Plant & Animal Genomes XIII Conference

January 15-19, 2005
Town & Country Convention Center
San Diego, CA

Transcriptome Analysis In Response To ABA, High Salt, And Osmotic Stress In Sorghum bicolor

Christina D. Buchanan² , Sanghyun Lim² , Ron A. Salzman² , Ioannis Kagiampakis¹ , Robert R. Klein⁴ , Lee H. Pratt⁵ , Marie-Michèle Cordonnier-Pratt⁵ , Patricia E. Klein^2,3 , John E. Mullet^1,2

¹  Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, 77843, USA

²  Institute for Plant Genomics and Biotechnology, Texas A&M University, College Statin, TX, 77843, USA

³  Department of Horticultural Sciences, Texas A&M University, College Station, TX, 77843, USA

⁴  USDA-ARS, Southern Plains Agricultural Research Center, College Station, TX, 77845, USA

⁵  Department of Plant Biology, University of Georgia, Athens, GA, 30602, USA

Genome wide changes in gene expression were monitored in Sorghum bicolor seedlings following exposure to high salinity (150 mM NaCl), osmotic stress (20% polyethylene glycol) or abscisic acid (ABA; 125 µM). A sorghum cDNA microarray providing useful data for 12,982 unique gene clusters was used to examine gene expression in roots and shoots at 3 and 27 hours post treatment. Expression of ~2,200 genes was altered by ABA, high salinity or osmotic stress. The modulated genes included novel gene discoveries as well as genes involved in stress signal transduction, transcription/translation, growth/cell walls/cytoskeleton functions, membrane/protein turnover/repair, metabolic/transport functions, dehydration protection, reactive oxygen scavenging, and plant defense mechanisms. Quantitative real-time PCR was used to quantify changes in relative mRNA abundance for ~337 genes whose expression was responsive to ABA, NaCl or osmotic stress. Analysis of response profiles and the identification of regulons by cluster analysis demonstrated the existence of a complex gene regulatory network that differentially modulates gene expression in a tissue-specific manner in response to ABA, high salinity and water deficit. Expression of 22 transcription factors including members of the bZIP, HD-ZIP, Myb, AP2/ERBP, NAC, MADS-box, WRKY, CONSTANS and NAM families was modulated in a complex manner contributing to sorghum’s overlapping but nonetheless distinct responses to ABA, high salinity, and osmotic stress.