Engineering sHsp17 and Hsp90 in Zea mays to Develop Thermotolerance

Background

Genetically modified (GM) crops have shown a considerable success worldwide in improving farm incomes and reducing environmental pollution by limiting the use of synthetic chemicals. Maize is an important cereal crop of Pakistan and majorly grown in Punjab under Spring and Autumn seasons. There is a temperature shift in both seasons which bring a stress on crop plant, as a result of which the yield of the hybrids drops drastically due to failure of pollinations or heat coupled with drought causes reduced seed growth and hence less yield. This makes maize yield unstable over the years and keeps the farmer at risk. Current study was proposed keeping the above situation in mind. shsp-17 from Nicotiana tabacum and ATHSP-90 from Arabidopsis thaliana have been transformed in maize to play its role under biotic and abiotic stresses. Though maize plant also produces them, the target was to enhance the natural production of these proteins by genetic engineering in maize. In planta transformation protocols were equipped for the recovery of transgenic plants carrying reporter gene and gene of interest ( sHSP-17 ). Putative transgenic plants for HSP-90 were not achieved, at this we compared tissue culture/regeneration after bombarding immature zygotic embryos with selectable marker gene and found out that the said gene was perhaps deleterious for plant survival. The transgenic plants carrying reporter gene were checked for the presence of reporter protein by providing enzyme substrate which proved the transformation and expression of reporter gene for protein. The transgenic plants carrying sHSP-17 were grown till maturity, confirmation for the presence of gene in maize genome was done using PCR and Southern blot while expression was checked using reverse transcriptase PCR. Seed of the transgenic plants were grown to get T1 generation which were found to be unable to attain maturity and produce progeny. It indicates that may be the expression of this gene too was deleterious for embryo survival and only those seeds could be developed where transgene was not available due to normal gene reshuffling during sexual reproduction.