A standing crop of pearl millet. Credit: Pixabay

Researchers have identified a large number of structural variations in the genomes of pearl millet, a crop that grows in arid and semi-arid regions1. The variations affect the expression of specific genes that helped the plant to cope with high temperatures as it became domesticated.

The genes are related to endoplasmic reticulum, a cellular organelle that acts as a scaffold for protein synthesis.

The researchers say this study provides a foundation for generating more robust crops able to withstand the changing climate.

Few studies have thrown light on how pearl millet responds to heat stress. To better understand this, scientists sequenced pearl millet genomes from eight major geographical regions.

The team, which included a researcher at the International Crops Research Institute for the Semi-Arid Tropics in Hyderabad, zeroed in on 424,085 genomic structural variations. They found expansion of specific genes that belong to a transcription factor family called RWP-RK. This family of genes is known to respond to environmental stresses such as heat.

The leaves of a transgenic rice plant expressing a pearl millet RWP-RK gene withered less than the leaves of wild-type rice plants when subjected to high temperatures. The activity of this gene also increased the levels of antioxidant enzymes in the transgenic plants after exposure to heat stress.

The researchers detected that genes located near structural variations are probably more responsive to heat stress. They say these results will help select suitable targets for breeding stress-tolerant pearl millet.