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Attempts on using fungal enzymes in weed biocontrol

Presentation · November 2014

DOI: 10.13140/RG.2.1.1704.9682

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2 authors:

Some of the authors of this publication are also working on these related projects:

Evaluation of phytopathogens associated with some major aquatic weeds with emphasis on their toxin production View project

Studies on enhancing biological control mechanism of aquatic weed, water hyacinth through integration of insects and fungal agents View project

Writuparna Dutta

Presidency University, Kolkata

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Puja Ray

Presidency University, Kolkata

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Writuparna Dutta & Puja Ray

ATTEMPTS

Department of Biological Sciences,

Presidency University, 86/1 College Street, Kolkata-700073, India

e-mail- writuparnadutta08@gmail.com

Eichhornia crassipes :

• Commonly known as water hyacinth

• Is an aquatic plant native to the Amazon basin

• Considered a highly problematic invasive species outside its

native range.

WORLDWIDE DISTRIBUTION OF THE WEED

PROGRESSION OF THE PLANT

Water Hyacinth

Invasiveness

breeding places for

mosquitoes & other

creatures

excessive wastage of

water through transpiration

reducing its levels of

oxygen, thus loss of aquatic

organisms

difficulty for some fishing

methods

Curtail recreation

activities , i.e. swimming,

boating, etc.

disrupt hydro-electric power

generation

block pipes pumping water from

the dam, impair

navigation

IN THE BULLETIN, SPREADING TERROR

HOW CAN WE CONTROL THE INVASIVENESS?

CONTROL METHODOLOGIES:

MANUAL CONTROL MECHANICAL CONTROL

CONTROL METHODOLOGY:

CHEMICAL CONTROL BIOLOGICAL CONTROL

1. INSECTS

2. FUNGUS

Let’s look into ways of controlling the weed from its core level

ULTRASTRUCTURE OF THE CELL WALL

Cellulose microfibrils are linked via hemicellulosic tethers to form the cellulose-

hemicellulose network, which is embedded in the pectin matrix

Cellulose:

35-50%

Xylan:

20-35%

Lignin:10-25%

LET’S BREAK THE RIGIDITY…

Hydrolytic enzymes like cellulase and pectinase, "degrade" cell walls by breaking

polymers into smaller subunits or by breaking crosslinks.

AIMS & OBJECTIVES

Isolation and purification of fungal strains

from infected water hyacinth

Studies on biocontrol potential of the enzymes

Enhancing lytic activities by enzymes from

non-pathogenic/ less pathogenic/ potential

fungal species

FROM WHERE DO WE GET THE ENZYMES?

Isolation and purification of fungal strains from infected water hyacinth

ISOLATION AND PURIFICATION OF FUNGAL STRAINS

Leaf pieces of about 2mm square

were cut from the margins of

necrotic or chlorotic lesions on

the surface.

Pieces were placed on earlier

prepared petri-plates containing

potato dextrose agar (PDA)

medium and incubated for 3-4

days at 27o

C.

The fungal species isolated earlier

were purified by streak-plate and

sub culturing techniques.

It was carried out until fresh true

monoculture of each fungus was

obtained.

Pure cultures of some fungi flora isolated from water hyacinth.

ENZYMES FROM FUNGUS INOCULATED

Inoculation of the fungi with different substrates

Enzymes were produced, from different fungi subsequently, and were stored.

STUDIES ON BIOCONTROL POTENTIAL OF FUNGAL

ENZYMES

PATHOGENICITY TEST OF THE FUNGI

Disease severity rating:

- no symptom (healthy plant)

+ mild symptom (>15% of leaf area)

++ moderate symptom (16-59% of leaf area)

+++ severe symptom (60-100% of leaf area)

THE STORY DOESN’T END HERE…

LYTIC ACTIVITIES OF VARIOUS FUNGI:

0

100

200

300

400

500

600

700

800

cellulolytic pectinolytic xylanolytic

En

zym

e A

cti

vit

y (U

/m

l)

Types of Lytic Enzymes

Myrothecium

Fusarium

Curvularia

Rhizoctonia

Trichoderma

Alternaria

EFFECT OF VARIOUS SUBSTRATES (ENZYMES RELEASED) FROM

Trichoderma sp.

0

100

200

300En

zym

e A

ctiv

ity

( U

/ml )

Pectinases and hemicellulases (β –glucosidase, endoglucanase and

endoxylanase) shows the maximum production. So, they were carried for

experimentation into the next level.

Preparing various extracellular enzymes in submerged fermentation (SmF).

STABILITY AND ACTIVITY OF THE LYTIC ENZYME FROM Trichoderma sp.

ENZYME OVER TOXIN?ENZYME IS A PRIMARY METABOLITE WHILE TOXINS ARE USUALLY SECONDARY METABOLITE

Primary metabolite is produced during the growth period (Lag phase).

While, secondary metabolite is produced only after the logarithmic phase

(Trophophase) is completed, during the stationary phase (Idiophase)

1. All fungi do not produce effective toxins2. Primary metabolite are also effective from early phase of the micro-organisms

CONCLUSION

The invasive weed:

Different enzymes could be produced from fungal-infected

weeds.

Utilising the enzymes in fungal biocontrol, which causes much

quicker application.

Lytic enzymes from Trichoderma sp. :

With high pH and temp stability

So far the literature study is concerned, this is the first report of

utilization of enzymes from fungal strains, collected from water

hyacinth, for the biocontrol of the invasive weed.

I got a competitor

now!! !

Thank you

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