The first step in flower development is the generation of a floral meristem by inflorescence meristem. We have analyzed how this process affected mutant alleles Arabidopsis gene LEAFY. show that LEAFY interacts with another control gene, APETALA1, to promote transition from cloned and, consistent phenotype, we find RNA expressed strongly young primordia. expression procedes homeotic genes AGAMOUS and APETALA3, which specify organ identify within flower. Furthermore, demonstrate homolog...

ABSTRACT Mutations in the APETALA1 gene disturb two phases of flower development, meristem specification and floral organ specification. These effects become manifest as a partial conversion flowers into inflorescence shoots disruption sepal petal development. We describe changes an allelic series nine apetala1 mutants show that functions are separable. have also studied interaction between other genes by examining phenotypes multiply mutant plants situ hybridization using probes for several...

The systemic model for floral induction, dubbed florigen, was conceived in photoperiod-sensitive plants but implies, its ultimate form, a graft-transmissible signal that, although activated by different stimuli flowering systems, is common to all plants. We show that SFT ( SINGLE-FLOWER TRUSS ), the tomato ortholog of FLOWERING LOCUS T FT induces day-neutral and tobacco encoded . sft mutant are late-flowering, with altered architecture flower morphology. -dependent signals complement...

ABSTRACT Vegetative and reproductive phases alternate regularly during sympodial growth in tomato. In wild-type ‘indeterminate’ plants, inflorescences are separated by three vegetative nodes. ‘determinate’ plants homozygous for the recessive allele of SELF-PRUNING (SP) gene, segments develop progressively fewer nodes until shoot is terminated two consecutive inflorescences. We show here that SP gene tomato ortholog CENTRORADIALIS TERMINAL FLOWER1, genes which maintain indeterminate state...

Members of the KANADI gene family in Arabidopsis thaliana regulate abaxial identity and laminar growth lateral organs. Promoter APETALA3-mediated ectopic expression restricts petal expansion was used a genetic screen for factors involved KANADI-mediated signaling. Through this screen, mutations ETTIN (ETT; also known as Auxin Response Factor3 [ARF3]) were isolated second site suppressors found to ameliorate activity throughout plant well. Mutant phenotypes ett are restricted flowers;...

Summary A series of mutants Arabidopsis thaliana was selected in which the inflorescence stem elongates but loses ability to produce flower primordia on its flanks. Mutants fell into two classes, further occurrences pin‐formed and mutations at a new locus named pinoid . As well as causing defects, result pleiotropic defects development floral organs, cotyledons leaves. Most changes involve number organs produced rather than their differentiation suggesting that PINOID controls an early...

Abstract Recent studies demonstrated that pattern formation in plants involves regulation of transcription factor families by microRNAs (miRNAs). To explore the potency, autonomy, target range, and functional conservation miRNA genes, a systematic comparison between ectopically expressing pre-miRNAs with corresponding multiple mutant combinations genes was performed. We show regulated expression several Arabidopsis thaliana pre-miRNA induced range phenotypic alterations, most extreme ones...

The florigen paradigm implies a universal flowering-inducing hormone that is common to all flowering plants. Recent work identified FT orthologues as originators of and their polypeptides the likely systemic agent. However, developmental processes targeted by remained unknown. Here we identify local balances between SINGLE FLOWER TRUSS (SFT), tomato precursor florigen, SELF-PRUNING (SP), potent SFT-dependent SFT inhibitor prime targets mobile florigen. graft-transmissible impacts on...

Leaves are formed at the flanks of shoot apical meristem (SAM) and develop into a variety forms. In tomato, prolonged leaf patterning enables elaboration compound leaves by reiterative initiation leaflets with lobed margins. goblet (gob) loss-of-function mutants,primary often fused, secondary marginal serrations absent, SAMs terminate precociously. We show that GOBencodes NAC-domain transcription factor expressed in narrow stripes margins, flanking distal side future leaflet primordia,...

To help understand the process of carpel morphogenesis, roles three development genes have been partitioned genetically. Mutants CRABS CLAW cause gynoecium to develop into a wider but shorter structure, and two carpels are unfused at apex. second gene, SPATULA, show reduced growth style, stigma, septum, transmitting tract is absent. Double mutants crabs claw spatula with homeotic that ectopic demonstrate SPATULA necessary for, inseparable from, development, their action negatively regulated...

Summary Growth of flowering stems in wild‐type Arabidopsis is indeterminate. Many flowers arise sequentially on the flanks apical meristems a phyllotactic spiral. We have isolated eight recessive mutants gene, terminal flower , which inflorescences become determinate. Flower primordia sooner or later ‘invade’ meristem summit leading to cessation its further growth. Primary usually terminate with several part‐flowers lack pedicels, and normal pedicellate may first. By contrast secondary...

SPINDLY (SPY) is a negative regulator of gibberellin (GA) responses; however, spy mutants exhibit various phenotypic alterations not found in GA-treated plants. Assaying for additional roles SPY revealed that are resistant to exogenously applied cytokinin. GA also repressed the effects cytokinin, suggesting there cross talk between two hormone-response pathways, which may involve function. Two alleles showing severe (spy-4) and mild (spy-3) GA-associated phenotypes exhibited similar...

Variation in the branching of plant inflorescences determines flower number and, consequently, reproductive success and crop yield. Nightshade (Solanaceae) species are models for a widespread, yet poorly understood, program eudicot growth, where short side branches initiated upon floral termination. This "sympodial" produces few-flowered tomato inflorescence, but classical mutants compound inflorescence (s) anantha (an) highly branched, s bears hundreds flowers. Here we show that S AN, which...

Shoot apical meristems (SAMs) are self-sustaining groups of cells responsible for the ordered initiation all aerial plant tissues, including stems and lateral organs. The precise coordination these processes argues crosstalk between different SAM domains. products YABBY (YAB) genes limited to organ primordium domains, which situated at periphery SAMs separated by a margin three seven from central meristem zone marked WUSCHEL CLAVATA3 expression. Mutations in two related YAB1 genes,...

Neofunctionalization following gene duplication is thought to be one of the key drivers in generating evolutionary novelty. A a common ancestor land plants produced two classes KNOTTED-like TALE homeobox genes, class I (KNOX1) and II (KNOX2). KNOX1 genes are linked tissue proliferation maintenance meristematic potentials flowering plant moss sporophytes, modulation activity implicated contributing leaf shape diversity plants. While KNOX2 function has been shown repress gametophytic (haploid)...

Leaves are flat determinate organs derived from indeterminate shoot apical meristems. The presence of a specific leaf meristem is debated, as anatomical features typical meristems not present in leaves. Here we demonstrate that multiple NGATHA (NGA) and CINCINNATA-class-TCP (CIN-TCP) transcription factors act redundantly, shortly after initiation, to gradually restrict the activity Arabidopsis thaliana marginal basal domains, their absence confers persistent growth leaves, cotyledons floral...

Abstract Floral organ identities are specified by a few transcription factors that act as master regulators. Subsequently, specification of axes programs the distribution distinct tissue types within organs themselves develop unique identities. The C-class, AGAMOUS-clade MADS box genes primary promoters gynoecium, which is divided into distal style and subtending ovary along apical-basal axis. We show members clade B3 domain factors, NGATHA1 (NGA1) to NGA4, expressed distally in all lateral...

Abstract Interfering with small RNA production is a common strategy of plant viruses. A unique class RNAs that require microRNA and short interfering (siRNA) biogenesis for their termed trans-acting (ta-siRNAs). Tomato (Solanum lycopersicum) wiry mutants represent phenotype mimics viral infection symptoms, including shoestring leaves lack leaf blade expansion. Here, we show four WIRY genes are involved in siRNA biogenesis, corresponding mutants, levels ta-siRNAs regulate AUXIN RESPONSE...

CRABS CLAW (CRC), a member of the YABBY gene family, is required for nectary and carpel development. To further understand CRC regulation in Arabidopsis thaliana, we performed phylogenetic footprinting analyses 5' upstream regions orthologs from three Brassicaceae species, including Arabidopsis. Phylogenetic efficiently identified functionally important regulatory (modules), indicating that expression regulated by combination positive negative elements modules. Within conserved modules,...

The Arabidopsis gynoecium is a complex organ that facilitates fertilization, later developing into dehiscent silique protects seeds until their dispersal. Identifying genes important for development often hampered by functional redundancy. We report unequal redundancy between two closely related genes, SPATULA (SPT) and ALCATRAZ (ALC), revealing previously unknown developmental roles each. SPT known to support septum, style stigma in the flower, whereas ALC involved dehiscence zone fruit....

The superiority of hybrids has long been exploited in agriculture, and although many models explaining "heterosis" have put forth, direct empirical support is limited. Particularly elusive cases heterozygosity for single gene mutations causing heterosis under a genetic model known as overdominance. In tomato (Solanum lycopersicum), plants carrying SINGLE FLOWER TRUSS (SFT) encoding the flowering hormone florigen are severely delayed flowering, become extremely large, produce few flowers...

A plethora of developmental and physiological processes in land plants is influenced by auxin, to a large extent via alterations gene expression AUXIN RESPONSE FACTORs (ARFs). The canonical auxin transcriptional response system plant innovation, however, charophycean algae possess orthologues at least some classes ARF AUXIN/INDOLE-3-ACETIC ACID (AUX/IAA) genes, suggesting that elements the existed an ancestral alga. We reconstructed phylogenetic relationships between streptophyte AUX/IAA...