Improving abiotic stress tolerance in durum wheat

Posted on Jan 1 2019 by Sam Le Gallou

Sustainable agriculture largely relies on maximising crop production under the challenges of climate change.

Naturally occurring abiotic stresses such as drought and extreme temperatures cause substantial losses in grain yield and quality downgrades.

In the Australian wheat belt, crops are often exposed to multiple abiotic stress episodes at different stages of the growing season. Water-deficit stress usually occurs before flowering during springtime while heat stress often occurs post-anthesis at later reproductive stages during grain filling. Both stresses can induce a series of physiological changes including photosynthetic efficiency, evapotranspiration, nutrient and water uptake, nutrient metabolism and transport.

A significant body of work has demonstrated that exposure to different types of abiotic stress (stress priming) can impact how plants cope with subsequent stress episodes. Stress priming provides new opportunities to improve stress tolerance in crops via different stress memory mechanisms, which could involve adaptive changes at both the physiological and molecular levels.

Small RNAs (sRNAs) are new molecular targets for improving crop yield and grain quality as well as tolerance to abiotic stresses.

Plant sRNAs - mainly microRNAs (miRNAs) and small interfering RNAs (siRNAs) – are one of the most important types of epigenetic regulators. Plant miRNAs can rapidly respond to different environmental and developmental signals, causing dynamic gene expression changes which lead to adaptive physiological traits that may contribute to plant fitness and survival.

In cereals, a number of miRNAs (e.g. miR156, miR160 and miR396) have been demonstrated to regulate the crosstalk between water-deficit and heat stress responses. These miRNAs are also capable of providing stress memory to recurring abiotic stress within the generation. However, the miRNA‐conferred stress memory mechanisms in durum wheat remain unexplored.

Key references

Project aims

Investigate the effects of pre-anthesis water deficit‐stress priming to the performance of elite durum wheat germplasm under post-anthesis heat stress.
Assess miRNA expression dynamics, physiological activities, grain yield and quality under the impact of stress priming.
Evaluate the effects of miRNA‐conferred stress memory and its potential value in next‐generation breeding.

Research outcomes could provide new insights for crop improvement using miRNA‐based technologies.

A publication in a peer-reviewed journal article is highly likely.

Skills developed

Crop phenotyping techniques including measurement of photosynthetic activity, transpiration activity, leaf water status.
Growing and maintaining cereal crops under controlled environments (glasshouse and controlled environmental chambers located at Waite campus).
Evaluation of cereal crop yield and quality traits including protein content, starch content and antioxidant levels.
Molecular biology techniques including RNA extraction, cDNA synthesis, PCR and qRT-PCR.
Next-generation sequencing techniques and competency in bioinformatic platforms such as CLC Genomics Workbench.
Experimental design, project management, statistical analysis, and scientific writing.

Study honours in agricultural science

Historically, honours projects in our group have focused on a wide range of research areas. For example, we have coordinated projects on examining grain quality and the diversity within germplasm pools; isolating and deciphering the function of genes that are involved in reproduction and ripening processes; and understanding what molecules regulate and which genes are targets during water-stress.

In addition to the specific project outlined above, we can tailor the honours project around your interests. If you like the idea of working on a project from the ground-up, please get in contact to have a chat.

In summary, these projects will ideally suit enthusiastic students interested in learning more about plant breeding, genetics, molecular biology, abiotic and biotic stress, and/or plant reproduction.