Characterization and diversity of seed endophytic bacteria of the endemic holoparasitic plant Cistanche armena (Orobanchaceae) from a semi-desert area in Armenia

Abstract

We explored the seed-associated bacterial endophytic microbiome in seeds of the endemic holoparasitic species Cistanche armena from a saline and arid habitat in Armenia. A combination of culture-dependent and molecular techniques was employed for identifying the seed endomicrobiome (culturable and unculturable). From surface-sterilized seeds, 10 phyla, comprising 256 endophytic bacterial genera, were identified. Of the culturable strains, we also investigated the plant growth-promoting (PGP) traits. Most of the isolates were spore forming, halotolerant and alkaliphile Bacillus spp., indicating that the endophytic bacteria of C. armena seeds own traits related to the natural habitat of their host plant. Our results confirm that Bacillus species are common and dominated endophytes from plants growing on saline and arid soils. Pantoea spp. and Stenotrophomonas spp. are more favourable PGP endophytes in seeds of C. armena. The PGP traits of these bacteria, such as production of indole, a precursor of auxin, ACC-deaminase and organic acids have the potential to improve the tolerance of their host plants against the abiotic stresses present in their natural habitat. To the best of our knowledge, this is the first report concerning bacterial seed endophytes of the C. armena.

Analysis of endophytic bacterial diversity in seeds of different genotypes of cotton and the suppression of Verticillium wilt pathogen infection by a synthetic microbial community

“…3 A, B). Recent studies have reported the enrichment of potentially beneficial endophytic bacteria, such as Paenibacillus and Bacillus [ 70 , 71 ], in some plant seeds. These microbes may preferentially colonize seeds, thus, providing a barrier against pathogens.…”

Interspecies and temporal dynamics of bacterial and fungal microbiomes of pistil stigmas in flowers in holoparasitic plants of the Orobanche series Alsaticae (Orobanchaceae)

“…These microorganisms can have the potential to mitigate the impacts of unfavourable environmental conditions, as well as the negative effects of plant pathogen infections 19 , 35 , 36 . Due to the dynamic and brief development of species from the Orobanchaceae family, microorganisms can respond to and potentially aid the current needs of these heterotrophic plants; for example, microorganisms in the sunflower rhizosphere affect parasitic seed germination and growth 46 as well as endophytic bacteria in seeds of Cistanche armena are able to improve the tolerance of parasitic plants under stress conditions in their natural habitat 37 . On the other hand, for the few parasitic plants that are dangerous weeds of economic importance, microbial communities may play an important role in mitigating the negative effects of infections caused by these plants.…”

“…Orobancheae species are poorly known in terms of the bacterial and fungal microbiota that inhabit them [32][33][34][35][36][37][38] . These microorganisms can have the potential to mitigate the impacts of unfavourable environmental conditions, as well as the negative effects of plant pathogen infections 19,35,36 .…”

“…For the Cistanche armena (K. Koch) M. V. Agab. seeds, confirmed Proteobacteria, Firmicutes and Actinobacteriota, followed by Bacteroidetes, Acidobacteria, Verrucomicrobia, Mixococcota, Planctomycetes, Patescibacteria and Chloroflexi were less abundant 37 . In floral nectar, bacteria and yeasts such as Enterobacteriaceae in Orobanche rapum-genistae Thuill., and Pseudomonas sp.…”

Analysis of Endophytic Bacterial Diversity in Seeds of Different Genotypes of Cotton and the Suppression of Verticillium Wilt Pathogen Infection by a Synthetic Microbial Community

“…3A, B). Recent studies have reported the enrichment of potentially bene cial endophytic bacteria, such as Paenibacillus and Bacillus [71,72], in some plant seeds. These microbes may preferentially colonize seeds, thus, providing a barrier against pathogens.…”