[Show abstract][Hide abstract] ABSTRACT: Globally, about 20% of cultivated land is now affected by salinity. Salt tolerance is a trait of importance to all crops in saline soils. Previous efforts to improve salt tolerance in crop plants have met with only limited success. Bacteria of the genus Deinococcus are known for their ability to survive highly stressful conditions, and therefore possess a unique pool of genes conferring extreme resistance. In Deinococcus radiodurans, the irrE gene encodes a global regulator responsible for extreme radioresistance.
Using plate assays, we showed that IrrE protected E. coli cells against salt shock and other abiotic stresses such as oxidative, osmotic and thermal shocks. Comparative proteomic analysis revealed that IrrE functions as a switch to regulate different sets of proteins such as stress responsive proteins, protein kinases, glycerol-degrading enzymes, detoxification proteins, and growth-related proteins in E. coli. We also used quantitative RT-PCR to investigate expression of nine selected stress-responsive genes in transgenic and wild-type Brassica napus plants. Transgenic B. napus plants expressing the IrrE protein can tolerate 350 mM NaCl, a concentration that inhibits the growth of almost all crop plants.
Expression of IrrE, a global regulator for extreme radiation resistance in D. radiodurans, confers significantly enhanced salt tolerance in both E. coli and B. napus. We thus propose that the irrE gene might be used as a potentially promising transgene to improve abiotic stress tolerances in crop plants.
[Show abstract][Hide abstract] ABSTRACT: Gene flow from transgenic plants to compatible wild relatives is one of the major impediments to the development of the culture
of genetically engineered crop plants. In this work, the flow of EPSPS (conferring resistance to glyphosate) gene of transgene Brassica napus toward the untransgene B. napus and wild relative species Orychophragmus violaceus in an open field (1ha) was studied. The data related to only the 2004 and 2005 autumn season on one location of southwest
of China. Pollen dispersal and fertilization of the target plants were favored and a detailed analysis of the hybrid offspring
was performed. In field, the data studied show that the gene flow frequency was 0.16% between GM and non-GM B. napus at a distance of 1m from the transgenic donor area. The crosspollination frequency was 0.05% between GM and non-GM B. napus at a distance of 5m from the transgenic donor area. At a distance of 10m, no crosspollination was observed. According to
the results of this study, B. napus transgene flow was low. However, the wild relative species O. violaceus could not be fertilized by the transgenic pollen of B. napus, no matter what the distance was.
No preview · Article · Dec 2008 · Acta Physiologiae Plantarum