Ectopic expression of coffee HD-ZIP CAHB12 confers drought tolerance to Arabidopsis thaliana

ALVES FERREIRA M; CRUZ F; ROMANO E; CHAN RL; BARTELS D

Hawai US

Congreso; Plant Biology; 2009

ASPP

Title:    Ectopic expression of coffee HD-ZIP CAHB12 confers drought tolerance to Arabidopsis thalianaPoster Category:      Abiotic StressConsider for Talk:      YesPossible ASPB Minisymposium Category:      Abiotic StressAbstract: Homeobox genes present a conserved 61-amino acid motif (homeodomain/HD) and are found in all eukaryotic organisms, generally regulating cellular development and differentiation. Recent studies have shown that homeobox genes of the HD-Zip family are also involved in transcriptional regulation of stress responses in plants. HD-Zip proteins have the HD associated to a leucine zipper and are exclusively found in plants. In our previous work, we identified two contigs named CAHB12 and CAHB1 (Coffee Arabica Homeobox12 and 1) in Genoma Cafe Sequencing Project Consortium database combining phylogenetic methods and in silico analysis of gene expression. To gain futher information in the CAHB12 and CAHB1 gene function, a comprehensive expression analysis were carried on in coffe plants. qPCR experiments showed that CAHB1 and CAHB12 are induced in leaves and roots of C. arabica submitted to drought. In addition CAHB1 shows a conspicuous expression along this organ, while CAHB12 is preferentially expressed in lateral roots, and in upper part of the main root. Spatial analysis of gene expression by in situ hybridization experiments revealed that CAHB1 and CAHB12 are expressed in root phloem. cDNAs of both genes were cloned in binary vectors, and those vectors were used for transformation of Arabidopis plants. Transgenic Arabidopis ectopically expressing CAHB12 presented a higher tolerance level to drought stress during the transition from the reproductive to frutification phases. 35S:CAHB12 seedlings are also more tolerant to salt stress. Our data strongly suggest that at least one homeobox gene of HD zip I family in Coffee has a crucial role in the tolerance to drought stress. These results indicate that CAHB12 can be a key gene in coffee response to drought stress.Broader Impacts: Coffee is an important commodity in several underdeveloped countries, including Brazil, and coffee productivity is highly susceptible to drought stress. The results described in our poster are an important step toward the comprehension of how coffee plants respond to drought stress at molecular level. Moreover, the identification of CAHB12 as a key regulator of coffee plant transcriptional program under water deficit can help traditional breeding and biotech strategies to develop coffee plants tolerant to drought- a crucial trait for a crop that may be specially affect by the Global Warming.   Presenter: Alves-Ferreira, Marcio Authors: Alves-Ferreira, Marcio (A)  alvesfer@biologia.ufrj.br; Cruz, Fernanda (A)  nandacruz@hotmail.com; Romano, Eduardo (B)  romano@cenargen.embrapa.br; Chan, Raquel (D)  rchan@fbcb.unl.edu.ar; Bartels, Dorothea (C)  dbartels@uni-bonn.de; Affiliations: (A): Federal University of Rio de Janeiro(B): Embrapa Recursos Geneticos e Biotecnologia(C): Institute of Molecular Physiology and Biotechnology of Plants, University of Bonn(D): Facultad de Bioquimica y Ciencias Biologicas, Universidad Nacional del Litoral