Integrated Application of Salicylic Acid and PGPRs to Control Fusarium Wilt of Chickpea

Background: Fusarium wilt and Ascochyta blight are the most important diseases of chickpea. The current study was designed to investigate the individual and combined effect of salicylic acid (SA) with Pseudomonas stutzeri and Pseudomonas putida to suppress Fusarium wilt and promote growth of chickpea varieties: Thal-2006 and Punjab-2008. Methods: At the time of sowing, inoculum of Fusarium oxysporum was applied to the soil and the incidence of Fusarium wilt was recorded after 60 days. The seeds were inoculated with Pseudomonas stutzeri and Pseudomonas putida prior to sowing. Chickpea plants were treated with salicylic acid at seedling stage. Results: The combination of P. stutzeri and SA significantly increased root length (166% and 145%), shoot height (50% and 47%) and shoot biomass (300% and 233%) in cv. Thal-2006 and cv. Punjab-2008, respectively, in infected plants. Similarly, the combined treatment of P. putida + SA, also enhanced the plant growth parameters of chickpea varieties. Maximum reduction in disease severity was observed in both P. stutzeri + SA (90% and 84%) and P. putida + SA (79% and 77%) treatments in cv. Thal-2006 and Punjab-2008, respectively. Both P. putida + SA and P. stutzeri + SA treatments resulted in increased leaf relative water and total protein content, peroxidase, superoxide dismutase, phenylalanine ammonia-lyase and polyphenol oxidase activities in both resistant (cv. Thal-2006) and susceptible (cv. Punjab-2008) cultivars. Both treatments also significantly reduced malondialdehyde (MDA) and proline content in cv. Thal-2006 and Punjab-2008. Cultivar Thal-2006 was more effective than cv. Punjab-2008. Conclusions: The results suggested that, in combination, salicylic acid and P. stutzeri may play an important role in controlling Fusarium wilt diseases by inducing systemic resistance in chickpea.