{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/21846"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/21846","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Molecular and biochemical characterization of thevp12 mutant of maize (Zea mays L.)","abstract":"The mutant vp12 is a single locus mutation that conditions lemon endosperm, viviparous embryos and white seedlings. Previous genetic analysis demonstrated that vp12 is not allelic to other viviparous mutants of maize. In this work, the objectives are to characterize vp12 at both molecular and biochemical levels. First, levels of the hormone ABA were measured at several stages during embryo development and also in isolated organs, under drought stress. In mutant embryos, ABA levels were lower than in normal ones, at all stages analyzed. Under drought stress, mutant organs from both 3-day and 9-day old seedlings accumulated less ABA than corresponding normal organs. However, the hormone levels in some stressed mutant organs, such as roots and leaves, are higher than in non-stressed organs. These results suggest that the ability of ABA synthesis is not completely blocked in vp12. Expression of several ABA-responsive genes, such as Em, glb1, glb2 and rab17, was detected in RNA extracts from mutant immature embryos, despite the lower ABA levels observed in those. In addition, transcripts corresponding to vp1, a transcriptional activator for embryo ABA-mediated responses, were also observed in mutant embryos. Therefore, it can be suggested that the ABA signal transduction pathway is not impaired in vp12 embryos.","abstract_html":"The mutant vp12 is a single locus mutation that conditions lemon endosperm, viviparous embryos and white seedlings. Previous genetic analysis demonstrated that vp12 is not allelic to other viviparous mutants of maize. In this work, the objectives are to characterize vp12 at both molecular and biochemical levels. First, levels of the hormone ABA were measured at several stages during embryo development and also in isolated organs, under drought stress. In mutant embryos, ABA levels were lower than in normal ones, at all stages analyzed. Under drought stress, mutant organs from both 3-day and 9-day old seedlings accumulated less ABA than corresponding normal organs. However, the hormone levels in some stressed mutant organs, such as roots and leaves, are higher than in non-stressed organs. These results suggest that the ability of ABA synthesis is not completely blocked in vp12. Expression of several ABA-responsive genes, such as Em, glb1, glb2 and rab17, was detected in RNA extracts from mutant immature embryos, despite the lower ABA levels observed in those. In addition, transcripts corresponding to vp1, a transcriptional activator for embryo ABA-mediated responses, were also observed in mutant embryos. Therefore, it can be suggested that the ABA signal transduction pathway is not impaired in vp12 embryos.","abstract_has_math":false,"creators":["Maluf, Mirian Perez"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Crop Sciences","degree_department":null,"school":null,"contributors":["Sachs, Martin M."],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2011,"date_issued":"2011-05-07T13:20:56Z","date_published":"2011-05-07T13:20:56Z","updated_at":"2026-07-22T22:25:18Z","subjects":["Biology, Molecular","Biology, Genetics","Biology, Plant Physiology"],"languages":["eng"],"rights":["Copyright 1996 Maluf, Mirian Perez"],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["AAI9625162","(UMI)AAI9625162"],"render_values":[{"text":"AAI9625162","href":null,"code":true},{"text":"(UMI)AAI9625162","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/2142/21846","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Sachs, Martin M."]},{"key":"dc:creator","label":"Author","values":["Maluf, Mirian Perez"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2011-05-07T13:20:56Z","10000-01-01","1996"]},{"key":"dc:type","label":"Dc Type","values":["text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Crop Sciences"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph.D."]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Illinois at Urbana-Champaign"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Biology, Molecular","Biology, Genetics","Biology, Plant Physiology"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["eng"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 1996 Maluf, Mirian Perez"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["AAI9625162","(UMI)AAI9625162","http://hdl.handle.net/2142/21846"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["The mutant vp12 is a single locus mutation that conditions lemon endosperm, viviparous embryos and white seedlings. Previous genetic analysis demonstrated that vp12 is not allelic to other viviparous mutants of maize. In this work, the objectives are to characterize vp12 at both molecular and biochemical levels. First, levels of the hormone ABA were measured at several stages during embryo development and also in isolated organs, under drought stress. In mutant embryos, ABA levels were lower than in normal ones, at all stages analyzed. Under drought stress, mutant organs from both 3-day and 9-day old seedlings accumulated less ABA than corresponding normal organs. However, the hormone levels in some stressed mutant organs, such as roots and leaves, are higher than in non-stressed organs. These results suggest that the ability of ABA synthesis is not completely blocked in vp12. Expression of several ABA-responsive genes, such as Em, glb1, glb2 and rab17, was detected in RNA extracts from mutant immature embryos, despite the lower ABA levels observed in those. In addition, transcripts corresponding to vp1, a transcriptional activator for embryo ABA-mediated responses, were also observed in mutant embryos. Therefore, it can be suggested that the ABA signal transduction pathway is not impaired in vp12 embryos.","At the carotenoid level, analysis of carotenoid extracts from normal and lemon endosperms showed that no colored precursors are accumulated in vp12 endosperms. Also, HPLC analysis indicated that phytoene, the first non-colored carotenoid precursor, is not present in mutant endosperms. In order to verify the presence of enzymes from the carotenoid biosynthetic pathway, their expression was analyzed in vp12 endosperms. Phytoene synthase accumulation was detected using a corresponding maize polyclonal antibody. Transcripts corresponding to two other enzymes, phytoene desaturase (PDS) and geranylgeranyl pyrophosphate synthase (GGPPS), were detected by RT-PCR. PDS transcripts levels were similar in both normal and vp12 immature endosperm RNA. However, GGPPS transcripts accumulated at lower levels in mutant immature endosperms than normal ones. These results, combined with the profile of carotenoid accumulation, suggest that the block in the carotenoid pathway in vp12 occurs in the GGPP synthesis.","Made available in DSpace on 2011-05-07T13:20:56Z (GMT). No. of bitstreams: 2 license.txt: 4922 bytes, checksum: 910b249b4beec47e7ab768910c8f966f (MD5) 9625162.pdf: 4811745 bytes, checksum: 0de25a1a0a8d1a427de5387f6cd5181b (MD5) Previous issue date: 1996","Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Howard Ding (hding2@illinois.edu) on 2011-05-07T14:53:36Z Item is restricted indefinitely.","Restriction data tranferred 2014-07-01T11:24:48-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: ETDs are only available to UIUC Users without author permission","ETDs are only available to UIUC Users without author permission","U of I Only"]},{"key":"dc:title","label":"Title","values":["Molecular and biochemical characterization of thevp12 mutant of maize (Zea mays L.)"]}]}],"canonical_facts":{"dc:contributor":["Sachs, Martin M."],"dc:creator":["Maluf, Mirian Perez"],"dc:date":["2011-05-07T13:20:56Z","10000-01-01","1996"],"dc:description":["The mutant vp12 is a single locus mutation that conditions lemon endosperm, viviparous embryos and white seedlings. Previous genetic analysis demonstrated that vp12 is not allelic to other viviparous mutants of maize. In this work, the objectives are to characterize vp12 at both molecular and biochemical levels. First, levels of the hormone ABA were measured at several stages during embryo development and also in isolated organs, under drought stress. In mutant embryos, ABA levels were lower than in normal ones, at all stages analyzed. Under drought stress, mutant organs from both 3-day and 9-day old seedlings accumulated less ABA than corresponding normal organs. However, the hormone levels in some stressed mutant organs, such as roots and leaves, are higher than in non-stressed organs. These results suggest that the ability of ABA synthesis is not completely blocked in vp12. Expression of several ABA-responsive genes, such as Em, glb1, glb2 and rab17, was detected in RNA extracts from mutant immature embryos, despite the lower ABA levels observed in those. In addition, transcripts corresponding to vp1, a transcriptional activator for embryo ABA-mediated responses, were also observed in mutant embryos. Therefore, it can be suggested that the ABA signal transduction pathway is not impaired in vp12 embryos.","At the carotenoid level, analysis of carotenoid extracts from normal and lemon endosperms showed that no colored precursors are accumulated in vp12 endosperms. Also, HPLC analysis indicated that phytoene, the first non-colored carotenoid precursor, is not present in mutant endosperms. In order to verify the presence of enzymes from the carotenoid biosynthetic pathway, their expression was analyzed in vp12 endosperms. Phytoene synthase accumulation was detected using a corresponding maize polyclonal antibody. Transcripts corresponding to two other enzymes, phytoene desaturase (PDS) and geranylgeranyl pyrophosphate synthase (GGPPS), were detected by RT-PCR. PDS transcripts levels were similar in both normal and vp12 immature endosperm RNA. However, GGPPS transcripts accumulated at lower levels in mutant immature endosperms than normal ones. These results, combined with the profile of carotenoid accumulation, suggest that the block in the carotenoid pathway in vp12 occurs in the GGPP synthesis.","Made available in DSpace on 2011-05-07T13:20:56Z (GMT). No. of bitstreams: 2 license.txt: 4922 bytes, checksum: 910b249b4beec47e7ab768910c8f966f (MD5) 9625162.pdf: 4811745 bytes, checksum: 0de25a1a0a8d1a427de5387f6cd5181b (MD5) Previous issue date: 1996","Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Howard Ding (hding2@illinois.edu) on 2011-05-07T14:53:36Z Item is restricted indefinitely.","Restriction data tranferred 2014-07-01T11:24:48-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: ETDs are only available to UIUC Users without author permission","ETDs are only available to UIUC Users without author permission","U of I Only"],"dc:identifier":["AAI9625162","(UMI)AAI9625162","http://hdl.handle.net/2142/21846"],"dc:language":["eng"],"dc:rights":["Copyright 1996 Maluf, Mirian Perez"],"dc:subject":["Biology, Molecular","Biology, Genetics","Biology, Plant Physiology"],"dc:title":["Molecular and biochemical characterization of thevp12 mutant of maize (Zea mays L.)"],"dc:type":["text"],"thesis:degree_discipline":["Crop Sciences"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Ph.D."],"thesis:institution_name":["University of Illinois at Urbana-Champaign"]},"updated_at":"2026-07-22T22:25:18Z"}