The arabidopsis book最新文献

Unlabelled: Arabidopsis has been well studied as a model plant for plant pathogen interactions. While a large portion of the literature has been devoted to interactions between Arabidopsis and Pseudomonas and Peronospora species, a small cadre of researchers have been making inroads on the response of Arabidopsis to Xanthomonas. Differential responses of Arabidopsis accessions to isolates of Xanthomonas campestris pv campestris include tolerance, a hypersensitive response, resistance without a hypersensitive response and disease which is characterized by chlorosis and necrosis. Loci that govern the recognition of X. c. campestris have been identified and are the focus of on-going positional cloning efforts. Signaling and other downstream molecules involved in manifestation of resistance to Xanthomonas have been investigated resulting in the identification of many components of the resistance response. Parallel to the characterization of the host response, molecular and genomic efforts focused on the pathogen have the potential to reveal the mechanisms by which this bacterium can invade and colonize host tissues.

Abbreviations: colony forming units (CFU), Columbia (Col-0), days post inoculation (dpi), hypersensitive response (HR), Landsberg erecta (Ler), pathogenesis-related protein 1 (PR-1), phenylalanine ammonia lyase (PAL), Xanthomonas campestris pv campestris (Xcc).

Parasitic plants invade host plants in order to rob them of water, minerals and nutrients. The consequences to the infected hosts can be debilitating and some of the world's most pernicious agricultural weeds are parasitic. Parasitic genera of the Scrophulariaceae and Orobanchaceae directly invade roots of neighboring plants via underground structures called haustoria. The mechanisms by which these parasites identify and associate with host plants present unsurpassed opportunities for studying chemical signaling in plant-plant interactions. Seeds of some parasites require specific host factors for efficient germination, thereby insuring the availability of an appropriate host root prior to germination. A second set of signal molecules is required to induce haustorium development and the beginning of heterotrophy. Later stages in parasitism also require the presence of host factors, although these have not yet been well characterized. Arabidopsis is being used as a model host plant to identify genetic loci associated with stimulating parasite germination, haustorium development, and parasite support. Arabidopsis is also being employed to explore how host plants respond to parasite attack. Current methodologies and recent findings in Arabidopsis - parasitic plant interactions will be discussed.

Studying salt stress is an important means to the understanding of plant ion homeostasis and osmo-balance. Salt stress research also benefits agriculture because soil salinity significantly limits plant productivity on agricultural lands. Decades of physiological and molecular studies have generated a large body of literature regarding potential salt tolerance determinants. Recent advances in applying molecular genetic analysis and genomics tools in the model plant Arabidopsis thaliana are shading light on the molecular nature of salt tolerance effectors and regulatory pathways.

Plant chitinases (EC 3.2.1.14) belong to relatively large gene families subdivided in classes that suggest class-specific functions. They are commonly induced upon the attack of pathogens and by various sources of stress, which led to associating them with plant defense in general. However, it is becoming apparent that most of them display several functions during the plant life cycle, including taking part in developmental processes such as pollination and embryo development. The number of chitinases combined with their multiple functions has been an obstacle to a better understanding of their role in plants. It is therefore important to identify and inventory all chitinase genes of a plant species to be able to dissect their function and understand the relations between the different classes. Complete sequencing of the Arabidopsis genome has made this task feasible and we present here a survey of all putative chitinase-encoding genes accompanied by a detailed analysis of their sequence. Based on their characteristics and on studies on other plant chitinases, we propose an overview of their possible functions as well as modified annotations for some of them.

The availability of the Arabidopsis thaliana genome sequence allows a comprehensive analysis of transcriptional regulation in plants using novel genomic approaches and methodologies. Such a genomic view of transcription first necessitates the compilation of lists of elements. Transcription factors are the most numerous of the different types of proteins involved in transcription in eukaryotes, and the Arabidopsis genome codes for more than 1,500 of them, or approximately 6% of its total number of genes. A genome-wide comparison of transcription factors across the three eukaryotic kingdoms reveals the evolutionary generation of diversity in the components of the regulatory machinery of transcription. However, as illustrated by Arabidopsis, transcription in plants follows similar basic principles and logic to those in animals and fungi. A global view and understanding of transcription at a cellular and organismal level requires the characterization of the Arabidopsis transcriptome and promoterome, as well as of the interactome, the localizome, and the phenome of the proteins involved in transcription.