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The saccharopine pathway in seed development and stress response of maize

Texto completo
Kiyota, Eduardo [1] ; Pena, Izabella Agostinho [1] ; Arruda, Paulo [1, 2]
Número total de Autores: 3
Afiliação do(s) autor(es):
[1] Univ Estadual Campinas, Ctr Biol Mol & Engn Genet, BR-13083875 Sao Paulo - Brazil
[2] Univ Estadual Campinas, Dept Genet & Evolucao, Inst Biol, BR-13083875 Sao Paulo - Brazil
Número total de Afiliações: 2
Tipo de documento: Artigo Científico
Fonte: PLANT CELL AND ENVIRONMENT; v. 38, n. 11, p. 2450-2461, NOV 2015.
Citações Web of Science: 10

Lysine is catabolized in developing plant tissues through the saccharopine pathway. In this pathway, lysine is converted into -aminoadipic semialdehyde (AASA) by the bifunctional enzyme lysine-ketoglutarate reductase/saccharopine dehydrogenase (LKR/SDH). AASA is then converted into aminoadipic acid (AAA) by aminoadipic semialdehyde dehydrogenase (AASADH). Here, we show that LKR/SDH and AASADH are co-expressed in the sub-aleurone cell layers of the developing endosperm; however, although AASADH protein is produced in reproductive and vegetative tissues, the LKR/SDH protein is detectable only in the developing endosperm. AASADH showed an optimum pH of 7.4 and Kms for AASA and NAD(+) in the micromolar range. In the developing endosperm, the saccharopine pathway is induced by exogenous lysine and repressed by salt stress, whereas proline and pipecolic acid synthesis are significantly repressed by lysine. In young coleoptiles, the LKR/SDH and AASADH transcriptions are induced by abiotic stress, but while the AASADH protein accumulates in the stressed tissues, the LKR/SDH protein is not produced. In the developing seeds, the saccharopine pathway is used for pipecolic acid synthesis although proline may play a major role in abiotic stress response. The results indicate that the saccharopine pathway in maize seed development and stress responses significantly differ from that observed for dicot plants. Although ear emergence strongly alters C/N partitioning in wheat, phenology driven modifications in leaf in proteomic profile, metabolite content and nutrition of wheat exposed to elevated {[}CO2] remain to be elucidated. Our study revealed that, compared with vegetative stage, growth at elevated CO2 altered photosynthate export and tended to accelerate leaf N remobilization during grain filling period. Protein derived N remobilization modulated leaf proteins and amino acids profile. Finally our study highlighted the fact that under elevated {[}CO2] nitrogen use efficiency improvement might represent a target goal for breeding programmes. (AU)

Processo FAPESP: 10/50114-4 - O papel da via da sacaropina em diversos modelos biológicos
Beneficiário:Paulo Arruda
Linha de fomento: Auxílio à Pesquisa - Regular
Processo FAPESP: 12/00235-5 - Mecanismos de indução da via da sacaropina em células humanas
Beneficiário:Izabella Agostinho Pena
Linha de fomento: Bolsas no Brasil - Doutorado Direto