Skip to content
Login Register

#Agrobacterium

16 public questions tagged with this topic.

Plant tissue culture 3

Hairy root inducing plasmid is called:

Agrobacterium plasmids determine disease phenotype. Ti plasmid, tumor-inducing, contains T-DNA with iaaM, iaaH, and ipt genes overproducing auxin and cytokinin, causing undifferentiated gall. Ri plasmid, root-inducing, carries TL and TR T-DNA regions in agropine strains; TL harbors rol cluster essential for hairy root syndrome and TR carries auxin genes and agropine synthesis. Virulence region mediates T-strand excision and transfer via type IV secretion. Upon integration, rol gene expression modifies host signaling, stimulating root proliferation rather than callus. Laboratory disarmed Ri vec

Ref: White & Nester J Bacteriol 1980 Ri structure; Nilsson & Olsson Physiol Plant 1997 rol; NCBI NBK21414 Ti vs Ri; https://www.ncbi.nlm.nih.gov/books/NBK21414/

View Details
Plant tissue culture 3

Hairy root cultures are induced by infection with:

Hairy root syndrome originates when wounded dicot tissue is invaded by soil bacterium carrying root inducing plasmid. Transfer of T-DNA segment harboring rolA, rolB, rolC, rolD loci plus opine synthesis genes into host chromosome rewires hormone balance. rolB encodes tyrosine phosphatase increasing auxin sensitivity, rolC cytokinin glucosidase adjusting growth, together triggering extensive adventitious root emergence directly from callus. Roots grow plagiotropically, highly branched, hormone independent, and genetically stable for decades. In contrast Agrobacterium tumefaciens produces crown

Ref: Chilton Nature 1982 Ri plasmid; Tepfer PNAS 1984 hairy root; NCBI NBK21344 rol genes; PubMed 17302573 hairy root review 2014.

View Details
Gene and Genome

Acquisition of new genes by Agrobacterium is an example of:

Horizontal gene transfer refers to non-vertical transmission of genetic material between unrelated organisms via transformation, transduction, conjugation or vectors. Agrobacterium tumefaciens exemplifies natural inter-kingdom transfer, possessing Ti plasmid bearing T-DNA flanked by border repeats. Virulence proteins excise T-DNA and deliver it through type IV secretion system into plant nucleus where it integrates, expressing oncogenes inducing crown gall formation. This natural gene delivery system underlies plant transgenesis. Acquisition of novel genes through such mechanisms spreads antib

Ref: Chilton et al., Cell 1977: Agrobacterium T-DNA Transfer as Example of Horizontal Gene Transfer

View Details