Development of a genetic system in Medicago truncatula : production and characterization of developmental and symbiotic mutants /
model legume for biological questions unique to, or well suited for study in legume series. An efficient mutagenesis protocol using ethyl methane sultanate (EMS) was developed for M. truncatula. Ecotype A20 was identified as a suitable mapping parent. Three developmental mutants, a male sterile-fema...
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| Format: | Thesis Book |
| Language: | English |
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[Place of publication not identified] :
[publisher not identified] ;
1998.
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| Subjects: | |
| Online Access: | http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=733039531&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD |
| Summary: | model legume for biological questions unique to, or well suited for study in legume series. An efficient mutagenesis protocol using ethyl methane sultanate (EMS) was developed for M. truncatula. Ecotype A20 was identified as a suitable mapping parent. Three developmental mutants, a male sterile-female fertile mutant, mtapetala, a shoot meridiem initiation mutant, palmyra, and, a spontaneous pigmentation mutant. speckle were identified and characterized. Screening for altered symbiotic mutants identified 57 mutants from which six non- allelic mutants affected At distinct early stages were characterized in detail. The dom! mutant is blocked in the initiation of both infection threads and nodule primordia. In the poodle mutant, infection numbers are simile to those in wild ty-; however, no nodule primordia develop. The lin mutant exhibits reduced infection number, but is not affected in nodule initiation. ne bonbon mutant displays premature nodule meridiem senescence. Two additional mutants, sun and sickle, exhibit distinctive super-nodulation phenotypes. The two super-nodulating mutants, sickle and sun, both exhibit a >10-fold increase in the number of nodules, but are readily distinguished by genetic, physiological and anatomical criteria. In addition to increased persistent infections, the sickle mutation confers insensitivity to the plant hormone ethylene for multiple aspects of plant development, indicating that ethylene is a component of the infection of legumes. In contrast, sun exhibits normal sensitivity to ethylene, although signaling pathway controlling rhizobial elongation of seedling roots is insensitive to exogenous auxin. Thus, these data support a model for nodule development wherein the plant hormone development wherein the plant hormone ethylene regulates rhizobial infection, and auxin regulates nodule organogenesis. In order to initiate cloning of these genes mapping populations for the five symbiotic mutants were established. In particular, M. truncatula homology of ethylene-response loci (ein3, ein2,and hls1) were identified with the goal Of testing cc-segregation with the sickle locus. Epistatic analyses of pair-wise combinations of these modulations mutants suggest a genetic model for modulation in M. truncatula. In an ongoing study, double mutant combinations of these five genes are being examined to establish a genetic model for modulation. |
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| Item Description: | Vita. "Major Subject: Genetics". |
| Physical Description: | xi, 107 leaves : illustrations ; 28 cm. Issued also on microfiche from University Microfilm Inc. |
| Bibliography: | Includes bibliographical references (leaves 95-105). |