Unravelling the Roles of Nitrogen Nutrition in Plant Disease Defences

Abstract

Nitrogen (N) is one of the most important elements that has a central impact on plant growth and yield. N is also widely involved in plant stress responses, but its roles in host-pathogen interactions are complex as each affects the other. In this review, we summarize the relationship between N nutrition and plant disease and stress its importance for both host and pathogen. From the perspective of the pathogen, we describe how N can affect the pathogen’s infection strategy, whether necrotrophic or biotrophic. N can influence the deployment of virulence factors such as type III secretion systems in bacterial pathogen or contribute nutrients such as gamma-aminobutyric acid to the invader. Considering the host, the association between N nutrition and plant defence is considered in terms of physical, biochemical and genetic mechanisms. Generally, N has negative effects on physical defences and the production of anti-microbial phytoalexins but positive effects on defence-related enzymes and proteins to affect local defence as well as systemic resistance. N nutrition can also influence defence via amino acid metabolism and hormone production to affect downstream defence-related gene expression via transcriptional regulation and nitric oxide (NO) production, which represents a direct link with N. Although the critical role of N nutrition in plant defences is stressed in this review, further work is urgently needed to provide a comprehensive understanding of how opposing virulence and defence mechanisms are influenced by interacting networks.

Optimized Nitrogen Topdressing Strategies Enhance Steviol Glycoside Productivity in Stevia (Stevia rebaudiana Bertoni) Plants

“…Precise N fertilization management is important in improving N use efficiency (NUE) and final crop productivity (Quebrajo et al 2015). N can sensitively impact plant growth and metabolism and plays irreplaceable roles during all plant growth stages (Sun et al 2020). However, N is easily leached to the lowest soil layers in the form of nitrate, which would reduce NUE and increase the environmental impacts of N (Min et al 2012).…”

Nitrogenous Nutrition Affects Uptake of Arsenic and Defense Enzyme Responses in Wheat

“…The available nutrient resources for each plant are considered limited, and there exists a trade-off between investments (directing resources) to growth and defense [60]. A surplus of N has been shown to alleviate the toxicity of As 5+ , possibly by fuelling and boosting the antioxidative apparatus [48,56].…”

“…5). Nevertheless, the generally accepted positive correlation between N nutrition, activity of PR proteins and final resistance [60] apparently should be re-considered or at least handled more carefully since it applies for a few isoforms only (Table 1). Star plots on responses of individual enzyme isoforms show an obvious suppression of several chitinase and β-1,3glucanase members by high N in roots at the same time point (Figs.…”

Physiological significance of pedospheric nitric oxide for root growth, development and organismic interactions

“…The involvement of NO as a signalling molecule during plant immuneresponses has been early identified and received much scientific attention during the past years (Martinez-Medina, Pescador, Fernandez, et al, 2019;Martinez-Medina, Pescador, Terron-Camero, et al, 2019;Figure 3). Several studies have highlighted the role of the nitrite-dependent NR-mediated NO biosynthesis during plantpathogen interaction, rendering the NO-mediated immunity responses highly dependent on plant N-nutrition (Gupta et al, 2013;Sun, Wang, Mur, Shen, & Guo, 2020). In A. thaliana, the NR-double mutant (nia1, nia2) was hypersensitive response-defective against Pseudomonas syringae infection, while NO fumigation alleviated symptoms and restored the transcription of defence-related genes (Vitor et al, 2013).…”

“…In A. thaliana, the NR-double mutant (nia1, nia2) was hypersensitive response-defective against Pseudomonas syringae infection, while NO fumigation alleviated symptoms and restored the transcription of defence-related genes (Vitor et al, 2013). NO has been implicated in many aspects of the interaction between plants and pathogens and the subsequent immunity responses, including the transcriptional regulation of many pathogenesis-related (PR) genes (Bellin et al, 2013), the cross-talk with ROS for triggering hypersensitive responses and programmed cell death at the infection site (Wang, Loake, & Chu, 2013), and the metabolic reprograming towards the biosynthesis of secondary metabolites, acting as phytoalexins and SA (Sun et al, 2020). Martinez-Medina, Pescador, Fernandez, et al, 2019;Martinez-Medina, Pescador, Terron-Camero, et al, 2019).…”