University Of Tasmania

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The Pea Gene NA Encodes ent-Kaurenoic Acid Oxidase

journal contribution
posted on 2023-05-16, 14:33 authored by Davidson, SE, Elliott, RC, Helliwell, CA, Poole, AT, James ReidJames Reid
The gibberellin (GA)-deficient dwarf na mutant in pea (Pisum sativum) has severely reduced internode elongation, reduced root growth, and decreased leaflet size. However, the seeds develop normally. Two genes, PsKAO1 and PsKAO2, encoding cytochrome P450 monooxygenases of the subfamily CYP88A were isolated. Both PsKAO1 and PsKAO2 had ent-kaurenoic acid oxidase (KAO) activity, catalyzing the three steps of the GA biosynthetic pathway from ent-kaurenoic acid to GA 12 when expressed in yeast (Saccharomyces cerevisiae). In addition to the intermediates ent-7α-hydroxykaurenoic acid and GA 12-aldehyde, some additional products of the pea KAO activity were detected, including ent-6α,7α-dihydroxykaurenoic acid and 7β-hydroxykaurenolide. The NA gene encodes PsKAO1, because in two independent mutant alleles, na-1 and na-2, PsKAO1 had altered sequences and the five-base deletion in PsKAO1 associated with the na-1 allele cosegregated with the dwarf na phenotype. PsKAO1 was expressed in the stem, apical bud, leaf, pod, and root, organs in which GA levels have previously been shown to be reduced in na plants. PsKAO2 was expressed only in seeds and this may explain the normal seed development and normal GA biosynthesis in seeds of na plants.


Publication title

Plant Physiology








School of Natural Sciences


American Society of Plant Biologists

Place of publication

United States

Repository Status

  • Restricted

Socio-economic Objectives

Grain legumes

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