigenes with an N50 of 1,906 and 1,929 bases for the purple and white varieties, respectively. Comparative analysis of two transcriptomes demonstrated that they are highly similar but also highlighted genes that are presumably lineage specific, which explains the phenotypes of each variety. Additionally, a shared transcriptional signature across the floral developmental stages was identified in both M. malabathricum varieties; this signature included pathways related to secondary metabolite synthesis, plant hormone signaling and production, energy homeostasis and nutrient assimilation pathways, and cellular proliferation. The expression levels of flavonoid accumulation and candidate flavonoid biosynthesis-related genes in M. malabathricum flower development stages validated the transcriptome findings. The transcriptome data presented in this study will serve as a valuable resource for future work on the exploitation of M. malabathricum and other related species. The gene expression dynamics during flower development will facilitate the discovery of lineage-specific genes associated with phenotypic characteristics and will elucidate the mechanism of the ontogeny of individual flower types.

Floral development and the formation of functionally unisexual flowers in Xanthoceras sorbifolium (Sapindaceae), a morphologically andromonoecious tree endemic to northern China

KEY MESSAGE: Xanthoceras sorbifolium is apparently andromonoecious but exhibits a cryptically monoecious breeding system. Sexual differentiation in male and functional female flowers occurs 2 weeks before flowering. Individual trees of Xanthoceras sorbifolium bear male and morphologically bisexual flowers but functionally female flowers, and show labile sex expression. Investigations of the floral development are of significant value for understanding the breeding system and elucidating the systematic relationships. We studied floral development of male and bisexual flowers using scanning electron and light microscopy. The early stages of floral development were essentially the same, and all floral organ primordia were initiated in the two types of flowers of X. sorbifolium. Later, the stamens in bisexual flowers and the gynoecium in male flowers were aborted. We divided floral development into nine stages. Morphological differences between male and bisexual flowers appeared first at stage 8, when the style elongated obviously and the stigma papillae began to expand in the bisexual flowers but not in the male flowers. Ovule development was arrested shortly after formation of megaspore mother cells or during meiosis in the male flowers, whereas anther development was aberrant in the bisexual flowers. Morphologically bisexual flowers of X. sorbifolium do not have male function and are functionally female. Comparison of floral developmental characters did not support the separation of the Chinese monotypic genus Xanthoceras from the family Sapindaceae.

The Development of Lulo Plants (Solanum quitoense Lam. var. septentrionale) Characterized by BBCH and Landmark Phenological Scales

ABSTRACT The landmark and the Biologische Bundesantalt, Bundessortenamt, and Chemische Industrie (BBCH) scales describe the phenology of lulo plants. The landmark scale comprises six main stages, 1.0 seed germination, 2.0 seedling growth, 3.0 early vegetative growth, 4.0 leaf development, 5.0 floral, and 6.0 fruit development. Seed gemination stages describe seed sowing, imbibition, and subsequent germination. Seedling growth stages include the emergence of hypocotyl hook, seedling growth, the development of cotyledons, and true leaves. During the early vegetative shoot stages, plants increase in height, pubescence turns dark, cotyledons abscise, and thorns become visible at the base of the leaf. Leaf development stages comprise the emergence of young, true leaves, and leaf expansion. During this period, leaf color changes from light green to mature dark green and ends with leaf senescence. Floral development stages include the emergence of the swollen generative buds, early floral-bud development, inflorescence enlargement, anthesis in hermaphrodite or male flowers, and floral parts decay and abscission. Fruit development stages include fruit developing below the petals, the light green tiny fruit enlarges forming the small, enlarged, intermediate, and light green fruit. Fruit turns dark green until reaching the mature dark orange color. The BBCH scale depicts eight principal stages such as seed germination, leaf development, formation of side shoots, inflorescence emergence, flowering, fruit development, fruit maturation, and senescence. The BBCH mesostages and secondary growth stages were described and coded according to the two- and three-digit-code system. The secondary stages were used as precise steps during development of the plants. Flower and fruit production occurred throughout the year. This research can be used to better understand the flowering and fruiting process and it can be applied to breeding and production programs.

Isolation of 2-phenylethanol biosynthesis related gene and developmental patterns of emission of scent compounds in Persian musk rose (Rosa moschata Herrm.)

Abstract The molecular properties of 2-phenylethanol were investigated in the single petals of Persian Musk rose at four floral developmental stages. The chemical compositions of the floral scent emissions were analyzed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). In this plant, the relative percentage of 2-phenylethanol increased as flowers developed. In the early stage of flower development, the patterns of emission of 2-phenylethanol were very low and then progressively increased reaching its highest value at full bloom stage. The partial CDS of phenyl acetaldehyde reductase (PAR) were isolated in the petals of Persian musk rose. Moreover, the expression pattern of RmPAR showed a significant difference during flower developmental stages and floral organ parts of Rosa moschata. The expression level of RmPAR constantly decreased from the budding stage (stage 1) to the full bloom stage (stage 3); It is reached at the highest level in the budding stage and rapidly decreases in the full bloom stage, and then increases again in the senescence stage (stage 4). In addition, the highest expression level of RmPAR was in the stamen and slightly higher in the petal, and the expression amount in the pistil was about half that in the stamen. Nevertheless, in the calyxes, RmPAR was lowly expressed.

CjPLE, a PLENA-like gene, is a potential regulator of fruit development via activating the FRUITFUL homolog in Camellia.

Fruit patterning involves the cooperation of multiple processes, including metabolic change, cell differentiation, and cell expansion. The FRUITFUL (FUL) and SHATTERPROOF1/2 (SHPs) MADS-box genes are master regulators directing fruit patterning in several eudicots. However, the regulatory mechanisms of the FUL-SHP network in different fruit types remain unclear. Here, we characterized the functions of an ortholog (CjPLE) of SHPs from Camellia japonica. We showed that CjPLE was predominantly expressed in stamen and carpel tissues during the early stage of floral development and that transcripts were abundant in the pericarp tissues during fruit development. The ectopic expression of CjPLE in Arabidopsis caused enhanced development of the carpels, whereas no defects in floral identity were observed. To investigate the downstream targets of CjPLE, overexpression transformants were analysed through a callus transformation system in Camellia azalea. We examined the expression levels of potential downstream target genes and found that two previously identified APETALA1-like genes (CjAPL1/2) were significantly up-regulated. We showed that CjPLE directly bound to the CArG motifs in the promoter region of CjAPL1 (the FUL ortholog). Taken together, our results reveal a possible positive regulation of FUL by SHP in the control of fruit development in Camellia.

Composition analysis of floral scent within genus Camellia uncovers substantial interspecific variations

The great diversity and complexity of floral scent originate from specialized metabolic pathways partly due to the ever-evolving plant and pollinator interaction. However, the diversity of floral scent compositions in plant species remains to be elucidated. Genus Camellia contains a large number of species including several famous ornamental species, and species within the section Theopsis possess distinctive floral scent traits. In this study, we have collected 22 species from Theopsis and performed headspace- solid phase microextration coupled with gas chromatography mass spectrum (HS-SPME-GC–MS) analysis to investigate the scent compositions. In total, we identified 223 volatile compounds belonging to benzenoids, phenyl propanoids, terpenes, and other components. Remarkable interspecific variations in composition and quantity were revealed. We characterized the relationships of different types of volatile compounds by hierarchical clustering and principal component analysis, and showed that small amount of chemicals could affect the scent effects significantly. Moreover, we compared the volatile emission patterns between different floral organ types and developmental stages in Camellia buxifolia. We revealed that stamens emitted more volatiles than petals, and the emission reached the maximum at the stage of flower half opening. This work provides fundamental information for breeding Camellia cultivars with scent traits.

The Effects of DNA Methylation Inhibition on Flower Development in the Dioecious Plant Salix Viminalis

DNA methylation, an important epigenetic modification, regulates the expression of genes and is therefore involved in the transitions between floral developmental stages in flowering plants. To explore whether DNA methylation plays different roles in the floral development of individual male and female dioecious plants, we injected 5-azacytidine (5-azaC), a DNA methylation inhibitor, into the trunks of female and male basket willow (Salix viminalis L.) trees before flower bud initiation. As expected, 5-azaC decreased the level of DNA methylation in the leaves of both male and female trees during floral development; however, it increased DNA methylation in the leaves of male trees at the flower transition stage. Furthermore, 5-azaC increased the number, length and diameter of flower buds in the female trees but decreased these parameters in the male trees. The 5-azaC treatment also decreased the contents of soluble sugars, starch and reducing sugars in the leaves of the female plants, while increasing them in the male plants at the flower transition stage; however, this situation was largely reversed at the flower development stage. In addition, 5-azaC treatment decreased the contents of auxin indoleacetic acid (IAA) in both male and female trees at the flower transition stage. These results indicate that hypomethylation in leaves at the flower transition stage promotes the initiation of flowering and subsequent floral growth in Salix viminalis, suggesting that DNA methylation plays a similar role in vegetative–reproductive transition and early floral development. Furthermore, methylation changes during the vegetative–reproductive transition and floral development were closely associated with the biosynthesis, metabolism and transportation of carbohydrates and IAA. These results provide insight into the epigenetic regulation of carbohydrate accumulation.

Identification of heat tolerance loci in broccoli through bulked segregant analysis using whole genome resequencing

Most broccoli cultivars are sensitive to high temperatures during the early stages of floral development causing a severe decline of head quality or even complete lack of head formation under superoptimal crop production temperatures. Several heat tolerant lines have been developed in recent years but there have been few studies of the genetic basis of this complex, polygenic trait. A doubled haploid population of broccoli was evaluated for head quality across two summer field trials with the phenotypic extremes validated in two additional summer fields. Whole-genome resequencing of the bulked segregants was used for a quantitative trait loci (QTL)-seq analysis of heat tolerance. Two novel QTL, which differ from previously reported QTL, were identified. Nonsynonymous SNPs were found in a block of flowering time genes within QHT_C09.2 and may explain the significant negative correlation between time to head maturity and heat tolerance. Breeding further genetic gains in this complex, polygenic trait could be expedited through marker assisted selection and gene pyramiding using markers developed from the QTL identified herein.

Inhibition of post-transcriptional gene silencing of chalcone synthase genes in petunia picotee petals by fluacrypyrim.

In petals of picotee petunia (Petunia hybrida) cultivars, margin-specific post-transcriptional gene silencing (PTGS) of chalcone synthase A (CHSA) inhibits anthocyanin biosynthesis, resulting in marginal white tissue formation. In this study, we found that a low molecular mass compound, fluacrypyrim, inhibits PTGS of CHSA, and we explored the site-specific PTGS mechanism of operation. Fluacrypyrim treatment abolished the picotee pattern and eliminated site-specific differences in the levels of anthocyanin-related compounds, CHSA expression, and CHSA small interfering RNA (siRNA). In addition, fluacrypyrim abolished the petunia star-type pattern, which is also caused by PTGS of CHSA. Fluacrypyrim treatment was effective only at the early floral developmental stage and predominantly eliminated siRNA derived from CHS genes; i.e. siRNA derived from other genes remained at a comparable level. Fluacrypyrim probably targets the induction of PTGS that specifically operates for CHS genes in petunia picotee flowers, rather than common PTGS maintenance mechanisms that degrade mRNAs and generate siRNA. Upon treatment, the proportion of colored tissue increased due to a shift of the border between white and colored sites toward the margin in a time- and dose-dependent manner. These findings imply that the fluacrypyrim-targeted PTGS induction is completed gradually and its strength is attenuated from the margins to the center of petunia picotee petals.

Transcriptomes Divergence of Ricotia lunaria Between the Two Micro-Climatic Divergent Slopes at "Evolution Canyon" I, Israel.

As one of the hotspot regions for sympatric speciation studies, Evolution Canyon (EC) became an ideal place for its high level of microclimatic divergence interslopes. In this study, to highlight the genetic mechanisms of sympatric speciation, phenotypic variation on flowering time and transcriptomic divergence were investigated between two ecotypes of Ricotia lunaria, which inhabit the opposite temperate and tropical slopes of EC I (Lower Nahal Oren, Mount Carmel, Israel) separated by 100 m at the bottom of the slopes. Growth chamber results showed that flowering time of the ecotype from south-facing slope population # 3 (SFS 3) was significantly 3 months ahead of the north-facing slope population # 5 (NFS 5). At the same floral development stage, transcriptome analysis showed that 1,064 unigenes were differentially expressed between the two ecotypes, which enriched in the four main pathways involved in abiotic and/or biotic stresses responses, including flavonoid biosynthesis, α-linolenic acid metabolism, plant–pathogen interaction and linoleic acid metabolism. Furthermore, based on Ka/Ks analysis, nine genes were suggested to be involved in the ecological divergence between the two ecotypes, whose homologs functioned in RNA editing, ABA signaling, photoprotective response, chloroplasts protein-conducting channel, and carbohydrate metabolism in Arabidopsis thaliana. Among them, four genes, namely, SPDS1, FCLY, Tic21 and BGLU25, also showed adaptive divergence between R. lunaria and A. thaliana, suggesting that these genes could play an important role in plant speciation, at least in Brassicaceae. Based on results of both the phenotype of flowering time and comparative transcriptome, we hypothesize that, after long-time local adaptations to their interslope microclimatic environments, the molecular functions of these nine genes could have been diverged between the two ecotypes. They might differentially regulate the expression of the downstream genes and pathways that are involved in the interslope abiotic stresses, which could further diverge the flowering time between the two ecotypes, and finally induce the reproductive isolation establishment by natural selection overruling interslope gene flow, promoting sympatric speciation.

Influence of fertilization on growth and generative parameters of two short day strawberry cultivars grown in substrate, and evaluation of analysing tools for leaf nitrate and potassium

We examined the influence of fertigation on vegetative and generative parameters of strawberry plants (Fragaria × ananassa Duch.) and evaluated rapid analysing tools for N and K in leaf tissue. The experiments were undertaken in an open polytunnel on “table top” with ‘Sonata’ and ‘Korona’ grown in 2-L pots filled with a peat-based soil mixture. The experimental design was a randomized plot with three replications. Plants were fertigated with EC levels of 0.5, 1.0, 1.5 and 2.0 mS cm-1, based on two stock solutions of 7.5 kg YaraLiva™ Calcinit and 7.5 kg Kristalon™ Indigo, both dissolved in 100 L of water. Percentage N and K in leaves differed between analysing methods, cultivars, EC and date. We found interactions between the cultivar and EC level and between date and cultivar for N and K in leaf. Analysing NO(3)- by a photometric method (PM) in a lab, and by Laqua twin (LT), showed significant interaction with N% of leaf dry matter (DM) only for LT (r(2)=0.36). N% increased with higher EC level, more for ‘Korona’ than for ‘Sonata’. LT K+ did not correlate with K% (r(2)=0.014). The number of crowns and runners increased for both cultivars up to EC 1.5, while the number of leaves was unaffected. Petioles were the shortest at the lowest EC. Flower initiation was earlier at low EC in both cultivars. In the following spring, the time to flowering and first harvest was reduced with the decreasing EC. The number of flowers per plant increased up to EC 1.5, but dropped strongly at EC 2.0 for ‘Korona’, while ‘Sonata’ had a gradual increase of flowers with the increasing EC, but the number was only a third of ‘Korona’, except at EC 2.0, where the amount was equal for both cultivars. The conclusion can be drawn that LT correlated better than ChlDualex with N in strawberry leaves. However, r2 was only 0.36 indicating that LT NO(3)- is a coarse management tool. LT K+ was not a promising tool for rapid K+ test in these experiments. ‘Korona’ seemed to benefit of higher N levels for both vegetative growth and generative development than ‘Sonata’ up to EC 1.5, but ‘Sonata’ reached a higher floral primordia development stage in early October.

Functional analysis of a homologue of the FLORICAULA/LEAFY gene in litchi (Litchi chinensis Sonn.) revealing its significance in early flowering process.

Litchi (Litchi chinensis Sonn.) is an important subtropical fruit crop with high commercial value due to its high nutritional values and favorable tastes. However, irregular bearing attributed to unstable flowering is a major ongoing problem for litchi producers. Previous studies indicate that low-temperature is a key factor in litchi floral induction. In order to reveal the genetic and molecular mechanisms underlying the reproductive process in litchi, we had analyzed the transcriptome of buds before and after low-temperature induction using RNA-seq technology. A key flower bud differentiation associated gene, a homologue of FLORICAULA/LEAFY, was identified and named LcLFY (GenBank Accession No. KF008435). The cDNA sequence of LcLFY encodes a putative protein of 388 amino acids. To gain insight into the role of LcLFY, the temporal expression level of this gene was measured by real-time RT-PCR. LcLFY was highly expressed in flower buds and its expression correlated with the floral developmental stage. Heterologous expression of LcLFY in transgenic tobacco plants induced precocious flowering. Meantime, we investigated the sub-cellular localization of LcLFY. The LcLFY-Green fluorescent protein (GFP) fusion protein was found in the nucleus. The results suggest that LcLFY plays a pivotal role as a transcription factor in controlling the transition to flowering and in the development of floral organs in litchi.

The transcriptome of flower development provides insight into floral scent formation in Freesia hybrida

Freesia hybrida is a popular cut flower that is globally cultivated. Despite fragrance being an important floral trait, little is known of its associated molecular mechanisms in F. hybrida. In this study, cDNA libraries were constructed for three floral developmental stages in F. hybrida. A total of 74,660 unigenes were obtained from RNA sequencing and de novo assembly, of which 72.20% were annotated by seven public protein databases. Approximately 12,420 differentially expressed genes were identified during flower development. Gas chromatography–mass spectrometry analysis detected a total of 34 floral volatile compounds, primarily volatile monoterpenes, which accounted for approximately 90% of the volatiles. Using a system analysis-based approach, 36 candidate genes related to volatile terpenes were identified, in which the majority of up-regulated genes associated with the biosynthesis of monoterpenes and the majority of down-regulated genes associated with the biosynthesis of sesquiterpenes. Of these, FhDXS2A, FhGPPs and FhTPSs were considered to be important in floral scent formation. This study provides an in-depth assessment of floral scent and a reference for the future molecular breeding of floral scent in ornamental plants.

Evidence for the Involvement of Fatty Acid Biosynthesis and Degradation in the Formation of Insect Sex Pheromone-Mimicking Chiloglottones in Sexually Deceptive Chiloglottis Orchids.

Hundreds of orchid species secure pollination by sexually luring specific male insects as pollinators by chemical and morphological mimicry. Yet, the biochemical pathways involved in the synthesis of the insect sex pheromone-mimicking volatiles in these sexually deceptive plants remain poorly understood. Here, we explore the biochemical pathways linked to the chemical mimicry of female sex pheromones (chiloglottones) employed by the Australian sexually deceptive Chiloglottis orchids to lure their male pollinator. By strategically exploiting the transcriptomes of chiloglottone 1-producing Chiloglottis trapeziformis at distinct floral tissues and at key floral developmental stages, we identified two key transcriptional trends linked to the stage- and tissue-dependent distribution profiles of chiloglottone in the flower: (i) developmental upregulation of fatty acid biosynthesis and β-oxidation genes such as KETOACYL-ACP SYNTHASE, FATTY ACYL-ACP THIOESTERASE, and ACYL-COA OXIDASE during the transition from young to mature buds and flowers and (ii) the tissue-specific induction of fatty acid pathway genes in the callus (the insectiform odor-producing structure on the labellum of the flower) compared to the labellum remains (non-odor-producing) regardless of development stage of the flower. Enzyme inhibition experiments targeting KETOACYL-ACP SYNTHASE activity alone in three chiloglottone-producing species (C. trapeziformis, C. valida, and C. aff. valida) significantly inhibited chiloglottone biosynthesis up to 88.4% compared to the controls. These findings highlight the role of coordinated (developmental stage- and tissue-dependent) fatty acid gene expression and enzyme activities for chiloglottone production in Chiloglottis orchids.

Quantitative developmental analysis of two phenotypes of Hibiscus rosa-sinensis in the context of homeosis

The flowers of Hibiscus rosa-sinensis L. (Malvaceae) exist in two floral morphologies: a single phenotype, and a double phenotype. This study focused on the early stages of floral development, just before the initiation of petal primordia and up until the bifurcation of the stamen primordia. The two phenotypes were compared using logistic regression and bootstrapping techniques. Four aspects of floral development were considered: (i) organogenesis of petal and stamen primordia, and stamen bifurcation; (ii) allometry of stamen primordia; (iii) morphology of stamen primordia; and (iv) size of stamen primordia. The single and double buds initiated petal primordia at the same bud radii, but double buds initiated stamen primordia and stamen bifurcation at larger bud radii than the single phenotype. Double stamen primordia were shorter, wider, and more spherical than single stamen primordia, although the sizes of the single and double stamen primordia (defined as the sum of their length and width measurements) were not different. Results suggest that the additional space on the floral meristem of the double phenotype is linked to the divergent development of stamen primordia occupying this extra space.

Floral development stage and its implications for the reproductive success of Passiflora L.

Abstract Most Passiflora species present self-incompatibility and thus depend on cross-pollination for fruit production. Therefore, the objective of this work was to evaluate the floral and reproductive biology of 17 Passiflora species, through pollen viability, stigma receptivity, fruit and seed set formation, as well as the pollen-pistil interaction in three floral development stages (pre-anthesis, anthesis and post-anthesis), seeking to maximize the efficiency of controlled pollinations. Pollen viability was estimated by in vitro pollen germination, fluorochromatic reaction and Alexander’s solution, as well as fruiting and pollen-pistil interaction. The stigma receptivity was determined in alpha-naphthyl acetate. The highest percentages of pollen viability, stigma receptivity, fruit and seed set were observed during floral anthesis for all Passiflora species studied, while the lowest values were observed in pre-anthesis. The species P. rubra L. presented the highest percentages of in vitro pollen germination, viability with FDA, stigma receptivity, pollen/pistil compatibility, and high fruit set in anthesis. In contrast, the lowest values of these traits were observed in P. galbana L. The results obtained can support the selection of genetic material and allow inferences about the best pollen collection moment and the peak stigma receptivity to maximize the chances of pollen germination and consequently increase the efficiency of controlled pollinations for both agronomic and ornamental purposes.

Effects of 6-Benzyladenine on Jatropha Gene Expression and Flower Development

Jatropha curcas L. has been considered as a potential source of biodiesel feedstock due to its highly seed oil content. However, Jatropha exhibits low numbers of female flowers leading to insufficient seed yields for biodiesel production. Previous studies showed that application of 6-benzyladenine (BA) on Jatropha flower buds significantly increased female flower numbers and seed yield. However, the underlining molecular mechanism remained unclear. In this study, 160 mg/L of BA was applied on the Jatropha flower buds. As a result, BA significantly increased female flowers, male flowers, and seed yield (P < 0.05). BA also affected the inflorescences area, number and length of pedicel, all of which were appreciably greater than control (P < 0.05). The effect of BA to flower bud development was observed using Scanning Electron Microscope (SEM). SEM revealed that the stages of floral development between control and BA-treatment were similar indicating that BA might affect floral development at the transcriptomic level. Flower buds at 0, 4, and 24 h were selected based on the presence of sex organs for genes involved in flower development investigation. The expression analysis of 23 genes showed that CYTOKININ OXIDASE/DEHYDROGENASE5 (JcCKX5) was highly expressed at the transition stage (P< 0.05) subsequently enhanced the inflorescences area, increased organogenic capacity and ovule primordia formation. Moreover, application of BA increased the expression of SUPERMAN (JcSUP) and decreased the expression of TASSELSEED2 (JcTS2) during sex organs differentiated stage. Therefore, JcSUP might play a role in female flower formation parallel with arrested stamen formation through the down-regulation of JcTS2.

The reproductive biology of two poorly known relatives of the fig (Ficus ) and insights into the evolution of the fig syconium

We conducted the first detailed investigation of the floral architecture and reproductive biology of two species from the genus Dorstenia, which are poorly known relatives of Ficus (Moraceae). Our aims were to extend and refine knowledge of the understudied genus Dorstenia and to explore possible insights into the evolution of the fig syconium. We characterised four key stages of floral development using light microscopy, scanning electron microscopy and histological staining. Reproductive biology was found to be complex and species-specific. Both study species are monoecious and produce an inflorescence of minute male and female flowers. Protogyny, associated with a spatial separation of male and female flowers and asynchronous stamen development, was species-specific, as was seed set. Our results reveal novel insights into the complex reproductive biology of an under-studied genus in the family Moraceae. We propose that exploring the reproductive biology of Dorstenia and other poorly known Ficus relatives will provide insights into the evolution of the fig syconium – the unique reproductive structure of this economically and ecologically important genus.

Identification of Blueberry miRNAs and Their Targets Based on High-Throughput Sequencing and Degradome Analyses.

miRNAs are important regulators of plant gene expression. To better characterize their functions, we applied high-throughput sequencing and degradome analyses to investigate three blueberry (Vaccinium ashei) tissues. A total of 127 known and 101 novel miRNAs were identified. Moreover, 141 targets for 42 known and 19 novel miRNAs were experimentally validated by degradome sequencing. A functional analysis of these miRNA targets revealed they were associated with diverse biological activities and several pathways, e.g., anthocyanin biosynthesis and cytokinin signal transduction. The data presented herein expand our understanding of the regulation of blueberry miRNAs during floral and fruit development stages. They may also provide new insights into the roles of miRNAs during anthocyanin biosynthesis in blueberry fruits.

Plant and Floret Growth at Distinct Developmental Stages During the Stem Elongation Phase in Wheat.

Floret development is critical for grain setting in wheat (Triticum aestivum), but more than 50% of grain yield potential (based on the maximum number of floret primordia) is lost during the stem elongation phase (SEP, from the terminal spikelet stage to anthesis). Dynamic plant (e.g., leaf area, plant height) and floret (e.g., anther and ovary size) growth and its connection with grain yield traits (e.g., grain number and width) are not clearly understood. In this study, for the first time, we dissected the SEP into seven stages to investigate plant (first experiment) and floret (second experiment) growth in greenhouse- and field-grown wheat. In the first experiment, the values of various plant growth trait indices at different stages were generally consistent between field and greenhouse and were independent of the environment. However, at specific stages, some traits significantly differed between the two environments. In the second experiment, phenotypic and genotypic similarity analysis revealed that grain number and size corresponded closely to ovary size at anthesis, suggesting that ovary size is strongly associated with grain number and size. Moreover, principal component analysis (PCA) showed that the top six principal components PCs explained 99.13, 98.61, 98.41, 98.35, and 97.93% of the total phenotypic variation at the green anther, yellow anther, tipping, heading, and anthesis stages, respectively. The cumulative variance explained by the first PC decreased with floret growth, with the highest value detected at the green anther stage (88.8%) and the lowest at the anthesis (50.09%). Finally, ovary size at anthesis was greater in wheat accessions with early release years than in accessions with late release years, and anther/ovary size shared closer connections with grain number/size traits at the late vs. early stages of floral development. Our findings shed light on the dynamic changes in plant and floret growth-related traits in wheat and the effects of the environment on these traits.