isr in plants through fungal biocontrol agents

05/02/2023 Dept. of Plant Pathology 1

welcomeINDUCED SYSTEMIC RESISTANCE IN PLANTS THROUGH FUNGAL

BIOCONTROL AGENTS

JayappaSr. M.Sc (Agri)

PALB 4255


Flow of seminar

o Introductiono Mechanisms of Fungal Biocontrol Agents(BCF)o Different Plant responses to BCF’so Case studieso Conclusion


Introduction

• Contact with pathogenic and non-pathogenic microorganisms

activates a broad range of defense mechanisms in plants

• Two main mechanisms are recognized;

1. Systemic acquired resistance

2. Induced systemic resistance

• Biocontrol fungi (BCF) are agents that control plant diseases

which includes Trichoderma spp, Ampelomyces quisqualis,

Paecilomyces lilacinus and others


Host – Pathogen interaction

05/02/2023 Dept. of Plant Pathology 5(Pieterse et al., 2009)


Fungal biocontrol (BCF) agents

Bio agent Target diseases / pathogen Trichoderma spp. Soil borne disease

Cryptococcus albidus Botrytis spp., Penicillium spp.

Gleocladium virens Rhizoctonia solani, Pythium, Phytophthora

Ampelomyces quisqualis Powdery MildewRhizobium

leguminosorumFusarium oxysporum f. sp. ciceris

Glomus mosseae , Paecilomyces lilacinus

Nematodes

Verticillium lecanii Penicillium digitatum(Burges et al., 1998)


Reduce the negative effects of plant pathogens and promote positive responses in plant.

Inoculated plants are sensitized to respond more rapidly to pathogen attack

Alleviation of abiotic stresses Improve photosynthetic efficiency, especially in plants subjected to

various stresses Increase nutrients absorption and nitrogen use efficiency in plants Enhance the growth and yield parameters

Role of BCF’s

(Shoresh et al., 2010)


Mechanisms of Fungal Biocontrol Agents


Mycoparasitism

(Irina et al., 2011)


“ Interactions that involve a low-molecular weight compound or an antibiotic produced by microorganism that has a direct effect on another microorganism”

Antibiosis


Fungal biocontrol agents and their metabolites

(Butt et al., 2001)


Competition

• Competition for nutrient and space. • Biocontrol agent decreases the availability of a particular

substance thus limiting the growth of the plant pathogenic agentsTypes :• Exploitation Competition• Interference Competition• Preemptive Competition

• Trichoderma spp produce siderophores that chelate iron and stop the growth of other fungi

(Chet and Inbar ,1994)

Competitive exclusion Coexistence Mutual extinction


Fungal compounds involved in induction of plant responses

Compounds that are released by Trichoderma spp. into the zone of interaction induce resistance in plants

Primarily proteins with enzymatic activity

xylanase, cellulase, swollenin and endochitinase

Enhance defense, through induction of plant defense–related proteins and peptides that are active in inducing terpenoid, phytoalexin biosynthesis and peroxidase activity.


Elicitation of plant to pathogen attack

Elicitors of plant defense includes

oligosaccharides

low-molecular weight compounds

secondary metabolites

produced by different Trichoderma spp induce expression of pathogenesis

related (PR) proteins when applied to plants and reduce disease symptoms

05/02/2023 Dept. of Plant Pathology 15(Yedidia et al., 2003)

Bacterial cell colonization of leaves sampled from non elicited and preelicited cucumber plants

Psuedomonas syringae pv. Lachrymans progresses towards the inner leaf tissues mainly by intercellular (IS) growth

Considerably fewer P. syringae pv. Lachrymans cells are observed


Systemic induction of defense-related genes and proteins

• After treatment with T. harzianum, many defense/stress-related proteins functions were upregulated.

• Stress response enzymes such as1. Oxalate oxidase and superoxide dismutase (roots)2. Methionine synthases, glutathione-S-transferase and glutathione dependent

formaldehyde dehydrogenase (FALDH) (shoots)• They acts as..

Detoxifying enzymes, peroxidase, scavenging enzyme, Heat shock proteins (stress proteins).

(Yadav et al., 2015)


Gene expression in Trichoderma harzianum T22 Inoculated Maize

up-regulated of defense- and stress-related genes

Down regulated

( Shoresh and Harman, 2008)


Abiotic stress induced ROS production and cell death

Alleviation of damage by reactive oxygen species

Equilibrium


Major ROS scavenging antioxidant enzymes

Enzymatic antioxidants Reactions catalyzed

Superoxide dismutase (SOD) O₂⁻ + O₂ ⁻+ 2H+ → 2H₂O₂ + O₂

Catalase (CAT) H₂O₂ ̶ →H₂O + ½ O₂

Ascorbate peroxidase (APX) H₂O₂ + AA →2H₂O + DHA

Guaicol peroxidase (GPX) H₂O₂ + GSH → H₂O + GSSG

Monodehydroascorbate reductase (MDHAR) MDHA + NAD(P)H → AA + NAD(P)+

Dehydroascorbate reductase (DHAR) DHA + 2GSH → AA + GSSG

Glutathione reductase (GR) GSSG + NAD(P)H → 2GSH + NAD(P)+

(Gill and Tuteja, 2010)

05/02/2023 Dept. of Plant Pathology

Perception of the signal and activation of MAPK signaling cascade

Interaction of the signal molecules from the BCF with particular plant receptor

molecules in the interaction zone, activates a MAPK signaling cascade

Plant interaction with Trichoderma results in induction of NBS/leucine rich

repeat resistance protein.

NBS/ LRR are determinants of plant immune system and it trigger a cascade of

signal transduction results in resistance response

20

05/02/2023 Dept. of Plant Pathology (Shoresh et al., 2010)

Cont..

21


Trichoderma MAMPs currently identified in different species

(Hermosa et al ., 2012)


Plant signaling pathways induced by BCF leading to disease resistance

Trichoderma upregulate the Pal1, which encodes for phenylalanine ammonia-lyase

Pal1 is activate JA/ethylene signaling

It catalyzes the first step of phenyl propanoid pathway, leading to production of

phenolic compounds, including phytoalexins

Defense of the plants against infection

(PAL)


Plant growth enhancement by BCF inoculation

Trichoderma species inoculation induces root and shoot growth

The application of Trichoderma lead to an

Increase in dry matter content

Starch and soluble sugars

Germination percentage

Importantly, the effect of BCF on plant growth has a long duration and

even lasts for the entire life of annual plants


CASE STUDIES


Plant Protection Institute, Hungarian Academy of Sciences, H-1525 Budapest, HungaryPNAS September 20, 2005 vol. 102 no. 38

Objective :To test the effect of P. indica on barley to salt stress tolerance and disease resistance.


Impact of Piriformospora indica on salt-stress tolerance and root infections by Fusarium culmorum.

Plants was determined in final 2 weeks ( totally 5weeks ) in the presence of 0,100 and 300 mM NaCl, in three independent experiments.

Plant phenotypes demonstrating the protective potential of P. indica toward F. culmorum.

(Waller et al., 2005)


Ascorbate and DHA reductase (DHAR) activity in P. indica-infested roots.

measured in roots of 1-, 2-, and 3-week-old P. indica-infested (shaded columns) and control (free of P. indica, open columns) barley plants.

(Waller et al., 2005)

ba


Objective:

To prove that suppression of Rhizoctonia solani-incited cotton seedling disease by

T. virens is the result of induction of resistance mechanisms in the cotton host.

Southern Crops Research Laboratory, United States Department of Agriculture-Agriculture Research Service, 2765 F&B Road, College Station, Phytopathology, 24 November 2000.


Effect of Trichoderma virens on terpenoid concentrations in cotton roots inoculated with Rhizoctonia solani

HG = Hemigossypol, dHG = Desoxyhemigossypol,G = Gossypol

(Howel et al., 2000)

HPLC analyses of seedling radicle extracts for terpenoid content

120.0022.6239.79


Assay of the biocontrol efficacy of strains of T. virens, T. koningii and T. harzianum

1. T. virens strains : G-6, G-11, G6-5, G-4, and GTH-34

2. T. harzianum strain TH-23 ,GTK-53 and GTK-56

3. T. koningii strain TK-7, the T. virens mutant strain G6-4, and WB+PM

control

Significant reduction


Objective : To evaluate the potential of fungal bio control agent, Trichoderma harzianum to control the root-knot nematode Meloidogyne javanica.

Department of Nematology, Agricultural Research Organization (ARO), The Volcani Center, P.O.B. 6, Bet- Dagan 50250, Israel; The American Phytopathological Society, Vol. 91, No. 7, 2001.


Effect of Trichoderma harzianum on Meloidogyne javanica

Green house condition

Natural condition


Evaluation of the activity of Trichoderma proteinase Prb1-transformed lines

Non treated control (C)Wild-type (WT)Prb1-transformed strainsP-1, P-2, P-5, and P-6


Objectives :

• To test Growth enhancement ( increased root production) in treated plants • The mechanisms of control of the seed and root pathogen Pythium ultimum

and the foliar pathogen Colletotrichum graminicola in maize

Departments of Horticultural Sciences and Plant Pathology, Cornell University, Geneva, NY 14456, The American Phytopathological Society, Vol. 94, No. 2.

05/02/2023 36

Interactions Between Trichoderma harzianum Strain T22 and Maize Inbred Line Mo17

Seedlings of maize line Mo17 (10 days old) grown with or without a seed treatment with T22

( Harman et al., 2004)

Dept. of Plant Pathology


Plant height and stalk diameter are greater in the presence of T22.

Eight week old plants of maize line Mo17

Cont’d…,


Effect of T22 on Pythium ultimum

(Harman et al., 2004)

5 day old Maize inbred line Mo17 in 2 separate experiment


Effect of T22 on C. graminicola

More diseased and chlorotic

leaf area control

Seed treated with T22

(Harman et al., 2004)


Advantages

• More sustainable method of crop production

• Reduce environmental pollution

• Increased biodiversity

• More target specific than chemicals

• Consequently, plants treated with beneficial fungi will be larger and

healthier and have better yields than plants without them.


Conclusion

isr in plants through fungal biocontrol agents

Education