Terrestrial plants host phylogenetically and functionally diverse groups of below-ground microbes, whose community structure controls plant growth/survival in both natural and agricultural ecosystems. Therefore, understanding the processes by which whole root-associated microbiomes are organized is one of the major challenges in ecology and plant science. We here report that diverse root-associ...

Recent analyses of the small subunit ribosomal DNA (srDNA) from dinoflagellate symbionts of cnidaria have confirmed historical descriptions of a diverse but well-defined clade, Symbiodinium, as well as several other independent symbiont lineages (Rowan 1991; Rowan and Powers 1992; Sadler et al. 1992; McNally et al 1994). Dinoflagellates also occur as intracellular symbionts in a number of pelag...

Deep-sea mussels of the genus Bathymodiolus are numerically dominant macrofauna in many cold seep and hydrothermal vent ecosystems worldwide, and they depend on organic carbon produced by symbionts present in the epithelial cells of the gills. Although Bathymodiolus platifrons represents typical methanotrophic endosymbiosis, our understanding of molecular mechanisms of methane oxidization and c...

The light-organ symbiosis between the squid Euprymna scolopes and the luminous bacterium Vibrio fischeri offers the opportunity to decipher the hour-by-hour events that occur during the natural colonization of an animal's epithelial surface by its microbial partners. To determine the genetic basis of these events, a glass-slide microarray was used to characterize the light-organ transcriptome o...

Almost all aphids harbour an endosymbiotic bacterium, Buchnera aphidicola, in bacteriocytes. Buchnera synthesizes essential nutrients and supports growth and reproduction of the host. Over the long history of endosymbiosis, many essential genes have been lost from the Buchnera genome, resulting in drastic genome reduction and the inability to live outside the host cells. In turn, when deprived ...

Marine sponges host bacterial communities with important ecological and economic roles in nature and society, yet these benefits depend largely on the stability of host-symbiont interactions and their susceptibility to changing environmental conditions. Here, we investigated the temporal stability of complex host-microbe symbioses in a temperate, seasonal environment over three years, targeting...

The mutualism between fungus-growing termites (Macrotermitinae) and their mutualistic fungi (Termitomyces) began in Africa. The fungus-growing termites have secondarily colonized Madagascar and only a subset of the genera found in Africa is found on this isolated island. Successful long-distance colonization may have been severely constrained by the obligate interaction of the termites with fun...

BACKGROUND A host obtains symbionts by horizontal transmission when infected from the environment or contagiously from other hosts in the same generation. In contrast, vertical transmission occurs when a host obtains its symbionts directly from its parents. Either vertical or horizontal transmission can sustain an association between a host and its symbiont. QUESTIONS What evolutionary forces...

Homologous recombination is a fundamental mechanism for the genetic diversification of free-living bacteria. However, recombination may be limited in endosymbiotic bacteria, as these taxa are locked into an intracellular niche and may rarely encounter sources of foreign DNA. This study tested the hypothesis that vertically transmitted endosymbionts of deep-sea clams (Bivalvia: Vesicomyidae) sho...

While past work has often examined the effects of transmission mode on virulence evolution in parasites, few studies have explored the impact of horizontal transmission on the evolution of benefits conferred by a symbiont to its host. Here, we identify three mechanisms that create a positive covariance between horizontal transmission and symbiont-provided benefits: pleiotropy within the symbion...