Untangling the Pea Root Rot Complex Reveals Microbial Markers for Plant Health

Abstract

Plant health is recognised as a key element to ensure global food security. While plant breeding has substantially improved crop resistance against individual pathogens, it showed limited success for diseases caused by the interaction of multiple pathogens such as root rot in pea (Pisum sativum L.). To untangle the causal agents of the pea root rot complex and determine the role of the plant genotype in shaping its own detrimental or beneficial microbiome, fungal and oomycete root rot pathogens, as well as previously identified beneficials, i.e., arbuscular mycorrhizal fungi (AMF) and Clonostachys rosea, were qPCR quantified in diseased roots of eight differently resistant pea genotypes grown in four agricultural soils under controlled conditions. We found that soil and pea genotype significantly determined the microbial compositions in diseased pea roots. Despite significant genotype x soil interactions and distinct soil-dependent pathogen complexes, our data revealed key microbial taxa that were associated with plant fitness. Our study indicates the potential of fungal and oomycete markers for plant health and serves as a precedent for other complex plant pathosystems. Such microbial markers can be used to complement plant phenotype- and genotype-based selection strategies to improve disease resistance in one of the world’s most important pulse crops of the world.

A fine-tuned defense at the pea root caps: Involvement of border cells and arabinogalactan proteins against soilborne diseases

“…interact synergistically to infect the plant forming the pea root rot complex (PRRC) that aggravates pea root rot disease. The involvement of multi-species pathogens in the PRRC is a major limiting factor for plant breeding making complete pea resistance highly complex ( Chatterton et al., 2019 ; Wille et al., 2021 ; Wu et al., 2022 ). However, plant beneficial microorganisms such as arbuscular mycorrhizal fungi (AMF) Glomus intraradices and Glomus claroideum were reported to slightly increase pea tolerance to root rot development ( Thygesen et al., 2004 ).…”

Pea Breeding for Resistance to Rhizospheric Pathogens

“…Thus, good husbandry practices with the use of certified disease-free seeds, seed treatment with fungicides or starter macro-nutrients are useful control strategies. This would improve seedling vigour and limit the inoculum of R. solani [ 129 ].…”

“…These mycoviruses have the ability to reduce the mycelial growth of many fungi [ 135 ]. Some microbial markers associated with pea roots have also been elucidated and show promise as a R. solani control [ 129 ]. Thus, they could be useful as biocontrol agents to control R. solani in pea.…”

“…Progress has been made in identifying sources of resistance to pea rhizosphere root diseases. The effects of these diseases are determined by multiple soil microbial factors and host plant attributes [ 129 ]. Conventional breeding approaches are expected to remain viable in disease screening for many decades and beyond.…”

A comprehensive evaluation of pea germplasm resources based on cluster analysis and grey relational analysis

“…Pea is the most widely cultivated legume in temperate zones (Wille et al 2021) and forms an integral part of the human diet in many countries for its abundant nutritional value. Pea is an essential source of highquality proteins, starch, micronutrients, dietary bers, phenolic compounds, and antioxidants (Kaur and Dhar 2019; Tarasevičienė et al 2019;Yu et al 2021).…”