| Summary: | The production of rice is projected to decline because of the increase in global temperatures. Developing climate-resilient rice varieties is an urgent necessity to guarantee food security in the future. It is crucial to understand the genetic foundation and molecular mechanisms of plant responses to high temperatures to improve their heat stress tolerance through genetic manipulation. Although many studies have focused on improving rice heat tolerance through genetic engineering, few studies have focused on identifying heat-tolerant traits from natural variations. African rice (Oryza glaberrima) evolved separately from Asian rice (Oryza sativa) and poses an important source of natural variations for abiotic stress resilience. The research described here used 155 accessions of O. glaberrima to investigate different heat-responsive traits and identify heat-tolerant accessions. This research also endeavoured to dissect transcriptomic responses to high temperatures in these accessions.
Initially O. glaberrima accessions and two O. sativa accessions were analysed for nitrogen recycling efficiency under heat stress, which is an important part of nitrogen metabolism. Further to this, phenotypic, physiological and biochemical characterisation focusing on antioxidant properties were conducted. Photosynthetic characteristics were measured using gas exchange and chlorophyll fluorescence to explore the effect of heat stress on these traits. An RNA sequencing study was completed to investigate the gene expression patterns in response to high temperatures and to identify novel candidate genes related to heat tolerance.
This research identified O. glaberrima accessions tolerant to high-temperature stress and explored their antioxidant properties and physiological traits relevant to heat tolerance. Investigating the transcriptomic responses to high temperatures novel candidate genes were identified from heat tolerant accessions which can be utilised to study molecular mechanisms of heat tolerance and can be a valuable source for future crop improvement efforts.
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