Table of Contents

PLANT RESEARCH NEWS

Conventional Breeding Used to Improve Bt Cotton
John J. Adamczyk, O. P. Perera, and W. R. Meredith
Cotton plants genetically engineered to contain a gene from Bacillus thuringiensis (Bt) (Bollgard®, Monsanto Co., St. Louis, MO) have been used to manage caterpillar pests for over 10 years. Overall Cry1Ac levels among Bollgard cultivars have been correlated to survival levels in various caterpillar pests that are naturally tolerant to this Bt protein. Differences in Cry1Ac protein levels among commercial cultivars can vary as much as five-fold throughout the season. Furthermore, these cultivar differences are heritable and controlled by a small number (1 – 2) of genetic factors. This current study suggests that genetic factors are impacting the overall cry1Ac mRNA transcript levels among different Bollgard lines. However, post-translational effects or environmental factors that could further impact available Cry1Ac protein levels cannot be excluded.

Altered Polyamine Catabolism: Producing Transgenic Plants with Enhanced Tolerance to Bacteria and Oomycetes
K. A. Roubelakis-Angelakis, P. N. Moschou, P. F. Sarris, N. J. Panopoulos
Molecular approaches are used to unravel the mechanisms by which tolerant plants cope with invading pathogens. Polyamines (PAs) are aliphatic amines present in all eukaryotic cells, with Putrescine (Put), Spermidine (Spd), and Spermine (Spm) the more prevalent ones. Polyamine oxidase (PAO) oxidizes PAs, generating hydrogen peroxide (H2O2). Overexpression of the PAO gene increases apoplastic H2O2, which induces expression of antioxidant enzymes. Abiotic stress induces Spd secretion into the apoplast, where it is oxidized by PAO to produce H2O2. New research adds insight into the participation of the PAO gene in the generation of apoplastic H2O2, which signals plant-pathogens interactions. Overexpression of this gene confers tolerance to specific pathogens that use the apoplast for their colonization, and presents a novel means for generating plants tolerant to pathogenic invasion. Thus, genetically engineering PAO can be an efficient method for enhancing tolerance of plants to bacteria and fungi.

RISK ASSESSMENT NEWS

Global Profiling Technologies Assess Unintended Effects in Transgenic Plants
Jaimie Schnell, Phil Macdonald, and Brian Miki
In the creation of a transgenic plant, one or more transgenes are inserted into the plant genome. While this is typically done to introduce some novel trait, there is also the possibility for other unintended effects. It is important to understand the nature of these effects and their potential for occurring in order to identify any potential risks that could affect the safe use of transgenic plants. Global profiling technologies provide an additional tool for assessing the safety of transgenic plants. These technologies contribute a comprehensive, global view of the levels of transcripts, proteins, and metabolites.

Full report: http://www.isb.vt.edu/news/2009/oct09.pdf
 

Website: http://www.isb.vt.edu

Published: November 19, 2009