Molecular Characterization of the Plant Growth Promoting Bacterium Enterobacter sp. SA187 upon Contact with Arabidopsis thaliana
Salt stress is a severe environmental challenge in agriculture, limiting the quality and productivity of the crops around the globe. Plant growth promoting rhizobacteria (PGPR) is proposed as a friendly solution to overcome those challenges. The desert plant endophytic bacterium, Enterobacter sp. SA...
Main Author: | |
---|---|
Other Authors: | |
Language: | en |
Published: |
2018
|
Subjects: | |
Online Access: | http://hdl.handle.net/10754/627801 |
id |
ndltd-kaust.edu.sa-oai-repository.kaust.edu.sa-10754-627801 |
---|---|
record_format |
oai_dc |
spelling |
ndltd-kaust.edu.sa-oai-repository.kaust.edu.sa-10754-6278012020-12-08T05:08:58Z Molecular Characterization of the Plant Growth Promoting Bacterium Enterobacter sp. SA187 upon Contact with Arabidopsis thaliana Alsharif, Wiam Hirt, Heribert Biological and Environmental Sciences and Engineering (BESE) Division Arold, Stefan T. Blilou, Ikram plant growth promoting rhizobacteria (PGPR) Salt stress Entero bacteria ceae carotenoids biosynthesis pathway Salt stress is a severe environmental challenge in agriculture, limiting the quality and productivity of the crops around the globe. Plant growth promoting rhizobacteria (PGPR) is proposed as a friendly solution to overcome those challenges. The desert plant endophytic bacterium, Enterobacter sp. SA187 has shown plant growth promotion and salt stress tolerance beneficial effect on the model plant Arabidopsis thaliana in vitro as well as under the field conditions on different crops. SA187 has a distinguished morphology of yellow colonies (SA187Y) that could be due to carotenoid biosynthesis. However, the bacteria tend to lose the yellow color upon incubation with the plants and the colonies turn to white (SA187W). In comparison to SA187Y, SA187W shows 50% reduction on the beneficial impact on A. thaliana fresh and dry weight of root and shoot system. By counting the CFU/plant, we showed that SA187Y and SA187W both have similar colonization rate in both shoots and roots. Under non-salt conditions, optimal bacterial colonization was observed on day 8 after inocubation, however, under the salt stress condition, the optimal colonization was observed at day 4. Moreover, during the time period of the incubation of the SA187Y with the plants, there was a consistent noticeable loss of the yellow color of the colonies. This change in color is only observed eight days after transfer and the number of white colonies increases with the increase of the incubation time. In addition, SA187W was GFP-tagged by Tn7 transposon system and visualized by confocal laser scanning microscopy. The SA187W-GFP colonies have shown a similar colonization pattern as SA187Y-GFP, bacteria were colonizing the differentiation zone and cell elongation zone in the roots. Finally, the gene expression of the carotenoid biosynthesis pathways genes in SA187Y showed an overall higher gene expression compared to SA187W. In conclusion, the color loss seems to affect the beneficial impact of the bacteria on plants. However, the reduced beneficial impact is not due to the colonization efficiency of bacteria on the plant roots but could be due to a regulation of gene expression of carotenoid biosynthesis. 2018-05-09T13:03:32Z 2019-05-08T00:00:00Z 2018-05 Thesis 10.25781/KAUST-296O3 http://hdl.handle.net/10754/627801 en 2019-05-08 At the time of archiving, the student author of this thesis opted to temporarily restrict access to it. The full text of this thesis became available to the public after the expiration of the embargo on 2019-05-08. |
collection |
NDLTD |
language |
en |
sources |
NDLTD |
topic |
plant growth promoting rhizobacteria (PGPR) Salt stress Entero bacteria ceae carotenoids biosynthesis pathway |
spellingShingle |
plant growth promoting rhizobacteria (PGPR) Salt stress Entero bacteria ceae carotenoids biosynthesis pathway Alsharif, Wiam Molecular Characterization of the Plant Growth Promoting Bacterium Enterobacter sp. SA187 upon Contact with Arabidopsis thaliana |
description |
Salt stress is a severe environmental challenge in agriculture, limiting the quality and productivity of the crops around the globe. Plant growth promoting rhizobacteria (PGPR) is proposed as a friendly solution to overcome those challenges. The desert plant endophytic bacterium, Enterobacter sp. SA187 has shown plant growth promotion and salt stress tolerance beneficial effect on the model plant Arabidopsis thaliana in vitro as well as under the field conditions on different crops. SA187 has a distinguished morphology of yellow colonies (SA187Y) that could be due to carotenoid biosynthesis. However, the bacteria tend to lose the yellow color upon incubation with the plants and the colonies turn to white (SA187W). In comparison to SA187Y, SA187W shows 50% reduction on the beneficial impact on A. thaliana fresh and dry weight of root and shoot system. By counting the CFU/plant, we showed that SA187Y and SA187W both have similar colonization rate in both shoots and roots. Under non-salt conditions, optimal bacterial colonization was observed on day 8 after inocubation, however, under the salt stress condition, the optimal colonization was observed at day 4. Moreover, during the time period of the incubation of the SA187Y with the plants, there was a consistent noticeable loss of the yellow color of the colonies. This change in color is only observed eight days after transfer and the number of white colonies increases with the increase of the incubation time. In addition, SA187W was GFP-tagged by Tn7 transposon system and visualized by confocal laser scanning microscopy. The SA187W-GFP colonies have shown a similar colonization pattern as SA187Y-GFP, bacteria were colonizing the differentiation zone and cell elongation zone in the roots. Finally, the gene expression of the carotenoid biosynthesis pathways genes in SA187Y showed an overall higher gene expression compared to SA187W. In conclusion, the color loss seems to affect the beneficial impact of the bacteria on plants. However, the reduced beneficial impact is not due to the colonization efficiency of bacteria on the plant roots but could be due to a regulation of gene expression of carotenoid biosynthesis. |
author2 |
Hirt, Heribert |
author_facet |
Hirt, Heribert Alsharif, Wiam |
author |
Alsharif, Wiam |
author_sort |
Alsharif, Wiam |
title |
Molecular Characterization of the Plant Growth Promoting Bacterium Enterobacter sp. SA187 upon Contact with Arabidopsis thaliana |
title_short |
Molecular Characterization of the Plant Growth Promoting Bacterium Enterobacter sp. SA187 upon Contact with Arabidopsis thaliana |
title_full |
Molecular Characterization of the Plant Growth Promoting Bacterium Enterobacter sp. SA187 upon Contact with Arabidopsis thaliana |
title_fullStr |
Molecular Characterization of the Plant Growth Promoting Bacterium Enterobacter sp. SA187 upon Contact with Arabidopsis thaliana |
title_full_unstemmed |
Molecular Characterization of the Plant Growth Promoting Bacterium Enterobacter sp. SA187 upon Contact with Arabidopsis thaliana |
title_sort |
molecular characterization of the plant growth promoting bacterium enterobacter sp. sa187 upon contact with arabidopsis thaliana |
publishDate |
2018 |
url |
http://hdl.handle.net/10754/627801 |
work_keys_str_mv |
AT alsharifwiam molecularcharacterizationoftheplantgrowthpromotingbacteriumenterobacterspsa187uponcontactwitharabidopsisthaliana |
_version_ |
1719368503659593728 |