Tocopherols are one of the most important antioxidants with roles in living
organisms. The functions of tocopherols have been characterized in animals
and artificial membranes. However, the genetic and molecular functions of
tocopherols in plants are less understood. The team of Yunhui Zhang from
Jiangsu Academy of Agricultural Sciences aims to study a
tocopherol-deficient mutant rice, rtd1.

The rtd1 mutant showed overall growth retardation throughout its growth
period. Most of the agronomic traits were also impaired in rtd1. Analysis
revealed that the RTD1 gene encoded homogentisate phytyltransferase, an
enzyme catalyzing a key step in tocopherol biosynthesis. RTD1 was also found
to be expressed in green leafy tissues, and the protein was located in
chloroplasts. Cold tolerance was also found to be reduced in the rtd1
mutant.

The rtd1 mutant also exhibited a reduced response to gibberellin (GA).
However, the GA content was not changed, suggesting a transcriptional
regulation of SLR1.

These findings implied that tocopherols play important roles in regulating
rice growth and development.

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