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Morphological characteristics, anatomical structure, and gene expression: novel insights into gibberellin biosynthesis and perception during carrot growth and development.

Wang GL, Xiong F, Que F, Xu ZS, Wang F, Xiong AS - Hortic Res (2015)

Bottom Line: Carrot undergoes significant alteration in organ size during its growth and development.Gibberellin levels in the roots initially increased and then decreased, but these levels were lower than those in the petioles and leaves.The results suggested that gibberellin level may play a vital role in carrot elongation and expansion.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Horticulture, Nanjing Agricultural University , Nanjing 210095, China.

ABSTRACT
Gibberellins (GAs) are considered potentially important regulators of cell elongation and expansion in plants. Carrot undergoes significant alteration in organ size during its growth and development. However, the molecular mechanisms underlying gibberellin accumulation and perception during carrot growth and development remain unclear. In this study, five stages of carrot growth and development were investigated using morphological and anatomical structural techniques. Gibberellin levels in leaf, petiole, and taproot tissues were also investigated for all five stages. Gibberellin levels in the roots initially increased and then decreased, but these levels were lower than those in the petioles and leaves. Genes involved in gibberellin biosynthesis and signaling were identified from the carrotDB, and their expression was analyzed. All of the genes were evidently responsive to carrot growth and development, and some of them showed tissue-specific expression. The results suggested that gibberellin level may play a vital role in carrot elongation and expansion. The relative transcription levels of gibberellin pathway-related genes may be the main cause of the different bioactive GAs levels, thus exerting influences on gibberellin perception and signals. Carrot growth and development may be regulated by modification of the genes involved in gibberellin biosynthesis, catabolism, and perception.

No MeSH data available.


Proposed pathway for gibberellin (GA) biosynthesis in plants.
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fig1: Proposed pathway for gibberellin (GA) biosynthesis in plants.

Mentions: In higher plants, GAs originate from geranylgeranyl diphosphate (GGPP), which is synthesized from isopentenyl pyrophosphate (IPP)8. GGPP is then converted into ent-kaurene by ent-copalyl diphosphate synthase (CPS) and ent-kaurene synthase (KS). Ent-kaurene is oxidized to GA12-aldehyde, a precursor of all GAs. Finally, GA12-aldehyde is then transformed into various GAs in a process catalyzed by GA20-oxidase (GA20ox), GA3-oxidase (GA3ox), GA2-oxidase (GA2ox), and other enzymes9,10 (Figure 1). Biochemical, molecular, and genetic studies have shown that genes that encode the enzymes in this pathway are essential for GA accumulation and plant growth11–13. The downregulation of the StGA3ox genes in potato alters GA content and affects plant and tuber growth14. Similarly, PsGA3ox1 transgene expression exhibits higher GA1 levels and alters GA biosynthesis and catabolism gene expression as well as plant phenotype15. Gibberellin metabolism, stem growth, and biomass production in tobacco (Nicotiana tabacum) either increase or decrease when AtGA20ox or AtGA2ox is overexpressed16. Thus, the genes involved in GA biosynthesis and catabolism should be identified to better control GA accumulation and plant growth.


Morphological characteristics, anatomical structure, and gene expression: novel insights into gibberellin biosynthesis and perception during carrot growth and development.

Wang GL, Xiong F, Que F, Xu ZS, Wang F, Xiong AS - Hortic Res (2015)

Proposed pathway for gibberellin (GA) biosynthesis in plants.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4595985&req=5

fig1: Proposed pathway for gibberellin (GA) biosynthesis in plants.
Mentions: In higher plants, GAs originate from geranylgeranyl diphosphate (GGPP), which is synthesized from isopentenyl pyrophosphate (IPP)8. GGPP is then converted into ent-kaurene by ent-copalyl diphosphate synthase (CPS) and ent-kaurene synthase (KS). Ent-kaurene is oxidized to GA12-aldehyde, a precursor of all GAs. Finally, GA12-aldehyde is then transformed into various GAs in a process catalyzed by GA20-oxidase (GA20ox), GA3-oxidase (GA3ox), GA2-oxidase (GA2ox), and other enzymes9,10 (Figure 1). Biochemical, molecular, and genetic studies have shown that genes that encode the enzymes in this pathway are essential for GA accumulation and plant growth11–13. The downregulation of the StGA3ox genes in potato alters GA content and affects plant and tuber growth14. Similarly, PsGA3ox1 transgene expression exhibits higher GA1 levels and alters GA biosynthesis and catabolism gene expression as well as plant phenotype15. Gibberellin metabolism, stem growth, and biomass production in tobacco (Nicotiana tabacum) either increase or decrease when AtGA20ox or AtGA2ox is overexpressed16. Thus, the genes involved in GA biosynthesis and catabolism should be identified to better control GA accumulation and plant growth.

Bottom Line: Carrot undergoes significant alteration in organ size during its growth and development.Gibberellin levels in the roots initially increased and then decreased, but these levels were lower than those in the petioles and leaves.The results suggested that gibberellin level may play a vital role in carrot elongation and expansion.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Horticulture, Nanjing Agricultural University , Nanjing 210095, China.

ABSTRACT
Gibberellins (GAs) are considered potentially important regulators of cell elongation and expansion in plants. Carrot undergoes significant alteration in organ size during its growth and development. However, the molecular mechanisms underlying gibberellin accumulation and perception during carrot growth and development remain unclear. In this study, five stages of carrot growth and development were investigated using morphological and anatomical structural techniques. Gibberellin levels in leaf, petiole, and taproot tissues were also investigated for all five stages. Gibberellin levels in the roots initially increased and then decreased, but these levels were lower than those in the petioles and leaves. Genes involved in gibberellin biosynthesis and signaling were identified from the carrotDB, and their expression was analyzed. All of the genes were evidently responsive to carrot growth and development, and some of them showed tissue-specific expression. The results suggested that gibberellin level may play a vital role in carrot elongation and expansion. The relative transcription levels of gibberellin pathway-related genes may be the main cause of the different bioactive GAs levels, thus exerting influences on gibberellin perception and signals. Carrot growth and development may be regulated by modification of the genes involved in gibberellin biosynthesis, catabolism, and perception.

No MeSH data available.