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Trichoderma harzianum elicits induced resistance in sunflower challenged by Rhizoctonia solani

Authors

  • B.N. Singh,

    1. Department of Mycology & Plant Pathology, Institute of Agricultural Sciences, Banaras Hindu University, Varanasi, India
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  • A. Singh,

    1. Department of Botany, Faculty of Science, Banaras Hindu University, Varanasi, India
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  • B.R. Singh,

    1. Department of Applied Physics, Z.H. College of Engg. & Tech., Centre of Excellence in Materials Science (Nanomaterials), Aligarh Muslim University, Aligarh, India
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  • H.B. Singh

    Corresponding author
    1. Department of Mycology & Plant Pathology, Institute of Agricultural Sciences, Banaras Hindu University, Varanasi, India
    • Correspondence

      Harikesh B. Singh, Department of Mycology & Plant Pathology, Institute of Agricultural Sciences, Banaras Hindu University, Varanasi–221 005, Uttar Pradesh, India.

      E-mail: hbs1@rediffmail.com

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Abstract

Aims

To investigate the efficacy of Trichoderma harzianum NBRI-1055 (denoted as ‘T-1055’) in suppression of seedling blight of sunflower caused by Rhizoctonia solani Kühn and their impact on host defence responses.

Methods and Results

T-1055 was applied as seed treatment, soil application and combined application (seed treatment + soil application). Higher protection afforded by combined application of T-1055 was associated with the marked induction of phenylalanine ammonia-lyase (PAL), polyphenol oxidase (PPO), peroxidase (PO) and cinnamyl alcohol dehydrogenase (CAD) activities. The activities of PAL and PPO reached maximum at 10 days after sowing (DAS), while PO and CAD levels reached maximum at 12 DAS. This was further supported by the accumulation of total phenolic content that showed an increase up to threefold at 14 DAS. In addition, HPLC analysis revealed that the contents of ferulic and p-coumaric acids increased by 6·3 and 4·6 times, respectively, at 14 DAS. Amount of gallic acid was also little more than double. Lignin deposition in sunflower root increased by 2·7, 3·4 and 3·7 times through combined application of T-1055 at 16, 18 and 20 DAS, respectively. Combined application also increased the accumulation of PR-2 and PR-3 proteins by 3·3 and 3·9 times, respectively, at 12 DAS in followed by seed treatment alone.

Conclusions

The combined application of T-1055 triggered defence responses in an enhanced level in sunflower than the soil and seed alone and provided better protection against Rhizoctonia seedling blight.

Significance and Impact of the Study

Rhizospheric fungal bioagent ‘T-1055’ can enhance protection in sunflower against the Rsolani pathogen through augmented elicitation of host defence responses.

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