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Euphytica

, 154:83 | Cite as

Constitutive expression of Cry proteins in roots and border cells of transgenic cotton

  • Oliver G. G. KnoxEmail author
  • Vadakattu V. S. R. Gupta
  • David B. Nehl
  • Warwick N. Stiller
Article

Abstract

Transgenic cotton plants expressing Cry1Ac and Cry2Ab, from the soil bacterium Bacillus thuringiensis (Bt), provide effective control of certain lepidopteran pests, however, little is known about the proteins below ground expression. We used ELISA to quantify in vitro expression of the Cry1Ac and Cry2Ab proteins in mucilage, root border cells and root tips in five transgenic cultivars of cotton compared to conventional cultivar Sicot 189. Expression of Cry proteins in roots and border cells of the transgenic cotton cultivars was constitutive and at detectable levels, with Cry1Ac and Cry2Ab protein expression ranging from <20 ppb to >100 pbb. To determine if genetically modified cotton demonstrated simple differences in properties of the root, when compared to an elite parental line (cv. Sicot 189), we enumerated border cells on seedling radicles. Border cell counts of 14 cultivars ranged from 0.2 to 1.1 × 104 cells per root tip with an average of 5 × 103 border cells. Border cell production in the transgenic cultivars was generally similar to that of both donor and elite parents, the exception being the cultivar Sicot 189, which had substantially more border cells than all of its transgenic derivatives. Comparison of border cell number with varietal disease resistance ranking found a limited relationship (r 2 = 0.65, n = 7) between border cell numbers and the commercial resistance rank against Fusarium wilt of cotton. The implications of differences in cotton cultivar border cell number and root tip expression of Cry proteins for plant–microbe interactions in the rhizosphere and the soil ecosystem are yet to be resolved.

Keywords

Border cells Cry protein Exudates Mucilage Gossypium hirsutum Fusarium oxysporum f. sp. vasinfectum Verticillium dahliae 

Notes

Acknowledgements

This work was carried out under funding provided by the Cotton Research and Development Corporation, and with the support of CSIRO Entomology, Land and Water, and Plant Industry, and the NSW Department of Primary Industries. The help of Dr Stephen Allen and Mr Brett Ross (Cotton Seed Distributors, Wee Waa, Australia) is acknowledged for providing disease resistance rankings for commercially unavailable cotton cultivars and help with ELISA.

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Copyright information

© Springer Science+Business Media B.V. 2006

Authors and Affiliations

  • Oliver G. G. Knox
    • 1
    Email author
  • Vadakattu V. S. R. Gupta
    • 2
  • David B. Nehl
    • 3
    • 4
  • Warwick N. Stiller
    • 5
  1. 1.CSIRO EntomologyNarrabriAustralia
  2. 2.CSIRO EntomologyGlen OsmondAustralia
  3. 3.NSW DPINarrabriAustralia
  4. 4.Cotton Catchment Communities Cooperative Research CentreNarrabriAustralia
  5. 5.CSIRO Plant IndustryNarrabriAustralia

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