Soybean Kunitz, C-II and PI-IV inhibitor genes confer different levels of insect resistance to tobacco and potato transgenic plants

In modern, highly intensive agriculture, the control of insect pests is basically achieved with the application of chemical pesticides. Heavy reliance on this sole strategy is associated with several drawbacks, and the development of alternative or complementary methods to chemical control is desirable. In this work, three soybean genes (KTi ₃ , C-II and PI-IV)coding for serine proteinase inhibitors were isolated by PCR and transferred to Agrobacterium tumefaciens EHA 105, which in turn was used for transforming tobacco leaf and potato tuber discs. Biochemical assays confirmed that transgenic plants synthesized serine proteinase inhibitors; rates of expression varied among plants. The level of insect resistance (tested with Spodoptera littoralis Boisduval) was particularly high in tobacco, where many plants caused the death of all larvae. In potatoes, larval mortality was much less frequently achieved, but the results were still encouraging in that larval weight gain was reduced by 50% in the presence of adequate amounts of inhibitor. When 8-day-old larvae were fed different KTi ₃ -expressing tobacco plants, a highly significant (P<0.01) correlation was observed between inhibitor content and larval live weight. Larval weight gain was found to be dependent on midgut proteolytic activity. On the basis of the evidence collected, it is suggested that further work is required to identify more specific inhibitors for the main proteinases of the target insect. Received: 30 March 1998 / Accepted: 9 December 1999     

Heat,drought, and combined stress effect on transgenic potato plants overexpressing the StERF94 transcription factor

Journal of Plant Research - Despite their economic importance worldwide, potato plants are sensitive to various abiotic constraints, such as drought and high temperatures, which cause significant...     

Isolation and characterization of an endonuclease synthesized by barley (Hordeum vulgare L.) uninucleate microspores

Few biochemical and molecular details are available on microspore growth and development. In this work, a nuclease was partially purified from diffusates of barley (Hordeum vulgare L.) microspores by using concanavalin-A as ligand. The chromatographic preparation contained a 34-kDa protein with nucleolytic activity; the enzyme (called BMN: barley microspore nuclease) was very stable at pH > 8.0 and temperatures below 50 degrees C. Activity was highest at pH 5.6 and increased almost exponentially with temperature until a breakpoint between activity and stability was reached at 70 degrees C. Although BMN was able to cleave RNA, the enzyme showed a remarkable preference for DNA, especially in the single-stranded form. The best homopolymeric substrates were poly(dA) and poly(A), whereas poly(dC), poly(G) and poly(I) were almost completely uncleaved. When incubated with intact nuclei, BMN caused a nucleosomal DNA ladder of approximately 200 bp. On the basis of DNA laddering, substrate specificity, Mg2+ -dependence and best performance at apoplastic pH, BMN can be referred to as a putative apoptotic nuclease involved in pollen development.     

Beneficial effects of Salvia officinalis essential oil on vanadium-induced testicular injury,DNA damage and histological alterations in Wistar rats

BioMetals - Vanadium has been shown to catalyze the generation of reactive oxygen species. Since free radical production and lipid peroxidation are potentially important mediators in testicular...     

Impact of the overexpression of the StDREB1 transcription factor on growth parameters,yields, and chemical composition of tubers from greenhouse and field grown potato plants

Journal of Plant Research - Potato plants are often exposed to biotic and abiotic stresses that negatively impact their growth, development, and yield. Plants respond to different stresses by...