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Unformatted text preview: Symbiosis between Xylella and sharpshooters Organism
Class of symbiosis A B
recent study show that
there is possibility that
xylella actually help
sharpshooter get its nutrient Mutualism + + Commensalism + 0 Parasitism + - Symbiosis between Xylella and sharpshooter?
Thursday, December 6, 12 Lecture 36 Outline
• Grapes and Their Problems
• How Pierce’s Disease Gets Around
• Phloem, Aphids and Their Symbionts
• Xylem, Sharpshooters and Their Symbionts 17
Thursday, December 6, 12 Xylem and Phloem Xylem sap: water
and minerals mostly
from roots to rest of
^nutrient poor Phloem sap:
as sugars to sites of
storage or use.
know a lot more about this and also there a
lot more organisms that feed on the phloem
instead of the xylem From Lodish et al. 2000
Thursday, December 6, 12 35.12 Aphids Live off Phloem Sap aphids is similar to the sharpshotter but feeds on the phloem aphids is a successful organism 19
Thursday, December 6, 12 Conundrum
• Phloem sap is filled with sugar(s) and a variety of other
• But low in most of the “essential” amino acids that
animals cannot synthesize
over evolutionary time, plants removed some of the things from phloem that animals need. [N-rich amino acid
also essential amino acids]
aphids is an obligate phloem feeder (don't eat anything else).
how do aphids (and other organisms) can survive from just eating plants that have low amount of essential A.A. 20
Thursday, December 6, 12 Aphids are very successful (> 4000 species, everywhere you look) 22
Thursday, December 6, 12 Plant response to sap feeders
• Possible solutions to low aa in phloem Eat other things Evolve metabolic pathways to synthesize missing
nutrients animals is not good at generating new metabolic pathway Find some poor sap to make the stuff for you
Thursday, December 6, 12 inside certain cells associated with their gut... there are microorganism in t...
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This document was uploaded on 04/13/2013.
- Fall '08