Rhizobium paknamense sp. nov., isolated from lesser duckweeds (Lemna aequinoctialis)

Abstract

A Gram-stain-negative, rod-shaped bacterium was isolated and designated strain L6-8 T during a study of endophytic bacterial communities in lesser duckweed (Lemna aequinoctialis). Cells of strain L6-8 T were motile with peritrichous flagella. The analysis of the nearly complete 16S rRNA gene sequence indicated that strain L6-8 T was phylogenetically related to species of the genus Rhizobium. Its closest relatives were Rhizobium borbori DN316 T (97.6 %), Rhizobium oryzae Alt 505 T (97.3 %) and Rhizobium pseudoryzae J3-A127 T (97.0 %). The sequence similarity analysis of housekeeping genes recA, glnII, atpD and gyrB showed low levels of sequence similarity (,91.5 %) between strain L6-8 T and other species of the genus Rhizobium with validly published names. The pH range for growth was 4.0-9.0 (optimum 6.0-7.0), and the temperature range for growth was 20-45 6C (optimum 30 6C). Strain L6-8 T tolerated NaCl up to 2 % (w/v) (optimum 1 % NaCl). The predominant components of cellular fatty acids were C 19 : 0 cyclo v8c (31.32 %), summed feature 8 (C 18 : 1 v7c and/or C 18 : 1 v6c; 25.39 %) and C 16 : 0 (12.03 %). The DNA G+C content of strain L6-8 T was 60.4 mol% (T m ). nodC and nifH were not amplified in strain L6-8 T . DNA-DNA relatedness between strain L6-8 T and R. borbori DN316 T , R. oryzae Alt505 T and R. pseudoryzae J3-A127 T was between 11.2 and 18.3 %. Based on the sequence similarity analyses, phenotypic, biochemical and physiological characteristics and DNA-DNA hybridization, strain L6-8 T could be readily distinguished from its closest relatives and represents a novel species of the genus Rhizobium, for which the name Rhizobium paknamense sp. nov. is proposed. The type strain is L6-8 T (5NBRC 109338 T 5BCC 55142 T ).

Allorhizobium sonneratiae sp. nov., an endophytic bacterium isolated from the root of Sonneratia apetala

“…Members of the genus Allorhizobium have been isolated from various environments, such as Allorhizobium borbori from activated sludge [3] and Allorhizobium terrae from paddy soil [4]. Additionally, seven species have been found in different plants, such as Allorhizobium oryzae [5], Allorhizobium pseudoryzae [6] and Allorhizobium oryziradicis [7] isolated from rice, Allorhizobium vitis isolated from grapevines [8], Allorhizobium undicola isolated from Neptuniu natans [1], Allorhizobium taibaishanense isolated from Kummerowia striata [9], and Allorhizobium paknamense isolated from Lemna aequinoctialis [10]. Members of the genus Allorhizobium have been characterized as Gram-negative, aerobic, non-spore-forming rods that are motile with polar flagella.…”

First report of bacterial black stripe on banana caused by Rhizobium paknamense in China

“…4). R. paknamense L6‐8T was first reported as an endophyte of lesser duckweed (Kittiwongwattana & Thawai, 2013), and later proposed to be reclassified as Allorhizobium paknamense (Mousavi et al ., 2015). BLAST analysis showed 99.43% identity between As‐1 and L6‐8T.…”

Rhizobium smilacinae sp. nov., an endophytic bacterium isolated from the leaf of Smilacina japonica

“…legume plants and legume plants, such as rice, wheat, maize, lesser duckweeds, Rosa rugosa and Phaseolus vulgaris (Bibi et al 2012;Kittiwongwattana and Thawai 2013;López-López et al 2010;Peng et al 2008;Rosenblueth and Martinez-Romero 2004;Schloter et al 1997). In this study, we report on the taxonomic characterization of an endophytic bacterial strain, PTYR-5 T , which was isolated from the surfacesterilized leaf of Smilacina japonica A.…”