Evaluation ofPantoea eucalyptiFBS135 for pine (Pinus massoniana) growth promotion and its genome analysis

Abstract

Aims Pinus massoniana is one of the most widely distributed forest plants in China. In this study, we isolated a bacterial endophyte (designated FBS135) from apical buds and needles of P. massoniana. Investigations were performed to understand the effects of the strain on pine growth, its genomic features and the functions of the plasmids it carries. Methods and Results Based on its morphological features and 16S rRNA sequence, strain FBS135 was primarily identified as Pantoea eucalypti. We found that FBS135 not only promoted the growth of P. massoniana seedlings, but also significantly increased the survival rate of pine seedlings. The whole genome of FBS135 was sequenced, which revealed that the bacterium carries one chromosome and four plasmids. Its chromosome is 4 023 751 bp in size and contains dozens of genes involved in plant symbiosis. Curing one of the four plasmids, pPant1, resulted in a decrease in the size of the FBS135 colonies and the loss of the ability to synthesize yellow pigment, indicating that this plasmid may be very important for FBS135. Conclusions Pantoea eucalypti FBS135 has a genomic basis to be implicated in plant‐associated lifestyle and was established to have the capability to promote pine growth. Significance and Impact of the Study To the best of our knowledge, this is the first report that such a bacterial species, P. eucalypti, was isolated from pine trees and evidenced to have pine beneficial activities. Our results elucidate the ecological effects of endophytes on forest plants as well as endophyte–plant interaction mechanisms.

Relationship of the Pine Growth Promoting Pantoea eucalypti FBS135 with Type Strains P. eucalypti LMG 24197T and P. vagans 24199T

“…Genome and plasmid information of the two strains have been summarized in Table 2 . Different from the two strains, FBS135 has four plasmids, one (pPant4) of which seems to be responsible and indispensable for its growth [ 17 ].…”

“…With the genome information, we precisely determined the taxonomic status of Pantoea sp. FBS135, an endophyte isolated from Pinus massoniana with evidenced ability of promoting pine growth and stress tolerance [ 17 ]. We also demonstrated that FBS135 can tolerate an extremely low nitrogen environment without fixing nitrogen in the air.…”

“…We have previously reported the beneficial effect of FBS135 on pine growth [ 17 ]; however, the phylogenetic status of FBS135 was only roughly determined on the basis of 16S sequence, which will hinder further studies on it. In recent years, precise identification of a bacterium using whole-genome sequence has been proposed to be the standard [ 28 , 39 ].…”

“…To date, research on endophytes mainly focuses on agricultural plants; only a few reports were performed on wood plants. Pantoea strain FBS135 is an endophytic bacterium isolated from the shoot of a healthy Pinus massoniana in Nanjing, China [ 17 ]. The greenhouse experiments evidenced that FBS135 can not only promote the growth of seedlings of P. massoniana , but also enhance the tolerance of pine seedlings under stress.…”

Coastal Ecosystems as Sources of Biofertilizers in Agriculture: From Genomics to Application in an Urban Orchard

“…In recent times, studies of the complete genomes of PGPR are elucidating the genes that explain the plant growth promoting activities and the plant-bacteria dialog in the rhizosphere (Song et al, 2012;Usha et al, 2015;Bhattacharyya et al, 2017). Accordingly, the draft genomes of several Pantoea strains with PGPR activities have been compared (Bruto et al, 2014;Palmer et al, 2018;Song et al, 2020). In general these microorganisms show wide versatility and adaptability, together with multiple PGP activities such as phosphate solubilization, nitrogen fixation, ACC deaminase activity, auxins production and secretion of siderophores (Shariati et al, 2017;Chen and Liu, 2019;Luziatelli et al, 2020a).…”