RESUMO
Axillary branching is controlled by a very complex mechanism involving various endogenous and environmental factors. Previous studies have shown that Tb1/BRC1 is the point of integration in the network of molecular mechanisms regulating axillary branching in plants. In this study, we cloned the Tb1/BRC1 ortholog, NtBRC1, from Nicotiana tabacum and functionally analyzed its role in the control of axillary branching in tobacco. Overexpression of NtBRC1 resulted in significant retardation of axillary branching, and downregulation of this gene resulted in significant acceleration of axillary branching after decapitation. This indicates a negative role for this gene in the regulation of axillary branching. In-line with previous reports, NtBRC1 was found to be expressed predominantly in axillary buds. Additionally, as expected, expression was decreased 8 h following decapitation, which further confirms its role in the suppression of axillary branching. Furthermore, the expression of NtBRC1 was significantly downregulated by cytokinin, but was not affected by GR24, a synthetic strigolactone. Based on the data collected in the present study, we demonstrate that NtBRC1 negatively regulates axillary branching in tobacco after decapitation and functions downstream of the cytokinin signaling pathway inside axillary buds.
Assuntos
Nicotiana/fisiologia , Proteínas de Plantas/genética , Fatores de Transcrição/genética , Clonagem Molecular , Citocininas/farmacologia , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Lactonas/farmacologia , Nicotiana/genéticaRESUMO
The oligosaccharide 3-deoxy-d-manno-oct-2-ulosonic acid (Kdo) is a key component of lipopolysaccharide in Gram-negative bacteria, and is also part of the pectic polysaccharide rhamnogalacturonan (RG-II) of the plant cell wall. The enzyme KDO-8-phosphate synthase (KDO8Ps), encoded by the 2-dehydro-3-deoxyphosphooctonate aldolase (KdsA) gene, catalyzes the first step in the synthesis of Kdo. In this study, the complete coding sequence of the KdsA gene from mulberry leaves was cloned and the primary structure of KDO8Ps was deduced. Alignment of the amino acid sequence of KDO8Ps from mulberry with those of five other plant species revealed a high level of evolutionary conservation. A phylogenetic tree analysis demonstrated a short genetic distance among KDO8Ps proteins of different species. Expression of the KdsA gene was higher in the second leaves than in the eighth leaves of mulberry, and was down-regulated under conditions of high salt or drought stress. Our results suggest that KdsA expression is important for the growth of new plant tissues, and is sensitive to harsh environments.
Assuntos
Aldeído Liases/metabolismo , Secas , Genes de Plantas , Morus/genética , Proteínas de Plantas/metabolismo , Salinidade , Estresse Fisiológico , Aldeído Liases/genética , Sequência de Aminoácidos , Regulação para Baixo , Dados de Sequência Molecular , Morus/metabolismo , Filogenia , Folhas de Planta/genética , Folhas de Planta/metabolismo , Proteínas de Plantas/genética , Tolerância ao Sal/genéticaRESUMO
Fatty acid synthase (FASN) is a key enzyme in fatty acid anabolism that plays an important role in the fat deposit of eukaryotic cells. Therefore, in this study, we detected 2 novel single-nucleotide polymorphisms (SNPs) in the FASN gene in 313 adult individuals of Datong yak using polymerase chain reaction-single strand conformation polymorphism and DNA sequencing techniques. SNP g.5477C>T is located in intron 3 of FASN, and 3 genotypes, HH, HG, and GG, were detected in this mutation site. SNP g.16930T>A is located in exon 37 of FASN, and 2 genotypes, EE and EF, were detected in this site. Association analysis of these 2 SNPs with meat quality traits showed that in SNP g.5477C>T, yaks with the HH genotype and HG genotype had significantly higher intramuscular fat content than individuals with the GG genotype (P < 0.01). In SNP g.16930T>A, yaks with the EE genotype also had significantly higher IMF content than individuals with the EF genotype (P < 0.01). The results indicate that FASN may be used as a candidate gene affecting intramuscular fat content in Datong yaks.