LEAF RUST RESPONSIVE EXPRESSION PROFILING OF GRAS TRANSCRIPTION FACTOR FAMILY IN WHEAT (TRITICUM AESTIVUM L)
Objective: Rusts are among the most important fungal diseases of wheat all over the world responsible for losses in yield ranging from 25% to 90%. Bread wheat (Triticum aestivum L.) is one of the major staple food crops all over the world but is greatly affected by leaf rust. GRAS is a plant-specific stress responsive transcription factor gene family. The objective of the present study is to carry out expression profiling of GRAS TFs during leaf rust pathogenesis.
Methods: SOLiD SAGE library preparation. GRAS TFs were mapped to the four libraries using the CLC genomics workbench to study their expression profiles. A Co-expression network of these TFs has been constructed using WGCNA (weighted gene co-expression network analysis).
Results: The four libraries have been prepared: S-M, S-PI, R-M R-PI. GRAS TFs were mapped to these libraries, giving different expression profiles of the 63 GRAS TFs. Pearson correlation coefficients were 0.56, 0.34 and 0.24 for R-M vs. R-PI, S-M vs. S-PI and S-PI vs. R-PI respectively. Highest difference in expression of TaGRAS genes was between two libraries S-PI vs. R-PI. TaGRAS genes have been clustered into seven (blue, turquoise, red, green, black, maroon and yellow) different modules in signed correlation.
Conclusion: TaGRAS genes which are upregulated during leaf rust might be plays important roles to provide resistance to the plants. The difference in Pearson correlation coefficient indicates that susceptible and resistant-NILs utilize a different set of TaGRAS genes to counter leaf rust pathogenesis. The genes which are clustered together in coexpression network might be expressed together during leaf rust pathogenesis to provide resistance to the plant.
Keywords: Leaf rust, Wheat. GRAS, Transcription Factors, SAGE, WGCNA
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