Role of Salicylic Acid in <em>Pseudomonas aeruginosa</em> Strain IE-6S+-Mediated Induction of Systemic Resistance against <em>Meloidogyne javanica</em> in Tomato

Root colonization by certain non-pathogenic bacteria can induce systemic resistance to pathogen infections in plants. In a split-root assay with tomato plants, we investigated which determinants of the rhizobacterium Pseudomonas aeruginosa IE-6S+ were important for induction of resistance to the roo...

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Main Authors: I.A. Siddiqui, S.S. Shaukat
Format: Article
Language:English
Published: Firenze University Press 2003-12-01
Series:Phytopathologia Mediterranea
Online Access:https://oajournals.fupress.net/index.php/pm/article/view/5020
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author I.A. Siddiqui
S.S. Shaukat
author_facet I.A. Siddiqui
S.S. Shaukat
author_sort I.A. Siddiqui
collection DOAJ
description Root colonization by certain non-pathogenic bacteria can induce systemic resistance to pathogen infections in plants. In a split-root assay with tomato plants, we investigated which determinants of the rhizobacterium Pseudomonas aeruginosa IE-6S+ were important for induction of resistance to the root-knot nematode Meloidogyne javanica. P. aeruginosa IE-6S+ produced 3.9±1.1 µg ml-1 salicylic acid (SA) in a liquid casamino acid medium under laboratory conditions. The bacterial inoculant induced resistance equivalent to the application of 10 mM synthetic SA. However, SA at this concentration did not produce significant mortality of M. javanica juveniles in vitro. Soil iron (2.4 mM FeCl3·6H2O) did not markedly alter the resistance that P. aeruginosa IE-6S+ induced in tomato roots, which suggested that P. aeruginosa IE-6S+ activity was not iron-regulated. However, the resistance reaction was greatly enhanced when IE-6S+ and SA were co-inoculated with 0.5% Tween-20. While IE-6S+ colonized the tomato rhizosphere at 6.38 log cfu per g fresh weight of root during the first 3 days after inoculation, the bacterial populations declined steadily, reaching a mean population density of 4.73 log cfu g-1 fresh weight of root at 21 days. The bacterium was not isolated from the unbacterized half of the split root system.
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spelling doaj.art-832e27f5e2d04f78b7ed70482be937f62022-12-22T01:13:47ZengFirenze University PressPhytopathologia Mediterranea0031-94651593-20952003-12-0142310.14601/Phytopathol_Mediterr-17141710Role of Salicylic Acid in <em>Pseudomonas aeruginosa</em> Strain IE-6S+-Mediated Induction of Systemic Resistance against <em>Meloidogyne javanica</em> in TomatoI.A. SiddiquiS.S. ShaukatRoot colonization by certain non-pathogenic bacteria can induce systemic resistance to pathogen infections in plants. In a split-root assay with tomato plants, we investigated which determinants of the rhizobacterium Pseudomonas aeruginosa IE-6S+ were important for induction of resistance to the root-knot nematode Meloidogyne javanica. P. aeruginosa IE-6S+ produced 3.9±1.1 µg ml-1 salicylic acid (SA) in a liquid casamino acid medium under laboratory conditions. The bacterial inoculant induced resistance equivalent to the application of 10 mM synthetic SA. However, SA at this concentration did not produce significant mortality of M. javanica juveniles in vitro. Soil iron (2.4 mM FeCl3·6H2O) did not markedly alter the resistance that P. aeruginosa IE-6S+ induced in tomato roots, which suggested that P. aeruginosa IE-6S+ activity was not iron-regulated. However, the resistance reaction was greatly enhanced when IE-6S+ and SA were co-inoculated with 0.5% Tween-20. While IE-6S+ colonized the tomato rhizosphere at 6.38 log cfu per g fresh weight of root during the first 3 days after inoculation, the bacterial populations declined steadily, reaching a mean population density of 4.73 log cfu g-1 fresh weight of root at 21 days. The bacterium was not isolated from the unbacterized half of the split root system.https://oajournals.fupress.net/index.php/pm/article/view/5020
spellingShingle I.A. Siddiqui
S.S. Shaukat
Role of Salicylic Acid in <em>Pseudomonas aeruginosa</em> Strain IE-6S+-Mediated Induction of Systemic Resistance against <em>Meloidogyne javanica</em> in Tomato
Phytopathologia Mediterranea
title Role of Salicylic Acid in <em>Pseudomonas aeruginosa</em> Strain IE-6S+-Mediated Induction of Systemic Resistance against <em>Meloidogyne javanica</em> in Tomato
title_full Role of Salicylic Acid in <em>Pseudomonas aeruginosa</em> Strain IE-6S+-Mediated Induction of Systemic Resistance against <em>Meloidogyne javanica</em> in Tomato
title_fullStr Role of Salicylic Acid in <em>Pseudomonas aeruginosa</em> Strain IE-6S+-Mediated Induction of Systemic Resistance against <em>Meloidogyne javanica</em> in Tomato
title_full_unstemmed Role of Salicylic Acid in <em>Pseudomonas aeruginosa</em> Strain IE-6S+-Mediated Induction of Systemic Resistance against <em>Meloidogyne javanica</em> in Tomato
title_short Role of Salicylic Acid in <em>Pseudomonas aeruginosa</em> Strain IE-6S+-Mediated Induction of Systemic Resistance against <em>Meloidogyne javanica</em> in Tomato
title_sort role of salicylic acid in em pseudomonas aeruginosa em strain ie 6s mediated induction of systemic resistance against em meloidogyne javanica em in tomato
url https://oajournals.fupress.net/index.php/pm/article/view/5020
work_keys_str_mv AT iasiddiqui roleofsalicylicacidinempseudomonasaeruginosaemstrainie6smediatedinductionofsystemicresistanceagainstemmeloidogynejavanicaemintomato
AT ssshaukat roleofsalicylicacidinempseudomonasaeruginosaemstrainie6smediatedinductionofsystemicresistanceagainstemmeloidogynejavanicaemintomato