Determining the scale at which variation in a single gene changes population yields

• Main Authors: Erica McGale, Henrique Valim, Deepika Mittal, Jesús Morales Jimenez, Rayko Halitschke, Meredith C Schuman, Ian T Baldwin
• Format: Article
• Language: English
• Published: eLife Sciences Publications Ltd 2020-02-01
• Series: eLife
• Subjects: mitogen-activated protein kinase 4; field; scale; water-use efficiency; N. attenuata; arbuscular mycorrhizal fungi
• Online Access: https://elifesciences.org/articles/53517

Plant trait diversity is known to influence population yield, but the scale at which this happens remains unknown: divergent individuals might change yields of immediate neighbors (neighbor scale) or of plants across a population (population scale). We use Nicotiana attenuata plants silenced in mitogen-activated protein kinase 4 (irMPK4) – with low water-use efficiency (WUE) – to study the scale at which water-use traits alter intraspecific population yields. In the field and glasshouse, we observed overyielding in populations with low percentages of irMPK4 plants, unrelated to water-use phenotypes. Paired-plant experiments excluded the occurrence of overyielding effects at the neighbor scale. Experimentally altering field arbuscular mycorrhizal fungal associations by silencing the Sym-pathway gene NaCCaMK did not affect reproductive overyielding, implicating an effect independent of belowground AMF interactions. Additionally, micro-grafting experiments revealed dependence on shoot-expressed MPK4 for N. attenuata to vary its yield per neighbor presence. We find that variation in a single gene, MPK4, is responsible for population overyielding through a mechanism, independent of irMPK4’s WUE phenotype, at the aboveground, population scale.