The rhizomicrobiome of Sorghum ; impact on plant growth and stress tolerance

The overall objectives of my thesis are to investigate the dynamics of the sorghum root microbiome and to explore the beneficial effects of the root microbiome on sorghum growth and stress tolerance. In Chapter 2, I describe the differences in rhizobacterial community composition of seven different sorghum cultivars grown in the greenhouse in two different soil types at four different plant growth stages. in Chapter 3 I present the co-occurrence of bacterial and fungal communities in the rhizosphere of different sorghum cultivars. Chapter 4 addresses the effects of different rhizobacterial community compositions on growth and drought tolerance of sorghum. In Chapter 5, I described the effects of five endophytic bacterial strains on the growth of four sorghum cultivars. In Chapter 6, I provide a general discussion of the main findings of this thesis and highlight the importance of sorghum-microbiome interactions.Naturali

The rhizomicrobiome of Sorghum : impact on plant growth and stress tolerance

The overall objectives of my thesis are to investigate the dynamics of the sorghum root microbiome and to explore the beneficial effects of the root microbiome on sorghum growth and stress tolerance. In Chapter 2, I describe the differences in rhizobacterial community composition of seven different sorghum cultivars grown in the greenhouse in two different soil types at four different plant growth stages. in Chapter 3 I present the co-occurrence of bacterial and fungal communities in the rhizosphere of different sorghum cultivars. Chapter 4 addresses the effects of different rhizobacterial community compositions on growth and drought tolerance of sorghum. In Chapter 5, I described the effects of five endophytic bacterial strains on the growth of four sorghum cultivars. In Chapter 6, I provide a general discussion of the main findings of this thesis and highlight the importance of sorghum-microbiome interactions.Naturali

The rhizomicrobiome of Sorghum ; impact on plant growth and stress tolerance

The overall objectives of my thesis are to investigate the dynamics of the sorghum root microbiome and to explore the beneficial effects of the root microbiome on sorghum growth and stress tolerance. In Chapter 2, I describe the differences in rhizobacterial community composition of seven different sorghum cultivars grown in the greenhouse in two different soil types at four different plant growth stages. in Chapter 3 I present the co-occurrence of bacterial and fungal communities in the rhizosphere of different sorghum cultivars. Chapter 4 addresses the effects of different rhizobacterial community compositions on growth and drought tolerance of sorghum. In Chapter 5, I described the effects of five endophytic bacterial strains on the growth of four sorghum cultivars. In Chapter 6, I provide a general discussion of the main findings of this thesis and highlight the importance of sorghum-microbiome interactions.</p

Co-variation of bacterial and fungal communities in different sorghum cultivars and growth stages is soil dependent

Rhizosphere microbial community composition can be influenced by different biotic and abiotic factors. We investigated the composition and co-variation of rhizosphere bacterial and fungal communities from two sorghum genotypes (BRS330 and SRN-39) in three different plant growth stages (emergence of the second leaf, (day10), vegetative to reproductive differentiation point (day 35), and at the last visible emerged leaf (day 50)) in two different soil types, Clue field (CF) and Vredepeel (VD). We observed that either bacterial or fungal community had its composition stronger influenced by soil followed by plant growth stage and cultivar. However, the influence of plant growth stage was higher on fungal community composition than on the bacterial community composition. Furthermore, we showed that sorghum rhizosphere bacterial and fungal communities can affect each other’s composition and structure. The decrease in relative abundance of the fungus genus Gibberella over plant growth stages was followed by decrease of the bacterial families Oxalobacteracea and Sphingobacteriacea. Although cultivar effect was not the major responsible for bacterial and fungal community composition, cultivar SRN-39 showed to promote a stronger co-variance between bacterial and fungal communities

Rhizobacterial community structure differences among sorghum cultivars in different growth stages and soils

Plant genotype selects the rhizosphere microbiome. The success of plant–microbe interactions is dependent on factors that directly or indirectly influence the plant rhizosphere microbial composition. We investigated the rhizosphere bacterial community composition of seven different sorghum cultivars in two different soil types (abandoned (CF) and agricultural (VD)). The rhizosphere bacterial community was evaluated at four different plant growth stages: emergence of the second (day 10) and third leaves (day 20), the transition between the vegetative and reproductive stages (day 35), and the emergence of the last visible leaf (day 50). At early stages (days 10 and 20), the sorghum rhizosphere bacterial community composition was mainly driven by soil type, whereas at late stages (days 35 and 50), the bacterial community composition was also affected by the sorghum genotype. Although this effect of sorghum genotype was small, different sorghum cultivars assembled significantly different bacterial community compositions. In CF soil, the striga-resistant cultivar had significantly higher relative abundances of Acidobacteria GP1, Burkholderia, Cupriavidus (Burkholderiaceae), Acidovorax and Albidiferax (Comamonadaceae) than the other six cultivars. This study is the first to simultaneously investigate the contributions of plant genotype, plant growth stage and soil type in shaping sorghum rhizosphere bacterial community composition