title: Alteration of Arabidopsis SLAC1 promoter and its association with natural variation in drought tolerance.
abstract: Natural variation for drought tolerance is a major issue in adaptation and geographic distribution of terrestrial plants. Despite the importance, little is known about the genes and molecular mechanisms that determine its naturally occurring diversity. We analyzed the intraspecific drought tolerance variation between 2 accessions of Arabidopsis thaliana, Columbia (Col)-0 and Wassilewskija (Ws)-2. Measurement of weight loss in detached seedlings demonstrated a clear difference between drought-tolerant Col-0 and drought-sensitive Ws-2. They also differed in their stomatal response under drought condition. Using a quantitative genetic approach, we found a significant quantitative locus on chromosome 1. Surveying in the locus, we extrapolated that the SLAC1 gene, which is associated with stomatal closure, was likely responsible for the difference of drought tolerance. Comparison of their nucleotide and amino acid sequences revealed that there were few differences in regions encoding SLAC1 protein but was a large deletion in SLAC1 promoter of Ws-2. Histochemical GUS staining showed that the SLAC1 expressed dominantly in guard cells of Col-0, but did less in guard cells of Ws-2. Quantitative PCR analysis also showed that transcript level of SLAC1 in guard cells was higher in Col-0 than in Ws-2. The SLAC1 transcription analyses indicate low accumulation of SLAC1 in guard cells of Ws-2. When taken together, our results suggest that the low drought tolerance of Ws-2 was associated with the deletion of the promoter region of Ws-2 SLAC1.
authors.affiliation: a Graduate School of Life and Environmental Sciences ; University of Tsukuba; Tennohdai ; Tsukuba , Ibaraki , Japan.
authors.forename: Hiroe
authors.initials: H
authors.lastname: Imai
authors.forename: Yusaku
authors.initials: Y
authors.lastname: Noda
authors.forename: Masanori
authors.initials: M
authors.lastname: Tamaoki
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism; D000222:Adaptation, Physiological / Q000235:genetics*; D017360:Arabidopsis / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D032461:Chromosomes, Plant; D055864:Droughts; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D056426:Genetic Loci; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism; D010641:Phenotype; D059828:Plant Cells / Q000378:metabolism; D054046:Plant Stomata; D011401:Promoter Regions, Genetic; D036226:Seedlings; D013045:Species Specificity; D013312:Stress, Physiological; D014867:Water
chemical_list: D029681:Arabidopsis Proteins; D008565:Membrane Proteins; C528438:SLAC1 protein, Arabidopsis; D014867:Water; D000040:Abscisic Acid
keywords: ABA, abscisic acid; Arabidopsis thaliana; Arabidopsis, Arabidopsis thaliana (L.) Heynh; Col, Columbia; Columbia (Col); GUS, β-glucuronidase; QTL analysis; QTL, quantitative trait locus; RIL, recombinant inbred line; SLAC1; SLAC1, slow anion channel-associated 1; Wassilewskija (Ws); Ws, Wassilewskija; drought tolerance; natural variation; stomatal response