A stress response mechanism from ancestral species in allopolyploid plants

March 14, 2018

Provides a base for improving allopolyploid crops and exploring useful genes

Using biological experiments and informatics analysis of the allopolyploid grass Brachypodium hybridium and its diploid ancestor B. stacei and B. distachyon, a RIKEN CSRS and Yokohama City University research team has found that the high-temperature stress tolerance of the allopolyploid is due to the earlier response to heat stress condition of particular gene groups inherited form from B. stacei.

Allopolyploidization in plant genomes has played an important role in the birth of new species. Recent comparative genomics studies have shown that many plant species have experienced genomic polyploidization; it has also been hypothesized that polyploidization has played a role in the improvement of the environmental adaptability of species. Understanding the environmental adaptation mechanisms of allopolyploid plants allows us to identify useful genes for improving the environmental adaptability of plants, which may be useful to enhance crop productivity against adverse environments resulted from climate changes. However, because of the complicated genetic codes of polyploid species due to duplicated genomes, the relationships between the functions of genomes of ancestors and their progenitor remained largely unclear. To elucidate how allopolyploidization causes changes in genomic function and leads to improve environmental adaptability in hybrid species, the research team conducted research on the allopolyploid grass Brachypodium hybridium and its diploid ancestors B. stacei and B. distachyon with a comprehensive comparative analysis of their genomes and transcriptomes and examined relations to high-temperature stress response and tolerance.

They found a quantitative change in the gene expression patterns of the polyploid grass inherited from the ancestral diploid grass used in the study, and their results also suggest that its high- temperature stress tolerance resulted from the function of specific genes inherited from in the diploid ancestor.

These results are expected to serve as basic knowledge for improving plant biomass productivity through searching for useful genes related to environmental stress tolerance.

Original article
GigaScience doi:10.1093/gigascience/giy020
K. Takahagi, K. Inoue, M. Shimizu, Y. Uehara-Yamaguchi, Y. Onda, K. Mochida,
"Homoeolog-specific activation of genes for heat acclimation in the allopolyploid grass Brachypodium hybridum".
Keiichi Mochida; Team Leader
Kotaro Takahagi; Junior Research Associate
Cellulose Production Research Team