Poster: Oxidative Stress
Abs #
132: Gene expression profiling to understand early-responses of rice plant to UVB irradiation using cDNA microarray.
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Presenter: |
Kishimoto, Naoki , naoki@nias.affrc.go.jp |
Authors | Kishimoto, Naoki (A) Yazaki, Junshi (A) Fujii, Fumiko (A) Shimbo, Kanako (B) Shimatani, Zenpei (B) Nagata, Yuko (B) Hashimoto, Akiko (B) Ishikawa, Masahiro (A) Kojima, Keiichi (C) Takeuchi, Keiko (A) Toyoshima, Kazuko (A) Sasaki, Takuji (A) Kikuchi, Shoshi (A) | | Affiliations: |
(A): National Institute of Agrobiological Sciences
(B): STAFF-Institute
(C): Hitachi Software Engineering
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| Web Site: | http://microarray.rice.dna.affrc.go.jp/ | |
To understand UVB irradiation responses, we used microarrays with 8987 unique cDNAs of rice. Thirteen-day-old seedlings (= No-PG-plants) and pretreated seedlings (= PG-plants: pretreated for 2 days prior to UVB irradiation with an antioxidant, n-propyl gallate) were harvested 1, 2, 4, and 8hr after exposure to 0, 0.55, 1.1, or 2.2 kJ/m2 of UVB. Expression levels were compared between un-irradiated and irradiated No-PG plants, or un-irradiated and irradiated PG-plants. The microarray data were verified by real-time RT-PCR. Of the 8987 cDNAs, 2.2kJ/m2 of UVB regulated the expression of 256 genes. Two waves of expression change were distinguished, 1-2hr (61-66 genes) and 4-8hr (140-145 genes). The number of UVB-regulated genes in PG-plants was higher than that of No-PG-plants (>2-fold at the 4 sampling points). The number of UVB-regulated genes increased with increasing UVB dose in No-PG-plants, but not in PG-plants, after 8hr of irradiation. Clustering analysis of all the UVB-regulated genes revealed 6 major clusters, of which Cluster A showed down-regulation in PG-plants (declining expression from 1 to 8hr) and up-regulation in No-PG-plants (increasing). Cluster B contained two sub-clusters; B-1 showed up-regulation in PG-plants (increasing), and down-regulation in No-PG-plants (declining); B-2 showed up-regulation in PG-plants (declining), and down-regulation in No-PG-plants (declining). In additon to stress-inductive proteins, Cluster A included proteinases, cab/photosystem proteins, kinases, proteins involved in respiration, Cluster B-1 included triptophan synthase, ferredoxins, Cluster B-2 included VTC (= Vitamin C-deficient), polyamine oxidase, alternative oxidase. We also present results of cis-element analysis for the genes belonging to these clusters.
