The MdWRKY50-MdHD14 Module Regulates Fruit Senescence by Affecting γ-Aminobutyric Acid Synthesis.

Area of Science:

• Plant Biology
• Molecular Biology
• Biochemistry

Background:

• Fruit senescence significantly impacts apple quality and postharvest storage.
• γ-Aminobutyric acid (GABA) is known to accumulate under stress conditions.

Purpose of the Study:

• To elucidate the molecular mechanism by which GABA accumulation delays apple fruit senescence.
• To identify key transcription factors involved in regulating GABA synthesis and senescence.

Main Methods:

• Investigated the role of the HD-ZIP transcription factor MdHD14 in regulating GABA synthesis.
• Utilized gene overexpression and silencing techniques for MdGAD2, MdGAD4, MdHD14, and MdWRKY50.
• Assessed GABA content, reactive oxygen species levels, and antioxidant enzyme activity.

Main Results:

• MdHD14 induces GABA accumulation by upregulating MdGAD2 and MdGAD4, enhancing antioxidant activity and delaying senescence.
• MdGAD2 and MdGAD4 are crucial for GABA synthesis and senescence delay in apple fruit.
• MdWRKY50 regulates MdHD14 expression, collectively controlling GABA homeostasis and senescence.

Conclusions:

• A molecular pathway involving MdWRKY50, MdHD14, and MdGAD2/4 regulates GABA homeostasis and delays apple fruit senescence.
• This study clarifies the mechanisms underlying senescence resistance in apples.
• Findings provide targets for improving postharvest storage and quality of apples.