Chin J Plan Ecolo ›› 2010, Vol. 34 ›› Issue (6): 695-703.DOI: 10.3773/j.issn.1005-264x.2010.06.009

• Research Articles • Previous Articles     Next Articles

Systemic induced effects of mechanical wounding on the chemical defense of Bt corn (Zea mays)

FENG Yuan-Jiao1,2,3; JIN Qiong1,2,3; and WANG Jian-Wu1,2,3*   

  1. 1Institute of Tropical and Subtropical Ecology, South China Agricultural University, Guangzhou 510642, China;
    2Key Laboratory of Ecological Agriculture of Ministry of Agriculture, South China Agricultural University, Guangzhou 510642, China;
    3Key Laboratory of Agroecology and Rural Environment of Guangdong Regular Higher Education Institutions, South China Agricultural University, Guangzhou 510642, China
  • Received:2009-07-10 Online:2010-06-01 Published:2010-06-01
  • Contact: WANG Jian-Wu

Abstract: Aims The major objective was to explore the difference in the systematic induced effects of mechanical wounding on Bt corn and conventional corn after the first leaf of corn seedlings was mechanically wounded.
Methods Two Bt corns, ‘5422Bt1’ (Bt11) and ‘5422CBCL’ (Mon810), as well as their conventional corn ‘5422’ were used to detect changes in the content of direct defense chemical DIMBOA and expression of its genes (Bx1, Bx6 and Bx9), content of direct defense chemical total phenol and expression of its gene (PAL), direct defense protein genes (MPI and PR-2a), and the indirect defense chemical volatile genes (FPS and TPS) in the non-wounded parts (second leaf and roots) by employing chemical analysis and gene expression analysis methods after the first leaf of corn seedlings was mechanically wounded for 6 h.
Important findings Mechanical wounding systematically induced the expression of PAL and TPS in the second leaf and PAL and FPS in the roots of conventional corn ‘5422’ as compared with the healthy plants, which significantly increased the DIMBOA content in the second leaf but reduced the DIMBOA content and its gene expression of Bx6 and Bx9 in the roots. In addition, mechanical wounding systematically induced the gene expression of Bx6, PAL, PR-2a and TPS in the second leaf and Bx6, Bx9, PAL, MPI, PR-2a and TPS in the roots of Bt corn ‘5422Bt1’, resulting in increased DIMBOA content of the second leaf. In terms of ‘5422CBCL’, mechanical wounding systematically induced the gene expression of Bx9, PAL, PR-2a and TPS in the second leaf and the gene expression of Bx6, PAL, MPI and TPS in the roots, which remarkably increased the total phenol content in the roots. The systematic induced effect of mechanical wounding on the chemical defense response is more obvious in the two Bt corns as compared with the conventional corn ‘5422’, suggesting that there is a synergistic relationship between the Bt gene introduction and chemical defense response during the systematic induced defense processes inflicted by mechanical wounding.