Auxin production and plant growth promotion by sp. nov. from the rhizoplane of leafless Seidenf. orchid.

The strains of the genus , with more than 150 species, inhabit diverse environments; plant-associated bacteria reveal their plant growth-promoting activities due to a number of beneficial characteristics. Through the performance of diverse techniques and methods, including isolation of a novel strain from the aerial roots of leafless epiphytic orchid, Seidenf., its morphological and biochemical characterization, chemotaxonomy, phylogenetic and genome analysis, as well as bioassays and estimation of its auxin production capacity, a novel strain of ET2 is described.

Complete genome sequence of new sp. strain ET2, isolated from roots of leafless orchid.

Whole-genome sequence of ET2 strain, isolated from the roots of leafless orchid, constitutes a single circular chromosome of 3,604,840 bp (69.44% G + C content). BLAST+-based average nucleotide identity (ANIb) and digital DNA-DNA hybridization values indicate that ET2 may be a novel species.

Cyanobacterial Root Associations of Leafless Epiphytic Orchids.

The leafless orchids are rare epiphytic plants with extremely reduced leaves, and their aerial roots adopted for photosynthesis. The beneficial plant-microbial interactions contribute significantly to host nutrition, fitness, and growth. However, there are no data available on the bacterial associations, inhabiting leafless orchids.

Megasporogenesis, megagametogenesis, and embryogenesis in Dendrobium nobile (Orchidaceae).

The orchid reproductive strategy, including the formation of numerous tiny seeds, is achieved by the elimination of some stages in the early plant embryogenesis. In this study, we documented in detail the formation of the maternal tissues (the nucellus and integuments), the structures of female gametophyte (megaspores, chalazal nuclei, synergids, polar nuclei), and embryonic structures in Dendrobium nobile. The ovary is unilocular, and the ovule primordia are formed in the placenta before the pollination.

Colonization strategy of the endophytic plant growth-promoting strains of Pseudomonas fluorescens and Klebsiella oxytoca on the seeds, seedlings and roots of the epiphytic orchid, Dendrobium nobile Lindl.

Aims: Orchids form strong mycorrhizal associations, but their interactions with bacteria are poorly understood. We aimed to investigate the distribution of plant growth promoting rhizobacteria (PGPR) at different stages of orchid development and to study if there is any selective specificity in choosing PGPR partners.

Methods And Results: Colonization patterns of gfp-tagged Pseudomonas fluorescens and Klebsiella oxytoca were studied on roots, seeds, and seedlings of Dendrobium nobile.