A team of researchers including from the University of Adelaide have for the first time been able to pinpoint the genetic activity over time when rice is subject to salt stress.
The team from King Abdullah University of Science and Technology (KAUST) and the University of Adelaide’s Waite campus say their findings highlight the roles of different genes in the plant’s response to salt stress. This should help breeding programs around the world aiming to improve global rice productivity.
Rice is a staple food for over half of the world’s population, yet it is also the most salt-sensitive cereal crop.
Published in the journal Nature Communications, the study used cutting-edge research infrastructure at the Waite to grow different varieties of rice under moderately saline conditions, monitoring plant growth, shoot development and transpiration (water use).
“Thanks to the unique Plant Accelerator facility at the Waite campus, we could analyse numerous aspects of the growth of multiple plants simultaneously,” says project leader Professor Mark Tester at KAUST’s Center for Desert Agriculture, who supervised PhD student Nadia Al-Tamimi.
The Plant Accelerator is headquarters of the Australian Plant Phenomics Facility and funded under the National Collaborative Infrastructure Strategy (NCRIS). It provides scientists with the facilities to grow thousands of plants in pots on conveyor belts. Each plant moves automatically to be imaged daily by digital cameras, generating quantitative data on plant growth on a large scale – a pioneering technique called ‘high-throughput non-invasive phenotyping’.
“Our unique infrastructure 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, Scientific Director at The Plant Accelerator.
Some genes, for example those connected with signaling processes, were important to growth in the first two to six days, 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.
Two diverse sets of rice (indica and aus), with hundreds of rice varieties in each set, were grown under low and high salinity, and photographed daily over 13 days to monitor biomass and shoot development. Transpiration levels (how much water the plants used) were measured by weighing each pot daily.
The researchers found 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, the researchers could search for genetic activity related to specific plant traits.
“Providing high-quality research infrastructure, such as The Plant 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. This study makes the best use of the tools available to plant science,” says Dr Berger.