A cellulose binding domain protein restores female fertility when expressed in transgenic Bintje potato

Abstract

BackgroundExpression of a gene encoding the family 1 cellulose binding domain protein CBD1, identified in the cellulosic cell wall of the potato late blight pathogen Phytophthora infestans, was tested in transgenic potato to determine if it had an influence on plant cell walls and resistance to late blight.ResultsMultiple regenerants of potato (cv. Bintje) were developed and selected for high expression of CBD 1 transcripts. Tests with detached leaflets showed no evidence of increased or decreased resistance to P. infestans, in comparison with the blight susceptible Bintje controls, however, changes in plant morphology were evident in CBD 1 transgenics. Plant height increases were evident, and most importantly, the ability to produce seed berries from a previously sterile cultivar. Immunolocalization of CBD 1 in seed berries revealed the presence throughout the tissue. While Bintje control plants are male and female sterile, CBD 1 transgenics were female fertile. Crosses made using pollen from the late blight resistant Sarpo Mira and transgenic CBD1 Bintje as the female parent demonstrated the ability to introgress P. infestans targeted resistance genes, as well as genes responsible for color and tuber shape, into Bintje germplasm.ConclusionsA family 1 cellulose-binding domain (CBD 1) encoding gene from the potato late blight pathogen P. infestans was used to develop transgenic Bintje potato plants. Transgenic plants became female fertile, allowing for a previously sterile cultivar to be used in breeding improvement. Selection for the absence of the CBD transgene in progeny should allow for immediate use of a genetically enhanced material. Potential for use in other Solanaceous crops is proposed.

A Small Cellulose-Binding-Domain Protein (CBD1) in Phytophthora is Highly Variable in the Non-binding Amino Terminus

“…They are not an abundant protein in cell wall proteomic analyses [ 29 ] yet they are readily detected by immunolocalization [ 18 ], suggesting that proteomic analysis may be missing tightly bound wall proteins. Cellulose-binding domains are of interest in biotechnological applications that include cellulose bioprocessing [ 4 , 36 , 44 ], protein purification tags [ 25 , 31 ], and as modulators of plant growth [ 19 , 23 ]. Information on the native variations within the cellulose-binding domain can provide insight into the degree of substitutions that can be generated without compromising function [ 16 ].…”

“…The CBD1 protein from P . infestans has been shown to be cell-wall-bound, and it has been shown to bind to plant cell walls when expressed in transgenic potato plants [ 19 ]. In transgenic potatoes, the binding alters the expansion of ovary cell walls, allowing for fertility restoration.…”