Understanding gene expression under flooding and drought stress in Phalaris arundinacea and Dactylis glomerata

Perennial grasses are often thought of as a source for forage, as well as raw material for the bioenergy industry. Growing crops for biofuels could conflict with the demand for food crops to feed a growing population. Manfred Klaas and colleagues have been investigating how two grasses, Phalaris arundinacea and Dactylis glomerata, cope with drought and waterlogging. The ability to adapt to these conditions could prove environmentally valuable, say Klaas and colleagues in the Annals of Botany.

“Grass species exhibit a wide range of adaptability to a range of environments, but are also suitable as feedstock for combustion and for anaerobic digestion. It has been demonstrated that the cultivation of grass on degraded or exhausted soils can restore organic carbon content and physical properties of the soil. In some instances, maximum biomass production and minimum environmental impact can be achieved by utilizing pre-existing grassland.”

The team examined the transcriptome for two species. Cocksfoot (Dactylis glomerata ‘Sparta’) is thought to be well adapted for drought, while reed canary grass (Phalaris arundinacea ‘Venture’) is adapted to waterlogging. The scientists subjected to the plants to both waterlogging and drought stress. The authors found there were mixed results. “Reed canary grass showed increased accumulation of dry and fresh biomass under waterlogging conditions, followed by control and drought. In contrast, for cocksfoot, both waterlogging and drought conditions stressed the plant, with a follow on effect on reduced biomass accumulation.”

Understanding the transcriptome and how the genes respond to stress could provide useful information in breeding new, more resilient strains of the grasses. Klaas and colleagues see this as an urgent problem to be solved. “Given the fact that global bioenergy demand could double by 2030, it is evident that the development of previously unused or underutilized biomass potential is essential not only to meet demand but also to avoid potential conflict with food production.”