Host-parasite interactions of barley yellow dwarf virus and oats: Physiological and immunological studies

The symptoms of barley yellow dwarf, chlorosis, stunting, and reduced heading or sterility in cereals, are readily confused with mineral deficiency or other cultural stresses. The pathogen, barley yellow dwarf virus (BYDV) is restricted in its host to phloem tissue, and phloem blockage leads to the accumulation of photosynthate in the foliage. Diagnosis of the disease usually entails virus detection with strain-specific antibodies. Fourteen virus-specific monoclonal cell lines secreting antibodies (MAbs) directed to barley yellow dwarf virus (BYDV) strain MAV-NY were identified from two murine spleen fusions. All the monoclonals recognize native MAV, not pH-denatured virus. Three MAbs cross-react with strain PAV. High affinity antibodies of subclasses IgG1 and IgG2a were purified from ascitic fluids, and seven MAbs were biotinylated. The polyclonal antiserum resulting from four injections of purified MAV detects stress-related oat antigens. Two greenhouse experiments were conducted to study the induction of stress antigens. Several treatments were applied to uninoculated and MAV inoculated oats. Symptoms of BYDV, chlorosis, stunting, reduced root growth and tillering, were produced in uninoculated plants. Sucrose treatment caused aggravated symptoms and increased optical density in polyclonal ELISA of uninoculated plants. Cross absorption of enzyme conjugated polyclonal antibody using sap of senescing uninoculated oats reduced optical density to about one-half the amount with young plant sap for cross absorption. Significant cultivar interactions suggest that induction of stress antigens may be a major difference between susceptible and tolerant sister oat lines. The earliest cause of phloem blockage during BYD disease development may be layering of virus-membrane complexes along the interior plasma membrane surface. Virus movement appears to be restricted to passage through plasmodesmata in sieve cells that lack an endoplasmic reticulum (ER) lining. With a series of flotation gradients and antibody competition experiments, purified BYDV was shown to associate with isolated ER of oat roots in a specific manner. The existence of an ER docking site may help to explain the extreme severity of symptoms caused by the presence of BYDV in cereals at an extremely low concentration.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Plant Biology

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2011

Author dc:creator

• Lamboy, Jana Shaffer

Contributors dc:contributor

• Shaw, Paul D.

• Agriculture, Plant Pathology

Statement dc:rights

• Copyright 1992 Lamboy, Jana Shaffer

Language dc:language

eng

Identifier

AAI9215843
(UMI)AAI9215843

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/22836