Transgenic alteration of ethylene biosynthesis increases grain yield in maize under field drought‐stress conditions

Abstract

SummaryA 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 9 transgene) 9 environment interaction existed among the events, highlighting the need to better understand the context in which the downregulation 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 lownitrogen 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.

De novo transcriptome assembly of sugarcane leaves submitted to prolonged water-deficit stress

“…In 2014, silencing of the ACC genes was performed in a study on corn to modulate the levels of ethylene production. The results showed that a reduction in the biosynthesis pathway of ethylene could improve grain production by inhibiting their senescence (Habben et al, 2014). In the sensitive cultivar, this gene probably acts by increasing the synthesis of ethylene, inducing the maturation and senescence of leaves, which indeed was observed in this cultivar, although yellowing was discrete but perceptible when compared to the tolerant cultivar (data not shown).…”

Overexpression of ARGOS Genes Modifies Plant Sensitivity to Ethylene, Leading to Improved Drought Tolerance in Both Arabidopsis and Maize

“…Beltrano et al (1999) reported that exogenous application of the ethylene biosynthesis inhibitor aminoethoxyvinylglycine reversed a drought stress syndrome in wheat. Transgenic maize (Zea mays) plants with reduced ethylene biosynthesis, via silencing 1-AMINOCYCLOPROPANE-1-CARBOXYLATE SYNTHASE6, have shown enhanced yields compared with nontransgenic controls in water-deficit and low-nitrogen environments (Habben et al, 2014). Here, we report novel, negative regulators of ethylene signal transduction from maize and Arabidopsis.…”

Maize and Arabidopsis ARGOS Proteins Interact with Ethylene Receptor Signaling Complex, Supporting a Regulatory Role for ARGOS in Ethylene Signal Transduction

“…After a 22 to 24 h incubation period, 1-mL samples were taken from the headspace of each sealed vial. The ethylene content was quantified by gas chromatography, as previously described in Habben et al (2014). Ethylene production rate was expressed as pmol per h per milligram of dry weight.…”

“…Reducing ethylene biosynthesis by silencing aminocyclopropane-1-carboxylic acid synthase6 can improve maize (Zea mays) grain yield in water-limiting environments (Habben et al, 2014). Lowering plant sensitivity to ethylene by overexpressing maize ARGOS8 also enhances plant tolerance to drought and increases maize yield under water-deficit conditions (Shi et al, 2015).…”