Seminar Molekulare Mechanismen der Signaltransduktion Molekulare Mechanismen der Signaltransduktion 15 04 08 MQ 15.04.08 – MQ 1. Estelle and Somerville, (1987) Auxin resistant mutants of Arabidopsis thaliana with an altered morphology. MGG 206:200 2. Lincoln et al., (1990) Growth and development of the axr1 mutants of Arabidopsis. PC 2:1071 3. Leyser et al., (1993) Arabidopsis auxin‐resistance gene AXR1 encodes a protein related to ubiquitin‐activating enzyme E1. N 364:161
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Molekulare Mechanismen der Signaltransduktion · Seminar Molekulare Mechanismen der Signaltransduktion 15 04 0815.04.08 – MQ 1. Estelle and Somerville, (1987) Auxin resistant mutants
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SeminarMolekulare Mechanismen der SignaltransduktionMolekulare Mechanismen der Signaltransduktion
15 04 08 MQ15.04.08 – MQ1. Estelle and Somerville, (1987) Auxin resistant mutants of Arabidopsis
thaliana with an altered morphology. MGG 206:200 2. Lincoln et al., (1990) Growth and development of the axr1 mutants of
Arabidopsis. PC 2:10713. Leyser et al., (1993) Arabidopsis auxin‐resistance gene AXR1 encodes a
protein related to ubiquitin‐activating enzyme E1. N 364:161
Auxin - history and pioneering experimentsy p g p“When seedlings are freely exposed to a lateral light some influence is transmitted from influence is transmitted from the upper part of the coleoptile that acts on the lower part of the coleoptile”“The Power of Movement in The Power of Movement in Plants” (1880) by Darwin and Darwin.
Went (1920s-30s) Total darkness
Tip of coleoptileexcised
Replaced with agarblock containing IAA
Restored curvature
• auxein (greek) = to grow
IAA
indole-3-acetic acid
• first phytohormone to be identified
Auxin regulates plant development
Indole‐3‐acetic acid
E b i tt i
Growth & Apical dominance
Embryonic patterning
Growth & Apical dominance
Root developmentp
Tropic growth responses
wild‐type bdl axr1mutant
Auxin regulates plant development
Indole‐3‐acetic acid
E b i tt i
Growth & Apical dominance
Embryonic patterning
Growth & Apical dominance
Root developmentp
Tropic growth responses
wild‐type axr6‐3mutant
Auxin regulates plant development
Indole‐3‐acetic acid
E b i tt icycB1::GUS
Growth & Apical dominance
Embryonic patterning
Growth & Apical dominance
Root developmentp
Tropic growth responses
‐ auxin + auxin
Auxin regulates plant development
Indole‐3‐acetic acid
E b i tt i
Growth & Apical dominance
Embryonic patterning
Growth & Apical dominance
Root developmentp
Tropic growth responses
wild‐type aux1mutant
Arabidopsis thalianap
Arabidopsis thalianaSmall size (30 cm)
Rapid life cycle (6 weeks)Rapid life cycle (6 weeks)
SEM morphologische Defekte durch unterschiedliche Zellgrößen oder Gewebeorganisation?g g
WT
axr1‐12axr1 12
keine wesentlichen strukturellen Defektevaskuläre Strukturen etwas weniger differenziertvaskuläre Strukturen etwas weniger differenziertZellgrößen in etwa gleich
Auxin Response in der Wurzel:
90°
1. Gravitropismus
Graviresponse in den Mutanten 90
langsamer
nicht durch reduziertes Wurzel‐nicht durch reduziertes Wurzelwachstum!
WT
1 3/ 12axr1‐3/‐12
axr1‐3/‐12WT
Auxin Response in der Wurzel:
2. Wurzelelongation auf Auxin
klassischer Auxin Response Defekt
‐ auxin5d WTWT
auxin + auxin
axr1‐3axr1‐12
‐ auxin+ 3d
= 0 %
+ auxin+ 3d
= x %
Quantifizierung des Wurzelassays:
Genetische Kartierung von AXR1:RFLP – Restriktionsfragment‐Längenpolymorphismus
AXR1 ‐ Chromosome Walking
YAC
Cosmids
WT axr1 3 axr1 3WT axr1‐3 axr1‐3 [pOCA18‐H] Cosmid pOCA18‐H enthält das AXR1 Gen