The Current Status of Research on Gibberellin Biosynthesis

Hedden, Peter

doi:10.1093/pcp/pcaa092

Cited by 243 publications

(170 citation statements)

References 201 publications

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“…Gibberellins (GAs) are the most important hormones for plant extension growth and thus for internode elongation in maize (Sponsel, 1995). GAs in higher plants primarily stimulate organ growth through enhancement of cell elongation and cell division (Hedden, 2020), and they promote certain developmental switches, such as between vegetative and reproductive development by induction of flowering (Evans & Poethig, 1995), and have a large impact on fertility (Hedden & Thomas, 2012). Semi‐dwarf mutants with genetically inherent inhibition of gibberellin biosynthesis do exist also for maize (Fujioka et al., 1988; Harberd & Freeling, 1989), yet they are not used in commercial maize production because of negative effects on flower sexuality (Bortiri & Hake, 2007; Irish, 1996; Rood et al., 1980; Xu et al., 2004).…”

Section: Introductionmentioning

confidence: 99%

Can nutrient‐utilization efficiency be improved by reduced fertilizer supply to maize plants treated with the plant growth regulator paclobutrazol?

Hütsch

Schubert

2021

J Agronomy Crop Science

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In previous investigations of several maize cultivars, an improvement of the harvest index was obtained by paclobutrazol (PAC) application combined with an increase in water‐use efficiency. However, so far nutrient‐utilization efficiencies could not be enhanced when control and PAC‐treated maize plants received the same amount of fertilizers. With adjusted fertilizer supply according to the lower requirement of the smaller, PAC‐treated plants, an improvement of nutrient‐utilization efficiencies may be expected. Thus, in the present study, PAC was applied at growth stage V5 to two maize cultivars (Zea mays L. cvs. Galactus and Fabregas) grown in a container experiment. Shortly after PAC application, differential NPK fertilization was introduced in order to obtain a nutrient supply according to the requirement of control plants (100% NPK), the requirement of PAC‐treated plants (85% NPK) and a further slight decrease (78% NPK). Plant height and transpiration rates were significantly reduced due to PAC treatment with stronger effects on Galactus than on Fabregas. Pollen shed, silking and the anthesis‐silking interval (ASI) were unaffected by PAC application and fertilizer supply. Senescence of PAC‐treated plants was delayed, whereas it was accelerated with reduced fertilizer supply. The grain yield of cultivar Galactus was significantly decreased due to PAC application by 13% to 20%, and this effect was strengthened due to reduction in NPK supply. These grain yield reductions were solely caused by decreases in kernel number, which were closely linked to reductions in cob length. On the contrary, PAC treatment did not affect grain yield of Fabregas and reductions due to less NPK supply were small. Harvest index and water‐use efficiency were enhanced by PAC treatment. Plant nutrient contents were similar for control and PAC‐treated plants, but strongly related to fertilizer supply with significant decreases due to reductions in NPK application. The N‐, P‐ and K‐utilization efficiencies of both cultivars were either decreased or unaffected by PAC treatments. The key constraint for improvements of nutrient‐utilization efficiencies is grain yield reduction due to PAC. This problem should be addressed in further studies with avoidance of grain yield decreases by delayed application time combined with fine‐tuning of cultivar‐specific PAC application rates.

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Section: Introductionmentioning

confidence: 99%

Can nutrient‐utilization efficiency be improved by reduced fertilizer supply to maize plants treated with the plant growth regulator paclobutrazol?

Hütsch

Schubert

2021

J Agronomy Crop Science

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“…Gibberellic acid (GA) is the most common form of gibberellin [ 153 , 154 , 155 ]. The biosynthesis of GA is regulated by both developmental and environmental stimuli [ 156 ]. Salinity stress reduces endogenous GA content, resulting in plant’s hypersensitivity to salt [ 157 , 158 ].…”

Section: Effects Of Plant Growth Regulators On Plant Performance Under Saline Conditionsmentioning

confidence: 99%

Improving Performance of Salt-Grown Crops by Exogenous Application of Plant Growth Regulators

et al. 2021

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Soil salinity is one of the major abiotic stresses restricting plant growth and development. Application of plant growth regulators (PGRs) is a possible practical means for minimizing salinity-induced yield losses, and can be used in addition to or as an alternative to crop breeding for enhancing salinity tolerance. The PGRs auxin, cytokinin, nitric oxide, brassinosteroid, gibberellin, salicylic acid, abscisic acid, jasmonate, and ethylene have been advocated for practical use to improve crop performance and yield under saline conditions. This review summarizes the current knowledge of the effectiveness of various PGRs in ameliorating the detrimental effects of salinity on plant growth and development, and elucidates the physiological and genetic mechanisms underlying this process by linking PGRs with their downstream targets and signal transduction pathways. It is shown that, while each of these PGRs possesses an ability to alter plant ionic and redox homeostasis, the complexity of interactions between various PGRs and their involvement in numerous signaling pathways makes it difficult to establish an unequivocal causal link between PGRs and their downstream effectors mediating plants’ adaptation to salinity. The beneficial effects of PGRs are also strongly dependent on genotype, the timing of application, and the concentration used. The action spectrum of PGRs is also strongly dependent on salinity levels. Taken together, this results in a rather narrow “window” in which the beneficial effects of PGR are observed, hence limiting their practical application (especially under field conditions). It is concluded that, in the light of the above complexity, and also in the context of the cost–benefit analysis, crop breeding for salinity tolerance remains a more reliable avenue for minimizing the impact of salinity on plant growth and yield. Further progress in the field requires more studies on the underlying cell-based mechanisms of interaction between PGRs and membrane transporters mediating plant ion homeostasis.

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“…Gibberellic acids (GAs), a diterpenoid plant hormone, play an important role in various processes in the whole life cycle of plants, including seed germination, hypocotyl and stem elongation, leaf expansion, trichome development, flowering time, flower development and fruit development [2,3]. GA biosynthesis can be divided into three stages, which occur in three independent cell regions [3][4][5]. The first stage is the production of ent-kaurene from geranylgeranyl diphosphate (GGDP) catalyzed by ent-copalyl diphosphate synthase (CPS) and ent-kaurene synthase (KS).…”

Section: Introductionmentioning

confidence: 99%

Gibberellins Inhibit Flavonoid Biosynthesis and Promote Nitrogen Metabolism in Medicago truncatula

Sun

Cui

Zhang

et al. 2021

IJMS

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Bioactive gibberellic acids (GAs) are diterpenoid plant hormones that are biosynthesized through complex pathways and control various aspects of growth and development. Although GA biosynthesis has been intensively studied, the downstream metabolic pathways regulated by GAs have remained largely unexplored. We investigated Tnt1 retrotransposon insertion mutant lines of Medicago truncatula with a dwarf phenotype by forward and reverse genetics screening and phylogenetic, molecular, biochemical, proteomic and metabolomic analyses. Three Tnt1 retrotransposon insertion mutant lines of the gibberellin 3-beta-dioxygenase 1 gene (GA3ox1) with a dwarf phenotype were identified, in which the synthesis of GAs (GA3 and GA4) was inhibited. Phenotypic analysis revealed that plant height, root and petiole length of ga3ox1 mutants were shorter than those of the wild type (Medicago truncatula ecotype R108). Leaf size was also much smaller in ga3ox1 mutants than that in wild-type R108, which is probably due to cell-size diminution instead of a decrease in cell number. Proteomic and metabolomic analyses of ga3ox1/R108 leaves revealed that in the ga3ox1 mutant, flavonoid isoflavonoid biosynthesis was significantly up-regulated, while nitrogen metabolism was down-regulated. Additionally, we further demonstrated that flavonoid and isoflavonoid biosynthesis was induced by prohexadione calcium, an inhibitor of GA3ox enzyme, and inhibited by exogenous GA3. In contrast, nitrogen metabolism was promoted by exogenous GA3 but inhibited by prohexadione calcium. The results of this study further demonstrated that GAs play critical roles in positively regulating nitrogen metabolism and transport and negatively regulating flavonoid biosynthesis through GA-mediated signaling pathways in leaves.

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The Current Status of Research on Gibberellin Biosynthesis

Cited by 243 publications

References 201 publications

Can nutrient‐utilization efficiency be improved by reduced fertilizer supply to maize plants treated with the plant growth regulator paclobutrazol?

Can nutrient‐utilization efficiency be improved by reduced fertilizer supply to maize plants treated with the plant growth regulator paclobutrazol?

Improving Performance of Salt-Grown Crops by Exogenous Application of Plant Growth Regulators

Gibberellins Inhibit Flavonoid Biosynthesis and Promote Nitrogen Metabolism in Medicago truncatula

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