Ultrastructure of Leaf and Cloning, Expression of AbGLK1 in Ananas comosus var. bracteatus 'Chiyan'

Abstract:

In order to understand the function of Golden2-like (GLK) in green-white chimeric leaf formation of Ananas comosus var. bracteatus 'Chiyan', AbGLK1 gene was cloned by RT-PCR. The results showed that AbGLK1 contained an open reading frame with 1 371 bp, encoding a protein with 456 amino acids. AbGLK1 protein had a GOLDEN2 C-terminal box and a GAPR DNA-binding domain at the N terminal, belonged to GLK transcription factor family, which located in the nucleus. Transactivation analysis showed that AbGLK1 had transcriptional activation activity. And AbGLK1 was tissue-specific expressed in root, stem and leaf of 'Chiyan'. The expression of AbGLK1 in leaves was significantly higher than that in roots and stems (P < 0.05); which in albino tissues was about 1/3 in green tissues (P < 0.05). In albino tissue, there was no thylakoid in chloroplast, but large number of plastoglobulus and vesicles exist in chloroplast. Therefore, it is suggested that AbGLK1 might be involved in chloroplast development, and down expression of AbGLK1 might lead to immature chloroplast in albino tissue.

Key words:Ananas comosus var. bracteatus 'Chiyan';Chloroplast;Ultrastructure;AbGLK1;Gene cloning;Transcriptional activation;Gene expression