RESUMEN
Seed oil is a momentous agronomical trait of soybean (Glycine max) targeted by domestication in breeding. Although multiple oil-related genes have been uncovered, knowledge of the regulatory mechanism of seed oil biosynthesis is currently limited. We demonstrate that the seed-preferred gene GmZF351, encoding a tandem CCCH zinc finger protein, is selected during domestication. Further analysis shows that GmZF351 facilitates oil accumulation by directly activating WRINKLED1, BIOTIN CARBOXYL CARRIER PROTEIN2, 3-KETOACYL-ACYL CARRIER PROTEIN SYNTHASE III, DIACYLGLYCEROL O-ACYLTRANSFERASE1, and OLEOSIN2 in transgenic Arabidopsis (Arabidopsis thaliana) seeds. Overexpression of GmZF351 in transgenic soybean also activates lipid biosynthesis genes, thereby accelerating seed oil accumulation. The ZF351 haplotype from the cultivated soybean group and the wild soybean (Glycine soja) subgroup III correlates well with high gene expression level, seed oil contents and promoter activity, suggesting that selection of GmZF351 expression leads to increased seed oil content in cultivated soybean. Our study provides novel insights into the regulatory mechanism for seed oil accumulation, and the manipulation of GmZF351 may have great potential in the improvement of oil production in soybean and other related crops.
Asunto(s)
Glycine max/metabolismo , Aceites de Plantas/metabolismo , Proteínas de Plantas/metabolismo , Semillas/metabolismo , Dedos de Zinc , Secuencia de Aminoácidos , Arabidopsis/genética , Arabidopsis/metabolismo , Domesticación , Ácidos Grasos/metabolismo , Regulación de la Expresión Génica de las Plantas , Metabolismo de los Lípidos/genética , Lípidos/biosíntesis , Filogenia , Proteínas de Plantas/clasificación , Proteínas de Plantas/genética , Plantas Modificadas Genéticamente , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Semillas/genética , Homología de Secuencia de Aminoácido , Glycine max/genética , Glycine max/fisiología , Triglicéridos/metabolismoRESUMEN
Soybean is one of most important oil crops and a significant increase in lipid content in soybean seeds would facilitate vegetable oil production in the world. Although the pathways for lipid biosynthesis in higher plants have been uncovered, our understanding of regulatory mechanism controlling lipid accumulation is still limited. In this study, we identified 87 transcription factor genes with a higher abundance at the stage of lipid accumulation in soybean seeds. One of these genes, GmbZIP123, was selected to further study its function in regulation of lipid accumulation. Overexpression of GmbZIP123 enhanced lipid content in the seeds of transgenic Arabidopsis thaliana plants. The GmbZIP123 transgene promoted expression of two sucrose transporter genes (SUC1 and SUC5) and three cell-wall invertase genes (cwINV1, cwINV3, and cwINV6) by binding directly to the promoters of these genes. Consistently, the cell-wall invertase activity and sugar translocation were all enhanced in siliques of GmbZIP123 transgenic plants. Higher levels of glucose, fructose, and sucrose were also found in seeds of GmbZIP123 transgenic plants. These results suggest that GmbZIP123 may participate in regulation of lipid accumulation in soybean seeds by controlling sugar transport into seeds from photoautotrophic tissues. This study provides novel insights into the regulatory mechanism for lipid accumulation in seeds and may facilitate improvements in oil production in soybean and other oil crops through genetic manipulation of the GmbZIP123 gene.
Asunto(s)
Arabidopsis/genética , Genes de Plantas/genética , Glycine max/genética , Metabolismo de los Lípidos/genética , Proteínas de Plantas/genética , Semillas/genética , Metabolismo de los Hidratos de Carbono/genética , Regulación de la Expresión Génica de las Plantas , Estudios de Asociación Genética , Lípidos/biosíntesis , Aceites de Plantas/metabolismo , Proteínas de Plantas/metabolismo , Plantas Modificadas Genéticamente , Regiones Promotoras Genéticas/genética , Unión Proteica/genética , Multimerización de Proteína , Transporte de Proteínas , Fracciones Subcelulares/metabolismo , Factores de Transcripción/metabolismo , Activación Transcripcional/genéticaRESUMEN
MYB proteins play important roles in eukaryotic organisms. In plants, the R1R2R3-type MYB proteins function in cell cycle control. However, whether the R2R3-type MYB protein is also involved in the cell division process remains unknown. Here, we report that an R2R3-type transcription factor gene, AtMYB59, is involved in the regulation of cell cycle progression and root growth. The AtMYB59 protein is localized in the nuclei of onion epidermal cells and has transactivation activity. Expression of AtMYB59 in yeast cells suppresses cell proliferation, and the transformants have more nuclei and higher aneuploid DNA content with longer cells. Mutation in the conserved domain of AtMYB59 abolishes its effects on yeast cell growth. In synchronized Arabidopsis cell suspensions, the AtMYB59 gene is specifically expressed in the S phase during cell cycle progression. Expression and promoter-GUS analysis reveals that the AtMYB59 gene is abundantly expressed in roots. Transgenic plants overexpressing AtMYB59 have shorter roots compared with wild-type plants (Arabidopsis accession Col-0), and around half of the mitotic cells in root tips are at metaphase. Conversely, the null mutant myb59-1 has longer roots and fewer mitotic cells at metaphase than Col, suggesting that AtMYB59 may inhibit root growth by extending the metaphase of mitotic cells. AtMYB59 regulates many downstream genes, including the CYCB1;1 gene, probably through binding to MYB-responsive elements. These results support a role for AtMYB59 in cell cycle regulation and plant root growth.