RESUMO
Tea (Camellia sinensis L.) is a thermophilic evergreen woody plant that has poor cold tolerance. The SAD gene plays a key role in regulating fatty acid synthesis and membrane lipid fluidity in response to temperature change. In this study, full-length SAD cDNA was cloned from tea leaves using rapid amplification of cDNA ends and polymerase chain reaction (PCR)-based methods. Sequence analysis demonstrated that CsSAD had a high similarity to other corresponding cDNAs. At 25°C, the CsSAD transcriptional level was highest in the leaf and lowest in the stem, but there was no obvious difference between the root and stem organs. CsSAD expression was investigated by reverse transcription-PCR, which showed that CsSAD was upregulated at 4° and -5°C. At 25°C, CsSAD was induced by polyethylene glycol, abscisic acid, and wounding, and a similar trend was observed at 4°C, but the mean expression level at 4°C was lower than that at 25°C. Under natural cold acclimation, the 'CsCr05' variety's CsSAD expression level increased before decreasing. The CsSAD expression level in variety 'CsCr06' showed no obvious change at first, but rapidly increased to a maximum when the temperature was very low. Our study demonstrates that CsSAD is upregulated in response to different abiotic conditions, and that it is important to study the stress resistance of the tea plant, particularly in response to low temperature, drought, and wounding.
Assuntos
Adaptação Fisiológica , Camellia sinensis/enzimologia , Regulação da Expressão Gênica de Plantas , Proteínas de Plantas/genética , Estearoil-CoA Dessaturase/genética , Sequência de Aminoácidos , Camellia sinensis/genética , Camellia sinensis/fisiologia , Clonagem Molecular , Temperatura Baixa , Secas , Dados de Sequência Molecular , Filogenia , Componentes Aéreos da Planta/enzimologia , Componentes Aéreos da Planta/fisiologia , Proteínas de Plantas/química , Proteínas de Plantas/metabolismo , Raízes de Plantas/enzimologia , Raízes de Plantas/fisiologia , Alinhamento de Sequência , Estearoil-CoA Dessaturase/química , Estearoil-CoA Dessaturase/metabolismoRESUMO
The spermidine synthase (SPDS) gene exists widely in all types of plants. In this paper, the codon usage of the SPDS gene from Camellia sinensis (CsSPDS) was analyzed. The results showed that the codon usage of the CsSPDS gene is biased towards the T-ended or A-ended codons, which is similar to that observed in 73 genes selected from the C. sinensis genome. An ENC-plot for 15 SPDS genes from various plant species suggested that mutational bias was the major factor in shaping codon usage in these genes. Codon usage frequency analysis indicated that there was little difference between the CsSPDS gene and dicot genomes, such as Arabidopsis thaliana and Nicotiana tabacum, but significant differences in codon usage were observed between the CsSPDS gene and monocot genomes, such as Triticum aestivum and Zea mays. Therefore, A. thaliana and N. tabacum expression systems may be more suitable for the expression of the CsSPDS gene.