Role of endophytic Methylobacterium extorquens in growth and development of Scots pine seedlings

Funded by Academy of Finland, projects no. 118569, 129852

Researchers:

Interaction between methylobacterium endophytes and Scots Pine (Pinus sylvestris L.)

In recent years several plant-associated microbial endophytes have been reported to promote plant viability, growth and defense in various species.

We have identified a distinctive plant-endophyte interaction between Methylo-bacterium extorquens sp. and Scots pine. Methylobacterium spp. are the most dominant endophytic species in the cells of meristemic bud tissues of Scots pine (Pinus sylvestris L.).

Our preliminary results indicate that Methylobacterium inoculated pine seedlings have increased lateral root formation, root length and aboveground biomass compared to controls.The aim of our study is to define the interactions between these two species at molecular level.

microarray

Microarray studies

RNA

RNA analysis with bioanalyzer


Interactions between Ectomycorrhizal Fungi, Methylobacteria and Scots Pine (Pinus sylvestris L.)
- Consequences to Growth and Development of Scots Pine

Funded by Finnish cultural foundation, North Osthrobotnia Regional fund

Traditionally, plants have been considered as single organisms but in nature, plants associate with diverse microorganisms including several endo- and epiphytic microbes. Despite of long history of symbiosis studies the details of interaction are still unclear and there is very little if any information about plants interacting with several types of symbionts at the same time.

The network of interactions between different symbiotic organisms and the host plant likely have a huge importance for the plant growth and development. We study the in vitro interactions between an endophytic methylobacterium (Metylobacterium extorquens), two ectomycorrhizal fungi (Pisolithus tinctorius and Suillus variegatus) and Scots pine (Pinus sylvestris L.). We explore the effect of M. extorquens on growth of ectomycorrhizal fungi, compare the growth, polyamine metabolism, nutrient uptake and gene expression of inoculated pine seedlings and study the colonization pattern and distribution of M. extorquens in host plant.

pine

1) Pinus sylvestris control seedlings, 2) Methylobacterium extorquens inoculated pine seedlings, 3) Pine seedlings inoculated with ectomycorrhizal fungus Pisolithus tinctorius and endophytic M. extorquens, 4) Pine seedlings inoculated with Pisolithus tinctorius (PT) or P. tinctorius and M. extorquens (PTmb), 5) Root hairs of M. extorquens inoculated pine seedlings, 6) Pine root covered with P. tinctorius mycelia and pink pigmented methylobacteria

Antimicrobial and antioxidative compounds of plants and endophytes

Isolation of antimicrobial and anti-oxidant compounds from endophytes of woody plants

Funded by EU FP7 People Programme: TEJAM and New Antimicrobials (NAM)

Researchers:

endophyte

A fungal endophyte growing from the needle tissue
of Scots pine (Pinus sylvestris L.)

Plant tissues provide a niche for a diversity of fungal and bacterial endophytes. Endophytes are found within all plant tissues, such as leaves, twigs, wood and bark. The diversity of endophytes provides a versatile arsenal of interactions which are still largely unstudied. Some endophyte species may restrict growth of bacteria, fungi, or protect the host against attacks by herbivores.

Due to their high capacity of producing secondary metabolites, endophytes are being developed as pharmaceutical tools or as biocontrol agents. Endophytes are a rich untapped source of natural products and provide a high industrial promise for the future.

screening

Fungal endophytes of Labrador tea (Rhododendron tomentosum L.)
growing in liquid still cultures on a 24-well plate

Antibacterial resistance is spreading globally at an alarming rate and continues to increase. New potent antibacterial agents and therapies are therefore continually needed. In recent years, new antibacterial compounds have mainly been additions to the existing classes of drugs and truly new structures have not been developed. The derivatives of existing drugs however raise bacterial resistance much faster than completely new compounds. To overcome the chronic problem of antibiotic resistance, totally new compounds and approaches are required.

The search for new antioxidant molecules is ever growing, particularly for those that can prevent the deleterious effects of free radicals in the human body. Antioxidants are capable of stabilizing or deactivating free radicals before they attack cells. Natural antioxidants are more preferred rather than from synthetic sources because they are less toxic in nature.

We are isolating antimicrobial, antioxidant and antihypertensive compounds from fungal endophytes of plants such as Pinus sylvestris, Picea abies and Rhododendron tomentosum. We are also developing the metagenomic and metatranscriptomic tools to study the products of unculturable endophytes.

Fungi

Fungal endophytes of Pinus Sylvestris


Biotechnical applications of Potato

Researchers:

Endophytic bacteria play significant but poorly characterized role in the life style of the host plant, especially with respect to plant defense. Our results show that endophytic methylobacteria of potato exhibit antagonistic activity towards several phytopathogens. They induce disease resistance of potato by mechanisms that resemble priming by rhizobacteria through induced systemic resistance (ISR). We are also addressing the question on the role of the existing microbial community of potato plants in Methylobacterium-induced disease resistance and investigating the regulatory pathways and mechanisms involved in ISR development.

potato endophyte

Left: Potato in vitro cultivation. Right: Bacterial endophyte of potato


In addition we are studying cryopreservation of potato (Solanum tuberosum) with respect to endophytic bacteria during the cryopreservation process. The work is done in collaboration with Estonian Research Institute of Agriculture.