Lecture 21 Flashcards
Name two disease causing microbes
•Viruses
•Bacteria
How do bacteria gain food
Via photosynthesis for example cyanobacteria.
What are scavengers
Share the environment around them. For example some bacterial endophytes gain nutrients from the leaf apoplast (space between cells).
What are pathogens in terms of bacteria gaining food
Gain nutrients by infect other living organisms. Plant pathogenic bacteria (heterotrophic).
What is Binary fission
A process where one cells divides to form two identical cells it is an example of Asexual reproduction
Name the stages of bacterial growth
•Lag
•Log
•Stationary
•Death
The market value for cut flowers and fresh foliage is around how much annually.
€16 billion
Name a serious disease on cherry laurel
Shot Hole
Symptoms of Shot Hole disease
Spots or lesions on the leaf, expanding in size as the population of the bacteria grows.
Kochs Postulate
• The pathogen must be present in every case of the disease.
• The pathogen must be isolated from the host with the disease and grown in pure culture.
• The specific disease must be reproduced when a pure culture of the pathogen is inoculated into a healthy susceptible host.
Name the shot hole disease levels
(A) Rotundifolia’. (B) ‘Novita’. (C) ‘Etna’. (D) ‘Caucasica’.
Definition of a virus
Sub microscopic entity consisting of a single nucleic acid (RNA/DNA) surrounded by a protein coat.
Viruses are only capable of replication when they are
within the living cells of plants, animals or bacteria.
What is the smallest organism
Viruses
Are viruses mobile or immobile
Immobile
How can viruses be transmitted
Via animal or insect vectors
Symptoms of Potato virus Y
•The disease induces symptoms including crinkling,necrosis(death
of tissues) and ultimately leaf drop.
• Stunted growth of plants .
• Lower leaves have black necrotic veins
•Size,number and quality of tubers are reduced
How is Potato virus Y mainly spread
By Aphids
Of the 12,845 samples, ____ samples (19%) tested positive for at least one of the five viruses screened for.
Potato Virus Y (PVY)
Potato Virus X (PVX) Potato Virus A (PVA) Potato Virus S (PVS)
Potato Leafroll Virus (PLRV)
2,265 samples (19%)
Are bacteria prokaryotic or eukaryotic
Prokaryotic
Do bacteria reproduce asexually or sexually
Asexually via binary fission
