Disease resistant plant

Disease resistant plants

1. Production of Disease and Stress Resistant Plants III B.SC., BIOTECHNOLOGY COURSE TEACHER Dr. M. PAVUNRAJ

2. PLANT DISEASES AND RESISTANCE The relationship between a plant and a pest1 is very complex. The ability of a pest to cause disease in a plant depends on environmental conditions, the properties of the organism itself and the capacity of the plant to defend itself. Varieties within a plant species can differ in their ability to defend themselves. Under different climatic conditions the interaction between the same plant and pest may have different outcomes. Pathogens are known to develop and form new biotypes – pathotypes , races or strains that can cause damage to plants, which remain unaffected by the original form of the pathogen. Resistance is the ability of a plant variety to restrict the growth and development of a specified pathogen or the damage they cause when compared to susceptible plant varieties under similar environmental conditions and pathogen pressure. Resistant varieties may exhibit some disease symptoms or damage under heavy pathogen pressure.

3. Rank Virus Author of virus description 1 Tobacco mosaic virus  (TMV) Karen‐Beth G. Scholthof 2 Tomato spotted wilt virus  (TSWV) Scott Adkins 3 Tomato yellow leaf curl virus  (TYLCV) Henryk Czosnek 4 Cucumber mosaic virus  (CMV) Peter Palukaitis 5 Potato virus Y  (PVY) Emmanuel Jacquot 6 Cauliflower mosaic virus  (CaMV) Thomas Hohn and Barbara Hohn 7 African cassava mosaic virus  (ACMV) Keith Saunders 8 Plum pox virus  (PPV) Thierry Candresse 9 Brome mosaic virus  (BMV) Paul Ahlquist 10 Potato virus X  (PVX) Cynthia Hemenway

4. Tobacco mosaic virus  (TMV). (A) Systemic infection of  Nicotiana tabacum  cv. Turk plants showing TMV‐associated mosaic. (B) Necrotic local lesions on  N.  tabacum  cv. Glurk leaf, demonstrating Holmes'  N ‐gene resistance following inoculation with TMV.