RESUMO
Global agriculture in the context of growing and expanding populations is under huge pressure to provide increased food, feed, and fiber. The recent phenomenon of climate change has further added fuel to the fire. It has been practically established now that the global temperature has been on the increase with associated fluctuations in annual rainfall regimes, and the resultant drought and flood events and increasing soil and water salinization. These challenges would be met with the introduction and utilization of new technologies coupled with conventional approaches. In recent years, transgenic technology has been proved very effective in terms of production of improved varieties of crop plants, resistant to biotic stresses. The abiotic stresses such as salt and drought are more complex traits, controlled by many genes. Transgenic plant development for these stresses has utilized many single genes. However, much emphasis has been placed on genes catalyzing the biosynthetic pathways of osmoprotectants. This review focuses on the current status of research on osmoprotectant genes and their role in abiotic stress tolerance in transgenic plants.
Assuntos
Adaptação Fisiológica , Plantas Geneticamente Modificadas/genética , Tolerância ao Sal/genética , Estresse SalinoRESUMO
A preliminary characterization was undertaken to describe genetic structure of mango ginger (Curcuma amada) acquired from farmers and ex situ genebank in Myanmar using neutral (rice SSR based RAPDs) and functional genomic (P450 based analog) markers. The high polymorphism (> 91 percent) depicted has displayed existence of genetic variability in the germplasm investigated. Large number of source-specific alleles (neutral-markers = 78, functional-markers = 63) was amplified which revealed that neutral regions of the mango ginger were more variable compared with the functional regions. The major fraction of the molecular variance (neutral-markers = 85 percent, functional-markers = 93 percent) was explained within germplasm acquisition sources and this tendency was also supported by the estimate of gene diversity. The genebank accessions have shown comparatively more genetic variability than farmers' accessions. The variability observed in mango ginger may possibly be associated with the long history of its cultivation under diverse ecological conditions. The two marker systems elucidated their high resolving power which detected variability even in fewer genotypes assayed. As the target sites of these markers are different, therefore, the variability detected is believed to cover diverse part of the genome together with neutral and functional regions. We found the concurrent use of the different types of molecular markers valuable to comprehend a dependable variability pattern in the germplasm assayed.