mRNA Expression and Bioinformatics Analysis of Cysteine Synthase in Allium sativum

doi:10.13560/j.cnki.biotech.bull.1985.2016.08.015

Abstract

Abstract: The cysteine synthesized by cysteine synthase is an important source of amino acids containing sulfur in plants. The amino acid with sulfur in garlic is abundant,thus we studied the properties and biological functions of garlic cysteine synthase in order to clarify its role in the metabolism of garlic. Three cysteine synthase genes of garlic,AsGCS2,AsGCS3 and AsGCS4were found from NCBI database,and then bioinformatics analysis and RT-PCR were conducted. The lengths of their open reading frames were 1 152 bp,1 296 bp,and 1 236 bp,respectively. The theoretical relative molecular weights of their encoded enzymes were 40.6 kD,34.1 kD,and 36.1 kD,respectively. By subcellular localization,AsGCS2 was localized in the chloroplasts,while AsGCS3 and AsGCS4 were localized in the cytoplasm. The results of the amino acid sequence alignment revealed that the similarity of AsGCS2 with AsGCS3 was 70%,and that with AsGCS4 was 59%,while it was 68% between AsGCS3 and AsGCS4. Phylogenetic analysis showed that AsGCS2 belonged to Bsas2,AsGCS3 belonged to Bsas1,but AsGCS4 was different from all known cysteine synthases,possibly belonging to Bsas6. RT-PCR expression analysis indicated that the expression levels of CSase varied in various tissues. The expression level of AsGCS2 was the highest in the leaves,the highest expression of AsGCS3 was in the root,and AsGCS4 expressed highly in both leaves and roots. In conclusion,3 cysteine synthase gene AsGCS2,AsGCS3,and AsGCS4 belong to the different subfamilies of Bsas,their tissue expression characteristics were not the same,and they play a role in different tissues of garlic in cysteine biosynthesis.

Key words: Allium sativum, cysteine synthase, qRT-PCR

GUO Tian-lu, ZHANG Huan-huan, DU Jian-zhong, HAO Yao-shan, WANG Yi-xue, SUN Yi. mRNA Expression and Bioinformatics Analysis of Cysteine Synthase in Allium sativum[J]. Biotechnology Bulletin, 2016, 32(8): 96-102.

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