Significant genetic differences among Heterodera schachtii populations within and among sugar beet production areas

Abstract

Summary Characterising the non-neutral genetic variation within and among populations of plant-parasitic nematodes is essential to determine factors shaping the population genetic structure. This study describes the genetic variation of the parasitism gene vap1 within and among geographic populations of the beet cyst nematode Heterodera schachtii. Forty populations of H. schachtii were sampled at four spatial scales: 695 km, 49 km, 3.1 km and 0.24 km. DGGE fingerprinting showed significant differences in vap1 patterns among populations. High similarity of vap1 patterns appeared between geographically close populations, and occasionally among distant populations. Analysis of spatially sampled populations within fields revealed an effect of tillage direction on the vap1 similarity for two of four studied fields. Overall, geographic distance and similarity of vap1 patterns of H. schachtii populations were negatively correlated. In conclusion, the population genetic structure was shaped by the interplay between the genetic adaptation and the passive transport of this nematode.

Genetic Variation among Heterodera schachtii Populations Coincided with Differences in Invasion and Propagation in Roots of a Set of Cruciferous Plants

“…Populations of plant-parasitic nematodes (PPNs) differ in their intraspecific genotypes and pathotypes [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 ], complicating nematode management since each population may require appropriate measures adjusted to its specific virulence.…”

“…Among the PPNs that showed high genetic variability within and among its geographical populations is the beet cyst nematode Heterodera schachtii [ 5 , 7 ]. This nematode causes significant losses in the production of sugar beet and other crops from 23 plant families [ 10 , 11 ].…”

“…Hence, the management of H. schachtii depends on plant genes that limit nematode propagation, either by providing an unsuitable environment in the case of non-host plants or through resistance genes. However, because of the genetic variability among H. schachtii populations [ 5 , 7 ], the plant–nematode interaction will occur in a population-specific manner. A resistant variety may reduce the nematode density of some populations without affecting others [ 4 ].…”

“…An in-depth study of population characteristics will therefore provide suggestions for plant breeders to produce resistant varieties that are specialized, effective, and more sustainable toward PPNs. In addition, some agricultural practices such as the passive transfer of PPNs, plowing, and the continuous cultivation of the resistant cultivar affect the genetic structure of PPNs [ 7 ]. Monitoring the characteristics of nematode populations will help to limit those measures that lead to the spread of virulent genes and that increase the adaptability of nematode populations [ 7 ].…”

Effects of Cover Cropping on Microbial Communities Associated with Heterodera schachtii and Nematode Virulence

“…Furthermore, sugar beet cultivars and crop rotations shape the genetic variation of H. schachtii within and among sugar beet areas [25]. Therefore, selecting an efficient crop rotation is important to preserve the plant resistance.…”