Arabidopsis SMALL DEFENSE-ASSOCIATED PROTEIN 1 Modulates Pathogen Defense and Tolerance to Oxidative Stress

Abstract

Salicylic acid (SA) and reactive oxygen species (ROS) are known to be key modulators of plant defense. However, mechanisms of molecular signal perception and appropriate physiological responses to SA and ROS during biotic or abiotic stress are poorly understood. Here we report characterization of SMALL DEFENSE-ASSOCIATED PROTEIN 1 (SDA1), which modulates defense against bacterial pathogens and tolerance to oxidative stress. sda1 mutants are compromised in defense gene expression, SA accumulation, and defense against bacterial pathogens. External application of SA rescues compromised defense in sda1 mutants. sda1 mutants are also compromised in tolerance to ROS-generating chemicals. Overexpression of SDA1 leads to enhanced resistance against bacterial pathogens and tolerance to oxidative stress. These results suggest that SDA1 regulates plant immunity via the SA-mediated defense pathway and tolerance to oxidative stress. SDA1 encodes a novel small plant-specific protein containing a highly conserved seven amino acid (S/G)WA(D/E)QWD domain at the N-terminus that is critical for SDA1 function in pathogen defense and tolerance to oxidative stress. Taken together, our studies suggest that SDA1 plays a critical role in modulating both biotic and abiotic stresses in Arabidopsis (Arabidopsis thaliana) and appears to be a plant-specific stress responsive protein.

Accumulation of the Auxin Precursor Indole-3-Acetamide Curtails Growth through the Repression of Ribosome-Biogenesis and Development-Related Transcriptional Networks

“…Further analysis of the network, focusing on the node with the highest degree of connectivity and betweenness centrality [ 54 ], SMALL DEFENSE-ASSOCIATED PROTEIN 1 (SDA1) , provided a subnet with 7 nodes and 12 edges. Along with the genes ZAT11 and CML37 , the central SDA1 hub could be associated with oxidative stress responses [ 55 ]. For the downregulated DEGs, we inferred a network with 198 nodes and 422 edges.…”

Transcriptomic changes induced by applications of a commercial extract of Ascophyllum nodosum on tomato plants

“…The metabolic role of these genes represents an under-utilized genetic resource in understanding the complex impact of biostimulants and in expanding the limited marker gene profile used in qPCR-based studies. Such targets might represent unique elements involved in plant defence pathways, pattern recognition receptors (PRRs) which are not fully characterised in plants and mitigating factors reducing the metabolic burden of defence pathway up-regulation 38 – 40 . Further understanding can be achieved using comparative phenotype and gene expression studies utilizing Arabidopsis mutants of key defence and metabolic pathways 40 .…”

“…Such targets might represent unique elements involved in plant defence pathways, pattern recognition receptors (PRRs) which are not fully characterised in plants and mitigating factors reducing the metabolic burden of defence pathway up-regulation 38 – 40 . Further understanding can be achieved using comparative phenotype and gene expression studies utilizing Arabidopsis mutants of key defence and metabolic pathways 40 . Docking studies can also be employed utilizing tertiary and secondary protein and RNA structures of hypothetical proteins from this present study to determine their role, if any, in interactions which lead to the key primed AN-SWE molecular events documented here.…”

The involvement of AtMKK1 and AtMKK3 in plant-deleterious microbial volatile compounds-induced innate immunity.

“…Finally, by network component analysis, STZ was identi ed as the novel immune regulator. Within the hub network of E. aerogenes VCs up-regulated genes, 9 genes including MPK3, MPK11, WRKY40, WRKY33, XLG2, SOBIR1, SYP122, CNI1, AT1G19020 are the important components in plant immune signaling and disease resistance (Zhang et al 2007b;Zhu et al 2009;Pandey et al 2010;Bethke et al 2012;Birkenbihl et al 2012;Maekawa et al 2012;Takahashi et al 2016;Lang et al 2017;Dutta et al 2020). STZ is the regulator of abiotic stress tolerance (Sakamoto et al 2004;Mittler et al 2006).…”