Term

Description

About

Phytopathogenic fungi are fungi that cause plant diseases, leading to economic losses in agriculture and horticulture.

These fungi infect various parts of plants, including roots, stems, leaves, flowers, and fruit.

Fungi Types

Most phytopathogenic fungi belong to Ascomycetes and Basidiomycetes.

Strategies of Infection

These fungi use various strategies to infect plants, such as producing enzymes that destroy polymers in plant cell walls.

Some are necrotrophs (kill and feed on dead material), while others are biotrophs (colonize living tissue).

Leaf Disease

A collective term for fungal and bacterial infections causing lesions or spots on the leaves of plants. The spots can vary in size, color, and shape and can seriously affect plant health.

Cause of Leaf Disease

Primarily caused by pathogenic fungi, though some are caused by bacteria.

These pathogens often proliferate on the leaf surface, leading to the development of visible stains or lesions.

Category

Description

Definition

Eukaryotic organisms, including moulds, yeasts, and mushrooms; may be unicellular (yeasts) or multicellular (moulds like Rhizopus, Mucor, Penicillium).

Study Field

Mycology

Cellular Structure

Cell Wall: Contains Glucans, Chitin.

Plasma Membrane: Contains ergosterol.

Organelles: Similar to other eukaryotes (mitochondria, ribosomes, nuclei).

Morphology

Hyphae: Tubular structures of uninterrupted cells.

Stolons: Specialized hyphae for horizontal growth.

Mycelium: Vegetative part consisting of hyphae.

Septa: Cross-walls with pores for communication.

Nutrition

Heterotrophs: Can be saprophytic, parasitic, or predatory.

Symbiosis: Examples include lichens (fungi + algae) and mycorrhiza (fungi + plant roots).

Reproduction

Asexual: Fragmentation, budding, spores (e.g., Rhizopus, Saccharomyces). Sexual: Occurs under unfavorable conditions, introduces genetic diversity (e.g., Ascospores, Basidiospores).

Classification

1. Yeasts: Unicellular, e.g., Saccharomyces, Cryptococcus neoformans (pathogenic).

2. Yeast-like Fungi: E.g., Candida albicans (causes candidiasis).

3. Filamentous Fungi (Moulds): E.g., Mucor, Penicillium, Aspergillus.

4. Dimorphic Fungi: Switch between yeast and mould forms, e.g., Histoplasma capsulatum, Blastomyces dermatitidis.

Key Examples

Yeasts: Saccharomyces, Cryptococcus Filamentous: Penicillium, Rhizopus Dimorphic: Histoplasma, Blastomyces

PRACTICE QUESTION

Q.Which of the following statements regarding Epicoccum indicum is/are correct?

1. Epicoccum indicum is a new species of phytopathogenic fungi identified through morpho-cultural characteristics and molecular phylogenetic analysis.
2. It is associated with the development of lesions on the leaves of Chrysopogon zizanioides (Vetiver).
3. Phytopathogenic fungi like Epicoccum indicum are primarily responsible for causing leaf diseases in plants.

Select the correct answer from the options given below:

(A) 1 and 2 only

(B) 1 and 3 only

(C) 2 and 3 only

(D) 1, 2 and 3

Answer: A

Explanation:

Statement 1 is correct: Epicoccum indicum is a new species of phytopathogenic fungi identified through morpho-cultural characteristics and molecular phylogenetic analysis.

Statement 2 is correct: The species Epicoccum indicum is associated with the development of shoes on a cloud in Chrysopogon zizanioides (Vetiver).

Statement 3 is incorrect: While phytopathogenic fungi can cause leaf diseases, Epicoccum indicum is specifically associated with the Chrysopogon zizanioides plant, not primarily responsible for leaf diseases in general.