Brassica napus phyllosphere bacterial composition changes with growth stage

Abstract

Aims Phyllosphere bacteria play critical roles in plant growth promotion, disease suppression and global nutrient cycling but remain understudied. Methods In this project, we examined the bacterial community on the phyllosphere of eight diverse lines of Brassica napus for ten weeks in Saskatoon, Saskatchewan Canada. Results The bacterial community was shaped largely by plant growth stage with distinct communities present before and after flowering. Bacterial diversity before flowering had 111 core members with high functional potential, with the peak of diversity being reached during flowering. After flowering, bacterial diversity dropped quickly and sharply to 16 members of the core community, suggesting that the plant did not support the same functional potential anymore. B. napus line had little effect on the larger community, but appeared to have more of an effect on the rare bacteria. Conclusions Our work suggests that the dominant bacterial community is driven by plant growth stage, whereas differences in plant line seemed to affect rare bacteria. The role of these rare bacteria in plant health remains unresolved.

Impacts of global change on the phyllosphere microbiome

“…In addition, invasive plants caused by global change may influence the phyllosphere microbiome by altering soil properties and microbial communities and plant–soil feedback (McLeod et al ., 2021 ). Phyllosphere microbiome composition is believed to be closely related to the surrounding environment of host plants, such as soil, air and nearby plant (Brown et al ., 2020 ; Bell et al ., 2021 ; Bernard et al ., 2021 ). For example, soil microbes may enter the root tissues from emerging roots or wounds and constitute the root microbiota (Singh et al ., 2020a ), and part of this microbiota can be transferred to the aerial part of plants (i.e.…”

“…For example, soil microbes may enter the root tissues from emerging roots or wounds and constitute the root microbiota (Singh et al ., 2020a ), and part of this microbiota can be transferred to the aerial part of plants (i.e. phyllosphere) through xylem and phloem systems (Bell et al ., 2021 ). This could partially explain the observations of microbial overlap between plant tissues and soil (Bai et al ., 2015 ; Zarraonaindia et al ., 2015 ; Chen et al ., 2017 ; Xu et al ., 2018 ).…”

Phyllosphere Microorganisms: Sources, Drivers, and Their Interactions with Plant Hosts

“…47 The soil microorganisms may enter the root tissues from emerging roots and constitute the rhizosphere microorganisms, 48 after which part of them transfer to the phyllosphere. 49 The atmospheric environment is also a source of phyllosphere microorganisms. There is a pathway by opening leaf stomata and wounds for the transformation and migration between endophytes and epiphytes.…”

Brassica napus Bacterial Assembly Processes Vary with Plant Compartment and Growth Stage but Not between Lines

“…The rhizosphere effect has been well documented ( 25 , 35 , 36 ) wherein the rhizosphere exhibits changes in bacterial richness compared to the bulk soil. Given the rhizosphere effect is consistent and drastic, there must be deterministic selection processes at work.…”