# Populations of Heterodera schachtii Differ in Susceptibility to Rhizosphere Bacteria Structured by Plant Age

## TL;DR

This study shows that the effectiveness of bacteria in resisting beet cyst nematodes depends on the nematode population and the age of the plant.

## Contribution

The study reveals how plant age and nematode genetics influence bacterial suppression of H. schachtii.

## Key findings

- Nematode populations differ in susceptibility to rhizosphere bacteria.
- Plant age affects the diversity and attachment of rhizosphere bacteria.
- Resistant catch crops' effectiveness depends on nematode pathogenicity and microbial interactions.

## Abstract

Rhizosphere microbes, particularly bacteria, are essential for controlling plant-parasitic nematodes (PPNs) through various mechanisms. However, the plant’s age and the genetic composition of nematode populations can significantly influence the inhibitory effectiveness of these microbes against the beet cyst nematode Heterodera schachtii. In this study, rhizosphere microbes were isolated from 39-day-old and 69-day-old resistant oilseed radish plants to evaluate their impact on the penetration of the second-stage juveniles (J2s) originating from four genetically distinct H. schachtii populations. The suppression of J2s penetration by the attached microbes varied across the nematode populations, which displayed differing levels of aggressiveness toward the resistant oilseed radish. Furthermore, differences in the alpha and beta diversity of rhizosphere bacteria were observed between the 39-day-old and 69-day-old plants, leading to variations in the bacterial attachment among the four nematode populations. In summary, the effectiveness of resistant catch crops against H. schachtii is influenced by the pathogenicity of the nematode populations and their interactions with the rhizosphere microbial community shaped by the plant’s age.