Core Viewpoint - The article discusses recent research that uncovers the biosynthesis pathway of salicylic acid in plants, which is crucial for their defense mechanisms and has implications for developing disease-resistant crop varieties [4][14][20]. Group 1: Research Findings - A team from Sichuan University published a study in Nature revealing a three-step biosynthesis pathway of salicylic acid from benzoyl-CoA in plants [4][5]. - The study identified three key enzymes involved in this pathway: BEBT, BBO, and BSH, which are conserved across various plant species [13][14]. - The research provides a molecular basis for understanding the differences in disease resistance among different plant groups, particularly major food crops [6][14]. Group 2: Comparative Studies - Concurrently, two other studies from Zhejiang University and Zhejiang Normal University also published in Nature focused on the biosynthesis of salicylic acid from phenylalanine, contributing to a more comprehensive understanding of this process [16][18][20]. - These studies collectively address the long-standing gaps in knowledge regarding salicylic acid biosynthesis pathways in plants [20].

Core Viewpoint - The article discusses recent research on the biosynthesis of salicylic acid (SA) in plants, highlighting its importance in plant defense mechanisms and its historical significance in human medicine, particularly in the development of aspirin [2][5][13]. Group 1: Research Findings - The study conducted by teams from Zhejiang University and others revealed a three-step enzymatic reaction module (BEBT-BBH-BSE) that facilitates the conversion of benzoyl-CoA to salicylic acid in rice, demonstrating that this pathway is conserved across various crops [3][8]. - The research identified three specific enzymes involved in this pathway: benzoyl-CoA:benzyl transferase (BEBT), benzyl benzoate hydroxylase (BBH), and salicylic acid benzyl ester hydrolase (BSE), which sequentially convert benzoyl-CoA into salicylic acid [6][8]. - The findings fill a significant knowledge gap in the biosynthesis of key plant defense hormones, providing a foundation for developing disease-resistant crops [8][14]. Group 2: Related Studies - Concurrently, two other studies published in Nature also focused on salicylic acid biosynthesis, confirming the conservation of the PAL synthesis pathway in seed plants and its implications for understanding disease resistance mechanisms in various plant groups [9][10]. - The research from Sichuan University and Zhejiang Normal University further elucidated the complete biosynthesis pathway of salicylic acid from phenylalanine, reinforcing the idea of its evolutionary conservation in most seed plants [10][14].

Core Viewpoint - The recent studies from Zhejiang Normal University, Sichuan University, and Zhejiang University have successfully elucidated the biosynthesis pathways of salicylic acid in plants, particularly focusing on the phenylalanine ammonia-lyase (PAL) pathway, which is crucial for plant defense mechanisms [2][10][18]. Group 1: Research Findings - The study published by the team from Zhejiang Normal University and Brookhaven National Laboratory provides a complete analysis of the PAL biosynthesis pathway of salicylic acid from phenylalanine in rice, confirming its conservation in most seed plants [2][9]. - The activation of the PAL pathway in rice significantly enhances salicylic acid levels and the plant's immune capacity [9][10]. - The research identifies three key enzymes involved in the biosynthesis of salicylic acid, filling a long-standing gap in understanding this critical defense hormone [18]. Group 2: Methodology - The PAL biosynthesis pathway involves several steps: 1. OSD1 catalyzes the conversion of trans-cinnamic acid to cinnamoyl-CoA, which is then transformed into benzoyl-CoA through β-oxidation in peroxisomes [6]. 2. Benzoyl-CoA is converted to benzyl benzoate by the action of OSD2 [6]. 3. Finally, benzyl benzoate is hydroxylated to benzyl salicylate by cytochrome P450 enzyme OSD3, which is then hydrolyzed to salicylic acid by OSD4 [5][6][10]. Group 3: Broader Implications - The completion of the PAL pathway provides critical insights into the primary biosynthesis route of salicylic acid across different plant species, offering a precise target for regulating crop immunity [10]. - The findings from these studies contribute to understanding the differences in disease resistance mechanisms among various plant groups, particularly major food crops [13][18].