Endophytic bacteria: co-existence and chemical warfare

Lead Research Organisation: Aberystwyth University
Department Name: IBERS

Abstract

Endophytic bacteria (EB) live within plant tissues without causing signs of disease. They may be horizontally or vertically
transmitted and can be considered to sit at the benign end of the spectrum between mutualists and pathogens. EB have
been reported to confer benefits to the host plant in terms of growth promotion and protection from pests and pathogens. In
order to maintain an endophytic lifestyle these bacteria must both interact with the host plant and other bacterial and fungal
endophytes without triggering defence mechanisms (co-operation), yet assist the plant in identifying and attacking
pathogens (chemical warfare). These ancient relationships are not only fascinating from an evolutionary perspective but
are potentially of great value for both sustainable crop production and as novel sources of bioactive natural products
including antimicrobials and antifungals.
In the past it was postulated that the states of symbiosis and pathogenesis were readily interchangeable, largely dependent
on environmental conditions. However, evidence from genomic studies do not support this, as symbionts tend to
demonstrate reduced genomes, lacking the necessary components required for pathogenesis. To date the majority of data
is from animal symbionts, and so it is important to analyse EB to determine whether this is also the case for plant
endosymbionts. If true, this has major implications for the application of these organisms in crop production and protection,
as biofertilisers, biopesticides, antifungals etc. (for both food and industrial crops), as co-operative adaptation may render
them inherently safer than predicted. Furthermore, chemical compounds may be isolated for application as antimicrobials
for human and animal health. A number of novel antibiotics have been isolated from EB over recent years, indicating that
EB remain a relatively untapped resource with high potential for discovery of novel bioactives.
This project will utilise the EB collection at IBERS developed in a previous BBSRC iCASE project BB/G017484/1 'Bacterial
endophytes in the energy crop Miscanthus'. Genomic analysis, mutagenesis and in planta screening will provide insight into
the adaptations required for an endophytic lifestyle. Concurrently, functional testing and subsequent chemical isolation and
characterisation will elucidate bioactive compounds produced by the EB for commercial application, e.g., as either crop
production/protection, or antimicrobial products. This project therefore addresses a number of BBSRC strategic priorities
including: Sustainably enhancing agricultural production; Food, nutrition and health; Bioenergy; and Combatting
antimicrobial resistance.

Publications

10 25 50

Studentship Projects

Project Reference Relationship Related To Start End Student Name
BB/M01505X/1 01/10/2015 30/09/2019
1646214 Studentship BB/M01505X/1 21/09/2015 30/09/2019 Gareth William Raynes
 
Description 61 endophytic bacterial isolates were isolated from plants growing in high-salinity coastal soils in Wales, all of which are capable of growing in the presence of 5% NaCl or higher. 57 of these have been identified using a combination of 16SrRNA analysis and genomic sequencing. These isolates represent a potential source of novel plant growth promoting bacteria and as such have been tested in a large scale experiment in the National Plant Phenomics Centre for their impacts on growth characteristics under salt stress conditions in the model grass species Brachypodium distachyon by growing the plants having been inoculated with the bacterial isolates and then applying salt pressures. Several isolates demonstrated significant effects upon plant stress phenotypes including reduction of the stress response, increasing leaf area and increasing the growth period of the host plants under both salt and control conditions leading to 8 isolates being selected for full genome sequencing and further testing. One Isolate in particular, Bacillus velezensis strain CBE, has been further tested for transcriptome effects in the host plant under stress conditions due to its demonstrated ability to ameliorate the salt stress effects during this work.
Additionally, isolates are currently undergoing screening using Gas Chromatography/Mass Spectroscopy, High Performance Liquid Chromatography and Linear Trap Quadrupole Mass Spectroscopy in order to investigate whether they are producing bioactive secondary metabolites as part of the project's relationship with PhytoQuest Ltd. Initial analysis of the results has shown production of iminosugars by multiple isolates, and further analysis is currently ongoing.
Exploitation Route This research has the potential to impact upon a number of different fields and sectors. Primarily, isolates identified to show plant growth promoting behaviours could be used for agricultural crop yield improvement, including upon land currently rendered unusable by high salinity levels. Further testing following the genomic sequencing of the most promising isolates could highlight novel genes associated with plant growth promotion, which could impact upon agricultural use of endophytic bacteria as well as enhancing future attempts to screen for plant growth promoting bacteria.
Depending on the nature of the bioactive compounds detected by the biochemical testing, different applications could be pursued. Novel antimicrobial and anti-helminthic compounds would have medical impacts, while compounds such as iminosugars would have other potential uses. Iminosugars have been shown to impact upon aspects of human and animal health as well as having commercial applications.
Sectors Agriculture, Food and Drink,Chemicals,Environment,Healthcare,Pharmaceuticals and Medical Biotechnology

 
Description KESS2
Amount £52,885 (GBP)
Organisation European Social Fund (Welsh Government/ EU) 
Sector Public
Country United Kingdom
Start 12/2018 
End 12/2021
 
Description NRN-LCEE Returning Fellowships
Amount £9,990 (GBP)
Funding ID R39GO1/CC8004/RFS008 
Organisation Welsh Assembly 
Sector Public
Country United Kingdom
Start 05/2018 
 
Description PhytoQuest 
Organisation PhytoQuest Ltd
Country United Kingdom 
Sector Private 
PI Contribution 3 month in house placement within PhytoQuest ltd (Durently underway). Samples have been contributed derived from the main work, namely samples of liquid cultures of identified bacterial environmental isolates. Experiments to identify via Gas Chromotograph Mass Spectrometry the compounds produced by said isolates are underway, with early results looking promising.
Collaborator Contribution Training and expertise, as well as Supervisory assistance throughout the project. Training of use of ion exchange resins, equipment including rotary evaporators and Gas Chromatograph Mass Spectrometers as well as analysis of data outputs from the same.
Impact Multi disciplinary (plant biology, microbiology, natural product chemistry) training and expertise.
Start Year 2015
 
Description Aberystwyth University Science Fair 2019 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Schools
Results and Impact Every year during Science Week, 1700+ school children and their teachers visit Aber to be enthused about science via a diverse range of hand-on exhibits.
Year(s) Of Engagement Activity 2018
 
Description Articles for Biochemical Society's blog 
Form Of Engagement Activity Engagement focused website, blog or social media channel
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Other audiences
Results and Impact Experience communicating with a wider audience about the experience of being a PhD student and the research project. Raise awareness of the research group.
https://thebiochemistblog.com/2017/05/18/phyte-club-inside-the-plant-microbiome/
https://thebiochemistblog.com/2017/03/27/the-very-best-things-about-phd-life/
Year(s) Of Engagement Activity 2017
URL https://thebiochemistblog.com/2017/05/18/phyte-club-inside-the-plant-microbiome/
 
Description British Science Week 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Schools
Results and Impact 2016 - PhD students presented a poster of their research project with an audience of school children and teachers. Posters were later copied and sent to teachers for display in schools.
Students from 9 Secondary schools were in attendance over the course of the week.
2017 - PhD students organised and ran a stand for the three day event, supervising a team of undergraduate students.
• A three day event demonstrating chemical changes and properties to early secondary school aged children from several local schools using hands-on experiments they could try.
• Voted third place out of around 40 different stands at the event.
• Over 3000 schoolchildren attended over the event.
• Video online including PhD student talking about endophytes https://www.aber.ac.uk/en/news/archive/2017/03/title-198574-en.html
Year(s) Of Engagement Activity 2016,2017
URL https://www.aber.ac.uk/en/news/archive/2017/03/title-198574-en.html
 
Description British Science Week 2019 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Schools
Results and Impact An Outreach/engagement stand displayed during Aberystwyth University's event for British Science Week. Over 1700 students from a large number of schools visit the university over a three day period. The stand included elements of research from this project as well as others from the same research group. The event is still ongoing, finishing on the 14th of March, so impacts and outputs are unclear as of yet but in previous years a large positive response has been recorded, and already we have received feedback on increased understanding of beneficial microbes and plant-microbe interactions.
Year(s) Of Engagement Activity 2019
 
Description Excellence with Impact Poster session 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Other audiences
Results and Impact Presenting a poster of my own research as part of an in-house event preceding the Excellence with Impact national competition. Around 80 postgraduate students and members of academic staff attended to share ideas and find out about other research occurring within the institution.
Year(s) Of Engagement Activity 2016
 
Description Presentation to School Teachers 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Schools
Results and Impact A ten minute oral presentation delivered to local secondary school teachers on my research, followed by questions and discussion.
Year(s) Of Engagement Activity 2016
 
Description Public Research Poster Session 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Public/other audiences
Results and Impact A poster session open to the general public over the course of the day. This sparked interest and discussion with members of the public in attendance, and furthered knowledge and discussion among postgraduates in attendance.
Year(s) Of Engagement Activity 2016
 
Description Second article written for Biochemical Society 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact An article written for the Biochemical Society's online publication 'The Biochemist' as part of their series on microbiomes. The article covered plant microbiomes as an overview, as well as touching on my area of research (bacterial endophytes). The article generated online discussion and interest.
Year(s) Of Engagement Activity 2017
URL https://thebiochemistblog.com/2017/05/18/phyte-club-inside-the-plant-microbiome/
 
Description SusNet Poster Avenue British Science Week 2016 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Schools
Results and Impact Presenting a poster of my research project with an audience of school children and teachers with the aim of displaying my research as part of the research taking place at Aberystwyth University. Posters were later copied and sent to teachers for display in schools.
Year(s) Of Engagement Activity 2016
 
Description Various student engagement activities 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Public/other audiences
Results and Impact IBERS Excellence with Impact Poster session. 28th April 2016
• Presenting a poster of my research plans as part of the IBERS EWI event
• 80-100 people attended the event.
Presentation to School Teachers. 8th June 2016
• A ten minute oral presentation of research project to secondary school teachers.
• 20-30 teachers were in attendance.
Public Engagement Poster Session. 18th June 2016
• Presented a research poster to an audience of the general public.
• Over 100 people attended
World Food Day poster. 16th October 2016
• Public outreach event marking World Food Day, organised and hosted with fellow postgraduate students.
• The event illustrated the journey of food from production, through processing, to consumption, and waste, and highlighting environmental impacts.
• ~50 people attended.
Science and Energy Lecture. 19th May 2017
• Delivering a 2 hour lecture to primary school children on energy changes, with hands on demonstrations of a range of experiments.
• Groups from three primary schools were in attendance, totalling over 80 children.
• There will hopefully be a repeat of this event 2018.
Worcester Postgraduate Research Conference 29th June 2017
• 15 minute oral research presentation to a conference session of academic researchers and other postgraduate students from a range of disciplines and institutions.
• 80-100 people were at the event.
Online Outreach
• Blog (friendlybacteria.wordpress.com) writing about Science (mainly microbiology) for a general audience. I'm not sure how many people this has reached.
• Social Media: use of Instagram to post about Science and Nature (@friendly_bacteria) and Twitter to do the same (@frndlybacteria). Over 500 followers on Instagram and nearly 1300 on Twitter.
Year(s) Of Engagement Activity 2016,2017