Location
University of Utah
Start Date
6-19-1998 10:00 AM
Description
In spaceflight conditions, plants are subjected to a variety of environmental stresses which may promote microbial growth and potential pathogenicity. Among the changes that may occur in the plant is a decrease in freely available carbohydrates, resulting in the microbe having to look for alternative carbon sources. A seed-borne fungal endophyte, an Acremonium species, was identified as the symptom-causing agent in Super Dwarf seedlings grown in a spaceflight mission in 1995. Plants bearing the endophyte grew without symptoms in the greenhouse in open conditions. The isolated Acremonium grew well on different carbohydrates available in wheat leaf apoplastic fluids as well as isolated wheat leaf cell walls and a common component of plant walls, pectin. Invertase, an enzyme that degrades sucrose, a major carbon molecule transported in plants, was detected in Acremonium grown in sucrose medium. The requirement of sucrose for invertase induction by sucrose and growth of Acremonium on isolated wheat leaf cell walls suggest that the fungus may turn to degradation of the plant cell wall when the plant becomes stressed. A voidance of plant stress during spaceflight may help the plants defend themselves against pathogens.
Plant Growth Conditions In Spaceflight and Pathogenicity of Microbes
University of Utah
In spaceflight conditions, plants are subjected to a variety of environmental stresses which may promote microbial growth and potential pathogenicity. Among the changes that may occur in the plant is a decrease in freely available carbohydrates, resulting in the microbe having to look for alternative carbon sources. A seed-borne fungal endophyte, an Acremonium species, was identified as the symptom-causing agent in Super Dwarf seedlings grown in a spaceflight mission in 1995. Plants bearing the endophyte grew without symptoms in the greenhouse in open conditions. The isolated Acremonium grew well on different carbohydrates available in wheat leaf apoplastic fluids as well as isolated wheat leaf cell walls and a common component of plant walls, pectin. Invertase, an enzyme that degrades sucrose, a major carbon molecule transported in plants, was detected in Acremonium grown in sucrose medium. The requirement of sucrose for invertase induction by sucrose and growth of Acremonium on isolated wheat leaf cell walls suggest that the fungus may turn to degradation of the plant cell wall when the plant becomes stressed. A voidance of plant stress during spaceflight may help the plants defend themselves against pathogens.