SEMESTER – IV
DSC – 3D
APMB 243 PLANT PATHOLOGY (3 credits)
(Biological Science - II)
Unit - I
Concept of plant disease – definitions of disease, disease cycle and pathogenicity, symptoms associated with microbial plant diseases, types of plant pathogens, economic losses and social impact of plant diseases. Significant contributions by scientists in the field of plant pathology.
Unit- II
Infection, invasion, colonization, dissemination of pathogens and perennation. Concepts of monocyclic, polycyclic and polyetic diseases, disease triangle and disease pyramid, forecasting of plant diseases and its relevance in Indian context.
Unit - III
Virulence factors of pathogens: enzymes, toxins (host specific and nonspecific) growth regulators, virulence factors in viruses (replicase, coat protein, silencing suppressors) in disease development. Effects of pathogens on host physiological processes (photosynthesis, respiration, cell membrane permeability, translocation of water and nutrients, plant growth and reproduction).
Unit - IV
Concept of resistance (r) gene and avirulence (avr) gene; gene for gene hypothesis, types of plant resistance – Concepts of constitutive defense mechanisms in plants, inducible structural defenses – inducible biochemical defenses hypersensitive response (HR), systemic acquired resistance (SAR), phytoalexins, pathogenesis related (PR) proteins,plantibodies, phenolics, quinones, oxidative bursts.
Unit - V
Basic principles of the disease management – study of important plant diseases with emphasis on its etiological agent, symptoms, epidemiology, life cycle and management: fungal diseases – diseases of phytopathogenic bacteria – phytoplasmas – viruses and viroids.
Text Books
1. Ravichandra N.G. (2013) Fundamentals of Plant Pathology, PHI Learning Pvt Ltd.
2. Vidyasekharan P. (2010) Principles of Plant Pathology. CBS Publishers & Distributor’s.
Reference Books
1. Vidhyasekaran P. (2004) Concise Encyclopedia of Plant Pathology. CRC Press.
2. Sharma J.N., Karthikeyan G. and Sh. Mohinder Singh (2007) Fundamentals of Plant pathology. ICAR E-course.
3. Agrios G.N. (2005) Plant Pathology, 5th Edn. Elsevier Academic Press.