, 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


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.


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



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.


  1. Aiken RM, Smucker AJM (1996) Root system regulation of whole plant growth. Annu Rev Phytopathol 34:325–346PubMedCrossRefGoogle Scholar
  2. Allen S (2003) Fusarium restistance ranking protocol for cotton cultivars in Australia. Proceedings of the Beltwide Cotton ConferenceGoogle Scholar
  3. Azevedo JL, Araujo WL (2003) Genetically modified crops: environmental and human health concerns. Mutat Res 544:223–233PubMedCrossRefGoogle Scholar
  4. Baluska F, Volkmann D, Hauskrecht M, Barlow PW (1996) Root cap mucilage and extracellular calcium as modulators of cellular growth in postmitotic growth zones of the maize root apex. Bot Acta 109:25–34Google Scholar
  5. Beckman CH (1987) The nature of wilt diseases of plants. St. Paul, Minesota, USA: APS PressGoogle Scholar
  6. Betz FS, Hammond BG, Fuchs RL (2000) Safety and advantages of Bacillus thuringiensis—protected plants to control insect pests. Regul Toxicol Pharmacol 32:156–173PubMedCrossRefGoogle Scholar
  7. Bowers JE, Chapman BA, Rong JK, Paterson AH (2003) Unravelling angiosperm genome evolution by phylogenetic analysis of chromosomal duplication events. Nature 422:433–438PubMedCrossRefGoogle Scholar
  8. Brigham LA, Woo HH, Nicoll SM, Hawes MC (1995) Differential expression of proteins and messenger-RNAs from border cells and root-tips of pea. Plant Physiol 109: 457–463PubMedGoogle Scholar
  9. Brigham LA, Woo HH, Wen F, Hawes MC (1998) Meristem-specific suppression of mitosis and a global switch in gene expression in the root cap of pea by endogenous signals. Plant Physiol 118:1223–1231PubMedCrossRefGoogle Scholar
  10. Bruinsma M, Kowalchuk GA, Van Veen JA (2003) Effects of genetically modified plants on microbial communities and processes in soil. Biol Fertil Soils 37:329–337Google Scholar
  11. Fitt GP (2000) An Australian approach to IPM in cotton: integrating new technologies to minimise insecticide dependence. Crop Prot 19:793–800CrossRefGoogle Scholar
  12. Gazaway WS, Mclean KS (2003) A survey of plant-parasitic nematodes associated with cotton in Alabama. J Cotton Sci 7:1–7Google Scholar
  13. Goldberg NP, Hawes MC, Stanghellini ME (1989) Specific attraction to and infection of cotton root cap cells by zoospores of Pythium dissotocum. Can J Bot-Rev Can Bot 67:1760–1767CrossRefGoogle Scholar
  14. Gunawardena U, Hawes MC (2002) Tissue specific localization of root infection by fungal pathogens: role of root border cells. Mol Plant-Microbe Interact 15:1128–1136PubMedGoogle Scholar
  15. Gunawardena U, Rodriguez M, Straney D, Romeo JT, VanEtten HD, Hawes MC (2005) Tissue-specific localization of pea root infection by Nectria haematococca. Mechanisms and consequences. Plant Physiol 137(4):1363–1374PubMedCrossRefGoogle Scholar
  16. Gupta VVSR, Roberts GN, Neate SN, Crisp P, McClure S, Watson SK (2001) Impact of Bt-cotton on biological processes in Australian soils. In: Akhurst RJ, Beard CE, Hughes P (eds) Proceedings of the 4th Pacific Rim conference on the biotechnology of Bt-environmental impacts. CSIRO, Australia pp. 191–194Google Scholar
  17. Gupta VVSR, Watson SK (2004) Ecological impacts of GM cotton on soil biodiversity. A final report for the Australian Government Department of the Environment and Heritage by CSIRO Land and Water. Glen Osmond, SAGoogle Scholar
  18. Haberlandt G (1914) Physiological plant anatomy London: McMillan and CoGoogle Scholar
  19. Hawes MC, Bengough G, Cassab G, Ponce G (2003) Root caps and rhizosphere. J Plant Growth Regul 21:352–367CrossRefGoogle Scholar
  20. Hawes MC, Brigham LA, Wen F, Woo HH, Zhu Y (1998) Function of root border cells in plant health: pioneers in the rhizosphere. Annu Rev Phytopathol 36:311–327PubMedCrossRefGoogle Scholar
  21. Hawes MC, Gunawardena U, Miyasaka S, Zhao X (2000) The role of root border cells in plant defence. Trends Plant Sci 5:128–133PubMedCrossRefGoogle Scholar
  22. Koenning SR, Overstreet C, Noling JW, Donald PA, Becker JO, Fortnum BA (1999) Survey of crop losses in response to phytoparasitic nematodes in the United States for 1994. J Nematol 31:587–618PubMedGoogle Scholar
  23. Kowalchuk GA, Bruinsma M, Van Veen JA (2003) Assessing responses of soil microorganisms to GM plants. Trends Ecol Evol 18:403–410CrossRefGoogle Scholar
  24. Monsanto Australia Limited (2003) Bollgard II Cotton Technical ManualGoogle Scholar
  25. Nehl DB, Allen SJ, Brown JF (1997) Deleterious rhizosphere bacteria: an integrating perspective. Appl Soil Ecol 5:1–20CrossRefGoogle Scholar
  26. Robinson AF, Cook CG (2001) Root-knot and reniform nematode reproduction on kenaf and sunn hemp compared with that on nematode resistant and susceptible cotton. Ind Crop Prod 13:249–264CrossRefGoogle Scholar
  27. Rodger S, Bengough AG, Griffiths BS, Stubbs V, Young IM (2003) Does the presence of detached root border cells of Zea mays alter the activity of the pathogenic nematode Meloidogyne incognita? Phytopathology 93:1111–1114PubMedGoogle Scholar
  28. Rodriguez-Galvez E, Mendgen K (1995) The infection process of Fusarium oxysporum in cotton root tips. Protoplasma 189:61–72CrossRefGoogle Scholar
  29. Saxena D, Stewart CN, Altosaar I, Shu Q, Stotzky G (2004) Larvicidal Cry proteins from Bacillus thuringiensis are released in root exudates of transgenic B. thuringiensis corn, potato, and rice but not of B. thuringiensis canola, cotton, and tobacco. Plant Physiol Biochem 42:383–387PubMedCrossRefGoogle Scholar
  30. Saxena D, Stotzky G (2001) Bacillus thuringiensis (Bt) toxin released from root exudates and biomass of Bt corn has no apparent effect on earthworms, nematodes, protozoa, bacteria, and fungi in soil. Soil Biol Biochem 33: 1225–1230CrossRefGoogle Scholar
  31. Sherwood RT (1987) Papilla formation in corn root-cap cells and leaves inoculated with Colletotrichum graminicola. Phytopathology 77:930–934Google Scholar
  32. Sims SR (1995) Bacillus thuringiensis var Kurstaki [CryIa(C)] protein expressed in transgenic cotton: effects on beneficial and other non-target insects. Southwest Entomol 20: 493–500Google Scholar
  33. Sisterson M, Biggs R, Olson C, Carriere Y, Dennehy T, Tabashnik B (2004) Arthropod abundance and diversity in Bt and non-Bt cotton fields. Environ Entomol 33:921–929CrossRefGoogle Scholar
  34. Zhao X, Schmitt M, Hawes MC (2000) Species dependent effects of border cell and root tip exudates on nematode behavior. Phytopathology 90:1239–1245PubMedGoogle Scholar

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

Personalised recommendations