Bacterial and fungal endophyte communities in healthy and diseased oilseed rape and their potential for biocontrol of Sclerotinia and Phoma disease

Abstract

Phoma stem canker (caused by the ascomycetes Leptosphaeria maculans and Leptosphaeria biglobosa) is an important disease of oilseed rape. Its effect on endophyte communities in roots and shoots and the potential of endophytes to promote growth and control diseases of oilseed rape (OSR) was investigated. Phoma stem canker had a large effect especially on fungal but also on bacterial endophyte communities. Dominant bacterial genera were Pseudomonas, followed by Enterobacter, Serratia, Stenotrophomonas, Bacillus and Staphylococcus. Achromobacter, Pectobacter and Sphingobacterium were isolated only from diseased plants, though in very small numbers. The fungal genera Cladosporium, Botrytis and Torula were dominant in healthy plants whereas Alternaria, Fusarium and Basidiomycetes (Vishniacozyma, Holtermaniella, Bjerkandera/Thanatephorus) occurred exclusively in diseased plants. Remarkably, Leptosphaeria biglobosa could be isolated in large numbers from shoots of both healthy and diseased plants. Plant growth promoting properties (antioxidative activity, P-solubilisation, production of phytohormones and siderophores) were widespread in OSR endophytes. Although none of the tested bacterial endophytes (Achromobacter, Enterobacter, Pseudomonas, Serratia and Stenotrophomonas) promoted growth of oilseed rape under P-limiting conditions or controlled Phoma disease on oilseed rape cotyledons, they significantly reduced incidence of Sclerotinia disease. In the field, a combined inoculum consisting of Achromobacter piechaudii, two pseudomonads and Stenotrophomonas rhizophila tendencially increased OSR yield and reduced Phoma stem canker.

In vitro Screening of Sunflower Associated Endophytic Bacteria With Plant Growth-Promoting Traits

“…The screened twenty bacterial isolates showed multifunctional PGP traits. The bacteria identified in this study showed similarities to the previous studies by Ambrosini et al (2016) and Schmidt et al (2021), who reported similar bacteria from sunflowers. A study by Forchetti et al (2007) reported the isolation of Bacillus from sunflower plants.…”

Pathogenic potential of bacteria isolated from commercial biostimulants

“…Surprisingly, the genus Stenotrophomonas was isolated only from FP. Even if Stenotrophomonas species are isolated from rhizosphere and show antifungal activity (Jiang et al 2021 ; Schmidt et al 2021 ), Stenotrophomonas sp. strain I6 showed high similarity (identity ≥ 99.88%) with Stenotrophomonas maltophilia.…”

Seed Endophytic Achromobacter sp. F23KW as a Promising Growth Promoter and Biocontrol of Rhizoctonia Root Rot of Fenugreek

“…Under field evaluation, the current study reported obvious improvements in the performance of fenugreek growth, yield, and disease management. In this connection, singularly or combined bio inoculation by endophytic Azospirillum brasilense and/or A. lipoferum contributed remarkably to maize and wheat yields [ 58 ]; moreover, the inoculation by a consortium of deaminase-active endophytic bacteria has a significant influence on growth parameters especially plant height, productive tillers, panicle and spike lengths, harvest index, and grain, and straw yields, as well as the nutrient contents of rice and wheat [ 59 ]; however, several means were reported to promote plant growth, and physiology by endophytic bacteria, including increasing nutrient availability through phosphorus solubilization, and nitrogen fixation, siderophore production, modulating the stress responses of the plant via phytohormone biosynthesis, and finally, bio controlling pathogens via the secretion of antimicrobials [ 60 ].…”