Formation of 8-hydroxylinalool in tea plant

Area of Science:

• Plant biochemistry
• Food chemistry
• Aroma compound analysis

Background:

• Linalool and its derivatives are crucial for tea aroma.
• Identifying specific aroma compounds and their biosynthesis is vital for tea quality.

Purpose of the Study:

• To identify major linalool-derived aroma compounds in Camellia sinensis var. assamica 'Hainan dayezhong'.
• To elucidate the biosynthesis pathway of 8-hydroxylinalool in tea plants.
• To understand the role of 8-hydroxylinalool in black tea aroma formation.

Main Methods:

• Gas chromatography-mass spectrometry (GC-MS) for compound identification.
• Gene expression analysis (quantitative PCR).
• Subcellular localization studies (endoplasmic reticulum).

Main Results:

• 8-Hydroxylinalool, particularly the (E)-isomer, was identified as a major linalool derivative in tea.
• Two enzymes, CsCYP76B1 and CsCYP76T1, were identified as key catalysts for 8-hydroxylinalool synthesis.
• 8-Hydroxylinalool content increased significantly during black tea manufacturing (withering).
• Jasmonate treatment induced the expression of CsCYP76B1 and CsCYP76T1.

Conclusions:

• The study reveals the biosynthesis of 8-hydroxylinalool in tea plants.
• 8-Hydroxylinalool accumulation is influenced by enzymatic activity, precursor availability, and processing conditions.
• This research provides a deeper understanding of aroma development in black tea.