Transcriptional Regulation of Systemic Acquired Resistance in Plants

doi:10.11983/CBB25088

Abstract

Abstract: Systemic acquired resistance (SAR) is a crucial defense mechanism in plants, which can significantly enhance the plant’s resistance to pathogenic microorganisms. SAR has systemic, persistent, and broad-spectrum characteristics, whose transcriptional regulation plays a central role in the process. Here, the research progress on transcriptional regulation of SAR from the synthesis of salicylic acid (SA), Pip/NHP, transcriptional regulation of NPR1, NPR3/NPR4 receptors and Pip/NHP mobile signals, as well as TGA, WRKY transcription factor family regulation was reviewed, providing a reference for a deeper understanding of plant immune regulatory networks, and systematic exploration of the mechanisms by which plants balanced growth and defense in complex environments.

Key words: systemic acquired resistance, transcriptional regulation, salicylic acid, pipecolic acid, N-hydroxypipecolic acid

Su Silin, Tang Xianyu, Chen Yi, Wang Ting, Xia Shitou. Transcriptional Regulation of Systemic Acquired Resistance in Plants[J]. Chinese Bulletin of Botany, 2025, 60(5): 722-733.

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URL: https://www.chinbullbotany.com/EN/10.11983/CBB25088

https://www.chinbullbotany.com/EN/Y2025/V60/I5/722

Figures/Tables 1

Figure 1 Transcriptional regulation of systemic acquired resistance (SAR) in plants When local leaf cells of plants are infected by pathogens (bacteria or fungi) or salicylic acid (SA), is applied receptor like kinases (RLKs) are activated after local signal perception, leading to the influx of calcium ions. The calmodulin CAM1/4/6 then combines with calcium ions and interacts with CBP60g, triggeringa local resistance response through the phenylalanine ammonia-lyase (PAL) and isochorismate synthase 1 (ICS1) pathways to increase SA synthesis. Lysine, whereas, is catalyzed by ALD1 and SARD4 to form piperidine-2-carboxylic acid (Pip), which is then hydroxylated to N-hydroxy-piperidine-2-carboxylic acid (NHP) by FMO1. Pip/NHP can be transported to distal leaves through phloem transportation. After the levels of SA and Pip/NHP increase in systemic leaf cells, SA binds to the receptor NPR1, and triggers the conformational changes in NPR1, which enter into the nucleus, where NPR1 forms a complex with TGA2/5/6, and activates the expression of PRs genes and SAR. Moreover, SA can also directly bind NPR3/NPR4 to inhibit their transcriptional inhibitory activity, thereby relieving the inhibition of genes such as SARD1 and WRKY70, achieving the goal of fine tuning the SAR. The solid arrows indicate direct regulation; the dashed arrows indicate indirect regulation; the T-shaped line indicates inhibition.

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