Studies on the phytoalexin(s) of mulberry (Morus sp.) varieties resistant to leaf spot pathogen - Cercospora moricola Cooke

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1.

Project Code

:

-

2.

Title

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Studies on the phytoalexin(s) of mulberry (Morussp.) varieties resistant to leaf spot pathogen -Cercospora moricolaCooke.

3.

Investigators

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Nagaveni V, Shree MP

4.

Project period

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2002-2006

5.

Institute/ University

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Bangalore University, Bangalore, Karnataka

6.

Project cost

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-

7.

Objectives

  • To screen susceptible and resistant mulberry varieties againstCercospora moricolaby artificial induction.
  • To quantify biochemical components associated with resistance in mulberry varieties.
  • To know the enzyme activities associated with disease resistance and phytoalexin production.
  • To know the phytoalexin production in resistant varieties by spore germination and bioassay methods.

8.

Important findings

Thirteen mulberry varieties were screened for resistance against leaf spot disease, of which 6 were resistant, 3 were moderately resistant, 2 were moderately susceptible and 2 were susceptible. The biochemical components like phenols, OD phenols and protein contents increased in resistant varieties compared to others. The enzyme activities like ascorbic acid oxidase, catalase PO, PPO, PAL and TAL associated with disease resistance and PA production increased in resistant varieties. The synthesis of PA was high and earlier in resistant variety. The phytoalexin synthesized in resistant variety inhibited the growth of test pathogen on a pathogen and also the pathogen itself.

The study indicated that PA were produced in resistant variety, in response toC. moricolainfection. PAs are antifungal compounds formed in living cells of hypersensitive host in response to parasitic attack and inhibit further development of the pathogen. If PAs are isolated at micro levels can further be injected to the plants and control the disease at early stage of infection.

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