H2O2 Signature and Innate Antioxidative Profile Make the Difference Between Sensitivity and Tolerance to Salt in Rice Cells

Abstract

Salt tolerance is a complex trait that varies between and within species. H2O2 profiles as well as antioxidative systems have been investigated in the cultured cells of rice obtained from Italian rice varieties with different salt tolerance. Salt stress highlighted differences in extracellular and intracellular H2O2 profiles in the two cell cultures. The tolerant variety had innate reactive oxygen species (ROS) scavenging systems that enabled ROS, in particular H2O2, to act as a signal molecule rather than a damaging one. Different intracellular H2O2 profiles were also observed: in tolerant cells, an early and narrow peak was detected at 5 min; while in sensitive cells, a large peak was associated with cell death. Likewise, the transcription factor salt-responsive ethylene responsive factor 1 (TF SERF1), which is known for being regulated by H2O2, showed a different expression profile in the two cell lines. Notably, similar H2O2 profiles and cell fates were also obtained when exogenous H2O2 was produced by glucose/glucose oxidase (GOX) treatment. Under salt stress, the tolerant variety also exhibited rapid upregulation of K+ transporter genes in order to deal with K+/Na+ impairment. This upregulation was not detected in the presence of oxidative stress alone. The importance of the innate antioxidative profile was confirmed by the protective effect of experimentally increased glutathione in salt-treated sensitive cells. Overall, these results underline the importance of specific H2O2 signatures and innate antioxidative systems in modulating ionic and redox homeostasis for salt stress tolerance.

Fast Regulation of Hormone Metabolism Contributes to Salt Tolerance in Rice (Oryza sativa spp. Japonica, L.) by Inducing Specific Morpho-Physiological Responses

“…In particular, most of genes involved in photosynthesis, such as those encoding chlorophylls and photosystems subunits, were down-regulated ( Figure 2 B), indicating the programed dismantling of photosynthetic apparatus. This result was in line with our previous findings that VN plants (and cultured cells) under salt stress initiated a programmed cell death (PCD) response and leaf senescence [ 47 , 48 ]. On the contrary, tolerant Baldo plants regulated few genes that were grouped into stress response, transport, hormones, transcription, and protein catabolism categories ( Figure 2 A,C).…”

“…In previous works, we explored the salt tolerance/sensitivity of two Italian rice varieties of great economic relevance for both the internal (Vialone Nano, VN, salt sensitive) and external (Baldo, salt tolerant) Italian markets [ 47 , 48 ]. We demonstrated that prompt H 2 O 2 signaling at root level was of most importance in inducing salt tolerance in the Baldo variety and that a delay in response led the sensitive variety VN to a chaotic response and leaf senescence ( Figure 1 ).…”

“…The reduction in stomata aperture induced by ABA is a typical response of plants under water stress [ 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 ]. High soil salinity causes the decrease in the water potential at the root level and the loss of water (water stress).…”

A Meta-Analysis of Comparative Transcriptomic Data Reveals a Set of Key Genes Involved in the Tolerance to Abiotic Stresses in Rice

“…This difference can be ascribed to a delay of the response of the salt-susceptible genotype. Consistently, Formentin and colleagues [46,47] demonstrated that the salt-tolerant genotype is able to activate a faster stress response as compared to the salt-susceptible genotype, through an early activation of H 2 O 2 and hormone signalling pathways.…”

Redox Balance-DDR-miRNA Triangle: Relevance in Genome Stability and Stress Responses in Plants

“…GSH feeding of Arabidopsis seedlings appears to induce the expression of stress-related genes and down-regulates developmental correlated genes (Hacham et al, 2014). High GSH levels have also often been correlated to increased stress tolerance (Cao et al, 2017; Ferrer et al, 2018; Formentin et al, 2018). Conversely, GSH deficiency in Arabidopsis root meristem less 1 mutant ( rml1 ) has been shown to affect root growth and architecture through a massive transcriptome re-programming.…”