Silenciamento mediado por RNA interferente do gene sbe1 que codifica para a Enzima de Ramificação do Amido I (SBE I) em Milho (Zea mays L.)

AUTOR(ES)
DATA DE PUBLICAÇÃO

2008

RESUMO

Maize is a very important world-wide economic crop. The starch contained in its grains is highly used in human nutrition, animal feeding and fuel industry. Starch is composed of two types of structurally different glucose polymers: amylose, constituted by linear chain, hardwired for glucosidic linkage a-1,4; and amylopectin with glucosidic linkage a-1,4 and branchpoints a-1,6 ramified chains. The starch branching enzyme (SBE) catalyzes the formation of glucosidic linkage a-1,6, confering the amylopectin final structure. Three isoforms of the starch branching enzyme have been identified in maize: SBE I, SBE IIa and SBE IIb. The main objective of this work was to study the effect of starch branching enzyme I gene (sbe1) silencing and to monitor the possible alterations in the absence of the expression of the gene in the seeds. For inactivation of sbe1 gene a RNA interfering vector containing the selection marker bar gene was constructed. The vector was used to transform embryonic calli of maize via biobalistic method. Thirty maize transgenic lines (R0) were generated and characterized. The sbe1 silencing contributed to modify grains phenotype, resulting in wrinkled seeds in transgenic plants. The analysis of protein accumulation levels in different transgenic tissues demonstrated that SBE I was found in lower levels in transgenic endosperm when compared to the same tissue in non-transgenic plants, suggesting that target gene inactivation was carried out partial and efficiently in endosperm cells. In an analogous way seed glucose content was increased in most of transgenic maize lines.

ASSUNTO(S)

rna interferente silenciamento milho botanica

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