Transcriptional repression of TaNOX10 by TaWRKY19 compromises ROS generation and enhances wheat susceptibility to stripe rust

Abstract

Reactive oxygen species (ROS) are vital for plant immunity and regulation of their production is crucial for plant health. While the mechanisms that elicit ROS production have been relatively well studied, those that repress ROS generation are less well understood. Here, via screening Brachypodium distachyon RNA interference (RNAi) mutants, we identified BdWRKY19 as a negative regulator of ROS generation whose knockdown confers elevated resistance to the rust fungus Puccinia brachypodii. The three wheat paralogous genes TaWRKY19 are induced during infection by virulent P. striiformis f. sp. tritici (Pst) and have partially redundant roles in resistance. The stable overexpression of TaWRKY19 in wheat increased susceptibility to an avirulent Pst race, while mutations in all three TaWRKY19 copies conferred strong resistance to Pst by enhancing host plant ROS accumulation. We show that TaWRKY19 is a transcriptional repressor that binds to a W-box element in the promoter of TaNOX10, which encodes an NADPH oxidase and is required for ROS generation and host resistance to Pst. Collectively, our findings reveal that TaWRKY19 compromises wheat resistance to the fungal pathogen and suggest TaWRKY19 as a potential target to improve wheat resistance to the commercially important wheat stripe rust fungus.

Broad-spectrum chemicals block ROS detoxification to prevent plant fungal invasion

“…Oxidative burst, a rapid plant defense reaction after pathogen attack, is a critical and effective component of plant immunity. 9 , 10 Reactive oxygen species (ROS), including superoxide and the precursor H 2 O 2 , not only result in hypersensitive response (HR) and local cell death to block pathogen colonization but also act as signaling molecules to activate the expression of defense-related genes.11 In order to infect successfully, pathogens need to overcome oxidative burst by either incapacitating ROS production 12 or detoxifying ROS generated by the host. 13 One key way of ROS detoxification is by enzymatic mechanisms.…”

Advanced genes expression pattern greatly contributes to divergence in Verticillium wilt resistance between Gossypium barbadense and Gossupium hirsutum

“…Those genes’ functions were mainly concentrated in several processes, such as peroxidase activity, response to oxidative stress, cellular oxidant detoxification, hydrogen peroxide catabolic process, transferase activity: transferring hexosyl groups, and negative regulation of endopeptidase activity ( Figure 3C ). Most of these were related to scavenging reactive oxygen species (ROS), which is involved in the plant immune system ( Gao et al, 2021 ; Wang et al, 2022 ). The 2 cultivars showed a similar expression pattern for 347 genes jointly at 12 hpi, and the biological response processes were flavin adenine dinucleotide binding ( Li et al, 2021 ), nutrient reservoir activity, manganese ion and magnesium ion binding, and oxidoreductase activity ( Figure 3D ).…”

Arms Race between the Host and Pathogen Associated with Fusarium Head Blight of Wheat

“…More importantly, silencing TaWAK2A-800 reduced the expression levels of the chitin-triggering marker genes TaCERK1, TaRLCK1B, and TaMAPK3 under treatment with Fg [ 121 ]. MAPK-mediated phosphorylation of WRKYs was a exciter, which promoted the downstream signalings: the activated WRKYs then bind to and regulate the expression of NOX/RBOH genes [ 107 ].For example, TaWRKY19 repressed plant immunity against pathogens by negatively regulating the transcriptional level of TaNOX10 and compromising ROS generation in wheat [ 144 ]. In addition, Ca 2+ signaling was central to both pattern- and effector-triggered immunity activation of the immune system in plants [ 142 ].…”