In:
Plant Physiology, Oxford University Press (OUP), Vol. 131, No. 3 ( 2003-03-01), p. 998-1008
Abstract:
We report the isolation and characterization of a newMedicago truncatula hyper-nodulation mutant, designatedsunn (super numeric nodules). Similar to the previously described ethylene-insensitive mutant sickle,sunn exhibits a 10-fold increase in the number of nodules within the primary nodulation zone. Despite this general similarity, these two mutants are readily distinguished based on anatomical, genetic, physiological, and molecular criteria. In contrast to sickle, where insensitivity to ethylene is thought to be causal to the hyper-nodulation phenotype (R.V. Penmetsa, D.R. Cook [1997] Science 275: 527–530), nodulation in sunn is normally sensitive to ethylene. Nevertheless, sunnexhibits seedling root growth that is insensitive to ethylene, although other aspects of the ethylene triple response are normal; these observations suggest that hormonal responses might condition thesunn phenotype in a manner distinct fromsickle. The two mutants also differ in the anatomy of the nodulation zone: Successful infection and nodule development insunn occur predominantly opposite xylem poles, similar to wild type. In sickle, however, both infection and nodulation occur randomly throughout the circumference of the developing root. Genetic analysis indicates that sunnand sickle correspond to separate and unlinked loci, whereas the sunn/skl double mutant exhibits a novel and additive super-nodulation phenotype. Taken together, these results suggest a working hypothesis wherein sunn andsickle define distinct genetic pathways, withskl regulating the number and distribution of successful infection events, and sunn regulating nodule organogenesis.
Type of Medium:
Online Resource
ISSN:
1532-2548
,
0032-0889
Language:
English
Publisher:
Oxford University Press (OUP)
Publication Date:
2003
detail.hit.zdb_id:
2004346-6
detail.hit.zdb_id:
208914-2
SSG:
12
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