Cell-Cell Communication in Reproduction Flashcards
What happens in fertilisation?
Pollen tube moves down carpel into ovules, into embryo sacs.
In the ovule, the pollen tube bursts and there is synergid cell degeneration.
What do synergid cells do?
Nourish the ovum and give direction in the pollen tube.
What helps orient pollen tube growth on the stigma?
Protein concentration gradient of plantacyanin and chemocyanin.
What can overexpression of plantacyanin cause?
Disruption of pollen tube growth
What is anisotropic growth?
When growth rates are not equal in all directions
How do pollen tubes grow?
Anisotropically through the ECM of the transmitting tract.
Adhesin is required
What does pollen tube growth rely on?
Maintenance of cell wall integrity
What is the signals of pollen tube growth?
Peptide signals ->
Extensins and kinase receptors ->
Ca2+ oscillations and ROS ->
Maintenance of cell wall integrity
What genes are lost to affect peptide signals in pollen tube growth and what happens?
Loss of RALF4/9
Pollen tubes germinate and collapse
What genes are lost to affect extensins in pollen tube growth?
Loss of LRXs
Loss of burst pollen grains/tubes
What genes are lost to affect kinase receptors in pollen tube growth?
Loss of BUPS1/2 and ANX1/2
No fertilisation, doesn’t reach ovule
What are the signals of pollen tube attraction to the ovule?
Peptide signal ->
Receptor kinases ->
Ca2+ oscillations and ROS ->
Direction of pollen tube growth
What do HERK1 anj mutations result in?
Pollen tube overgrowth
What type of effect do HERK/anj mutations have?
Maternal reproductive
Only affect if it is a HERK/ANJ ovule
What do HERK1 and ANJ accumulate to form?
Filiform apparatus
