Week 13 L2: Plant Development - KNOX and ARP genes Flashcards
What are KNOX1 genes?
encode TF that important for identity of organs. help maintain the meristem in an indeterminate growth.
necessary for SAM formation in arabidopsis
Where are the KNO1 genes expressed?
meristem
Where are KNOX1 genes not expressed?!
peripheral zone to form primary organs
What happens when KNOX1 gene is expressed in maize?
meristem markers are excluded from lateral primordia
What is an example of KNOX1 gene ?
STM1
How does a plant differ in mutant STM gene?
plant will be shootmeristemmless thus have an absence of true leaf formation
What is STM?
shootmeristemless mutant
What do KNOX1 genes stimulate?
cytokinin synthesis
What are cytokinins?
any of a number of plant hormones that influence growth and the stimulation of cell division.
Regulate shoot meristem size, leaf primordia number, and leaf and shoot growth.
Keeps meristem in that interderminate state
What does cytokinin biosythetic gene encode?
IPT - isopentenyl transferase
What is the role of IPT?
It is a biosynthetic enzyme.
In a mutant STM1, plant cannot express leaves or little leave formation as they are not dividing much. To counteract this, IPT can induce CK syntheisis.
Where is IPT gene expressed?
Is expressed at the STM promoter at the SAM and rescues mutant.
What is STM?
A TF that induces expression of an IPT gene and thus leaf formation.
What is the effect of overexpression of KNOX genes in the meristem?
increase intermitancy and complexity in lateral organs.
What does the leaf look like in maize with KNOX-OE?
makes knots + extra growth