Dataset Information

Genetic control of abscisic acid biosynthesis in maize.

ABSTRACT: Abscisic acid (ABA), an apocarotenoid synthesized from cleavage of carotenoids, regulates seed maturation and stress responses in plants. The viviparous seed mutants of maize identify genes involved in synthesis and perception of ABA. Two alleles of a new mutant, viviparous14 (vp14), were identified by transposon mutagenesis. Mutant embryos had normal sensitivity to ABA, and detached leaves of mutant seedlings showed markedly higher rates of water loss than those of wild type. The ABA content of developing mutant embryos was 70% lower than that of wild type, indicating a defect in ABA biosynthesis. vp14 embryos were not deficient in epoxy-carotenoids, and extracts of vp14 embryos efficiently converted the carotenoid cleavage product, xanthoxin, to ABA, suggesting a lesion in the cleavage reaction. vp14 was cloned by transposon tagging. The VP14 protein sequence is similar to bacterial lignostilbene dioxygenases (LSD). LSD catalyzes a double-bond cleavage reaction that is closely analogous to the carotenoid cleavage reaction of ABA biosynthesis. Southern blots indicated a family of four to six related genes in maize. The Vp14 mRNA is expressed in embryos and roots and is strongly induced in leaves by water stress. A family of Vp14-related genes evidently controls the first committed step of ABA biosynthesis. These genes are likely to play a key role in the developmental and environmental control of ABA synthesis in plants.

SUBMITTER: Tan BC

PROVIDER: S-EPMC23760 | biostudies-literature | 1997 Oct

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Genetic control of abscisic acid biosynthesis in maize.

Tan B C BC Schwartz S H SH Zeevaart J A JA McCarty D R DR

Proceedings of the National Academy of Sciences of the United States of America 19971001 22

Abscisic acid (ABA), an apocarotenoid synthesized from cleavage of carotenoids, regulates seed maturation and stress responses in plants. The viviparous seed mutants of maize identify genes involved in synthesis and perception of ABA. Two alleles of a new mutant, viviparous14 (vp14), were identified by transposon mutagenesis. Mutant embryos had normal sensitivity to ABA, and detached leaves of mutant seedlings showed markedly higher rates of water loss than those of wild type. The ABA content of ...[more]

PMID: 9342392

Similar Datasets

Project description:BACKGROUND: Kernel moisture at harvest is an important trait since a low value is required to prevent unexpected early germination and ensure seed preservation. It is also well known that early germination occurs in viviparous mutants, which are impaired in abscisic acid (ABA) biosynthesis. To provide some insight into the genetic determinism of kernel desiccation in maize, quantitative trait loci (QTLs) were detected for traits related to kernel moisture and ABA content in both embryo and endosperm during kernel desiccation. In parallel, the expression and mapping of genes involved in kernel desiccation and ABA biosynthesis, were examined to detect candidate genes. RESULTS: The use of an intermated recombinant inbred line population allowed for precise QTL mapping. For 29 traits examined in an unreplicated time course trial of days after pollination, a total of 78 QTLs were detected, 43 being related to kernel desiccation, 15 to kernel weight and 20 to ABA content. Multi QTL models explained 35 to 50% of the phenotypic variation for traits related to water status, indicating a large genetic control amenable to breeding. Ten of the 20 loci controlling ABA content colocated with previously detected QTLs controlling water status and ABA content in water stressed leaves. Mapping of candidate genes associated with kernel desiccation and ABA biosynthesis revealed several colocations between genes with putative functions and QTLs. Parallel investigation via RT-PCR experiments showed that the expression patterns of the ABA-responsive Rab17 and Rab28 genes as well as the late embryogenesis abundant Emb5 and aquaporin genes were related to desiccation rate and parental allele effect. Database searches led to the identification and mapping of two zeaxanthin epoxidase (ZEP) and five novel 9-cis-epoxycarotenoid dioxygenase (NCED) related genes, both gene families being involved in ABA biosynthesis. The expression of these genes appeared independent in the embryo and endosperm and not correlated with ABA content in either tissue. CONCLUSIONS: A high resolution QTL map for kernel desiccation and ABA content in embryo and endosperm showed several precise colocations between desiccation and ABA traits. Five new members of the maize NCED gene family and another maize ZEP gene were identified and mapped. Among all the identified candidates, aquaporins and members of the Responsive to ABA gene family appeared better candidates than NCEDs and ZEPs.

Dataset Information

Genetic control of abscisic acid biosynthesis in maize.

Publications

Genetic control of abscisic acid biosynthesis in maize.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets