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1.
Proc Natl Acad Sci U S A ; 116(47): 23850-23858, 2019 Nov 19.
Artigo em Inglês | MEDLINE | ID: mdl-31685622

RESUMO

Increasing maize grain yield has been a major focus of both plant breeding and genetic engineering to meet the global demand for food, feed, and industrial uses. We report that increasing and extending expression of a maize MADS-box transcription factor gene, zmm28, under the control of a moderate-constitutive maize promoter, results in maize plants with increased plant growth, photosynthesis capacity, and nitrogen utilization. Molecular and biochemical characterization of zmm28 transgenic plants demonstrated that their enhanced agronomic traits are associated with elevated plant carbon assimilation, nitrogen utilization, and plant growth. Overall, these positive attributes are associated with a significant increase in grain yield relative to wild-type controls that is consistent across years, environments, and elite germplasm backgrounds.

2.
Plant Biotechnol J ; 12(6): 685-93, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24618117

RESUMO

A transgenic gene-silencing approach was used to modulate the levels of ethylene biosynthesis in maize (Zea mays L.) and determine its effect on grain yield under drought stress in a comprehensive set of field trials. Commercially relevant transgenic events were created with down-regulated ACC synthases (ACSs), enzymes that catalyse the rate-limiting step in ethylene biosynthesis. These events had ethylene emission levels reduced approximately 50% compared with nontransgenic nulls. Multiple, independent transgenic hybrids and controls were tested in field trials at managed drought-stress and rain-fed locations throughout the US. Analysis of yield data indicated that transgenic events had significantly increased grain yield over the null comparators, with the best event having a 0.58 Mg/ha (9.3 bushel/acre) increase after a flowering period drought stress. A (genotype × transgene) × environment interaction existed among the events, highlighting the need to better understand the context in which the down-regulation of ACSs functions in maize. Analysis of secondary traits showed that there was a consistent decrease in the anthesis-silking interval and a concomitant increase in kernel number/ear in transgene-positive events versus nulls. Selected events were also field tested under a low-nitrogen treatment, and the best event was found to have a significant 0.44 Mg/ha (7.1 bushel/acre) yield increase. This set of extensive field evaluations demonstrated that down-regulating the ethylene biosynthetic pathway can improve the grain yield of maize under abiotic stress conditions.


Assuntos
Secas , Etilenos/biossíntese , Sementes/crescimento & desenvolvimento , Estresse Fisiológico , Zea mays/crescimento & desenvolvimento , Zea mays/genética , Liases/metabolismo , Nitrogênio/farmacologia , Plantas Geneticamente Modificadas , Interferência de RNA/efeitos dos fármacos , Sementes/efeitos dos fármacos , Estresse Fisiológico/efeitos dos fármacos , Zea mays/efeitos dos fármacos , Zea mays/fisiologia
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