Looking Beyond Just the Hairs

1
Looking Beyond Just the Hairs

• Discovery Laboratory Lecture
• April 10, 2008

2
Apyrase Function Would Be Expected to Influence
Root Growth As Well As Root Hair Growth

• Apyrases are expressed strongly in roots
• Apyrase knockouts alter root growth and structure
• so do apyrase inhibitors affect root growth? (So
  far, inhibitors only tested on pollen tubes and
  root hairs)

3
Expression of Apyrase Transcripts in Roots

• In situ localization PromoterGUS

4
Rotation experiments show that apy1 and apy2
mutants show different gravity responses

• Graviresponse of apy2 is significantly depressed
• Graviresponse of apy1 is less than than of WT,
  but not statistically significant.

5
Different eATP on top and bottom of curving root

• Difference measured with endogenously expressed
  luciferase.
• This result means that growing roots do
  accumulate eATP in growth zone.
• This result predicts that washing before applying
  extracellular nucleotides should provide more
  consistent starting point for dose-response
  curves.

6
Root gravitropism suppressed in atapy2 knock-out
mutants
statistically different
from wild-type control (p lt 0.001)
7
Take home lessons

• How do your roots (not just root hairs) respond
  to your treatments?
• Whatever experiment you are doing, look beyond
  the immediate results you are primarily
  interested in.