Expression of a barley cystatin gene in maize enhances resistance against phytophagous mites by altering their cysteine-proteases

Phytocystatins are inhibitors of cysteine-proteases from plants putatively involved in plant defence based on their capability of inhibit heterologous enzymes. We have previously characterised the whole cystatin gene family members from barley (HvCPI-1 to HvCPI-13). The aim of this study was to assess the effects of barley cystatins on two phytophagous spider mites, Tetranychus urticae and Brevipalpus chilensis. The determination of proteolytic activity profile in both mite species showed the presence of the cysteine-proteases, putative targets of cystatins, among other enzymatic activities. All barley cystatins, except HvCPI-1 and HvCPI-7, inhibited in vitro mite cathepsin L- and/or cathepsin B-like activities, HvCPI-6 being the strongest inhibitor for both mite species. Transgenic maize plants expressing HvCPI-6 protein were generated and the functional integrity of the cystatin transgene was confirmed by in vitro inhibitory effect observed against T. urticae and B. chilensis protein extracts. Feeding experiments impaired on transgenic lines performed with T. urticae impaired mite development and reproductive performance. Besides, a significant reduction of cathepsin L-like and/or cathepsin B-like activities was observed when the spider mite fed on maize plants expressing HvCPI-6 cystatin. These findings reveal the potential of barley cystatins as acaricide proteins to protect plants against two important mite pests

Genetic modification of maize by introduction of antifungal genes to confer resistance to Fusarium Verticillioides

Please read the abstract in the dissertationDissertation (MSc)--University of Pretoria, 2004.Plant Scienceunrestricte

The humanitarian impact of plant biotechnology: recent breakthroughs vs bottlenecks for adoption

The deployment of genetically engineered (GE) crops in developing countries is regarded by some as a sinister manifestation of 'big business' in science. What is often overlooked, and sometimes even deliberately ignored by opponents of the technology, is that many researchers working in the field are not motivated by profits but by a desire to see such crops applied to humanitarian purposes. GE crops could help to address many of the world's most challenging, interrelated problems, including hunger, malnutrition, disease, and poverty. However, this potential will not be realized if the major barriers to adoption which are political rather than technical are not overcome

Going to ridiculous lengths-European coexistence regulations for GM crops

Even if a GM crop can surmount Europe's excessive product registration process, any farmer hoping to plant it must then navigate tortuous, arbitrary and scientifically unjustifiable coexistence regulations