Hormones and the Green Revolution

Salamini, F.

doi:10.1126/science.1090811

Cited by 44 publications

(22 citation statements)

References 10 publications

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“…In a broader context, DELLAs are well known for their prominent role in the green revolution spearheaded by Norman Borlaug that allowed food production to keep pace with worldwide population growth (Salamini, 2003;Swaminathan, 2009). Dominant DELLA gene mutations, selected by traditional breeding, led to the production of improved, higher yield dwarf crop varieties (Sun and Gubler, 2004;Fukao and Bailey-Serres, 2008;Gao et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

A DELLA in Disguise: SPATULA Restrains the Growth of the DevelopingArabidopsisSeedling

et al. 2011

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The period following seedling emergence is a particularly vulnerable stage in the plant life cycle. In Arabidopsis thaliana, the phytochrome-interacting factor (PIF) subgroup of basic-helix-loop-helix transcription factors has a pivotal role in regulating growth during this early phase, integrating environmental and hormonal signals. We previously showed that SPATULA (SPT), a PIF homolog, regulates seed dormancy. In this article, we establish that unlike PIFs, which mainly promote hypocotyl elongation, SPT is a potent regulator of cotyledon expansion. Here, SPT acts in an analogous manner to the gibberellin-dependent DELLAs, REPRESSOR OF GA1-3 and GIBBERELLIC ACID INSENSITIVE, which restrain cotyledon expansion alongside SPT. However, although DELLAs are not required for SPT action, we demonstrate that SPT is subject to negative regulation by DELLAs. Cross-regulation of SPT by DELLAs ensures that SPT protein levels are limited when DELLAs are abundant but rise following DELLA depletion. This regulation provides a means to prevent excessive growth suppression that would result from the dual activity of SPT and DELLAs, yet maintain growth restraint under DELLAdepleted conditions. We present evidence that SPT and DELLAs regulate common gene targets and illustrate that the balance of SPT and DELLA action depends on light quality signals in the natural environment.

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Section: Introductionmentioning

confidence: 99%

A DELLA in Disguise: SPATULA Restrains the Growth of the DevelopingArabidopsisSeedling

et al. 2011

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“…Mechanisms regulating organ size in plants are just beginning to be revealed, and only a few genetic factors controlling organ size have been identified (Gonzalez et al, 2009;Krizek, 2009). In the past, changes in growth of crop plants obtained by mutations in genes controlling the hormonal status have contributed significantly to increasing yield and were the basis for the green revolution (Hedden, 2003;Salamini, 2003). Therefore, a better understanding of the regulation of organ growth and size is relevant to improve rational approaches in plant breeding.…”

Section: Introductionmentioning

confidence: 99%

Root-Specific Reduction of Cytokinin Causes Enhanced Root Growth, Drought Tolerance, and Leaf Mineral Enrichment in Arabidopsis and Tobacco

et al. 2010

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Optimizing root system architecture can overcome yield limitations in crop plants caused by water or nutrient shortages. Classic breeding approaches are difficult because the trait is governed by many genes and is difficult to score. We generated transgenic Arabidopsis thaliana and tobacco (Nicotiana tabacum) plants with enhanced root-specific degradation of the hormone cytokinin, a negative regulator of root growth. These transgenic plants form a larger root system, whereas growth and development of the shoot are similar. Elongation of the primary root, root branching, and root biomass formation were increased by up to 60% in transgenic lines, increasing the root-to-shoot ratio. We thus demonstrated that a single dominant gene could regulate a complex trait, root growth. Moreover, we showed that cytokinin regulates root growth in a largely organ-autonomous fashion that is consistent with its dual role as a hormone with both paracrine and long-distance activities. Transgenic plants had a higher survival rate after severe drought treatment. The accumulation of several elements, including S, P, Mn, Mg, Zn, as well as Cd from a contaminated soil, was significantly increased in shoots. Under conditions of sulfur or magnesium deficiency, leaf chlorophyll content was less affected in transgenic plants, demonstrating the physiological relevance of shoot element accumulation. Our approach might contribute to improve drought tolerance, nutrient efficiency, and nutrient content of crop plants.

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“…Multiple phytohormones regulate the architecture of organs, the rate at which they grow, and their placement on the growing axes of plants (Sussex and Kerk, 2001;Jaillais and Chory, 2010;Depuydt and Hardtke, 2011). This regulation not only contributes to the diversity of plant form and the adaptation of plants to their environments (Orshan, 1986;Chapin et al, 1987) but has been central to major gains in crop yield in the 20th and 21st centuries (Salamini, 2003;Salas Fernandez et al, 2009). Phytohormone regulation of plant architecture and components such as plant height, branching, and floral organ development has been studied extensively (Evans and Poethig, 1995;Choe et al, 2001;Hong et al, 2004;Sakamoto et al, 2006).…”

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confidence: 99%

nana plant2 Encodes a Maize Ortholog of the Arabidopsis Brassinosteroid Biosynthesis Gene DWARF1, Identifying Developmental Interactions between Brassinosteroids and Gibberellins

et al. 2016

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A small number of phytohormones dictate the pattern of plant form affecting fitness via reproductive architecture and the plant's ability to forage for light, water, and nutrients. Individual phytohormone contributions to plant architecture have been studied extensively, often following a single component of plant architecture, such as plant height or branching. Both brassinosteroid (BR) and gibberellin (GA) affect plant height, branching, and sexual organ development in maize (Zea mays). We identified the molecular basis of the nana plant2 (na2) phenotype as a loss-of-function mutation in one of the two maize paralogs of the Arabidopsis (Arabidopsis thaliana) BR biosynthetic gene DWARF1 (DWF1). These mutants accumulate the DWF1 substrate 24-methylenecholesterol and exhibit decreased levels of downstream BR metabolites. We utilized this mutant and known GA biosynthetic mutants to investigate the genetic interactions between BR and GA. Double mutants exhibited additivity for some phenotypes and epistasis for others with no unifying pattern, indicating that BR and GA interact to affect development but in a context-dependent manner. Similar results were observed in double mutant analyses using additional BR and GA biosynthetic mutant loci. Thus, the BR and GA interactions were neither locus nor allele specific. Exogenous application of GA 3 to na2 and d5, a GA biosynthetic mutant, also resulted in a diverse pattern of growth responses, including BR-dependent GA responses. These findings demonstrate that BR and GA do not interact via a single inclusive pathway in maize but rather suggest that differential signal transduction and downstream responses are affected dependent upon the developmental context.

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Hormones and the Green Revolution

Cited by 44 publications

References 10 publications

A DELLA in Disguise: SPATULA Restrains the Growth of the DevelopingArabidopsisSeedling

A DELLA in Disguise: SPATULA Restrains the Growth of the DevelopingArabidopsisSeedling

Root-Specific Reduction of Cytokinin Causes Enhanced Root Growth, Drought Tolerance, and Leaf Mineral Enrichment in Arabidopsis and Tobacco

nana plant2 Encodes a Maize Ortholog of the Arabidopsis Brassinosteroid Biosynthesis Gene DWARF1, Identifying Developmental Interactions between Brassinosteroids and Gibberellins

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