title: Comparative genome-wide transcriptional analysis of Al-responsive genes reveals novel Al tolerance mechanisms in rice.
abstract: Rice (Oryza sativa) is the most aluminum (Al)-tolerant crop among small-grain cereals, but the mechanism underlying its high Al resistance is still not well understood. To understand the mechanisms underlying high Al-tolerance, we performed a comparative genome-wide transcriptional analysis by comparing expression profiling between the Al-tolerance cultivar (Koshihikari) and an Al-sensitive mutant star1 (SENSITIVE TO AL RHIZOTOXICITY 1) in both the root tips and the basal roots. Exposure to 20 µM AlCl(3) for 6 h resulted in up-regulation (higher than 3-fold) of 213 and 2015 genes including 185 common genes in the root tips of wild-type and the mutant, respectively. On the other hand, in the basal root, genes up-regulated by Al were 126 and 2419 including 76 common genes in the wild-type and the mutant, respectively. These results indicate that Al-response genes are not only restricted to the root tips, but also in the basal root region. Analysis with genes up- or down-regulated only in the wild-type reveals that there are other mechanisms for Al-tolerance except for a known transcription factor ART1-regulated one in rice. These mechanisms are related to nitrogen assimilation, secondary metabolite synthesis, cell-wall synthesis and ethylene synthesis. Although the exact roles of these putative tolerance genes remain to be examined, our data provide a platform for further work on Al-tolerance in rice.
authors.affiliation: Institute of Plant Science and Resources, Okayama University, Kurashiki, Japan.
authors.forename: Tomokazu
authors.initials: T
authors.lastname: Tsutsui
authors.forename: Naoki
authors.initials: N
authors.lastname: Yamaji
authors.forename: Chao Feng
authors.initials: CF
authors.lastname: Huang
authors.forename: Ritsuko
authors.initials: R
authors.lastname: Motoyama
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Nagamura
authors.forename: Jian Feng
authors.initials: JF
authors.lastname: Ma
mesh_terms: D000535:Aluminum / Q000633:toxicity*; D004361:Drug Tolerance / Q000235:genetics; D018506:Gene Expression Regulation, Plant / Q000187:drug effects / Q000235:genetics; D012275:Oryza / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D018517:Plant Roots / Q000187:drug effects / Q000235:genetics / Q000378:metabolism
chemical_list: D010940:Plant Proteins; D000535:Aluminum