Paper Title
Cloning And Sequence Analysis Of Banana Vnd1 Transcription Factor And Its Overexpression In Transgenic Banana Plants

Vascular related NAC (NAM, ATAF and CUC) domain-containing genes are plant specific transcription factors involved in regulation of tracheary element formation. Tracheary elements are elongated cells of xylem tissue characterized by thick secondary wall formation and functions in transport of water. Banana VND1 is a transcription factor isolated by PCR amplification from corm tissue of banana cultivar Rasthali and cloned in T- cloning vector for sequencing the amplified PCR product. Sequence analysis indicated that banana VND1 is a homologue of Arabidopsis VND1 and contains the highly conserved NAC domain. Banana VND1 was further cloned in plant specific cloning vector pCAMBIA1301 under the control of maize polyubiquitin promoter, pZmUbi. The cloning was confirmed by colony PCR and subsequent sequencing of the recombinant vector. Transgenic banana plants overexpressing banana VND1 were generated by Agrobacterium mediated genetic transformation of banana cultivar Rasthali embryogenic cells. Transgenic nature of the shoots were confirmed by genomic DNA PCR, Southern blot analysis and real time RT-PCR analysis. Transgenic plants displayed transdifferentiation of leaf epidermal cells into tracheary element-like cells with ectopic deposition of secondary wall. Further, transient overexpression of banana VND1 resulted in differentiation of banana embryogenic cells into tracheary element-like cells. These results indicated the role of banana VND1 transcription factor in regulating tracheary element development in banana.