ACC SYNTHASE4 inhibits gibberellin biosynthesis and FLOWERING LOCUS T expression during citrus flowering.

Flowering is an essential process in fruit trees. Flower number and timing have a substantial impact on the yield and maturity of fruit. Ethylene and gibberellin (GA) play vital roles in flowering, but the mechanism of coordinated regulation of flowering in woody plants by GA and ethylene is still unclear.

Citrus ACC synthase CiACS4 regulates plant height by inhibiting gibberellin biosynthesis.

Dwarfism is an agronomic trait that has substantial effects on crop yield, lodging resistance, planting density, and a high harvest index. Ethylene plays an important role in plant growth and development, including the determination of plant height. However, the mechanism by which ethylene regulates plant height, especially in woody plants, remains unclear.

Drought and low temperature-induced NF-YA1 activates FT expression to promote citrus flowering.

Flower induction in adult citrus is mainly regulated by drought and low temperatures. However, the mechanism of FLOWERING LOCUS T regulation of citrus flowering (CiFT) under two flower-inductive stimuli remains largely unclear. In this study, a citrus transcription factor, nuclear factor YA (CiNF-YA1), was found to specifically bind to the CiFT promoter by forming a complex with CiNF-YB2 and CiNF-YC2 to activate CiFT expression.

Mobility of FLOWERING LOCUS T protein as a systemic signal in trifoliate orange and its low accumulation in grafted juvenile scions.

The long juvenile period of perennial woody plants is a major constraint in breeding programs. FLOWERING LOCUS T (FT) protein is an important mobile florigen signal that induces plant flowering. However, whether FT can be transported in woody plants to shorten the juvenile period is unknown, and its transport mechanism remains unclear.

Functional analysis of a PISTILLATA-like gene CcMADS20 involved in floral organs specification in citrus.

PISTILLATA (PI), as a member of MADS-box transcription factor, plays an important role in petal and stamen specification in Arabidopsis. However, little is known about PI-like genes in citrus. To understand the molecular mechanism of PI during the developmental process of citrus flower, a PI-like gene CcMADS20 was isolated from Citrus Clemantina.

Citrus FRIGIDA cooperates with its interaction partner dehydrin to regulate drought tolerance.

Drought is a major environmental stress that severely affects plant growth and crop productivity. FRIGIDA (FRI) is a key regulator of flowering time and drought tolerance in model plants. However, little is known regarding its functions in woody plants, including citrus.

Transcriptomic and physiological analysis reveals interplay between salicylic acid and drought stress in citrus tree floral initiation.

Salicylic acid (SA) and drought stress promote more flowering in sweet orange. The physiological response and molecular mechanism underlying stress-induced floral initiation were discovered by transcriptome profiling. Numerous flowering-regulated genes were identified, and ectopically expressed CsLIP2A promotes early flowering in Arabidopsis.

Two citrus KNAT-like genes, CsKN1 and CsKN2, are involved in the regulation of spring shoot development in sweet orange.

Shoot-tip abortion is a very common phenomenon in some perennial woody plants and it affects the height, architecture, and branch orientation of trees; however, little is currently known about the underlying mechanisms. In this study, we identified a gene in sweet orange (Citrus sinensis) encoding a KNAT-like protein (CsKN1) and found high expression in the shoot apical meristem (SAM). Overexpression of CsKN1 in transgenic plants prolonged the vegetative growth of SAMs, whilst silencing resulted in either the loss or inhibition of SAMs.

High-Density Genetic Map Construction and Identification of QTLs Controlling Leaf Abscission Trait in .

A high-density genetic linkage map is essential for genetic and genomic studies including QTL mapping, genome assembly, and comparative genomic analysis. Here, we constructed a citrus high-density linkage map using SSR and SNP markers, which are evenly distributed across the citrus genome. The integrated linkage map contains 4163 markers with an average distance of 1.

A MADS-Box Gene Is Involved in Citrus Flowering and Leaf Development through Interaction with CiAGL9.

MADS-box genes are involved in various developmental processes including vegetative development, flower architecture, flowering, pollen formation, seed and fruit development. However, the function of most MADS-box genes and their regulation mechanism are still unclear in woody plants compared with model plants. In this study, a MADS-box gene () was identified in citrus.

Genome-Wide Identification and Expression Profiling of the Gene Family in and Functional Analysis of a Member.

-related homeobox () transcription factors (TFs) are well known for their role in plant development but are rarely studied in citrus. In this study, we identified 11 putative genes from the sweet orange genome and divided the citrus genes into three clades (modern/WUSCHEL(WUS), intermediate, and ancient). Subsequently, we performed syntenic relationship, intron-exon organization, motif composition, and -element analysis.

Comparative analysis of the transcriptome, methylome, and metabolome during pollen abortion of a seedless citrus mutant.

Pollen abortion could be mainly attributed to abnormal meiosis in the mutant. Multiomics analysis uncovered significant epigenetic variations between the mutant and its wild type during the pollen abortion process. Male sterility caused by aborted pollen can result in seedless fruit.

HD-ZIP I Transcription Factor () Negatively Regulates Citrus Flowering through Binding to Promoter.

For floral induction in adult citrus, low temperature is one of the most important environmental factors. () plays a very important role in low-temperature-induced flowering by repressed expression under exposure to prolonged low-temperature conditions. However, little is known about the regulation mechanism in perennial woody plants such as citrus.

Genome-Wide Identification and Characterization of SQUAMOSA-Promoter-Binding Protein (SBP) Genes Involved in the Flowering Development of .

SQUAMOSA-promoter binding protein (SBP)-box genes encode a family of plant-specific transcription factors that play vital roles in plant growth and development. In this study, 15 SBP-box genes were identified and isolated from (), where 10 of these genes were predicted to be putative targets of microRNA156 (CclmiR156). The 15 genes could be classified into six groups based on phylogenetic analysis, diverse intron⁻exon structure, and motif prediction, similar to the gene family of and .

Genome-wide genetic variation and comparison of fruit-associated traits between kumquat (Citrus japonica) and Clementine mandarin (Citrus clementina).

The comprehensive genetic variation of two citrus species were analyzed at genome and transcriptome level. A total of 1090 differentially expressed genes were found during fruit development by RNA-sequencing. Fruit size (fruit equatorial diameter) and weight (fresh weight) are the two most important components determining yield and consumer acceptability for many horticultural crops.

Transcriptome-wide identification and functional prediction of novel and flowering-related circular RNAs from trifoliate orange (Poncirus trifoliata L. Raf.).

A total of 558 potential circular RNAs (circRNAs) were identified in citrus, and these were analyzed and compared. One hundred seventy-six differentially expressed circRNAs were identified in two genotypes of trifoliate orange. Circular RNAs (circRNAs) play diverse roles in transcriptional control and microRNA (miRNA) function.

MicroRNA-Mediated Gene Silencing in Plant Defense and Viral Counter-Defense.

MicroRNAs (miRNAs) are non-coding RNAs of approximately 20-24 nucleotides in length that serve as central regulators of eukaryotic gene expression by targeting mRNAs for cleavage or translational repression. In plants, miRNAs are associated with numerous regulatory pathways in growth and development processes, and defensive responses in plant-pathogen interactions. Recently, significant progress has been made in understanding miRNA-mediated gene silencing and how viruses counter this defense mechanism.

Identification of Genes Associated with Lemon Floral Transition and Flower Development during Floral Inductive Water Deficits: A Hypothetical Model.

Unlabelled: Water deficit is a key factor to induce flowering in many woody plants, but reports on the molecular mechanisms of floral induction and flowering by water deficit are scarce. Here, we analyzed the morphology, cytology, and different hormone levels of lemon buds during floral inductive water deficits. Higher levels of ABA were observed, and the initiation of floral bud differentiation was examined by paraffin sections analysis.

Genome-wide screening and characterization of long non-coding RNAs involved in flowering development of trifoliate orange (Poncirus trifoliata L. Raf.).

Long non-coding RNAs (lncRNAs) have been demonstrated to play critical regulatory roles in post-transcriptional and transcriptional regulation in Arabidopsis. However, lncRNAs and their functional roles remain poorly characterized in woody plants, including citrus. To identify lncRNAs and investigate their role in citrus flowering, paired-end strand-specific RNA sequencing was performed for precocious trifoliate orange and its wild-type counterpart.

Characterization and Expression Analysis of PtAGL24, a SHORT VEGETATIVE PHASE/AGAMOUS-LIKE 24 (SVP/AGL24)-Type MADS-Box Gene from Trifoliate Orange (Poncirus trifoliata L. Raf.).

The transition from vegetative to reproductive growth in perennial woody plants does not occur until after several years of repeated seasonal changes and alternative growth. To better understand the molecular basis of flowering regulation in citrus, a MADS-box gene was isolated from trifoliate orange (precocious trifoliate orange, Poncirus trifoliata L. Raf.

Identifying the genome-wide genetic variation between precocious trifoliate orange and its wild type and developing new markers for genetics research.

To increase our understanding of the genes involved in flowering in citrus, we performed genome resequencing of an early flowering trifoliate orange mutant (Poncirus trifoliata L. Raf.) and its wild type.

Regulatory effects of cotranscriptional RNA structure formation and transitions.

RNAs, which play significant roles in many fundamental biological processes of life, fold into sophisticated and precise structures. RNA folding is a dynamic and intricate process, which conformation transition of coding and noncoding RNAs form the primary elements of genetic regulation. The cellular environment contains various intrinsic and extrinsic factors that potentially affect RNA folding in vivo, and experimental and theoretical evidence increasingly indicates that the highly flexible features of the RNA structure are affected by these factors, which include the flanking sequence context, physiochemical conditions, cis RNA-RNA interactions, and RNA interactions with other molecules.