Rice is a staple food for over half of the world’s population, yet it is also the most salt-sensitive cereal crop, putting it at risk to future environmental challenges.

Researchers have used high-throughput non-invasive phenotyping to investigate the early responses of rice plants to moderately-saline conditions.

Project lead, Professor Mark Tester from King Abdullah University of Science and Technology (KAUST), supervised PhD student Nadia Al-Tamini’s project which grew 297 indica and 256 aus rice varieties under low and high salinity. Moving on conveyer belts, the plants were imaged daily using digital cameras to monitor biomass and shoot development, and weighed to carefully measure transpiration levels (water use).

The results revealed new salt-tolerant genetic loci which could prove useful for breeding programs aimed at increasing rice production and addressing future global food shortages.

“Using The Plant Accelerator research facility at the University of Adelaide’s Waite Campus allowed us to analyse numerous aspects of the growth of multiple plants simultaneously,” says Professor Tester.

Using the facility’s cutting-edge technology, the researchers were able to show some genes, for example those connected with signaling processes, were important to plant growth in the first two to six days after salt application, while other genes became prominent later.

“This is perhaps the most astonishing aspect of this work – we can now obtain genetic details daily, pinpointing exactly when each locus comes into play in response to salinity,” says Professor Tester.

“Our unique infrastructure at The Plant Accelerator allowed us to screen hundreds of rice plants under controlled conditions. This was key to identifying novel genes contributing to salt tolerance in rice,” says Dr Bettina Berger, the facility’s Scientific Director.

“Providing high-quality research infrastructure, such as The Plan Accelerator, enables scientists in Australia and around the world to study novel aspects of crop tolerance to stress, which often require measurements over time instead of single time points,” says Dr Berger.

The researchers made no assumptions about plant growth in their analysis, using unbiased statistical methods to explore their results. They found that growth rate diminished in salt-treated soils, with a rapid slowing of growth immediately after salt addition. The indica lines fared better than aus leading the team to uncover significant genetic differences between the varieties. By combining data on relative growth rate, transpiration rate and transpiration use efficiency (TUE) with a genome-wide association analysis, the researchers could search for genetic loci related to specific plant traits.

The Plant Accelerator, Australian Plant Phenomics Facility, is funded under the National Collaborative Research Infrastructure Strategy (NCRIS). It provides the ability to grow thousands of plants and generate quantitative data on a large scale using high-throughput non-invasive phenotyping.