NO-deficient vs wild type Col-0 Arabidopsis seedlings

Nitric oxide regulates plant development and responses to stress. However, the mechanisms underlying its regulatory role are still poorly known, and the impact of endogenous NO on the genome-wide transcriptome of plants has not been studied. For that purpose, we compared the transcriptomes of NO-deficient nia1nia2, noa1-2 and nia1nia2noa1-2 mutant versus wild type Arabidopsis thaliana plants. A core comprising 66 NO-responsive genes with similar expression in all NO-deficient genotypes was identified. Among them, 46 were down- and 20 up-regulated in NO-deficient plants, and thus positively and negatively regulated by endogenous NO, respectively. Accordingly with changes in its transcriptome, the NO-deficient nia1nia2noa1-2 mutant accumulated anthocyanins and indolic glucosinolates, displayed abnormal iron homeostasis in shoots and roots, and also showed altered root sensitivity to hormones such as ABA, ET, CYK and IAA. Together the presented data suggest NO functions essentially as a modulator of hormone action.

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Gibbs DJ, Md Isa N, Movahedi M, Lozano-Juste J, Mendiondo GM, Berckhan S, Marín-de la Rosa N, Vicente Conde J, Sousa Correia C, Pearce SP, Bassel GW, Hamali B, Talloji P, Tomé DF, Coego A, Beynon J, Alabadí D, Bachmair A, León J, Gray JE, Theodoulou FL, Holdsworth MJ