scholarly journals Benzoic Acid and Its Hydroxylated Derivatives Suppress Early Blight of Tomato (Alternaria solani) via the Induction of Salicylic Acid Biosynthesis and Enzymatic and Nonenzymatic Antioxidant Defense Machinery

2021 ◽  
Vol 7 (8) ◽  
pp. 663
Author(s):  
Yasser Nehela ◽  
Naglaa A. Taha ◽  
Abdelnaser A. Elzaawely ◽  
Tran Dang Xuan ◽  
Mohammed A. Amin ◽  
...  
Keyword(s):  
Salicylic Acid ◽  
Benzoic Acid ◽  
Early Blight ◽  
Antioxidant Defense ◽  
Alternaria Solani ◽  
Protective Role ◽  
Growth And Yield ◽  
Fungistatic Activity ◽  
Pathogenesis Related Protein ◽  
Pathogenesis Related

Tomato early blight, caused by Alternaria solani, is a destructive foliar fungal disease. Herein, the potential defensive roles of benzoic acid (BA) and two of its hydroxylated derivatives, ρ-hydroxybenzoic acid (HBA), and protocatechuic acid (PCA) against A. solani were investigated. All tested compounds showed strong dose-dependent fungistatic activity against A. solani and significantly reduced the disease development. Benzoic acid, and its hydroxylated derivatives, enhanced vegetative growth and yield traits. Moreover, BA and its derivatives induce the activation of enzymatic (POX, PPO, CAT, SlAPXs, and SlSODs) and non-enzymatic (phenolics, flavonoids, and carotenoids) antioxidant defense machinery to maintain reactive oxygen species (ROS) homeostasis within infected leaves. Additionally, BA and its hydroxylated derivatives induce the accumulation of salicylic acid (SA) and its biosynthetic genes including isochorismate synthase (SlICS), aldehyde oxidases (SlAO1 and SlAO2), and phenylalanine ammonia-lyases (SlPAL1, SlPAL2, SlPAL3, SlPAL5, and SlPAL6). Higher SA levels were associated with upregulation of pathogenesis-related proteins (SlPR-1, SlPR1a2, SlPRB1-2, SlPR4, SlPR5, SlPR6), nonexpressor of pathogenesis-related protein 1 (SlNPR1), and salicylic acid-binding protein (SlSABP2). These findings outline the potential application of BA and its hydroxylated derivatives as a sustainable alternative control strategy for early blight disease and also deciphering the physiological and biochemical mechanisms behind their protective role.

Salicylic acid-induced suppression of Meloidogyne incognita infestation of okra and cowpea

Nematology ◽  
2003 ◽  
Vol 5 (5) ◽  
pp. 747-752 ◽  
Author(s):  
Bidyut Nandi ◽  
Santi Prasad Sinha Babu ◽  
Nirmalya Banerjee ◽  
Kabita Kundu
Keyword(s):  
Salicylic Acid ◽  
Meloidogyne Incognita ◽  
Phenylalanine Ammonia Lyase ◽  
Foliar Spray ◽  
In Vitro Test ◽  
Pal Activity ◽  
Pathogenesis Related Protein ◽  
Pathogenesis Related ◽  
Vitro Test

AbstractSalicylic acid (SA) applied as 10 mM foliar spray to okra (Abelmoschus esculentus) cv. Purbani Kranti and cowpea (Vigna unguiculata) cv. Pusa Ruby plants 24 h before inoculation of roots with Meloidogyne incognita juveniles, reduced infestation. Salicylic acid had no direct influence on plant growth and did not kill nematodes in an in vitro test. It induced increased accumulation of a 14 kDa pathogenesis-related protein (PR-1) in roots of both non-inoculated and inoculated salicylic acid-sprayed okra but not in the treated leaves. Salicylic acid sprays enhanced phenylalanine ammonia lyase (PAL) activity in roots of both non-inoculated and inoculated cowpea, estimated at 15 days after inoculation. Infected roots had higher PAL activity than roots of the corresponding non-inoculated treatments. Both PAL activity and SA-induced resistance gradually declined with plant age after treatment.

scholarly journals XCP1 is a caspase that proteolyzes Pathogenesis-related protein 1 to produce the cytokine CAPE9 for systemic immunity in Arabidopsis

2021 ◽  
Author(s):  
Ying-Lan Chen ◽  
Fan-Wei Lin ◽  
Kai-Tan Cheng ◽  
Hung-Yu Wang ◽  
Thomas Efferth ◽  
...  
Keyword(s):  
Salicylic Acid ◽  
Plant Immunity ◽  
Related Protein ◽  
Proteolytic Activation ◽  
Systemic Immunity ◽  
Pathogenesis Related Protein ◽  
Pathogenesis Related ◽  
Comparable Activity ◽  
Molecular Patterns ◽  
Substrate Motif

Abstract Proteolytic activation of cytokines regulates immunity in diverse organisms. In animals, cysteine-dependent aspartate-specific proteases (caspases) play central roles in cytokine maturation. Although the proteolytic production of peptide cytokines is also essential for plant immunity, evidence for a plant caspase is still lacking. In this study, we discovered that proteolysis of a caspase-like substrate motif “CNYD” within Pathogenesis-related protein 1 (AtPR1) in Arabidopsis generates an immunomodulatory cytokine (AtCAPE9). Salicylic acid enhances CNYD-targeted protease activity and the proteolytic release of AtCAPE9 from AtPR1 in Arabidopsis. We show that this process involves a caspase, identified as Xylem cysteine peptidase 1 (XCP1). XCP1 exhibits a calcium-modulated pH-activity profile and a comparable activity to human caspases. XCP1 is required to induce systemic immunity triggered by pathogen-associated molecular patterns. This work reveals XCP1 as the first known plant caspase, which produces the cytokine AtCAPE9 from the canonical salicylic acid signaling marker PR1 to activate systemic immunity.

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