A polyphasic analysis was carried out to clarify the taxonomic status of four marine actinomycete strains that share a phylogenetic relationship and phenotypic characteristics with the genus Salinispora. These strains formed a distinct lineage within the Salinispora 16S rRNA and gyrB trees and were found to possess a range of phenotypic properties and DNA:DNA hybridization values that distinguished them from the type strains of the two validly named species in this genus, Salinispora tropica (CNB-440(T), ATCC BAA-916(T)) and Salinispora arenicola (CNH-643(T), ATCC BAA-917(T)). The combined genotypic and phenotypic data support this conclusion. It is proposed that the strains be designated as Salinispora pacifica sp. nov., the type strain of which is CNR-114(T) (DSMZ YYYYT = KACC 17160(T)).

Lucerne (Medicago sativa), a major perennial pasture legume, belongs to a species complex that includes several subspecies with wild and cultivated populations. Stand establishment may be compromised by poor germination. Seed scarification, deterioration and temperature have an impact on germination. The objective of this study was to analyse the genetic diversity of lucerne germination in response to three factors: (1) temperature, with seven constant temperatures ranging from 5 to 40°C, was tested on 38 accessions, (2) seed scarification was tested on the same accessions at 5 and 22°C, (3) seed deterioration was tested on two accessions and two seed lots at the seven temperatures. The germination dynamics of seed lots over time was modelled and three parameters were analysed: germinability (germination capacity), maximum germination rate (maximum% of seeds germinating per time unit), and lag time before the first seed germinates. Seed scarification enhanced germinability at both temperatures and its effect was much higher on falcata and wild sativa accessions. Incomplete loss of the hardseededness trait during domestication and selection is hypothesised, indicating that the introduction of wild material in breeding programmes should be followed by the selection for germinability without scarification. Seed lots with altered germinability had low germination at extreme temperatures, both cold and hot, suggesting that mild temperatures are required to promote germination of damaged seed lots. A large genetic diversity was revealed for germination (both capacity and rate) in response to temperature. All accessions had an optimal germination at 15 or 22°C and a poor germination at 40°C. The sativa varieties and landraces had a high germination from 5 to 34°C while the germination of falcata and the wild sativa accessions were weakened at 5 or 34°C, respectively. These differences are interpreted in terms of adaptation to the climate of their geographical origin regions in order to escape frost or heat/drought risks. These new findings give insights on adaptation and domestication of lucerne in its wide geographic area. They suggest further improvement of germination is needed, especially when introducing wild material in breeding pools to remove scarification requirements and to limit differences in response to temperature.

The taxonomic position of three acidophilic actinobacteria, strains FGG38, FGG39 and FSCA67T, isolated from the fermentation litter layer of a spruce forest soil was established using a polyphasic approach. The strains were shown to have chemotaxonomic and morphological properties consistent with their classification in the genus Streptacidiphilus and formed a distinct phyletic line in the Streptacidiphilus 16S rRNA gene tree being most closely related to Streptacidiphilus albus DSM 41753T (99.4 % similarity). DNA:DNA relatedness data showed that isolate FSCA67T and the type strain of S. albus belonged to markedly distinct genomic species. The isolates had many phenotypic properties in common and were distinguished readily from their closest phylogenetic neighbours in the Streptacidiphilus gene tree using a broad range of these features. Based on the combined genotypic and phenotypic data the three isolates are considered to represent a new Streptacidiphilus species. The name Streptacidiphilus durhamensis sp. nov. is proposed for this taxon with isolate FSCA67T (=DSM 45796T = KACC 17154T = NCIMB 14829T) as the type strain.

Temperature is one of the major factors controlling plant development, in particular seed germination. Alfalfa is a perennial pasture legume that holds an important place in cultivated grasslands. Breeding alfalfa cultivars adapted to new ranges of temperature could be necessary, requiring knowledge of the variability in response to temperature among different accessions. Six accessions of Medicago sativa subsp. sativa and one wild population of M. sativa subsp. falcata were evaluated for their germination temperature response. Seeds were tested for germination in the dark at eight constant temperatures, from 5 to 40°C. Significant differences (P < 0.01) were found. The optimum temperature for germination ranged between 11.7 and 21.1°C, whereas two varieties, ‘Demnate’ and ‘Luzelle’ had a very wide range of temperatures favouring maximum germination. The findings of this study suggest that the germination of alfalfa was little affected by low temperature (5°C) whereas germination at 40°C was lower and showed high variability. Our results revealed variability in the response to temperature for germination of M. sativa that gives room for breeding new varieties adapted to future environmental conditions induced by the global climate change.