Physiological and molecular responses of Setaria viridis to osmotic stress

• Published in: Plant physiology and biochemistry 2020-10, Vol.155, p.114-125
• Main Authors: Valença, David da Cunha, de Moura, Stéfanie Menezes, Travassos-Lins, João, Alves-Ferreira, Marcio, Medici, Leonardo Oliveira, Ortiz-Silva, Bianca, Macrae, Andrew, Reinert, Fernanda
• Format: Article
• Language: English
• Subjects: C4 model plant; Chlorophyll A; Droughts; Gene expression analyses; Morphological traits; Osmotic Pressure; Photosynthesis; Plant Leaves; Plant Stomata; Proline accumulation; Setaria Plant - physiology; Stress, Physiological; Water; Water deficit
• ISSN: 0981-9428; 1873-2690
• DOI: 10.1016/j.plaphy.2020.07.019

Drought-tolerant species, such as Setaria viridis, a C4 model plant, make physiological and biochemical adjustments water limitation and recover from the stress upon its release. We investigated S. viridis (A10.1 accession) responses to continuing osmotic stress. The osmotic stress was imposed using polyethylene glycol (PEG) 8000 (7.5%) for 10 days. Morphological traits and stomatal conductance were measured daily for the 10 days. On days 6 and 10, the following traits were measured separately for root and shoot: relative water content (RWC), osmotic potential (OP), electrolytic leakage (EL), and proline content. qPCR analysis was used to evaluate the expression of five selected genes in roots (SvLEA, SvDREB1C, SvPIP2-1, SvHSP20, and SvP5CS2), and chlorophyll a fluorescence was measured on three key days. The morphological data demonstrated a drastic reduction in shoot biomass as an effect of water deficit caused by the osmotic stress. Shoot biomass reduction could be associated with putative ABA-dependent signaling involved in SvDREB1C expression. Stomatal conductance and photosynthesis were severely affected up until day 6, however, stomatal conductance and some photosynthetic parameters such as FV/FM, ABS/RC, and DI0/RC showed total or slight recovery on day 10. Root EL decreased in treated plants suggesting an investment in membrane protection by osmoregulator expression such as dehydrin (SvLEA) and proline (SvP5CS2) genes. Our data suggest that S. viridis exhibited a partial recovery from an imposed and constant osmotic stress within 10 days. •Setaria viridis under long-term stress showed some slight recovery.•Membrane protection investment prevents ion loss in stressed roots.•Tolerance to PEG induced water deficit was seen as less growth.•Marker genes responsive to abiotic stress correlates with physiological response.