UI - 0 PMID- 13130077 OWN - NLM STAT- pubmed-not-medline DA - 20030917 IS - 0027-8424 DP - 2003 Sep 16 TI - LAX and SPA: Major regulators of shoot branching in rice. AB - The aerial architecture of plants is determined primarily by the pattern of shoot branching. Although shoot apical meristem initiation during embryogenesis has been extensively studied by molecular genetic approaches using Arabidopsis, little is known about the genetic mechanisms controlling axillary meristem initiation, mainly because of the insufficient number of mutants that specifically alter it. We identified the LAX PANICLE (LAX) and SMALL PANICLE (SPA) genes as the main regulators of axillary meristem formation in rice. LAX encodes a basic helix-loop-helix transcription factor and is expressed in the boundary between the shoot apical meristem and the region of new meristem formation. This pattern of LAX expression was repeatedly observed in every axillary meristem, consistent with our observation that LAX is involved in the formation of all types of axillary meristems throughout the ontogeny of a rice plant. Ectopic LAX expression in rice caused pleiotropic effects, including dwarfing, an altered pattern of stem elongation, darker color, bending of the lamina joint, absence of the midribs of leaves, and severe sterility. AD - *Graduate School of Agriculture and Life Science, University of Tokyo, Yayoi 1-1-1, Bunkyo, Tokyo 113-8657, Japan; ()Research Institute for Bioresources, Okayama University, Chuou 2-20-1, Kurashiki, Okayama 710-0046, Japan; ()CREST, Japan Science and Technology Corporation, Honcho 4-1-8, Kawaguchi, Saitama 332-0012, Japan. AU - Komatsu K AU - Maekawa M AU - Ujiie S AU - Satake Y AU - Furutani I AU - Okamoto H AU - Shimamoto K AU - Kyozuka J LA - ENG PT - JOURNAL ARTICLE TA - Proc Natl Acad Sci U S A JID - 7505876 EDAT- 2003/09/18 05:00 MHDA- 2003/09/18 05:00 AID - 10.1073/pnas.1932414100 [doi] AID - 1932414100 [pii] PST - aheadofprint SO - Proc Natl Acad Sci U S A 2003 Sep 16;. UI - 0 PMID- 13129917 OWN - NLM STAT- pubmed-not-medline DA - 20030917 IS - 1083-351X DP - 2003 Sep 16 TI - Expression profiles of arabidopsis thaliana in mineral deficiencies reveal novel transporters involved in metal homeostasis. AB - Plants directly assimilate minerals from the environment and thus are key for acquisition of metals by all subsequent consumers. Limited bio-availability of copper, zinc and iron in soil decreases both the agronomic productivity and the nutrient quality of crops. Understanding the molecular mechanisms underlying metal homeostasis in plants is a pre-requisite to optimizing plant yield and metal nutrient content. To absorb and maintain a balance of potentially toxic metal ions, plants utilize poorly understood mechanisms involving a large number of membrane transporters and metal-binding proteins with overlapping substrate specificities and complex regulation. In order to better understand the function and the integrated regulation, we analyzed in Arabidopsis the expression patterns in roots and in leaves of 53 genes coding for known or potential metal transporters, in response to copper, zinc and iron deficiencies in Arabidopsis. Comparative analysis of gene expression profiles revealed specific transcriptional regulation by metals of the genes contrasting with the known wide substrate specificities of the encoded transporters. Our analysis suggested novel transport roles for several gene products and we used functional complementation of yeast mutants to correlate specific regulation by metals with transport activity. We demonstrate that two ZIP genes, ZIP2 and ZIP4 are involved in copper transport. We also present evidence that AtOPT3, a member of the oligopeptide transporter gene family with significant similarities to the maize iron-phytosiderophore transporter YSL1, is regulated by metals and heterologous expression AtOPT3 can rescue yeast mutants deficient in metal transport AD - Nutritional Sciences and Toxicology, University of California, Berkeley, CA 94720. AU - Wintz H AU - Fox TC AU - Wu YY AU - Feng V AU - Chen W AU - Chang HS AU - Zhu T AU - Vulpe CD LA - ENG PT - JOURNAL ARTICLE TA - J Biol Chem JID - 2985121R EDAT- 2003/09/18 05:00 MHDA- 2003/09/18 05:00 AID - 10.1074/jbc.M309338200 [doi] AID - M309338200 [pii] PST - aheadofprint SO - J Biol Chem 2003 Sep 16;. PMID- 13129600 UI - 22857338 OWN - NLM STAT- in-process DA - 20030917 IS - 0378-1097 VI - 226 IP - 1 DP - 2003 Sep 12 TI - Effect of Urtica dioica agglutinin and Arabidopsis thaliana Chia4 chitinase on the protozoan Phytomonas francai. PG - 1-7 AB - The genus Phytomonas is responsible for many diseases in different crop plant species. The finding that chitin is an exposed cell surface polysaccharide in Phytomonas francai and the observation that chitinases can inhibit fungal growth raises expectations about the potential effect of plant chitinases on the P. francai cell membrane surface. The plant chitinases Urtica dioica agglutinin (UDA) and Arabidopsis thaliana Chia4 (ATCHIT4) proteins were over-expressed in bacteria and the interaction between these proteins and P. francai surface was analyzed by immunocytochemistry. We showed that UDA and ATCHIT4 proteins can interact with surface-exposed chitin from P. francai. AD - Laboratorio de Genetica Molecular Vegetal, Instituto de Biologia, Dept. de Genetica, Universidade Federal do Rio de Janeiro, Av. Pau Brasil 211, AZ 76, 21944-970, Rio de Janeiro, RJ, Brazil FAU - Gomes Rocha, Graca Celeste AU - Gomes Rocha GC FAU - Nicolich, Rebecca AU - Nicolich R FAU - Romeiro, Alexandre AU - Romeiro A FAU - Margis-Pinheiro, Marcia AU - Margis-Pinheiro M FAU - Attias, Marcia AU - Attias M FAU - Alves-Ferreira, Marcio AU - Alves-Ferreira M LA - eng PT - Journal Article PL - Netherlands TA - FEMS Microbiol Lett JID - 7705721 SB - IM EDAT- 2003/09/18 05:00 MHDA- 2003/09/18 05:00 AID - S0378109703005263 [pii] PST - ppublish SO - FEMS Microbiol Lett 2003 Sep 12;226(1):1-7. UI - 0 PMID- 12975308 OWN - NLM STAT- pubmed-not-medline DA - 20030916 IS - 1088-9051 DP - 2003 Sep 15 TI - Mystery of Intron Gain. AB - For nearly 15 years, it has been widely believed that many introns were recently acquired by the genes of multicellular organisms. However, the mechanism of acquisition has yet to be described for a single animal intron. Here, we report a large-scale computational analysis of the human, Drosophila melanogaster, Caenorhabditis elegans, and Arabidopsis thaliana genomes. We divided 147,796 human intron sequences into batches of similar lengths and aligned them with each other. Different types of homologies between introns were found, but none showed evidence of simple intron transposition. Also, 106,902 plant, 39,624 Drosophila, and 6021 C. elegans introns were examined. No single case of homologous introns in nonhomologous genes was detected. Thus, we found no example of transposition of introns in the last 50 million years in humans, in 3 million years in Drosophila and C. elegans, or in 5 million years in Arabidopsis. Either new introns do not arise via transposition of other introns or intron transposition must have occurred so early in evolution that all traces of homology have been lost. AD - Department of Medicine, Medical College of Ohio, Toledo, Ohio 43614, USA. AU - Fedorov A AU - Roy S AU - Fedorova L AU - Gilbert W LA - ENG PT - JOURNAL ARTICLE TA - Genome Res JID - 9518021 EDAT- 2003/09/17 05:00 MHDA- 2003/09/17 05:00 AID - 10.1101/gr.1029803 [doi] AID - 1029803 [pii] PST - aheadofprint SO - Genome Res 2003 Sep 15;. UI - 0 PMID- 12974817 OWN - NLM STAT- pubmed-not-medline DA - 20030916 IS - 0960-7412 VI - 36 IP - 1 DP - 2003 Oct TI - Establishment of a high-efficiency SNP-based framework marker set for Arabidopsis. PG - 122-140 AB - The major goal of this project was the establishment of a tool for rapid mapping of new mutations and genotyping in Arabidopsis consisting of at least 100 evenly spaced framework markers. We assembled a single nucleotide polymorphism (SNP)-based marker set consisting of 112 polymorphic sites with average spacing of 1.15 Mbp derived from an SNP database that we recently developed. This information was used to set up efficient SNP detection reactions based on multiplexed primer extension assays. The 112 Columbia (Col-0)/C24 framework markers were used to assemble 18 multiplexed SNaPshot assays with which up to eight separate loci can be genotyped in a single-tube/single-capillary format. In addition, for 110 framework markers matrix-assisted laser desorption/ionization time of flight (MALDI-ToF) assays have been established for high throughput analyses. We demonstrated the usefulness and the robustness of both procedures of this tool by genotyping 48 BC3F1 individuals created between the accessions Col-0 and C24. Subsets of 10-62 of the established markers discriminate between various combinations of the accessions Col-0, C24, Landsberg erecta (Ler), Cape Verdi Islands (Cvi) and Niederzenz (Nd). Using a subset of 17 evenly distributed and established SNP markers that are also polymorphic between Ler and Col-0, we were able to rapidly map a mutant gene (tbr1) to an interval of 2.3 Mbp in an Ler (tbr1) x Col-0 cross. AD - University of Potsdam, Institute of Biochemistry and Biology - Genetics, Golm, Germany, Max-Planck-Institute of Molecular Plant Physiology, Golm, Germany, Max-Planck-Institute of Chemical Ecology, Jena, Germany, andMax-Planck-Institute for Plant Breeding Research, Cologne, Germany. AU - Torjek O AU - Berger D AU - Meyer RC AU - Mussig C AU - Schmid KJ AU - Rosleff Sorensen T AU - Weisshaar B AU - Mitchell-Olds T AU - Altmann T LA - ENG PT - JOURNAL ARTICLE TA - Plant J JID - 9207397 EDAT- 2003/09/17 05:00 MHDA- 2003/09/17 05:00 AID - 1861 [pii] PST - ppublish SO - Plant J 2003 Oct;36(1):122-140. PMID- 12974816 UI - 22856062 OWN - NLM STAT- in-process DA - 20030916 IS - 0960-7412 VI - 36 IP - 1 DP - 2003 Oct TI - Transgene-induced RNA interference: a strategy for overcoming gene redundancy in polyploids to generate loss-of-function mutations. PG - 114-21 AB - Gene redundancy in polyploid species complicates genetic analyses by making the generation of recessive, loss-of-function alleles impractical. We show that this problem can be circumvented using RNA interference (RNAi) to achieve dominant loss of function of targeted genes. Arabidopsis suecica is an allotetraploid (amphidiploid) hybrid of A. thaliana and A. arenosa. We demonstrate that A. suecica can be genetically transformed using the floral dip method for Agrobacterium-mediated transformation. Transgenes segregate as in a diploid, indicating that chromosome pairing occurs exclusively (or almost so) among homologs and not among homeologs. Expressing a double-stranded (ds) RNA corresponding to the A. thaliana gene, decrease in DNA methylation 1 (DDM1) caused the elimination of DDM1 mRNAs and the loss of methylation at both A. thaliana- and A. arenosa-derived centromere repeats. These results indicate that a single RNAi-inducing transgene can dominantly repress multiple orthologs. AD - Biology Department, Washington University, 1 Brookings Drive, St Louis, MO 63130, USA. FAU - Lawrence, Richard J AU - Lawrence RJ FAU - Pikaard, Craig S AU - Pikaard CS LA - eng PT - Journal Article PL - England TA - Plant J JID - 9207397 SB - IM EDAT- 2003/09/17 05:00 MHDA- 2003/09/17 05:00 AID - 1857 [pii] PST - ppublish SO - Plant J 2003 Oct;36(1):114-21. PMID- 12974815 UI - 22856061 OWN - NLM STAT- in-process DA - 20030916 IS - 0960-7412 VI - 36 IP - 1 DP - 2003 Oct TI - Distribution and characterization of over 1000 T-DNA tags in rice genome. PG - 105-13 AB - We generated T-DNA insertions throughout the rice genome for saturation mutagenesis. More than 1000 flanking sequences were mapped on 12 rice chromosomes. Our results showed that T-DNA tags were not randomly spread on rice chromosomes and were preferentially inserted in gene-rich regions. Few insertions (2.4%) were found in repetitive regions. T-DNA insertions in genic (58.1%) and intergenic regions (41.9%) showed a good correlation with the predicted size distribution of these sequences in the rice genome. Whereas, obvious biases were found for the insertions in the 5'- and 3'-regulatory regions outside the coding regions both at 500-bp size and in introns rather than in exons. Such distribution patterns and biases for T-DNA integration in rice are similar to that of the previous report in Arabidopsis, which may result from T-DNA integration mechanism itself. Rice will require approximately the same number of T-DNA insertions for saturation mutagenesis as will Arabidopsis. A database of the T-DNA insertion sites in rice is publicly available at our web site (http://www.genomics.zju.edu.cn/ricetdna). AD - The State Key Laboratory of Plant Physiology and Biochemistry, College of Life Science, Zhejiang University, Hangzhou 310029, China. FAU - Chen, Shuangyan AU - Chen S FAU - Jin, Weizheng AU - Jin W FAU - Wang, Mingyi AU - Wang M FAU - Zhang, Fan AU - Zhang F FAU - Zhou, Jie AU - Zhou J FAU - Jia, Qiaojun AU - Jia Q FAU - Wu, Yunrong AU - Wu Y FAU - Liu, Feiyan AU - Liu F FAU - Wu, Ping AU - Wu P LA - eng PT - Journal Article PL - England TA - Plant J JID - 9207397 SB - IM EDAT- 2003/09/17 05:00 MHDA- 2003/09/17 05:00 AID - 1860 [pii] PST - ppublish SO - Plant J 2003 Oct;36(1):105-13. PMID- 12974814 UI - 22856060 OWN - NLM STAT- in-process DA - 20030916 IS - 0960-7412 VI - 36 IP - 1 DP - 2003 Oct TI - The AtGRF family of putative transcription factors is involved in leaf and cotyledon growth in Arabidopsis. PG - 94-104 AB - Previously, we identified a novel rice gene, GROWTH-REGULATING FACTOR1 (OsGRF1), which encodes a putative transcription factor that appears to play a regulatory role in stem elongation. We now describe the GRF gene family of Arabidopsis thaliana (AtGRF), which comprises nine members. The deduced AtGRF proteins contain the same characteristic regions-the QLQ (Gln, Leu, Gln) and WRC (Trp, Arg, Cys) domains-as do OsGRF1 and related proteins in rice, as well as features indicating a function in transcriptional regulation. Most of the AtGRF genes are strongly expressed in actively growing and developing tissues, such as shoot tips, flower buds, and roots, but weakly in mature stem and leaf tissues. Overexpression of AtGRF1 and AtGRF2 resulted in larger leaves and cotyledons, as well as in delayed bolting of the inflorescence stem when compared to wild-type plants. In contrast, triple insertional null mutants of AtGRF1-AtGRF3 had smaller leaves and cotyledons, whereas single mutants displayed no changes in phenotype and double mutants displayed only minor ones. The alteration of leaf growth in overexpressors and triple mutants was based on an increase or decrease in cell size, respectively. These results indicate that AtGRF proteins play a role in the regulation of cell expansion in leaf and cotyledon tissues. AD - Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, MI 48824-1312, USA, andDepartment of Plant Biology, Michigan State University, East Lansing, MI 48824-1312, USA. FAU - Kim, Jeong Hoe AU - Kim JH FAU - Choi, Dongsu AU - Choi D FAU - Kende, Hans AU - Kende H LA - eng PT - Journal Article PL - England TA - Plant J JID - 9207397 SB - IM EDAT- 2003/09/17 05:00 MHDA- 2003/09/17 05:00 AID - 1862 [pii] PST - ppublish SO - Plant J 2003 Oct;36(1):94-104. UI - 0 PMID- 12974813 OWN - NLM STAT- pubmed-not-medline DA - 20030916 IS - 0960-7412 VI - 36 IP - 1 DP - 2003 Oct TI - Characterization and functional analysis of three wheat genes with homology to the CONSTANS flowering time gene in transgenic rice. PG - 82-93 AB - The CONSTANS (CO) gene of Arabidopsis plays a key role in the photoperiodic flowering pathway. To investigate photoperiod responses in cereals in more detail, we isolated three kinds of CO/Hd1 (rice ortholog of CO) homolog from hexaploid wheat, derived from the A, B, and D genomes and designated as wheat ortholog of CO from A genome (TaHd1-1), TaHd1-2, and TaHd1-3, respectively. They were highly similar to each other and to Hd1, and in addition harbored two conserved regions: two zinc finger motifs and CONSTANS, CONSTANS-LIKE and TIMING OF CAB EXPRESSION 1 (CCT) domain like CO/Hd1. They were located on the long arm of the homoeologous chromosome 6. TaHd1-2 harbored a 63-bp deletion at the promoter region containing the GATA-1 box, and consequently, we detected no subsequent transcript. The TaHd1-1 genomic clone was introduced to a rice line deficient in Hd1 function. Transgenic plants complemented the functions of rice Hd1: they promoted heading under short-day (SD) conditions and delayed it under long-day (LD)/natural conditions, indicating that Hd1 proteins from SD and LD plants share common structures and functions. AD - Kihara Institute for Biological Research and Graduate School of Integrated Science, Yokohama City University, Maioka-cho 641-12, Yokohama 244-0813, Japan, and Department of Molecular Genetics, National Institute of Agrobiological Resources, Tsukuba, Ibaraki 305-8602, Japan. AU - Nemoto Y AU - Kisaka M AU - Fuse T AU - Yano M AU - Ogihara Y LA - ENG PT - JOURNAL ARTICLE TA - Plant J JID - 9207397 EDAT- 2003/09/17 05:00 MHDA- 2003/09/17 05:00 AID - 1859 [pii] PST - ppublish SO - Plant J 2003 Oct;36(1):82-93. UI - 0 PMID- 12974811 OWN - NLM STAT- pubmed-not-medline DA - 20030916 IS - 0960-7412 VI - 36 IP - 1 DP - 2003 Oct TI - The YORE-YORE gene regulates multiple aspects of epidermal cell differentiation in Arabidopsis. PG - 55-66 AB - We have identified a new Arabidopsis mutant, yore-yore (yre), which has small trichomes and glossy stems. Adhesion between epidermal cells was observed in the organs of the yre shoot. The cloned YRE had high homology to plant genes involved in epicuticular wax synthesis, such as ECERIFERUM1 (CER1) and maize GLOSSY1. The phenotype of transgenic plants harboring double-stranded RNA interference (dsRNAi) YRE was quite similar to that of the yre mutant. The amount of epicuticular wax extracted from leaves and stems of yre-1 was approximately one-sixth of that from the wild type. YRE promoter::GUS and in situ hybridization revealed that YRE was specifically expressed in cells of the L1 layer of the shoot apical meristem and young leaves, stems, siliques, and lateral root primordia. Strong expression was detected in developing trichomes. The trichome structure of cer1 was normal, whereas that of the yre cer1 double mutant was heavily deformed, indicating that epicuticular wax is required for normal growth of trichomes. Double mutants of yre and trichome-morphology mutants, glabra 2 (gl2) and transparent testa glabra1 (ttg1), showed that the phenotype of the trichome structure was additive, suggesting that the wax-requiring pathway is distinct from the trichome development pathway controlled by GL2 and TTG1. AD - Plant Science Center, RIKEN, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan, Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kitashirakawa-Oiwake-cho, Sakyo-ku, Kyoto 606-8502, Japan, and Department of Botany, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwake-cho, Sakyo-ku, Kyoto 606-8502, Japan. AU - Kurata T AU - Kawabata-Awai C AU - Sakuradani E AU - Shimizu S AU - Okada K AU - Wada T LA - ENG PT - JOURNAL ARTICLE TA - Plant J JID - 9207397 EDAT- 2003/09/17 05:00 MHDA- 2003/09/17 05:00 AID - 1854 [pii] PST - ppublish SO - Plant J 2003 Oct;36(1):55-66. UI - 0 PMID- 12974810 OWN - NLM STAT- pubmed-not-medline DA - 20030916 IS - 0960-7412 VI - 36 IP - 1 DP - 2003 Oct TI - The SCARECROW gene's role in asymmetric cell divisions in rice plants. PG - 45-54 AB - Asymmetric cell division is one of the most important mechanisms in the diversification of cell function and fate. In Arabidopsis, SCARECROW (SCR) is essential for the asymmetric division of the cortex/endodermis progenitor cell in the root. To learn more about how SCR is involved in asymmetric division, we analyzed the rice SCR (OsSCR) expression. In the root tip, OsSCR expression was observed in the endodermal cell layer and downregulated in the daughter cortex cell after asymmetric division, just as with Arabidopsis SCR. In leaf primordia, expression of OsSCR was observed in stomatal and ligule formation. In stomatal development, OsSCR was specifically expressed in the stomatal cell files before formation of guard mother cells (GMCs), and then, its expression was localized in GMCs, when the first asymmetric division occurred to generate the GMCs. Before the second asymmetric division of subsidiary mother cells (SMCs), localized OsSCR expression was observed in SMCs in the area close to the GMCs. Before these asymmetric divisions, the localization of OsSCR mRNA in GMC-forming cells and SMCs was observed in the area of the daughter GMC and subsidiary cells. OsSCR expression was also observed in the initiation area of ligule formation, and its downregulation occurred in the inner L2 cells generated by asymmetric division. Based on these observations, we proposed that OsSCR is involved not only in the asymmetric division of the cortex/endodermis progenitor cell but also during stomata and ligule formation by establishing the polarization of cytoplasm. AD - BioScience Center, Nagoya University, Chikusa, Nagoya 464-8601, Japan, Graduate School of Agricultural and Life Sciences, University of Tokyo, Tokyo 113-8657, Japan, and College of Bioscience and Biotechnology, Chubu University, Kasugai, Aichi 487-8501, Japan. AU - Kamiya N AU - Itoh JI AU - Morikami A AU - Nagato Y AU - Matsuoka M LA - ENG PT - JOURNAL ARTICLE TA - Plant J JID - 9207397 EDAT- 2003/09/17 05:00 MHDA- 2003/09/17 05:00 AID - 1856 [pii] PST - ppublish SO - Plant J 2003 Oct;36(1):45-54. PMID- 12974806 UI - 22856052 OWN - NLM STAT- in-process DA - 20030916 IS - 0960-7412 VI - 36 IP - 1 DP - 2003 Oct TI - AHP2 is required for bivalent formation and for segregation of homologous chromosomes in Arabidopsis meiosis. PG - 1-11 AB - A new Arabidopsis meiotic mutant has been isolated. Homozygous ahp2-1 (Arabidopsis homologue pairing 2) plants were sterile because of failure of both male and female gametophyte development. Fluorescent in situ hybridisation showed that in ahp2-1 male meiocytes, chromosomes did not form bivalents during prophase I and instead seemed to associate indiscriminately. Chromosome fragmentation, chromatin bridges and unbalanced segregation were seen in anaphase I and anaphase II. The ahp2-1 mutation was caused by a T-DNA insertion in an Arabidopsis homologue of meu13+, which has been implicated in homologous chromosome pairing during meiosis in Schizosaccharomyces pombe. Our results suggest that meu13+ function is conserved in higher eukaryotes and support the idea that Arabidopsis, yeast and mouse share a pairing pathway that is not present in Drosophila melanogaster and Caenorhabditis elegans. AD - Department of Cell and Developmental Biology, John Innes Centre, Norwich NR4 7UH, UK. FAU - Schommer, Carla AU - Schommer C FAU - Beven, Ali AU - Beven A FAU - Lawrenson, Tom AU - Lawrenson T FAU - Shaw, Peter AU - Shaw P FAU - Sablowski, Robert AU - Sablowski R LA - eng PT - Journal Article PL - England TA - Plant J JID - 9207397 SB - IM EDAT- 2003/09/17 05:00 MHDA- 2003/09/17 05:00 AID - 1850 [pii] PST - ppublish SO - Plant J 2003 Oct;36(1):1-11. UI - 0 PMID- 12972671 OWN - NLM STAT- pubmed-not-medline DA - 20030915 IS - 1040-4651 DP - 2003 Sep 5 TI - IDA Controls Floral Organ Abscission in Arabidopsis and Identifies a Novel Family of Putative Ligands in Plants. AB - Abscission is an active process that enables plants to shed unwanted organs. Because the purpose of the flower is to facilitate pollination, it often is abscised after fertilization. We have identified an Arabidopsis ethylene-sensitive mutant, inflorescence deficient in abscission (ida), in which floral organs remain attached to the plant body after the shedding of mature seeds, even though a floral abscission zone develops. The IDA gene, positioned in the genomic DNA flanking the single T-DNA present in the ida line, was identified by complementation. The gene encodes a small protein with an N-terminal signal peptide, suggesting that the IDA protein is the ligand of an unknown receptor involved in the developmental control of floral abscission. We have identified Arabidopsis genes, and cDNAs from a variety of plant species, that encode similar proteins, which are distinct from known ligands. IDA and the IDA-like proteins may represent a new class of ligands in plants. AD - Division of Cell and Molecular Biology, University of Oslo, N-0315 Oslo, Norway. AU - Butenko MA AU - Patterson SE AU - Grini PE AU - Stenvik GE AU - Amundsen SS AU - Mandal A AU - Aalen RB LA - ENG PT - JOURNAL ARTICLE TA - Plant Cell JID - 9208688 EDAT- 2003/09/16 05:00 MHDA- 2003/09/16 05:00 AID - 10.1105/tpc.014365 [doi] AID - tpc.014365 [pii] PST - aheadofprint SO - Plant Cell 2003 Sep 5;. UI - 0 PMID- 12972670 OWN - NLM STAT- pubmed-not-medline DA - 20030915 IS - 1040-4651 DP - 2003 Sep 5 TI - The STT3a Subunit Isoform of the Arabidopsis Oligosaccharyltransferase Controls Adaptive Responses to Salt/Osmotic Stress. AB - Arabidopsis stt3a-1 and stt3a-2 mutations cause NaCl/osmotic sensitivity that is characterized by reduced cell division in the root meristem. Sequence comparison of the STT3a gene identified a yeast ortholog, STT3, which encodes an essential subunit of the oligosaccharyltransferase complex that is involved in protein N-glycosylation. NaCl induces the unfolded protein response in the endoplasmic reticulum (ER) and cell cycle arrest in root tip cells of stt3a seedlings, as determined by expression profiling of ER stress-responsive chaperone (BiP-GUS) and cell division (CycB1;1-GUS ) genes, respectively. Together, these results indicate that plant salt stress adaptation involves ER stress signal regulation of cell cycle progression. Interestingly, a mutation (stt3b-1) in another Arabidopsis STT3 isogene (STT3b) does not cause NaCl sensitivity. However, the stt3a-1 stt3b-1 double mutation is gametophytic lethal. Apparently, STT3a and STT3b have overlapping and essential functions in plant growth and developmental processes, but the pivotal and specific protein glycosylation that is a necessary for recovery from the unfolded protein response and for cell cycle progression during salt/osmotic stress recovery is associated uniquely with the function of the STT3a isoform. AD - Department of Horticultural Sciences, Texas A&M University, College Station, Texas 77843-2133. AU - Koiwa H AU - Li F AU - McCully MG AU - Mendoza I AU - Koizumi N AU - Manabe Y AU - Nakagawa Y AU - Zhu J AU - Rus A AU - Pardo JM AU - Bressan RA AU - Hasegawa PM LA - ENG PT - JOURNAL ARTICLE TA - Plant Cell JID - 9208688 EDAT- 2003/09/16 05:00 MHDA- 2003/09/16 05:00 AID - 10.1105/tpc.013862 [doi] AID - tpc.013862 [pii] PST - aheadofprint SO - Plant Cell 2003 Sep 5;. UI - 0 PMID- 12972669 OWN - NLM STAT- pubmed-not-medline DA - 20030915 IS - 0032-0889 DP - 2003 Sep 11 TI - Ethylene and Auxin Control the Arabidopsis Response to Decreased Light Intensity. AB - Morphological responses of plants to shading have long been studied as a function of light quality, in particular the ratio of red to far red light that affects phytochrome activity. However, changes in light quantity are also expected to be important for the shading response because plants have to adapt to the reduction in overall energy input. Here, we present data on the involvement of auxin and ethylene in the response to low light intensities. Decreased light intensities coincided with increased ethylene production in Arabidopsis rosettes. This response was rapid because the plants reacted within minutes. In addition, ethylene- and auxin-insensitive mutants are impaired in their reaction to shading, which is reflected by a defect in leaf elevation and an aberrant leaf biomass allocation. On the molecular level, several auxin-inducible genes are up-regulated in wild-type Arabidopsis in response to a reduction in light intensity, including the primary auxin response gene IAA3 and a protein with similarity to AUX22 and the 1-aminocyclopropane-1-carboxylic acid synthase genes ACS6, ACS8, and ACS9 that are involved in ethylene biosynthesis. Taken together, the data show that ethylene and auxin signaling are required for the response to low light intensities. AD - Department of Molecular Genetics, University of Ghent, Belgium. AU - Vandenbussche F AU - Vriezen WH AU - Smalle J AU - Laarhoven LJ AU - Harren FJ AU - Van Der Straeten D LA - ENG PT - JOURNAL ARTICLE TA - Plant Physiol JID - 0401224 EDAT- 2003/09/16 05:00 MHDA- 2003/09/16 05:00 AID - 10.1104/pp.103.022665 [doi] AID - pp.103.022665 [pii] PST - aheadofprint SO - Plant Physiol 2003 Sep 11;. UI - 0 PMID- 12972666 OWN - NLM STAT- pubmed-not-medline DA - 20030915 IS - 0032-0889 DP - 2003 Aug 14 TI - Arabidopsis Genes Encoding Mitochondrial Type II NAD(P)H Dehydrogenases Have Different Evolutionary Origin and Show Distinct Responses to Light. AB - In addition to proton-pumping complex I, plant mitochondria contain several type II NAD(P)H dehydrogenases in the electron transport chain. The extra enzymes allow the nonenergy-conserving electron transfer from cytoplasmic and matrix NAD(P)H to ubiquinone. We have investigated the type II NAD(P)H dehydrogenase gene families in Arabidopsis. This model plant contains two and four genes closely related to potato (Solanum tuberosum) genes nda1 and ndb1, respectively. A novel homolog, termed ndc1, with a lower but significant similarity to potato nda1 and ndb1, is also present. All genes are expressed in several organs of the plant. Among the nda genes, expression of nda1, but not nda2, is dependent on light and circadian regulation, suggesting separate roles in photosynthesis-associated and other respiratory NADH oxidation. Genes from all three gene families encode proteins exclusively targeted to mitochondria, as revealed by expression of green fluorescent fusion proteins and by western blotting of fractionated cells. Phylogenetic analysis indicates that ndc1 affiliates with cyanobacterial type II NADH dehydrogenase genes, suggesting that this gene entered the eukaryotic cell via the chloroplast progenitor. The ndc1 should then have been transferred to the nucleus and acquired a signal for mitochondrial targeting of the protein product. Although they are of different origin, the nda, ndb, and ndc genes carry an identical intron position. AD - Department of Cell and Organism Biology, Biology Building, Lund University, Solvegatan 35B, SE-223 62 Lund, Sweden. AU - Michalecka AM AU - Svensson AS AU - Johansson FI AU - Agius SC AU - Johanson U AU - Brennicke A AU - Binder S AU - Rasmusson AG LA - ENG PT - JOURNAL ARTICLE TA - Plant Physiol JID - 0401224 EDAT- 2003/09/16 05:00 MHDA- 2003/09/16 05:00 AID - 10.1104/pp.103.024208 [doi] AID - pp.103.024208 [pii] PST - aheadofprint SO - Plant Physiol 2003 Aug 14;. UI - 0 PMID- 12972665 OWN - NLM STAT- pubmed-not-medline DA - 20030915 IS - 0032-0889 DP - 2003 Aug 14 TI - Diurnal and Light-Regulated Expression of AtSTP1 in Guard Cells of Arabidopsis. AB - Guard cell chloroplasts are unable to perform significant photosynthetic CO2 fixation via Rubisco. Therefore, guard cells depend on carbon supply from adjacent cells even during the light period. Due to their reversible turgor changes, this import cannot be mediated by plasmodesmata. Nevertheless, guard cells of several plants were shown to use extracellular sugars or to accumulate sucrose as an osmoticum that drives water influx to increase stomatal aperture. This paper describes the first localization of a guard cell-specific Arabidopsis sugar transporter involved in carbon acquisition of these symplastically isolated cells. Expression of the AtSTP1 H(+)-monosacharide symporter gene in guard cells was demonstrated by in situ hybridization and by immunolocalization with an AtSTP1-specific antiserum. Additional RNase protection analyses revealed a strong increase of AtSTP1 expression in the dark and a transient, diurnally regulated increase during the photoperiod around midday. This transient increase in AtSTP1 expression correlates in time with the described guard cell-specific accumulation of sucrose. Our data suggest a function of AtSTP1 in monosaccharide import into guard cells during the night and a possible role in osmoregulation during the day. AD - Molekulare Pflanzenphysiologie, Universitat Erlangen-Nurnberg, Staudtstrasse 5, D-91058 Erlangen, Germany. AU - Stadler R AU - Buttner M AU - Ache P AU - Hedrich R AU - Ivashikina N AU - Melzer M AU - Shearson SM AU - Smith SM AU - Sauer N LA - ENG PT - JOURNAL ARTICLE TA - Plant Physiol JID - 0401224 EDAT- 2003/09/16 05:00 MHDA- 2003/09/16 05:00 AID - 10.1104/pp.103.024240 [doi] AID - pp.103.024240 [pii] PST - aheadofprint SO - Plant Physiol 2003 Aug 14;. UI - 0 PMID- 12972664 OWN - NLM STAT- pubmed-not-medline DA - 20030915 IS - 0032-0889 DP - 2003 Sep 11 TI - ADP-Glucose Pyrophosphorylase Is Activated by Posttranslational Redox-Modification in Response to Light and to Sugars in Leaves of Arabidopsis and Other Plant Species. AB - ADP-glucose pyrophosphorylase (AGPase) catalyzes the first committed reaction in the pathway of starch synthesis. It was recently shown that potato (Solanum tuberosum) tuber AGPase is subject to redox-dependent posttranslational regulation, involving formation of an intermolecular Cys bridge between the two catalytic subunits (AGPB) of the heterotetrameric holoenzyme (A. Tiessen, J.H.M. Hendriks, M. Stitt, A. Branscheid, Y. Gibon, E.M. Farre, P. Geigenberger [2002] Plant Cell 14: 2191-2213). We show here that AGPase is also subject to posttranslational regulation in leaves of pea (Pisum sativum), potato, and Arabidopsis. Conversion is accompanied by an increase in activity, which involves changes in the kinetic properties. Light and sugars act as inputs to trigger posttranslational regulation of AGPase in leaves. AGPB is rapidly converted from a dimer to a monomer when isolated chloroplasts are illuminated and from a monomer to a dimer when preilluminated leaves are darkened. AGPB is converted from a dimer to monomer when sucrose is supplied to leaves via the petiole in the dark. Conversion to monomeric form increases during the day as leaf sugars increase. This is enhanced in the starchless phosphoglucomutase mutant, which has higher sugar levels than wild-type Columbia-0. The extent of AGPB monomerization correlates with leaf sugar levels, and at a given sugar content, is higher in the light than the dark. This novel posttranslational regulation mechanism will allow starch synthesis to be regulated in response to light and sugar levels in the leaf. It complements the well-characterized regulation network that coordinates fluxes of metabolites with the recycling of phosphate during photosynthetic carbon fixation and sucrose synthesis. AD - Max Planck Institute of Molecular Plant Physiology, Am Muhlenberg 1, 14476 Golm, Germany. AU - Hendriks JH AU - Kolbe A AU - Gibon Y AU - Stitt M AU - Geigenberger P LA - ENG PT - JOURNAL ARTICLE TA - Plant Physiol JID - 0401224 EDAT- 2003/09/16 05:00 MHDA- 2003/09/16 05:00 AID - 10.1104/pp.103.024513 [doi] AID - pp.103.024513 [pii] PST - aheadofprint SO - Plant Physiol 2003 Sep 11;. UI - 0 PMID- 12972659 OWN - NLM STAT- pubmed-not-medline DA - 20030915 IS - 0032-0889 DP - 2003 Aug 21 TI - The G-Protein-Coupled Receptor GCR1 Regulates DNA Synthesis through Activation of Phosphatidylinositol-Specific Phospholipase C. AB - Different lines of evidence suggest that specific events during the cell cycle may be mediated by a heterotrimeric G-protein activated by a cognate G-protein coupled receptor. However, coupling between the only known Galpha-subunit of the heterotrimeric G-protein (GPA1) and the only putative G-protein coupled receptor (GCR1) of plants has never been shown. Using a variety of approaches, we show here that GCR1-enhanced thymidine incorporation into DNA depends on an increase in phosphatidylinositol-specific phospholipase C activity and an elevation of inositol 1,4,5-trisphosphate levels in the cells. Tobacco (Nicotiana tabacum) cells that overexpress either Arabidopsis GCR1 or GPA1 display this phenomenon. We suggest on the basis of these results that GCR1-controlled events during the cell cycle involve phosphatidylinositol-specific phospholipase C as an effector of GCR1 and inositol 1,4,5-trisphosphate as a second messenger, and that GCR1 and GPA1 are both involved in this particular signaling pathway. AD - Arena Pharmaceuticals, 6166 Nancy Ridge Drive, San Diego, California 92121. AU - Apone F AU - Alyeshmerni N AU - Wiens K AU - Chalmers D AU - Chrispeels MJ AU - Colucci G LA - ENG PT - JOURNAL ARTICLE TA - Plant Physiol JID - 0401224 EDAT- 2003/09/16 05:00 MHDA- 2003/09/16 05:00 AID - 10.1104/pp.103.026005 [doi] AID - pp.103.026005 [pii] PST - aheadofprint SO - Plant Physiol 2003 Aug 21;. UI - 0 PMID- 12972658 OWN - NLM STAT- pubmed-not-medline DA - 20030915 IS - 0032-0889 DP - 2003 Sep 11 TI - Development of Protoporphyrinogen Oxidase as an Efficient Selection Marker for Agrobacterium tumefaciens-Mediated Transformation of Maize. AB - In this article, we report the isolation of plant protoporphyrinogen oxidase (PPO) genes and the isolation of herbicide-tolerant mutants. Subsequently, an Arabidopsis double mutant (Y426M + S305L) was used to develop a selectable marker system for Agrobacterium tumefaciens-mediated transformation of maize (Zea mays) and to obtain multiple events tolerant to the PPO family of herbicides. Maize transformants were produced via butafenacil selection using a flexible light regime to increase selection pressure. Butafenacil selection per se did not change transgene copy number distribution relative to other selectable marker systems, but the most tolerant events identified in the greenhouse were more likely to contain multiple copies of the introduced mutant PPO gene. To date, more than 2,500 independent transgenic maize events have been produced using butafenacil selection. The high frequency of A. tumefaciens-mediated transformation via PPO selection enabled us to obtain single-copy transgenic maize lines tolerant to field levels of butafenacil. AD - Syngenta Biotechnology, Inc., P.O. Box 12257, 3054 Cornwallis Road, Research Triangle Park, North Carolina 27709-2257. AU - Li X AU - Volrath SL AU - Nicholl DB AU - Chilcott CE AU - Johnson MA AU - Ward ER AU - Law MD LA - ENG PT - JOURNAL ARTICLE TA - Plant Physiol JID - 0401224 EDAT- 2003/09/16 05:00 MHDA- 2003/09/16 05:00 AID - 10.1104/pp.103.026245 [doi] AID - pp.103.026245 [pii] PST - aheadofprint SO - Plant Physiol 2003 Sep 11;.