Plant & Animal Genomes XVII Conference

January 10-14, 2009
Town & Country Convention Center
San Diego, CA

Analysis Of Differential Gene Regulation By Salinity In Tolerant vs Sensitive Citrus Rootstocks

José M. Colmenero-Flores¹ , Javier Brumós¹ , Ana Conesa³ , Domingo J. Iglesias¹ , María F. López-Climent² , Aurelio Gómez-Cadenas² , Manuel Talon¹

¹  Instituto Valenciano de Investigaciones Agrarias, Centro de Genómica, Ctra Moncada-Náquera Km 4.6, 4611-Moncada, Valencia, Spain

²  Departament de Ciències Experimentals, Universitat Jaume I. Campus de Riu Sec (E.S.T.C.E.), E-12071-Castelló de la Plana, Spain

³  Department of Bioinformatics, Centro de Investigación Príncipe Felipe, Avda Autopista del Saler 16, Valencia, 46013, Spain.

Salinity response in Citrus is strongly related to leaf chloride ion build up, and can led to major perturbations of critical physiological processes. Both chloride homeostasis and specific genetic responses to Cl- stress are issues scarcely investigated in plants. We have utilized a comparative cDNA microarray approach on the sensitive Carrizo citrange (Citrus sinensis x Poncirus trifoliata), a poor Cl- excluder, and the tolerant Cleopatra mandarin (Citrus reshni), an efficient Cl- excluder, to discriminate the transcriptomic network related to salinity tolerance. Data indicated that changes in gene expression responses in Carrizo were much stronger in terms of number of differentially expressed ESTs. The tolerant rootstock induced wider stress responses in gene expression while repressing central metabolic processes such as photosynthesis, carbon utilization and energy. These features were in agreement with the changes in the patterns of phenotypic changes of photosynthesis, transpiration rate, stomatal conductance and other related physiological parameters observed between both rootstocks. Microarray analyses also identified several differentially expressed membrane transporters putatively implicated in chloride homeostasis such as NRT1-2, a gene belonging to the Proton-Dependent Oligopeptide Transporter family. The results indicated that major differences in the transcriptome of saline tolerant and sensitive Citrus rootstocks were circumscribed to the regulation of carbon metabolism and induction of stress responses