Does co-inoculation of Lactuca serriola with endophytic and arbuscular mycorrhizal fungi improve plant growth in a polluted environment?

Rafał Ważny,Marta Śliwa,Teresa Anielska,Katarzyna Turnau,Anna Stojakowska,Roman J Jędrzejczyk,Piotr Rozpądek

doi:10.1007/s00572-018-0819-y

Rafał Ważny, Marta Śliwa + Show 5 more

Open Access

https://doi.org/10.1007/s00572-018-0819-y

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Abstract

Phytoremediation of polluted sites can be improved by co-inoculation with mycorrhizal and endophytic fungi. In this study, the effects of single- and co-inoculation of Lactuca serriola with an arbuscular mycorrhizal (AM) fungus, Rhizoglomus intraradices, and endophytic fungi, Mucor sp. or Trichoderma asperellum, on plant growth, vitality, toxic metal accumulation, sesquiterpene lactone production and flavonoid concentration in the presence of toxic metals were evaluated. Inoculation with the AM fungus increased biomass yield of the plants grown on non-polluted and polluted substrate. Co-inoculation with the AM fungus and Mucor sp. resulted in increased biomass yield of plants cultivated on the polluted substrate, whereas co-inoculation with T. asperellum and the AM fungus increased plant biomass on the non-polluted substrate. In the presence of Mucor sp., mycorrhizal colonization and arbuscule richness were increased in the non-polluted substrate. Co-inoculation with the AM fungus and Mucor sp. increased Zn concentration in leaves and roots. The concentration of sesquiterpene lactones in plant leaves was decreased by AM fungus inoculation in both substrates. Despite enhanced host plant costs caused by maintaining symbiosis with numerous microorganisms, interaction of wild lettuce with both mycorrhizal and endophytic fungi was more beneficial than that with a single fungus. The study shows the potential of double inoculation in unfavourable environments, including agricultural areas and toxic metal-polluted areas.

Highlights

In nature, vegetation is almost always accompanied by fungi and bacteria which often are invisible to observers but can significantly influence plant biology
Seedlings were transferred into Murashige and Skooq (MS) medium and, after 2 days of adaptation, they were inoculated with the endophytic fungi Mucor sp. (NCBI accession number KU234656; strain UNIJAG.PL.50 from Arabidopsis arenosa (L.) Hayek seeds) or Trichoderma asperellum (NCBI accession number MG571529; strain UNIJAG.PL.6 from Deschampsia cespitosa (L.) P.B. leaves)
Endophytic Mucor increased chlorophyll a concentration when co-inoculated with arbuscular mycorrhizal (AM) fungus on P, whereas T. asperellum did not affect it

Summary

Introduction

Vegetation is almost always accompanied by fungi and bacteria which often are invisible to observers but can significantly influence plant biology. The effect of co-inoculation usually is beneficial for plant growth (Remans et al 2008; Liu et al 2012), but Flor-Peregrín et al (2014), while investigating co-inoculation with AMF and endophytic bacteria, found that co-inoculation had a negative effect on plants compared to single inoculation with AMF or endophytes. In order to gain a comprehensive understanding of the role of symbiotic microorganisms in plant biology, studies that include different types of microorganisms inhabiting the plant host in multi-microbe setups are necessary. The lack of such studies makes it difficult to understand the complexity of the symbiosis between plants and fungi (Omacini et al 2006)

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