Practice question
Question
Auxin-induced gene promoting root identity:
Explanation
PLETHORA family AP2-domain transcription factors PLT1, PLT2, PLT3, PLT5, PLT7 are directly transcriptionally induced by auxin maxima at root pole through ARF5, ARF7, ARF10, ARF16 after auxin-triggered degradation of AUX/IAA repressors via TIR1/AFB pathway. PLT proteins accumulate in graded manner highest near quiescent center promoting stemness, intermediate sustaining mitotic activity, low permitting differentiation and elongation. PLTs activate WOX5, PIN genes, and cell cycle regulators while repressing shoot determinants. Auxin-PLT-PIN positive feedback stabilizes auxin maximum defining stem cell niche patterning and regeneration.