FLOWER DEVELOPMENT IN NORMAL TOMATO AND A GIBBERELLIN‐DEFICIENT (ga‐2) MUTANT

Nester, Joan E.; Zeevaart, Jan A. D.

doi:10.1002/j.1537-2197.1988.tb12160.x

Cited by 65 publications

(36 citation statements)

References 17 publications

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“…On the other hand, the overall reduced number of flower buds suggests an effect of PhGI1 silencing on upstream events, possibly related the flower-meristem-identity genes PETUNIA FLOWERING GENE (PFG) and ALF (ABERRANT LEAF AND FLOWER) 41,63 . Mutants showing a developmental arrest in flower bud development all belong to the group of gibberellin deficient mutants, including gibberellin deficient (ga-2) 65 and gib-1 66 from tomato or ga1-1 from Arabidopsis 67 . The promotion of petal, stamen and anther development in Arabidopsis was proposed to occur by opposing the action of the DELLA proteins RGA, RGL1 and RGL2 68 .…”

Section: Discussionmentioning

confidence: 99%

The clock gene Gigantea 1 from Petunia hybrida coordinates vegetative growth and inflorescence architecture

Brandoli

Petri

Egea‐Cortines

et al. 2020

Sci Rep

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the gene GIGANTEA (GI) appeared early in land plants. it is a single copy gene in most plants and is found in two to three copies in Solanaceae. We analyzed the silencing of one GI copy, Petunia hybrida GI1 (PhGI1), by hairpin RNAs in Petunia in order to gain knowledge about its range of functions. Decreased transcript levels of PhGI1 were accompanied also by a reduction of PhGI2. They were further associated with increased time period between two consecutive peaks for PhGI1 and CHANEL (PhCHL), the orthologue of the blue light receptor gene ZEITLUPE (ZTL), confirming its role in maintaining circadian rhythmicity. Silenced plants were bigger with modified internode length and increased leaf size while flowering time was not altered. We uncovered a new function for PhGI1 as silenced plants showed reduction of flower bud number and the appearance of two flower buds in the bifurcation point, were normally one flower bud and the inflorescence meristem separate. Furthermore, one of the flower buds consistently showed premature flower abortion. Flowers that developed fully were significantly smaller as a result of decreased cell size. Even so the circadian pattern of volatile emission was unchanged in the silenced lines, flowers emitted 20% less volatiles on fresh weight basis over 24 hours and showed changes in the scent profile. Our results indicate a novel role of PhGI1 in the development of reproductive organs in Petunia. PhGI1 therefore represses growth in vegetative plant parts, maintains the typical cymose inflorescence structure, and inhibits premature flower abortion. The evolution of land plants has included amongst other adaptations the increase in complexity of the circadian clock. Predictable changes in the environment, as light and temperature, are anticipated by the plant circadian clock, which allows them to adjust their developmental and physiological traits. Most detailed studies on plant circadian clock have been performed in Arabidopsis thaliana 1. The plant circadian clock is based on a set of genes forming several overlapping loops interacting with each other via transcriptional and post-translational activation and repression 2. Based on the time of the day when the mRNA of the gene shows its expression maximum, the genes included in this oscillator have been classified as the morning loop, midday or core loop and evening loop 3. In Arabidopsis, LATE ELONGATED HYPOCOTYL (LHY) and CIRCADIAN CLOCK ASSOCIATED 1 (CCA1), two MYB transcription factors, form the central circadian oscillator complex, together with PSEUDO RESPONSE REGULATOR 1 (PRR1), better known as TIMING OF CAB1 (TOC1). PSEUDO-RESPONSE REGULATOR 9 (PRR9) and 7 (PRR7) form the morning loop genes and the evening complex is formed by the three proteins EARLY FLOWERING 3 and 4 (ELF3 and ELF4) and LUX ARHYTHMO (LUX). These clock genes are interconnected via negative autoregulatory feedback loops, meaning that they reciprocally regulate each other 1,4-6. Light input is received by ZEITLUPE (ZTL), a gene containing an F-box domain and a blue-li...

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Section: Discussionmentioning

confidence: 99%

The clock gene Gigantea 1 from Petunia hybrida coordinates vegetative growth and inflorescence architecture

Brandoli

Petri

Egea‐Cortines

et al. 2020

Sci Rep

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“…In the tomato gib‐2 mutant, which has a defect in the conversion of ent ‐7‐ α ‐hydroxykaurenoic acid to GA 12 ‐aldehyde, anther development is arrested at an early developmental stage and meiosis of microsporocytes does not occur. Cells of the sporogenous layer are initiated, but they later degenerate (Nester and Zeevaart 1988). In the tomato gib‐1 mutant, the conversion of geranylgeranyl pyrophosphate to copalyl diphosphate is blocked.…”

Section: Discussionmentioning

confidence: 99%

Gibberellin regulates post‐microsporogenesis processes in petunia anthers

Izhaki

Borochov

Zamski

et al. 2002

Physiologia Plantarum

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Previous studies have suggested that gibberellins (GAs) are produced in petunia anthers and transported to the corolla to induce growth and pigmentation. In this work, we studied the role of GA in the regulation of anther development. When petunia plants were treated with the GA-biosynthesis inhibitor paclobutrazol, anther development was arrested. Microscopic analysis of these anthers revealed that paclobutrazol inhibits post-meiotic developmental processes. The treated anthers contained pollen grains but the connective tissue and tapetum cells were degenerated. A similar phenotype was obtained when the Arabidopsis GA-signal repressor, SPY, was over-expressed in transgenic petunia plants, i.e. anther development was arrested following microsporogenesis. The expression of the GA-induced gene, GIP, can be used in petunia as a molecular marker to study GA responses. GA3 treatment of young anthers promoted, and paclobutrazol inhibited, GIP expression, suggesting that the hormone controls the natural activation of the gene in the anthers. Analyses of GIP expression during anther development revealed that the gene is induced only after microsporogenesis. This observation further suggests a role for GA in the regulation of post-meiotic processes during petunia anther development.

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“…It is interesting to note that in the tomato GA‐deficient mutant gib‐2 , the tapetum is the first cell type to degenerate due to the GA‐deficiency. In addition, in this mutant the ovary wall does not grow properly ( Nester & Zeevaart 1988). Therefore, Le20ox‐2 mRNA localized in tapetum and placenta may be responsible for GA biosynthesis required in these tissues.…”

Section: Discussionmentioning

confidence: 99%

Regulation of gibberellin biosynthesis genes during flower and early fruit development of tomato

et al. 1999

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SummaryGibberellins (GAs) are essential for the development of fertile flowers in tomato, and may also be required immediately after fertilization. In the GA-biosynthetic pathway, the reactions catalyzed by GA 20-oxidases have been implicated as site of regulation. To study the regulation of GA biosynthesis in flower and early fruit development, we isolated three tomato GA 20-oxidase cDNA clones, Le20ox-1, -2 and -3. The three genes showed different organ-specific patterns of mRNA accumulation. Analysis of the transcript levels of the three GA 20-oxidase genes, as well as those of copalyl diphosphate synthase (LeCPS) and GA 3β-hydroxylase (Le3OH-2) during flower bud and early fruit development, revealed temporally distinct patterns of mRNA accumulation. Up until anthesis, transcripts were observed for LeCPS, Le20ox-1, -2 and Le3OH-2, with an accumulation of Le20ox-1 mRNA. In contrast to the high level of Le3OH-2 transcripts in the fully open flower, mRNA levels of Le20ox-1, -2 and LeCPS were reduced at this stage. After anthesis, LeCPS and Le20ox-1 transcripts increased again. In addition, Le20ox-3 transcripts increased whereas the transcripts of Le3OH-2 decreased to an undetectable level. In situ hybridization results demonstrated that during early stages of bud development, Le20ox-2 transcripts were localized in the tapetum and placenta. The presented results supply novel data about localization of GA biosynthesis gene transcripts, and indicate that transcript levels of GA biosynthesis genes are all highly regulated during flower bud development.

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FLOWER DEVELOPMENT IN NORMAL TOMATO AND A GIBBERELLIN‐DEFICIENT (ga‐2) MUTANT

Cited by 65 publications

References 17 publications

The clock gene Gigantea 1 from Petunia hybrida coordinates vegetative growth and inflorescence architecture

The clock gene Gigantea 1 from Petunia hybrida coordinates vegetative growth and inflorescence architecture

Gibberellin regulates post‐microsporogenesis processes in petunia anthers

Regulation of gibberellin biosynthesis genes during flower and early fruit development of tomato

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