Maize plants with impaired cellular recycling yielded smaller kernels and less grain in a peer-reviewed experiment. Crosses between mutant and comparison plants traced much of the effect to the maternal plant. Kernels with different genotypes sharing an ear had similar sizes, while changing the maternal genotype shifted kernel size and yield.
Researchers separated the genetic contribution of a maize kernel from that of the plant carrying it. When genetically different kernels grew on the same ear, their dimensions and weights were similar. In reciprocal crosses, however, kernels borne by mutant maternal plants were smaller than those borne by comparison mothers. This placed the main contribution to the observed size difference in the maternal plant.[1]
The peer-reviewed Scientific Reports study examined maize with impaired ATG10 function. This gene participates in autophagy, the cellular process that breaks down and recycles internal material. Mutant plants had smaller kernels and fewer kernels, with total grain weight per plant falling by as much as 37 per cent in some lines. Ear length also declined, and flowering delays varied between genetic lines.[1]
The team looked for gross abnormalities in the developing grain. Measurements found no major difference in starch content or the storage proteins examined, and microscopy showed no large structural disruption of the endosperm, the grain’s food-storage tissue. The plants were grown under well-watered field conditions.[1]
The authors propose that reduced transfer of nutrients from maternal tissues to developing grain is a possible contributor to the result. They also discuss growth and allocation of resources within the mother plant. Nutrient transfer remains a possible mechanism, rather than a directly established causal chain in these crossing experiments.[1]
