Contribution of plants to human health and longevity: Utilization ofgenes for protecting plants against salt stress
Aftab AHMAD
Laboratory of Plant Molecular Improvement, Department of Food and Nutritional Sciences,
Graduate School of Nutritional and Environmental Sciences

The lifestyle-related illnesses caused by inappropriate intake of nutrients are themost serious for health and longevity in the advanced nations, although food starvation
ironically is the gravest in some countries. The green resources in terrestrial parts of theworld are necessary for food production, sustainable environment for humans, andalternative fuel production. Soil salinity is a major constraint to food production because
it affects plant growth, development and water quality hence reduction in crop yield.
Salinity is a worldwide problem and according to the currents estimates, 10-35% ofWorlds agricultural land is salt affected. Although careful water management practices
can reduce the loss to some extent but improved crop varieties have a vital role tomaintain the growth and yield of crops in salt affected area. Therefore to address theaspects of food security and sustainable agriculture it is important to understand themechanism of stress tolerance and identify new components of stress regulation in plants.
AtbHLH106 recognize GC-box (CACGTG) in promoter regions:Electrophoresis Mobility Shift Assay (EMSA) was performed to identify downstream
genes regulated by AtbHLH106. Most of the bHLH proteins recognize CANNTG region
in promoter but AtbHLH106 specifically recognized GC-box. In competition assay,
AtbHLH106 also interacted with other variants of GC-box however the intensity ofinteraction was weak. In-silico analysis of promoters of all genes from microarray data
produced that a number of genes had GC-box in their promoters. Short probes (24bp)
were designed for GC-box regions in promoters and we found that all these promotersalso interacted with AtbHLH106. More than 70 genes were found regulated by
AtbHLH106 and a few of them are already have established role in abiotic stress
tolerance. In addition, knock-out lines of interacting genes have also established somenew components of salt stress regulation through AtbHLH106.
Chromatin immunoprecipitation (ChIP) followed by Tilling array (CHIP):ChIP is powerful tool to study interaction of transcription factors with DNA in-vivo. To
further confirm our results of EMSA, we have generated and purified antibodies specificto AtBHLH106. Plant samples for ChIP-CHIP have also been fixed and experiment isunderway.
Tranformation of wild-type with 35S:AtWBC7: In one of our mutants stc5, agene responsible for ABC transporter AtWBC7 was activated and its knock-out line wassensitive to salt as well as abscisic acid. Over-expression lines were generated using oneof four alternative splice variants of AtWBC7 but expression was not significantly higher.
Presently we have been planning over-expression of three other splice variants.
Conclusions: We have presented a new model for identification of abiotic stressregulatory components in plants using activation tagging in dedifferentiated cells. In
addition we have also some new components of salt stress regulation in Arabidopsis.
Moreover, our results would strengthen ongoing efforts of research as well as foodsecurity.