Reference "PDX1 is essential for vitamin B6 biosynthesis, development and stress tolerance in Arabidopsis"

Reference ID

54972

Title

PDX1 is essential for vitamin B6 biosynthesis, development and stress tolerance in Arabidopsis

Source

Plant J, 2006, vol. 48, pp. 933-946

Authors (7)

Titiz-O	Tambasco-Studart-M
Warzych-E	Apel-K
Amrhein-N	Laloi-C
Fitzpatrick-T-B

Abstract

Vitamin B6 is an essential coenzyme for numerous metabolic enzymes and is a
potent antioxidant. In plants, very little is known about its contribution to
viability, growth and development. The de novo pathway of vitamin B6
biosynthesis has only been described recently and involves the protein PDX1
(pyridoxal phosphate synthase protein). Arabidopsis thaliana has three homologs
of PDX1, two of which, PDX1.1 and PDX1.3, have been demonstrated as functional
in vitamin B6 biosynthesis in vitro and by yeast complementation. In this study,
we show that the spatial and temporal expression patterns of PDX1.1 and PDX1.3,
investigated at the transcript and protein level, largely overlap, but PDX1.3 is
more abundant than PDX1.1. Development of single pdx1.1 and pdx1.3 mutants is
partially affected, whereas disruption of both genes causes embryo lethality at
the globular stage. Detailed examination of the single mutants, in addition to
those that only have a single functional copy of either gene, indicates that
although these genes are partially redundant in vitamin B6 synthesis, PDX1.3 is
more requisite than PDX1.1. Developmental distinctions correlate with the
vitamin B6 content. Furthermore, we provide evidence that in addition to being
essential for plant growth and development, vitamin B6 also plays a role in
stress tolerance and photoprotection of plants.