Mechanisms of invasive population establishment and spread of pinewood nematodes in China

Abstract

This paper summarizes the results of our study of the pinewood nematode (Bursaphelenchus xylophilus). By population genetic analysis, it was determined that there was no genetic bottle caused by the founder effect and genetic drift in the Chinese invasive population. Multiple invasions with large amounts of nematodes from different sources led to rich genetic diversity in the invasive population. Keeping high genetic diversity in the invasive process may be one of the genetic mechanisms in its successful invasion. By testing interspecies competition, it was shown that, with high fecundity and a strong competitive ability, B. xylophilus outcompeted the native species B. mucronatus in the natural ecosystem during the invasion process. Competitive displacement may be one of the ecological mechanisms of B. xylophilus's invasion. In addition, an unequal interspecific hybridization with introgress was in favor of the invasive species which also accelerated the replacement of B. mucronatus by B. xylophilus. The structures, functions and evolutions of a few important genes that are closely related to the ecological adaptation of pinewood nematodes were studied to explore the molecular mechanism of its ecological adaptations. Further, the resistance and resilience mechanism of the pine ecosystem invaded by pinewood nematodes was also investigated. The results of these studies uncovered a portion of the genetic and ecological mechanisms of PWN's successful invasion and laid a foundation for further study to obtain a comprehensive interpretation of the mechanisms of the nematode invasion. The results also provided a scientific basis for effectively controlling the occurrence and spread of pine wilt disease which is caused by nematodes. Various aspects requiring further investigation are considered.

Bacteria associated with the pinewood nematode Bursaphelenchus xylophilus collected in Portugal

“…Pine wilt disease (PWD) is considered a worldwide threat to pine forests, resulting in massive economic losses and negative ecological consequences for the affected countries (Rodrigues 2008;Xie et al 2009). In 1971, the pinewood nematode (PWN) Bursaphelenchus xylophilus was proven to be the causal pathogenic agent of PWD (Kiyohara and Tokushige 1971) and nowadays constitutes an important quarantine species.…”

Effects of pine wilt disease invasion on soil properties and Masson pine forest communities in the Three Gorges reservoir region, China

“…Moreover, the risk of the spread of PWD is increasing due to the high frequency of trade in the global economy, the active domestic economy, and the implementation of several national basic construction projects (Xie et al. 2009; Shi et al. 2013).…”

MicroRNA Discovery and Analysis of Pinewood Nematode Bursaphelenchus xylophilus by Deep Sequencing

“…The pinewood nematode, Bursaphelenchus xylophilus (Steiner et Burhrer), is a successful invasive plant parasitic nematode, which kills living pine trees and causes many thousands of pine trees to die in Asia [19]–[21]. This nematode species is believed to be native to North America, and usually only damages exotic pine trees there.…”

“…Moreover, the pinewood nematode has a widespread ecological adaptation, and an extensive distribution range [20], [28]. Cold and heat tolerance tests showed that the nematode has a strong tolerance to temperature stresses [21].…”