Functional Analysis and Localization of ABC (ATP-Binding Cassette) Transporter MhPDR1 and MhPDR2 from Banana
Date Issued
2008
Date
2008
Author(s)
Lin, Meng-Jin
Abstract
To understand the function of banana ABC (ATP-Binding cassette) transporter MhPDR1 and MhPDR2, CaMV 35S promoter was used to overexpress MhPDR1 and MhPDR2 in Nicotiana tabacum. The overexpressing plasmids were transferred to tobacco through Agrobacterium–mediated method for stable gene expression. One and six independeutly transgenic plants, for MhPDR1 and MhPDR2, respectively, were obtained and designated as Nt-MhPDR1-1 and Nt-MhPDR2-1~6. The results of β-glucuonidase (GUS) activity analysis showed that all of the transgenic lines expressed GUS. Southern hybridization analysis of genomic DNA from Nt-MhPDR2 transformants was further carried out to demonstrate the integration of foreign gene into the genome of transgenic plants. In contrast with untransformed plants, phenotype of tobacco transgenic lines of Nt-MhPDR1 and Nt-MhPDR2 showed higher growth potential. Mineral element content analysis showed that transgenic lines accumulated higher concentrations of magnesium, iron, and calcium, and accumulated lower concentrations of manganese. Chlorophyll content analysis showed that transgenic lines of Nt-MhPDR2 accumulate higher concentrations of chlorophyll a and carotenoids. The treatment of leaves of Nt-MhPDR2 with heavy metals indicated that transgenic lines had higher tolerance to aluminum, copper and cadmium ion. Besides, heavy metal content analysis showed that transgenic lines accumulated lower concentrations of aluminum, copper and cadmium. Therefore, we propose the possibility that ABC transporter MhPDR1 and MhPDR2 in banana contributes to strong growth potential of transgenic lines by pumping transport of magnesium, iron, calcium and manganese. On the other hand, MhPDR1 and MhPDR2 may also play the role of ion efflux pump for aluminium, copper and cadmium, leading to those transgenic lines achieve the tolerance of heavy metals. To investigate the localization of ABC transporter MhPDR1 and MhPDR2 in banana, we fused MhPDR1 and MhPDR2 with the green fluorescent protein (GFP). The fusing plasmids were transferred to onion epidermal cells via particle bombardment for transient assay. The green fluorescence of MhPDR1 and MhPDR2 were found mainly at the plasma membrane. The results suggest that ABC transporter MhPDR1 and MhPDR2 in banana are localized at the plasma membrane.
Subjects
Banana
ABC transporter
overexpression
heavy metal
Protein localization
Green fluorescence protein.
Type
thesis
File(s)![Thumbnail Image]()
Loading...
Name
ntu-97-R95628103-1.pdf
Size
23.53 KB
Format
Adobe PDF
Checksum
(MD5):1da98fb729caa3ee4681818690f8f99e