GEPHE SUMMARY Print
Entry Status
Published
GepheID
GP00000482
Main curator
Martin
PHENOTYPIC CHANGE
Trait Category
Trait State in Taxon A
Zea mays - resistant
Trait State in Taxon B
Zea mays - Pr and K61 - sensitive
Ancestral State
Taxon A
Taxonomic Status
Taxon A
Latin Name
Common Name
-
Synonyms
Zea mays var. japonica; maize; Zea mays L.; Zea mays mays
Rank
species
Lineage
Show more ... phyta; Euphyllophyta; Spermatophyta; Magnoliophyta; Mesangiospermae; Liliopsida; Petrosaviidae; commelinids; Poales; Poaceae; PACMAD clade; Panicoideae; Andropogonodae; Andropogoneae; Tripsacinae; Zea
NCBI Taxonomy ID
is Taxon A an Infraspecies?
No
Taxon B
Latin Name
Common Name
-
Synonyms
Zea mays var. japonica; maize; Zea mays L.; Zea mays mays
Rank
species
Lineage
Show more ... phyta; Euphyllophyta; Spermatophyta; Magnoliophyta; Mesangiospermae; Liliopsida; Petrosaviidae; commelinids; Poales; Poaceae; PACMAD clade; Panicoideae; Andropogonodae; Andropogoneae; Tripsacinae; Zea
NCBI Taxonomy ID
is Taxon B an Infraspecies?
Yes
Taxon B Description
Zea mays - Pr and K61 - sensitive
GENOTYPIC CHANGE
Generic Gene Name
hm2
Synonyms
-
String
-
Sequence Similarities
-
GO - Biological Process
-
GO - Cellular Component
-
UniProtKB
Zea mays subsp. parviglumis
GenebankID or UniProtKB
Presumptive Null
Yes
Molecular Type
Aberration Type
Deletion Size
unknown
Molecular Details of the Mutation
deletion from exon 2 (nucleotide 420) to beyond the confines of the hm2 gene into an unknown genomic region.
Experimental Evidence
Authors
Chintamanani S; Multani DS; Ruess H; Johal GS
Abstract
The maize Hm2 gene provides protection against the leaf spot and ear mold disease caused by Cochliobolus carbonum race 1 (CCR1). In this regard, it is similar to Hm1, the better-known disease resistance gene of the maize-CCR1 pathosystem. However, in contrast to Hm1, which provides completely dominant resistance at all stages of plant development, Hm2-conferred resistance is only partially dominant and becomes fully effective only at maturity. To investigate why Hm2 behaves in this manner, we cloned it on the basis of its homology to Hm1. As expected, Hm2 is a duplicate of Hm1, although the protein it encodes is grossly truncated compared with HM1. The efficacy of Hm2 in conferring resistance improves gradually over time, changing from having little or no impact in seedling tissues to providing complete immunity at anthesis. The developmentally specified phenotype of Hm2 is not dictated transcriptionally, because the expression level of the gene, whether occurring constitutively or undergoing substantial and transient induction in response to infection, does not change with plant age. In contrast, however, the Hm2 transcript is much more abundant in plants homozygous for this gene compared with plants that contain only one copy of the gene, suggesting a transcriptional basis for the dosage-dependent nature of Hm2. Thus, different mechanisms seem to underlie the developmentally programmed versus the partially dominant resistance phenotype of Hm2.
Additional References
COMMENTS
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