Plant growth in Arabidopsis is assisted by compost soil-derived microbial communities

Abstract

Plants in natural and agricultural environments are continuously exposed to a plethora of diverse microorganisms resulting in microbial colonization of roots and the rhizosphere. This process is believed to be accompanied by an intricate network of ongoing simultaneous interactions. In this study, we examined Arabidopsis thaliana roots and shoots in the presence or absence of whole microbial communities extracted from compost soil. The results show a clear growth promoting effect on Arabidopsis shoots in the presence of soil microbes compared to plants grown in microbe-free soil under otherwise identical conditions. Element analyses showed that iron uptake was facilitated by these mixed microbial communities which also led to transcriptional downregulation of genes required for iron transport. In addition, soil microbial communities suppressed the expression of marker genes involved in nitrogen uptake, oxidative stress/redox signaling, and salicylic acid (SA)-mediated plant defense while upregulating jasmonate (JA) signaling, cell wall organization/biosynthesis and photosynthesis. Multi-species analyses such as simultaneous transcriptional profiling of plants and their interacting microorganisms (metatranscriptomics) coupled to metagenomics may further increase our understanding of the intricate networks underlying plant-microbe interactions.

Kill or cure? The interaction between endophytic Paenibacillus and Serratia strains and the host plant is shaped by plant growth conditions

“…The PGP effect of some P. polymyxa spp. and diverse microbial communities on the host plants like Tobacco (Nicotiana tabacum) or A. thaliana grown in sterile soil has been shown by several groups (e.g., Phi et al 2010 andCarvalhais et al 2013). The situation where a PGP effect occurred in sterile soil while it was not observed in the non-sterile soil has to the best of our knowledge not been documented before.…”

Rhizobacterial volatiles and photosynthesis‐related signals coordinate MYB72 expression in Arabidopsis roots during onset of induced systemic resistance and iron‐deficiency responses

“…Selected bacterial strains of the natural Arabidopsis root microbiota belonging to the genus Pseudomonas and the class Actinobacteria were particularly potent in activating expression of the iron‐deficiency marker MYB72 (Table S2), suggesting that they collectively participate in stimulation of iron nutrition in their host plant. In support of this, microbial communities derived from compost soil were shown to improve iron content in Arabidopsis when introduced to germ‐free soil (Carvalhais et al ., ). However, the availability of iron in the root vicinity as affected by soil microbial communities did not in itself explain the positive impact of root‐colonizing microbes on plant iron nutrition (Carvalhais et al ., ).…”

“…In support of this, microbial communities derived from compost soil were shown to improve iron content in Arabidopsis when introduced to germ‐free soil (Carvalhais et al ., ). However, the availability of iron in the root vicinity as affected by soil microbial communities did not in itself explain the positive impact of root‐colonizing microbes on plant iron nutrition (Carvalhais et al ., ). Hence, in addition to directly enhancing iron mineralization and solubilization in the soil, stimulation of the iron‐acquisition machinery in the plant is an important function of specific rhizosphere microbiota.…”

Effect of long‐term organic and mineral fertilization strategies on rhizosphere microbiota assemblage and performance of lettuce

“…However, redox homeostasis and reactive oxygen species (ROS) production are associated with several biological processes in plants and the up-regulation of some gene families involved in oxidative stress signalling may also indicate enhanced tolerance to abiotic and biotic stresses (Miller et al, 2008). Increased oxidative activity in leaves can also occur during enhanced leaf growth and photosynthetic activity (Hideg and Schreiber, 2007), which has been shown to be augmented by the presence of active plant growth promoting rhizobacteria (PGPR) (Carvalhais et al, 2013). The here observed enhanced expression of the zinc-finger transcription factor ZAT10, which plays a key role in abiotic stress tolerance (Mittler et al, 2006), and MYB15, a member of the R2R3 MYB family of transcription factors in Arabidopsis reported to be upregulated by (a)biotic stresses (Liu et al, 2015), indicates an enhanced tolerance to stress in these plants.…”