An image of barley's progression from pistil to grain.
Researchers have identified a novel mechanism through which a protein in barley supports female fertility and could help safeguard yield security in the future.
University of Adelaide's Professor Matthew Tucker, Interim Director of the Waite Research Institute, led a team that found the protein, MADS31, functions in barley and bread wheat to create safe environments for seeds.
"Like babies in mammals, seeds in barley are produced after fertilisation of female germ cells buried deep within the reproductive organs," said Professor Tucker.
"In barley, the female reproductive organ is called the pistil; it starts preparing for fertilisation roughly eight weeks before fertilisation day."
The study, which was published in Nature Plants, found that within this preparation process, a single female germline cell is produced and is nursed by surrounding nucellar cells until fertilisation.
"We found MADS31 functions to prevent the expression of seed genes in the ovule until after fertilisation, allowing the mother plant to create a nurturing environment to give the seeds the best chance of survival," said Professor Tucker.
"While much research has focused on male pollen - given its sensitivity to environmental stress - this study sheds new light on the often-overlooked female side of reproduction. Successful grain development requires both a healthy male and female germline."
Mortlock Research Fellow and first author of the paper, Dr Xiujuan Yang said little is known about the genes involved in the formation of female tissues in barley.
"Cereal crops such as barley and wheat produce ovules and seeds that are quite different to those found in model "research plants" such as Arabidopsis," said Dr Yang.
"Also, cereal crop plants are more challenging to examine during early stages of sexual reproduction, because their floral organs are buried deep within the plant. This has made it difficult to find female targets for crop improvement.
"The research also reveals that MADS31 is switched on in cells that balance sugar and amino acid transport into the grain, and controls a secondary suite of genes that could be targeted in future studies to optimise grain formation and composition, adding value to cereal breeding programs.
"Australian crop breeders and growers need new genetics to protect yield in a changing climate and to optimise yield in years where conditions are optimal."
