scholarly journals EFFECT OF DIFFERENT PLANT ACTIVATORS AGAINST RHIZOCTONIA SOLANI CAUSING ROOT ROT OF CHILLI

2018 ◽  
Vol 30 (1) ◽  
pp. 45
Author(s):  
Muhammad S. Baloch ◽  
Nasir A. Rajput ◽  
Muhammad Atiq ◽  
Abdul Rehman ◽  
Samiya M. Khan ◽  
...  

Chilli is an important horticultural crop all over the world. Root rot of chilli is the most important disease caused by Rhizoctonia solani responsible for immense losses. Systemic acquired resistance (SAR) acting as a significant part in the proficiency of plants to protect themselves by means of hyper-sensitive reaction (HR) of plants toward the destructive pathogens. Additionally, SAR reveals as long time defense approach that may be weeks to months or sometimes throughout the entire season. The aim of this study was to induce systemic acquired resistance (SAR) against R. solani in chilli crop. Five plant activators salicylic acid, potassium dihydrogen phosphate (KH2PO4), di-potassium hydrogen phosphate (K2HPO4), benzoic acid and citric acid were evaluated under Lab. and field conditions with three different concentrations (1, 2 and 3%). Salicylic acid gave better result at 3% concentration. After 3rd application, salicylic acid at 21 days interval expressed minimum disease incidence as compared to others treatments. At concentration of 3 % after twenty-one days of spraying salicylic acid showed minimum disease incidence (9.667%) followed by KH2PO4 (16.433%), K2HPO4 (20.241%), benzoic acid (23.367%) and citric acid (28.667%) while control expressed maximum disease incidence (86.467%). So, it is concluded that salicylic acid gave better result than others treatments.

2010 ◽  
Vol 23 (1) ◽  
pp. 82-90 ◽  
Author(s):  
Po-Pu Liu ◽  
Yue Yang ◽  
Eran Pichersky ◽  
Daniel F. Klessig

Methyl salicylate (MeSA), which is synthesized in plants from salicylic acid (SA) by methyltransferases, has roles in defense against microbial and insect pests. Most of the MeSA that accumulates after pathogen attack is synthesized by benzoic acid/SA carboxyl methyltransferase 1 (AtBSMT1). To investigate the role of AtBSMT1 in plant defense, transgenic Arabidopsis with altered AtBSMT1 function or expression were assessed for their ability to resist pathogen infection. A knockout mutant (Atbsmt1) failed to accumulate MeSA following pathogen infection; these plants also failed to accumulate SA or its glucoside in the uninoculated leaves and did not develop systemic acquired resistance (SAR). However, the Atbsmt1 mutant exhibited normal levels of effector-triggered immunity and pathogen-associated molecular pattern (PAMP)-triggered immunity to Pseudomonas syringae and Hyaloperonospora arabidopsidis. Analyses of transgenic Arabidopsis plants overexpressing AtBSMT1 revealed that they accumulate elevated levels of MeSA in pathogen-infected leaves but fail to develop SAR. Since the levels of SA and its glucoside were reduced in uninoculated systemic leaves of these plants whereas MeSA levels were elevated, AtBSMT1-mediated conversion of SA to MeSA probably compromised SAR development by suppressing SA accumulation in uninoculated leaves. PAMP-triggered immunity also was compromised in the AtBSMT1 overexpressing plants, although effector-triggered immunity was not.


1995 ◽  
Vol 25 (9) ◽  
pp. 1479-1483 ◽  
Author(s):  
M. Gabrielle Pausler ◽  
William A. Ayer ◽  
Yasuyuki Hiratsuka

Trembling aspen (Populustremuloides Michx.) bearing certain types of black galls have a lower incidence of Phellinustremulae (Bond.) Bond. & Boriss. heartwood rot than do nongall-bearing trees. Extraction of finely ground black gall tissue with ethyl acetate and separation of the acidic components of the extract led to the isolation of benzoic acid, trans-cinnamic acid, p-hydroxybenzoic acid, p-hydroxycinnamic acid, naringenin, 7′-methyl-3-hydroxynaringen, aromadendrin, and taxifolin. Bioassays revealed that among these compounds, only benzoic acid showed significant activity against P. tremulae. An analytical procedure was developed to measure the concentration of benzoic acid in various types of aspen tissue. Tissue from the black galls showed a high concentration of benzoic acid, and tissue from gall-bearing trees contained significantly more benzoic acid than healthy nongalled trees. However, the amount of benzoic acid present in the gall-bearing trees may not be sufficient to prevent Phellinus decay. It is suggested that perhaps the benzoic acid serves as a precursor of salicylic acid, a signal molecule in systemic acquired resistance of plants.


2015 ◽  
Vol 112 (30) ◽  
pp. 9166-9173 ◽  
Author(s):  
Xiao-yu Zheng ◽  
Mian Zhou ◽  
Heejin Yoo ◽  
Jose L. Pruneda-Paz ◽  
Natalie Weaver Spivey ◽  
...  

The plant hormone salicylic acid (SA) is essential for local defense and systemic acquired resistance (SAR). When plants, such as Arabidopsis, are challenged by different pathogens, an increase in SA biosynthesis generally occurs through transcriptional induction of the key synthetic enzyme isochorismate synthase 1 (ICS1). However, the regulatory mechanism for this induction is poorly understood. Using a yeast one-hybrid screen, we identified two transcription factors (TFs), NTM1-LIKE 9 (NTL9) and CCA1 HIKING EXPEDITION (CHE), as activators of ICS1 during specific immune responses. NTL9 is essential for inducing ICS1 and two other SA synthesis-related genes, PHYTOALEXIN-DEFICIENT 4 (PAD4) and ENHANCED DISEASE SUSCEPTIBILITY 1 (EDS1), in guard cells that form stomata. Stomata can quickly close upon challenge to block pathogen entry. This stomatal immunity requires ICS1 and the SA signaling pathway. In the ntl9 mutant, this response is defective and can be rescued by exogenous application of SA, indicating that NTL9-mediated SA synthesis is essential for stomatal immunity. CHE, the second identified TF, is a central circadian clock oscillator and is required not only for the daily oscillation in SA levels but also for the pathogen-induced SA synthesis in systemic tissues during SAR. CHE may also regulate ICS1 through the known transcription activators CALMODULIN BINDING PROTEIN 60g (CBP60g) and SYSTEMIC ACQUIRED RESISTANCE DEFICIENT 1 (SARD1) because induction of these TF genes is compromised in the che-2 mutant. Our study shows that SA biosynthesis is regulated by multiple TFs in a spatial and temporal manner and therefore fills a gap in the signal transduction pathway between pathogen recognition and SA production.


2007 ◽  
Vol 97 (7) ◽  
pp. 794-802 ◽  
Author(s):  
Shobha D. Potlakayala ◽  
Darwin W. Reed ◽  
Patrick S. Covello ◽  
Pierre R. Fobert

Systemic acquired resistance (SAR) is an induced defense response that confers long-lasting protection against a broad range of microbial pathogens. Here we show that treatment of Brassica napus plants with the SAR-inducing chemical benzo-(1,2,3)-thiadiazole-7-carbothioic acid S-methyl ester (BTH) significantly enhanced resistance against virulent strains of the bacterial pathogen Pseudomonas syringae pv. maculicola and the fungal pathogen Leptosphaeria maculans. Localized preinoculation of plants with an avirulent strain of P. syringae pv. maculicola also enhanced resistance to these pathogens but was not as effective as BTH treatment. Single applications of either SAR-inducing pretreatment were effective against P. syringae pv. maculicola, even when given more than 3 weeks prior to the secondary challenge. The pretreatments also led to the accumulation of pathogenesis-related (PR) genes, including BnPR-1 and BnPR-2, with higher levels of transcripts observed in the BTH-treatment material. B. napus plants expressing a bacterial salicylate hydroxylase transgene (NahG) that metabolizes salicylic acid to catechol were substantially compromised in SAR and accumulated reduced levels of PR gene transcripts when compared with untransformed controls. Thus, SAR in B. napus displays many of the hallmarks of classical SAR including long lasting and broad host range resistance, association with PR gene activation, and a requirement for salicylic acid.


RSC Advances ◽  
2018 ◽  
Vol 8 (69) ◽  
pp. 39593-39601 ◽  
Author(s):  
Qi-Fan Wu ◽  
Bin Zhao ◽  
Zhi-Jin Fan ◽  
Jia-Bao Zhao ◽  
Xiao-Feng Guo ◽  
...  

Compound 6u exhibits ultrahigh fungicidal activity by acting at its potent target PcORP1 and induces systemic acquired resistance by activating the salicylic acid pathway.


2019 ◽  
Vol 20 (3) ◽  
pp. 671 ◽  
Author(s):  
Ning Li ◽  
Xiao Han ◽  
Dan Feng ◽  
Deyi Yuan ◽  
Li-Jun Huang

During their lifetime, plants encounter numerous biotic and abiotic stresses with diverse modes of attack. Phytohormones, including salicylic acid (SA), ethylene (ET), jasmonate (JA), abscisic acid (ABA), auxin (AUX), brassinosteroid (BR), gibberellic acid (GA), cytokinin (CK) and the recently identified strigolactones (SLs), orchestrate effective defense responses by activating defense gene expression. Genetic analysis of the model plant Arabidopsis thaliana has advanced our understanding of the function of these hormones. The SA- and ET/JA-mediated signaling pathways were thought to be the backbone of plant immune responses against biotic invaders, whereas ABA, auxin, BR, GA, CK and SL were considered to be involved in the plant immune response through modulating the SA-ET/JA signaling pathways. In general, the SA-mediated defense response plays a central role in local and systemic-acquired resistance (SAR) against biotrophic pathogens, such as Pseudomonas syringae, which colonize between the host cells by producing nutrient-absorbing structures while keeping the host alive. The ET/JA-mediated response contributes to the defense against necrotrophic pathogens, such as Botrytis cinerea, which invade and kill hosts to extract their nutrients. Increasing evidence indicates that the SA- and ET/JA-mediated defense response pathways are mutually antagonistic.


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