A rhizosphere paper

[dw1305]

Hi all,
I'm not quite sure where to put this, so I'll pop it in "Substrates".

I've talked a bit about plants being able to change the conditions in the substrate, in <"the rhizosphere">, to favour "beneficial microbes" and this paper quantifies that, using RNA libraries. It also talks about plant health in relation to microbial diversity.

It is a bit of a dense read, but the pictures are nice.

Lobanov V, Keesman KJ & Joyce A. (2022) "Plants Dictate Root Microbial Composition in Hydroponics and Aquaponics". Front Microbiol. 2022 Apr 18;13:848057. doi: 10.3389/fmicb.2022.848057. PMID: 35509321; PMCID: PMC9058158. <Plants Dictate Root Microbial Composition in Hydroponics and Aquaponics>

...... Despite widespread recognition regarding the dependency of plants on their rhizosphere, the extent to which upstream aquaculture influences downstream hydroponic root communities has been poorly described in the literature. In this study we performed a taxonomic survey (16S rRNA metabarcoding) of microbial communities originating in the facility water source, hydroponic nutrient solution (HNS) sump, nutrient supplemented biofilter effluent (BF) sump, and recirculating aquaculture system tanks stocked with Nile tilapia (Oreochromis niloticus). Lettuce (Lactuca sativa) was then grown using the HNS and BF effluent under sterilized or mature (prior aquaponics/hydroponics lettuce culture water) conditions, likewise, the influence of probiotic addition or inoculation with soil-grown lettuce rhizosphere was assessed. Compositional similarities across treatments suggest that under soil-less conditions, plants are able to exert a stronger discriminatory influence on their rhizosphere composition than is done by colonization from upstream sources. Furthermore, cluster dendrograms grouped the sterilized and unsterilized treatments more consistently together than hydroponics and aquaponics treatments. These findings contradict conventional beliefs that microbial communities in the water column colonize roots based on their presence alone, ignoring the role that plants play in rhizosphere community selection.

........ Firstly, our study suggests that aqueous nutrient concentration play a more predicative role in determining community composition than sterilization. While sterilization is a routine technique in aquaculture as well as hydroponics, it is nonetheless a tradeoff between pathogen suppression and total microbial diversity reduction. Future studies must likewise determine whether aquaponic facilities benefit from sterilization, or whether the co-cultivation of plants and fish in an environment promoting diversity leads to a more resilient facility-wide microbiome. Secondly, in line with previous work on the relationship between aqueous nutrient concentrations and plant health (Lobanov et al., 2021), more research is needed to determine whether a greater focus on maintaining plant health as opposed to only maximizing yield will lead to more disease-tolerant crops, and ultimately more productive crops..........

cheers Darrel