Beneficial native bacteria improve survival and mycorrhization of desert truffle mycorrhizal plants in nursery conditions

Abstract

Sixty-four native bacterial colonies were isolated from mycorrhizal roots of Helianthemum almeriense colonized by Terfezia claveryi, mycorrhizosphere soil, and peridium of T. claveryi to evaluate their effect on mycorrhizal plant production. Based on the phylogenetic analysis of the 16S rDNA partial sequence, 45 different strains from 17 genera were gathered. The largest genera were Pseudomonas (40.8 % of the isolated strains), Bacillus (12.2 % of isolated strains), and Varivorax (8.2 % of isolated strains). All the bacteria were characterized phenotypically and by their plant growth-promoting rhizobacteria (PGPR) traits (auxin and siderophore production, phosphate solubilization, and ACC deaminase activity). Only bacterial combinations with several PGPR traits or Pseudomonas sp. strain 5, which presents three different PGPR traits, had a positive effect on plant survival and growth. Particularly relevant were the bacterial treatments involving auxin release, which significantly increased the root-shoot ratio and mycorrhizal colonization. Moreover, Pseudomonas mandelii strain 29 was able to considerably increase mycorrhizal colonization but not plant growth, and could be considered as mycorrhiza-helper bacteria. Therefore, the mycorrhizal roots, mycorrhizosphere soil, and peridium of desert truffles are environments enriched in bacteria which may be used to increase the survival and mycorrhization in the desert truffle plant production system at a semi-industrial scale.

The crop of desert truffle depends on agroclimatic parameters during two key annual periods

“…to minimize large interannual fluctuations. For the proper management of T. claveryi plantations, it is essential to identify the biotic and abiotic factors that could explain this variability (Navarro-Ródenas et al 2016).…”

Micro-community associated with ectomycorrhizalRussulasymbiosis and sporocarp-producingRussulain Fagaceae dominant nature areas in southern China

“…Some studies have concentrated on mycorrhization helper bacteria (MHB) in facilitating mycorrhizal colonization of roots in forest nursery environments(43, 71). Rich in bacteria in the mycorrhizal roots, mycorrhizosphere soil and peridium of desert truffles may be used to increase the survival and mycorrhization in the desert truffle plant production system at a semi-industrial scale(72). The associated bacteria of Truffle brûlés are Pseudomonas and Flavobacteriaceae (73).…”

Harnessing plant-bacteria-fungi interactions to improve plant growth and degradation of organic pollutants

“…strain that promoted ectomycorrhizal colonization of Pisolithus tinctorius and Lactarius insulsus on Populus deltoids trees. Another example is that of Navarro-Ródenas et al (2016) who isolated a Pseudomonas mandelii strain that increased mycorrhizal colonization of Terfezia claveryi on Helianthemum almeriense. In addition, they also found that bacterial isolates that produced auxins, significantly increased the root-shoot ratio and mycorrhizal colonization (Navarro-Ródenas et al 2016).…”

“…Another example is that of Navarro-Ródenas et al (2016) who isolated a Pseudomonas mandelii strain that increased mycorrhizal colonization of Terfezia claveryi on Helianthemum almeriense. In addition, they also found that bacterial isolates that produced auxins, significantly increased the root-shoot ratio and mycorrhizal colonization (Navarro-Ródenas et al 2016). Also, endobiotic bacteria residing inside fungal hyphae can have positive effects on mycorrhizal growth.…”