Maize seed ‘Feed me’ gene identified

Maize (Corn) ears in China. Photo: Eloise Phipps, CIMMYT

Maize (Corn) ears in China. Photo: Eloise Phipps, CIMMYT

Unlike ‘Audrey 2’ – the plant which ate members of the cast from ‘The Little Shop of Horrors’ (botanically suspect but with some good songs) – the maize seed grows on the cob by extracting goodies from the mother plant.

YouTube has a great video of a production of Little Shop of Horrors: Feed me Seymour – embedding not possible so you need to jump to the link.

Now researchers at the Universities of Warwick and Oxford have discovered a key gene in this feeding process – prosaically named Meg1*. It seems that Meg1 converts the tissues surrounding the developing embryo into a placenta-like structure. The big surprise is that Meg1 is expressed only from the maternally-inherited copy, with the male copy remaining silenced. Some evolutionary biologists believe that this parent-of-origin ‘gene imprinting’, which also occurs in animals, is a result of a battle of the sexes in which the male sperm’s desire to make the ‘biggest and best’ seed is pitted against the female’s need to keep control over her resources so she has enough left to fill a number of seeds.

 

Whatever – Meg1 is almost certainly responsible for generating what you had for breakfast this morning and as such is a really, really important gene. Excitingly, the Warwick/Oxford researchers were also able to show that the output of Meg1 – like most animal imprinted genes – is strictly dosage-dependent – suggesting that it may be possible to improve seed yield by breeding plants with more copies of Meg1.

Meg1 effects on seed growth: maize ear and kernels are seen segregating for normal and Meg1 small seeds (top) while the difference in transfer-cell structure is seen in the lower micrographs. See Costa et al. http://dx.doi.org/10.1016/j.cub.2011.11.059 .

Meg1 effects on seed growth: maize ear and kernels are seen segregating for normal and Meg1 small seeds (top) while the difference in transfer-cell structure is seen in the lower micrographs. See Costa et al. http://dx.doi.org/10.1016/j.cub.2011.11.059 .

The Meg1 work was led by Jose Gutierrez-Marcos from Warwick’s School of Life Science, and Liliana Costa and Hugh Dickinson from Oxford’s Department of Plant Sciences.  As Jose says “these findings have significant implications for global agriculture and food security, as scientists now have the molecular know-how to manipulate this gene by traditional plant breeding or through other methods in order to improve seed traits, such as increased seed biomass yield. To meet the demands of the world’s growing population in years to come, scientists and breeders must work together to safeguard and increase agricultural production”.

 

* Liliana M. Costa, Jing Yuan, Jacques Rouster, Wyatt PaulHugh Dickinson and Jose F. Gutierrez-Marcos,  (2012) Maternal Control of Nutrient Allocation in Plant Seeds by Genomic Imprinting Current Biology.. 22, 160–165 doi:10.1016/j.cub.2011.11.059.