Functional characterization of <i>AL</i> genes.

Abstract

<p>(A) Tissue-specificity of <i>AL</i> gene expression. Relative expression levels of <i>AL1</i>, <i>AL2</i>, <i>AL5</i>, <i>AL6</i>, and <i>AL7</i> were determined by quantitative RT-PCR in different plant organs. Leaves: rosette leaves from 4-week-old plants; Buds: floral buds before anthesis; Flowers: flowers at anthesis; Seeds: dry seeds. Data represent means ± SD of three biological replicates. (B) <i>AL6</i> and <i>AL7</i> genomic structure and T-DNA insertion mutants. Genes are schematically represented by black boxes for exons, black lines for introns and dashed boxes for untranslated regions. Triangles indicate T-DNA insertion sites and arrowheads indicate RT-PCR primer positions. Relative expression levels of <i>AL6</i> and <i>AL7</i> in Col-0 and in <i>al6</i> and <i>al7</i> mutants are shown as means ± SD of three biological replicates. (C) Representative seed germination images of Col-0, <i>al6 al7</i> double mutant, and the double mutant complemented by the <i>AL6</i> promoter driving <i>GFP-AL6</i> fusion gene (<i>+pAL6:GFP-AL6</i>). Images were taken five days after stratification from plates containing MS media or MS supplemented with 100 mM NaCl (MS+NaCl). (D) Germination rate of Col-0, double mutants <i>al6 al7</i> and <i>Atbmi1a Atbmi1b</i>, and the quadruple mutant <i>al6 al7 Atbmi1a Atbmi1b</i> plated on MS (top graph), MS supplemented with 200 mM mannitol (middle graph) or with 100 mM NaCl (bottom graph). Data represent average germination percentages ± SD of three biological replicates, each >60 seeds, observed daily for 12 days after stratification.</p