LH stimulates cholesterol desmolase in the theca cells

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#Unit 6. System Physiology – Plant

TLS Online TPP Program

#Id: 7143

#Unit 6. System Physiology – Plant

TLS Online TPP Program

#Id: 7144

#Unit 6. System Physiology – Plant

TLS Online TPP Program

#Id: 7145

#Unit 6. System Physiology – Plant

Brassinolide binding to the brassinosteroid receptor kinase

BRASSINOSTEROID-INSENSITIVE1 (BRI1) on the plasma membrane triggers a phosphorylation cascade that causes a repressor protein, BRASSINOSTEROID-INSENSITIVE2

(BIN2), to become inactivated. This results in activation of the transcription factors BRI1-EMS SUPPRESSOR1 (BES1) and BRASSINAZOLE-RESISTANT1 (BZR1) and subsequent gene expression

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#Unit 6. System Physiology – Plant

In the presence of brassinolide, the activated phosphatase BSU1 dephosphorylates BIN2 and promotes its degradation by the 26S proteasome system, thus blocking its activity. BES1 and BZR1 are then dephosphorylated by PROTEIN PHOSPHATASE2A (PP2A), and the active forms of BES1 and BZR1 move into the nucleus where they regulate the expression of brassinolide response genes

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#Unit 6. System Physiology – Plant

There are three pathways for the synthesis of JAs, including the octadecane pathway starting from α-linolenic acid (18:3) and the hexadecane pathway starting from hexadecatrienoic acid (16:3). 

All three pathways require three reaction sites: the chloroplast, peroxisome, and cytoplasm.