{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/49781"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/49781","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Effect of nitrogen form and genetic variations of the Asparagine-cycling pathway on maize ear growth","abstract":"The positive growth response of maize ears to nitrate supplementation declines during late vegetative development, whereas ammonia addition continues to promote ear growth through the reproductive phase. The underlying genetic and physiological mechanisms for this phenomenon are currently unknown. Previous studies with DuPont Pioneer found that in the maize line Gaspé Flint, ear growth no longer responded to additional nitrate 20 days after emergence, but a subsequent addition of ammonia significantly increased ear dry weight as well as the transport amino acids asparagine and glutamine. This nitrogen-induction experiment was duplicated, and root, shoot, and ear tissues were profiled via RNA-Seq to characterize responses to ammonia or nitrate at four or eight hours after nitrogen treatment. Results suggest an upregulation of amino acid assimilation and metabolism genes in ammonia-treated plants. Illinois High Protein (IHP) differs from other genotypes in exhibiting an increased rate of nitrogen uptake, vigorous ear growth under low N conditions, very high levels of asparagine, but a reduced response to ammonia. These observations suggest that the mechanism for ammonia-induced ear growth in some genotypes may already be active in IHP even without ammonia supplementation. Compared to many other maize genotypes, IHP has functional variants of the two asparagine-cycling genes, Asparagine synthetase (AS) and Asparaginase (ASNase). We examined the effect of these two genes on ear growth using a range of populations that contain variants of these genes. Greater AS expression was associated with improved ear growth, whereas very low ASNase activity was associated with decreased developing ear size.","abstract_html":"The positive growth response of maize ears to nitrate supplementation declines during late vegetative development, whereas ammonia addition continues to promote ear growth through the reproductive phase. The underlying genetic and physiological mechanisms for this phenomenon are currently unknown. Previous studies with DuPont Pioneer found that in the maize line Gaspé Flint, ear growth no longer responded to additional nitrate 20 days after emergence, but a subsequent addition of ammonia significantly increased ear dry weight as well as the transport amino acids asparagine and glutamine. This nitrogen-induction experiment was duplicated, and root, shoot, and ear tissues were profiled via RNA-Seq to characterize responses to ammonia or nitrate at four or eight hours after nitrogen treatment. Results suggest an upregulation of amino acid assimilation and metabolism genes in ammonia-treated plants. Illinois High Protein (IHP) differs from other genotypes in exhibiting an increased rate of nitrogen uptake, vigorous ear growth under low N conditions, very high levels of asparagine, but a reduced response to ammonia. These observations suggest that the mechanism for ammonia-induced ear growth in some genotypes may already be active in IHP even without ammonia supplementation. Compared to many other maize genotypes, IHP has functional variants of the two asparagine-cycling genes, Asparagine synthetase (AS) and Asparaginase (ASNase). We examined the effect of these two genes on ear growth using a range of populations that contain variants of these genes. Greater AS expression was associated with improved ear growth, whereas very low ASNase activity was associated with decreased developing ear size.","abstract_has_math":false,"creators":["Postin, Cody"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"M.S.","degree_level":"Thesis","degree_discipline":"Crop Sciences","degree_department":null,"school":null,"contributors":["Moose, Stephen P."],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2014,"date_issued":"2014-05-30T17:17:22Z","date_published":"2014-05-30T17:17:22Z","updated_at":"2026-07-22T22:25:40Z","subjects":["RNA-Seq","ammonium","nitrate","asparagine synthetase","asparaginase","amino acid","corn"],"languages":["en"],"rights":["Copyright 2014 Cody Postin"],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/2142/49781","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Moose, Stephen P."]},{"key":"dc:creator","label":"Author","values":["Postin, Cody"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2014-05-30T17:17:22Z","2016-09-22T20:59:22Z","2014-05"]},{"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":["Thesis"]},{"key":"thesis:degree_name","label":"Degree Name","values":["M.S."]},{"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":["RNA-Seq","ammonium","nitrate","asparagine synthetase","asparaginase","amino acid","corn"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 2014 Cody Postin"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://hdl.handle.net/2142/49781"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["The positive growth response of maize ears to nitrate supplementation declines during late vegetative development, whereas ammonia addition continues to promote ear growth through the reproductive phase. The underlying genetic and physiological mechanisms for this phenomenon are currently unknown. Previous studies with DuPont Pioneer found that in the maize line Gaspé Flint, ear growth no longer responded to additional nitrate 20 days after emergence, but a subsequent addition of ammonia significantly increased ear dry weight as well as the transport amino acids asparagine and glutamine. This nitrogen-induction experiment was duplicated, and root, shoot, and ear tissues were profiled via RNA-Seq to characterize responses to ammonia or nitrate at four or eight hours after nitrogen treatment. Results suggest an upregulation of amino acid assimilation and metabolism genes in ammonia-treated plants. Illinois High Protein (IHP) differs from other genotypes in exhibiting an increased rate of nitrogen uptake, vigorous ear growth under low N conditions, very high levels of asparagine, but a reduced response to ammonia. These observations suggest that the mechanism for ammonia-induced ear growth in some genotypes may already be active in IHP even without ammonia supplementation. Compared to many other maize genotypes, IHP has functional variants of the two asparagine-cycling genes, Asparagine synthetase (AS) and Asparaginase (ASNase). We examined the effect of these two genes on ear growth using a range of populations that contain variants of these genes. Greater AS expression was associated with improved ear growth, whereas very low ASNase activity was associated with decreased developing ear size.","Item withdrawn by Mark Zulauf (zulauf@illinois.edu) on 2014-04-30T20:54:09Z Item was in collections: University of Illinois Theses & Dissertations (ID: 1) No. of bitstreams: 6 Cody Postin Thesis.docx: 2686001 bytes, checksum: f440ab84d17d4dbe55d333836f91b741 (MD5) Supplemental File 4 (Grain NIR).xlsx: 75780 bytes, checksum: dcbaecfa074c05564f4098cd4a0f2fdb (MD5) Supplemental File 3 (Grain & Cob).xlsx: 84019 bytes, checksum: 5b10bae10d2a036b70b59257f8f8b15a (MD5) Supplemental File 2 (Earshoot Amino Acids).xlsx: 104199 bytes, checksum: a989b962b09f5dcff4e220011b7d2c8d (MD5) Supplemental File 1 (Earshoot Size).xlsx: 100938 bytes, checksum: 9f261a57d56ff80438777f295d6db937 (MD5) Postin_Cody.pdf: 1879151 bytes, checksum: ad1ec590fdebcf29aaf4b75c688ea2ed (MD5)","Made available in DSpace on 2014-05-30T17:17:22Z (GMT). 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The underlying genetic and physiological mechanisms for this phenomenon are currently unknown. Previous studies with DuPont Pioneer found that in the maize line Gaspé Flint, ear growth no longer responded to additional nitrate 20 days after emergence, but a subsequent addition of ammonia significantly increased ear dry weight as well as the transport amino acids asparagine and glutamine. This nitrogen-induction experiment was duplicated, and root, shoot, and ear tissues were profiled via RNA-Seq to characterize responses to ammonia or nitrate at four or eight hours after nitrogen treatment. Results suggest an upregulation of amino acid assimilation and metabolism genes in ammonia-treated plants. Illinois High Protein (IHP) differs from other genotypes in exhibiting an increased rate of nitrogen uptake, vigorous ear growth under low N conditions, very high levels of asparagine, but a reduced response to ammonia. These observations suggest that the mechanism for ammonia-induced ear growth in some genotypes may already be active in IHP even without ammonia supplementation. Compared to many other maize genotypes, IHP has functional variants of the two asparagine-cycling genes, Asparagine synthetase (AS) and Asparaginase (ASNase). We examined the effect of these two genes on ear growth using a range of populations that contain variants of these genes. Greater AS expression was associated with improved ear growth, whereas very low ASNase activity was associated with decreased developing ear size.","Item withdrawn by Mark Zulauf (zulauf@illinois.edu) on 2014-04-30T20:54:09Z Item was in collections: University of Illinois Theses & Dissertations (ID: 1) No. of bitstreams: 6 Cody Postin Thesis.docx: 2686001 bytes, checksum: f440ab84d17d4dbe55d333836f91b741 (MD5) Supplemental File 4 (Grain NIR).xlsx: 75780 bytes, checksum: dcbaecfa074c05564f4098cd4a0f2fdb (MD5) Supplemental File 3 (Grain & Cob).xlsx: 84019 bytes, checksum: 5b10bae10d2a036b70b59257f8f8b15a (MD5) Supplemental File 2 (Earshoot Amino Acids).xlsx: 104199 bytes, checksum: a989b962b09f5dcff4e220011b7d2c8d (MD5) Supplemental File 1 (Earshoot Size).xlsx: 100938 bytes, checksum: 9f261a57d56ff80438777f295d6db937 (MD5) Postin_Cody.pdf: 1879151 bytes, checksum: ad1ec590fdebcf29aaf4b75c688ea2ed (MD5)","Made available in DSpace on 2014-05-30T17:17:22Z (GMT). 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