The reactive oxygen species network pathways: an essential prerequisite for perception of pathogen attack and the acquired disease resistance in plants

Abstract

Availability of complete Arabidopsis (Arabidopsis thaliana) and rice (Oryza sativa) genome sequences, together with molecular recourses of functional genomics and proteomics have revolutionized our understanding of reactive oxygen species (ROS) signalling network mediating disease resistance in plants. So far, ROS have been associated with aging, cellular and molecular alteration in animal and plant cells. Recently,concluding evidences suggest that ROS network is essential to induce disease resistance and even to mediate resistance to multiple stresses in plants. ROS are obligatory by-products emerging as a result of normal metabolic reactions. They have the potential to be both beneficial and harmful to cellular metabolism. Their dual effects on metabolic reactions are dosage specific. In this review we focus our attention on cellular ROS level to trigger beneficial effects on plant cells responding to pathogen attack. By exploring the research related contributions coupled with data of targeted gene disruption, and RNA interference approaches, we show here that ROS are ubiquitous molecules of redox-pathways that play a crucial role in plant defence mechanism. The molecular prerequisites of ROS network to activate plant defence system in response to pathogen infections are here underlined. Bioinformatic tools are now available to scientists for high throughput analysis of cellular metabolisms. These tools are used to illustrate crucial ROS-related genes that are involved in the defence mechanism of plants. The review describes also the emerging findings of ROS network pathways to modulate multiple stress resistance in plants.

Aclimatação ao estresse salino em plantas de arroz induzida pelo pré-tratamento com H2O2

“…Sabe-se que APX e CAT apresentam diferentes mecanismos de metabolizar o H 2 O 2 e que tais enzimas atuam em diferentes partes da célula vegetal (Foyer & Noctor, 2003;Mittler et al, 2004;Kotchoni & Gachomo, 2006;Rosa et al, 2010). Apesar de atuarem degradando o mesmo substrato, a APX e CAT apresentam diferenças de afinidade pelo H 2 O 2 e esta especificidade pode ser um aspecto fundamental para provocar a modulação no nível de H 2 O 2 que resultaria em sinalização e, consequentemente, proteção oxidativa (Shigeoka et al, 2002;Scandalios, 2002;2005).…”

“…O H 2 O 2 pode ser removido pelas CAT e APX através de diferentes mecanismos que resultam, igualmente, em água (Mittler, 2002;Foyer & Noctor, 2003). Quando o H 2 O 2 é produzido nos cloroplastos, este é eliminado pelas enzimas APX, enquanto aquele produzido nos peroxissomos/ glioxissomos é removido pelas CAT (Mittler et al, 2004;Kotchoni & Gachomo, 2006). Esta especificidade entre as enzimas e o H 2 O 2 reflete suas diferentes afinidades, em que a APX teria alta afinidade (µM) e a CAT baixa afinidade (mM) pelo H 2 O 2 .…”

Redox signaling mediated by the gut microbiota

“…Thus it is thought that ROS signaling represents an evolutionary ancient form of host cell and microbe cross-talk [49,54,68,69]. Of late, our research group and others reported that contact of certain symbiotic taxa with host epithelial cells can induce the generation of rapid, non-pathogenic levels of ROS, in a process that requires the catalytic activity of Nox1 in host cells.…”

“…Nox1 catalyzed generation of ROS within epithelial cells is hypothesized to function in regulating several signal transduction pathways, which was detected following the stimulation of Nox1 function by growth factors, hormones, and cytokines in a wide range of cells and tissues [45,47]. Indeed, Nox enzymes orthologs catalyze ROS production in a breadth of multi cellular organisms [49][50][51][52]. In plants, ROS generated Nox enzymes regulates the transition from proliferation to differentiation in root tips [53].…”

Non-enzymatic isolation of somatic cells fromKappaphycusspp. andEucheuma denticulatum(Solieriaceae, Rhodophyta)

“…The manifestations of ice-ice disease include softening of tissues, and in severe conditions liquefaction and loss of structural integrity of the thallus (Mendoza et al, 2002;Neish, 2003 (Kupper et al, 2001;Ross et al, 2005). These effects are mimicked in plant cells treated externally with high levels of H 2 O 2 (Wojtaszek, 1997), and the shift in plant responses from harmful to beneficial consequences is dose dependent (Kotchoni & Gachomo, 2006). In brown seaweeds for instance, Hasebe (1978) reported that the external application of 1-20% H 2 O 2 only caused stripping off of the 'outer wall and skin' (which we have interpreted to include the cortex).…”