Frankia as a Biodegrading Agent

Abstract

The Frankia actinorhizal plant symbiosis plays an important role in colonization of soils contaminated with toxic aromatic hydrocarbons. Our understanding of the bacterial partner, Frankia, in the actinorhizal symbiosis has been greatly facilitated by the availability of sequenced genomes. The analysis of these Frankia genomes has suggested that these bacteria are metabolically diverse and have potential for toxic aromatic hydrocarbon degradation. In this chapter, we explore what is known about that metabolic potential.Keywords: Frankias-triazines, aromatic hydrocarbon degradation, P"H, bioremediation, bioinformatics, actinobacteria . IntroductionFrankia are filamentous nitrogen-fixing Gram-positive actinobacteria that are found as freeliving microbes in the soil and in symbiotic associations with actinorhizal plants [ -]. These bacteria fix nitrogen by converting atmospheric N into biologically useful ammonia and supply the host plants with a source of reduced nitrogen. Frankia are developmentally complex and form three cell types vegetative hyphae, spores located in sporangia, and vesicles. Hyphae are septate structures and form the growing state of this microbe. Under appropriate conditions, either terminal or intercalary multilocular sporangia are produced and contain many spores. When mature, the spores are released from the sporangia. The spores are presumed to aid in the survival and dispersal of Frankia in the environment. Vesicles are produced under nitrogen-limited conditions and consist of unique lipid-enveloped cellular structures that contain the enzymes responsible for nitrogen fixation. Thus, vesicles act as specialized structures for the nitrogen fixation process. Frankia are able to establish symbiotic nitrogen-© 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.fixing associations with over species of woody dicotyledonous plants, termed actinorhizal plants, that are found in eight families of angiosperms [ , -]. The symbiosis with Frankia allows these actinorhizal host plants to colonize nutrient-poor soil and harsh environments. "ctinorhizal plants have been used to recolonize and reclaim industrial wastelands and environments contaminated with heavy metals and toxic aromatic hydrocarbon [ -]. The metabolic potential of these bacteria has only recently been investigated in the context of bioremediation [ -]. . . Frankia genomics and identification of metabolic potential"ased on phylogenetic analysis, Frankia strains have been classified into four main lineages [ -]. Members of lineage are found infective on host plants of the "etulaceae Alnus , Myricaceae, and Casuariaraceae families, while lineage represents strains that are infective on Rosaceae Dryas, etc. , Coriariaceae Coriaria , Datiscaceae Datisca , and the genus Ceanothus Rhamnaceae . Mem...

Permanent Draft Genome sequence for Frankia sp. strain CcI49, a Nitrogen-Fixing Bacterium Isolated from Casuarina cunninghamiana that Infects Elaeagnaceae

“…The bph operon is also present in Frankia sp. strains EuI1c and EUN1f genomes 20 and was also found in the genomes of Frankia sp. strains G2 and R43 11 , 12 , cluster 3 strains isolated from Casuarina root nodules.…”

In-Depth Characterization of Plant Growth Promotion Potentials of Selected Alkanes-Degrading Plant Growth-Promoting Bacterial Isolates

“…Earlier studies reported that other N-fixers such as Frankia spp. were found to harbored alkane genes in addition nifH gene ( Rehan et al, 2016 ). Diazotroph capable of coupling N-fixation to hydrocarbon degradation represent a key strategy to promote plant growth in N-limited marginal lands such as PHC-contaminated soils ( Foght, 2018 ).…”

Saf ve karışık halde yetiştirilen sakallı kızılağaç (Alnus glutinosa Gearth. subsp. barbata) ve Doğu Kayını (Fagus orientalis Lipsky) fidanlarının kısa dönem biyokütle değerleri

“…ve Frankia sp. bakterileridir ve simbiyotik bir ilişki sonucu havadaki azotu, bitkinin bulunduğu toprağa; azot tuzu olarak bağlarlar (Vessey 2003;Karthikeyan et al 2013;Rehan et al 2016). Azot bağlayıcı bakterilere sahip bitkiler, fakir toprakları ıslah etmekte ve bitki besin maddeleri bakımından zenginleştirmektedirler (Diagne et al 2013;Stokdyk ve Herrman 2014).…”