ISSN: 0973-7510

E-ISSN: 2581-690X

Rashmi Aggarwal , Sapna Sharma, Sangeeta Gupta, Kanchan B. M Singh and V. Shanmugam
Division of Plant Pathology, ICAR-Indian Agricultural Research Institute, New Delhi -110 012, India.
J. Pure Appl. Microbiol., 2016, 10 (3): 2071-2078
© The Author(s). 2016
Received: 07/09/2015 | Accepted: 03/11/2015 | Published: 30/09/2016

Spot blotch caused by Bipolaris sorokiniana (Sacc.) Shoem. (syn. Helminthosporium sativum, teleomorph Cochliobolous sativus)  and leaf (brown) rust caused by (Puccinia triticina Eriks) are serious diseases of wheat inflicting heavy yield losses. A highly antagonistic Chaetomium globosum strain, Cg-2 that inhibited the mycelial growth of B. sorokiniana was selected for assessing spot blotch and leaf rust control by pot culture experiments in the greenhouse. Pre-inoculation foliar spray of Cg-2 challenge-inoculated with B. sorokiniana and P. triticina resulted in significantly lower incidence relative to the pathogen control. On challenge inoculation with B. sorokiniana, the lower disease incidence coincided with increased plant vigor index (4007), relative to the pathogen control. Analysis of leaf samples also indicated increased induction of peroxidase (PO) by 2 and 3.8-fold, polyphenol oxidase (PPO) by 2 and 4-fold, phenylalanine ammonia lyase (PAL) by 5 and 6-fold and catalase by 1.8 and 2.4-fold, more than those of the pathogen controls, B. sorokiniana and P. triticina, respectively. In quantitative PCR assays, Cg-2 with challenge-inoculation, showed maximum expression of PO at 5 (5.6 fold) and 7 days (8.5 fold) of challenge inoculation with B. sorokiniana and P. triticina, respectively. Also, the maximum expression of PAL was noticed at 7 days of challenge inoculation with P. triticina. It is presumed that the induced peroxidase, polyphenol oxidase, phenylalanine ammonia lyase and catalase may be involved in the reduction of spot blotch and leaf rust development in wheat. Reduced disease severity coupled with enhanced enzyme production elicited by Chaetomium globosum in glasshouse experiments by foliar spray indicate that its mode of action for spot blotch and leaf rust suppression in wheat is through induced resistance.


Induced resistance, Wheat, spot blotch, Leaf rust, Chaetomium globosum, Defense enzymes.

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