The Submergence Tolerance Regulator SUB1A Mediates Crosstalk between Submergence and Drought Tolerance in Rice  

Abstract

Submergence and drought are major constraints to rice (Oryza sativa) production in rain-fed farmlands, both of which can occur sequentially during a single crop cycle. SUB1A, an ERF transcription factor found in limited rice accessions, dampens ethylene production and gibberellic acid responsiveness during submergence, economizing carbohydrate reserves and significantly prolonging endurance. Here, we evaluated the functional role of SUB1A in acclimation to dehydration. Comparative analysis of genotypes with and without SUB1A revealed that SUB1A enhanced recovery from drought at the vegetative stage through reduction of leaf water loss and lipid peroxidation and increased expression of genes associated with acclimation to dehydration. Overexpression of SUB1A augmented ABA responsiveness, thereby activating stressinducible gene expression. Paradoxically, vegetative tissue undergoes dehydration upon desubmergence even though the soil contains sufficient water, indicating that leaf desiccation occurs in the natural progression of a flooding event.Desubmergence caused the upregulation of gene transcripts associated with acclimation to dehydration, with higher induction in SUB1A genotypes. SUB1A also restrained accumulation of reactive oxygen species (ROS) in aerial tissue during drought and desubmergence. Consistently, SUB1A increased the abundance of transcripts encoding ROS scavenging enzymes, resulting in enhanced tolerance to oxidative stress. Therefore, in addition to providing robust submergence tolerance, SUB1A improves survival of rapid dehydration following desubmergence and water deficit during drought.

SALT-RESPONSIVE ERF1 Regulates Reactive Oxygen Species-Dependent Signaling during the Initial Response to Salt Stress in Rice

“…Oxidative stress tolerance tests were performed as previously described (Fukao et al, 2011) with the following modifications; 5 µM MV was used and the incubation time was extended to 36 h. Pigment content was spectrophotometrically quantified according to Wellburn (1994).…”

Ethylene response factors gene regulation and expression profiles under different stresses in rice

“…The overlapping expression of ERFs takes into account the hypothesis that these genes act as connectors in the signalling pathways that mediate responses to biotic and abiotic responses. This mediation has been proven, for instance, in submergence and drought (Fukao et al 2011).…”

“…Besides providing anoxia tolerance, this allele also provides drought and desubmergence (recovering the period after anoxia stress) tolerance. This ability is due to a reduction in water loss by leaves, decrease in lipid peroxidation, gene induction associated with acclimation to dehydration and reduction of reactive oxygen species (ROS) in leaf tissues during drought and desubmergence (Fukao et al 2011). Similarly, Arabidopsis plants overexpressing the gene HRE1 (gene belonging to the same group as SUB1A) showed increase in anoxia tolerance (Licausi et al 2010).…”

Spatial Variation in Surface Soil Total Carbon and Its Relationship with Soil Color in a River Floodplain Ecosystem of Northern Ghana

“…It could be said that depressions are high-risk, high-return environments. The utilization of such environments would require such submergence stress measures as introducing a genotype with submergence tolerance (Xu 2006, Fukao et al 2011 or crop management to avoid submergence stress, such as seed hydropriming (Matsushima and Sakagami 2013). In any case, an appropriate crop production strategy would be required depending on the microtopography.…”