Suppression Subtractive Hybridization Separation Of Drought Stress Of Maize Seedlings Specific Expression Of Cdna

Maize originates from the tropical zone of high temperature and humidity in Central and Southern America.so that it has poor tolerance to drought.With the aggravation of ecological conditions,drought has become the major limitative factor to maize production in many countries and regions.Significant difference of drought tolerance was found among maize inbred lines. Furthermore, this difference is caused by different morphological, structural, physiological and biochemical mechanisms. All of these mechanisms, however, are phenotypic characters expressed by proteins. Proteins are encoded with mRNA templates of gene transcripts.In this study, 16% PEG-6000 was used for simulant drought treatment to drought tolerant maize inbred line "81565". Suppression subtractive hybridization (SSH) technique was used to research mRNA differential expression under drought stress and irrigated control. Five specific fragments (B1, A2, C4, E4 and F4) were found specifically up-regulated under drought stress. By alignment analysis using BLAST and OFR finder software on NCBI database, B1 was similar (88% identieies) to mRNA sequence predicted from OSJNBa0072F16.5 protein with deduced domain DegQ (trypsin-like serine proteases) in rice. A2 showed similarity (91% identities) to mRNA sequence encoding the putative reductase with NADH dehydrogenase activity in rice. C4 was involved in the sixth exon of phosphoglycerate mutase gene encoding sequence and similar (97% identities) to the cofactor-independent phosphoglycerate mutase complete conserve domain mRNA sequence in maize. E4 showed similarity (99% identities) to PCO066914 mRNA sequence and F4 showed similarity (100% identities) to PCO113764 mRNA sequence in maize. According to founction of homologies, three (C4, E4 and F4) of the five fragments may be relevant to drought tolerance of maize inbred line "81565". It may be involved in drought respons that ATP-independent damaged protein degradation, opmizing efficiency of respiration and photosynthesis and ATP production and energy conversion in carbon metabolism.