Rapid growth in human population through the world is boosting demand for corresponding increase in grain yield and there is a need to increase production 50% more by 2025.Classical approaches for plant improvement including Plant breeding have been greatly supported by novel techniques of genome sequencing, gene tagging, gene cloning, bioinformatics etc., The present study was undertaken to study the selected genes of rice responsible for imparting the drought resistance to the plant. The genes selected for the study are LEA and DREB both of which are known for their ability to withstand the drought conditions. The gene sequences are collected from the NCBI Database and their complete characterization was performed. The Lab work included the collection of 4 drought resistant varieties form Rain Fed Paddy Research Station, Tuljapur, Maharashtra and 5 susceptible varieties from Directorate of Rice Research Centre Hyderabad. The seeds were sowed in small trays and cultivated in lab conditions for about two weeks. The leaf material was used for the extraction of DNA and the samples were used for sequencing. The complete insilico characterization of the two genes LEA and DREB was performed. Primers were designed for tehse genes which were used to amplify the genes from the Genomic DNA extracted from the above 9 samples. Based on the presence or absence of the gene in the genomes the amplification can be either positive or negative. These results would enable to classify the plant as drought resistant or sensitive. A complete characterization of the two genes was included in the study.
Rice, (Oryza sativa L.) is the most important food crop for nearly half of the world population (Sellamuthu et al., 2011). Worldwide, rice is cultivated on an area of 154 million hectors with an annual production of 700 million tones. Globally, India ranks first in cultivable area under rice and second in production, producing 131 million tones. Rice has also become a model organism for genome analysis, having a diploid chromosome number of 24 and the smallest genome size (430 Mb) of all major crops. (Arumuganathan and Earle, 1995).
Drought is an abiotic stress that limits productivity in both rainfed and upland ecosystems (Bimpong etal., 2011). In Asia, severe and minor drought occurs in East and Northeast India, East
China, Central Myanmar, Thailand. In the eastern states of India viz., Jharkhand, Orissa and Chhattisgarh, 40 per cent of the total rice production is lost in severe droughts valued at $650 million. (Pandey et al., 2005) and poorest rice farmers are most affected in these areas.
The genes DREB and LEA have been reported to be responsible for drought resistance in a number of plant species including rice. In this study rice varieties susceptible and resistant to drought were selected. The sequence analysis of DREB and LEA genes was conducted and primers were designed for selective amplification of these genes. Using these primers the amplified regions were sequenced and based on these in silico and in vitro studies efforts have been made to understand the effect of these genes on drought stress.
Deciphering sequences for a particular trait followed by primer designing to amplify an important conserved region of the gene is a useful strategy to find the functional and molecular characteristics of DREB and LEA genes and to use them in plant improvement programme. The work results showed a direct relation with the presence of these selected genes and the ability of the plant against drought conditions. From the results it can be concluded that the transgenic plants possessing these genes can be a beneficial approach for the improvement in the production of essential crops.
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