Addressing drought tolerance in maize by transcriptional profiling and mapping.

In order to unravel the genetic architecture underlying plant response to drought, we adopted an integrated approach, combining transcript profiling and quantitative trait loci (QTL) mapping. In fact, improving plant tolerance to water stress is an important, but, at the same time, a difficult task, since plant tolerance is the result of many complex mechanisms acting at different levels of plant organization, and its genetic basis is largely unknown. The phenotypic data, concerning yield components and flowering time, of a population of 142 maize Recombinant Inbred Lines (RILs), grown under well watered conditions or under water stress, were submitted to linkage analysis to detect drought-tolerance QTLs. Thirty genomic regions containing 50 significant QTLs distributed on nine chromosomes were identified. At the same time, a customized targeted oligoarray was used to monitor the expression levels of 1,000 genes, representative of the immature maize kernel transcriptome. Using this DNA array we compared transcripts from 10 days after pollination kernels of two susceptible and two drought tolerant genotypes (extracted from our RILs) grown under control and water stress field conditions. Two hundred and fifty-two genes were significantly affected by stress in at least one genotype. From a set of these, 49 new molecular markers were developed. By mapping most of them and by in silico mapping other regulated sequences, 88 differentially expressed genes were localized onto our linkage map, which, added to the existing 186 markers, brought their total number on the map to 274. Twenty-two of the 88 differentially expressed genes mapped in the same chromosomal segments harbouring QTLs for tolerance, thus representing candidate genes for further functional studies.

Glutathione transferases in the genomics era: new insights and perspectives.

In the last decade the tumultuous development of "omics" greatly improved our ability to understand protein structure, function and evolution, and to define their roles and networks in complex biological processes. This fast accumulating knowledge holds great potential for biotechnological applications, from the development of biomolecules with novel properties of industrial and medical importance, to the creation of transgenic organisms with new, favorable characteristics. This review focuses on glutathione transferases (GSTs), an ancient protein superfamily with multiple roles in all eukaryotic organisms, and attempts to give an overview of the new insights and perspectives provided by omics into the biology of these proteins. Among the aspects considered are the redefinition of GST subfamilies, their evolution in connection with structurally related families, present and future biotechnological outcomes.

Exploiting plant metabolism for the phytoremediation of persistent herbicides.

Weed control by herbicides has helped us to create the green revolution and to provide food for at least the majority of human beings living today. However, some herbicides remain in the environment and pose an ecological problem. The present review describes the properties and fate of four representative herbicides known to be presistent in ecosystems. Metabolic networks are depicted and it is concluded that removal of these compounds by the ecologically friendly technique of phytoremediation is possible. The largest problem is seen in the uptake of the compounds into suitable plants and the time needed for such an approach.