Inoculation With Ectomycorrhizal Fungi and Dark Septate Endophytes Contributes to the Resistance of Pinus spp. to Pine Wilt Disease

Pine wilt disease (PWD) is a deadly disease to pines (Pinus spp.) worldwide. The occurrence of PWD can reduce the relative abundance of root ectomycorrhizal fungi (ECMF) and dark septate endophytes (DSE). However, the effects of exogenous ECMF/DSE inoculation on the rhizosphere microbial community structure of Pinus tabulaeformis infected by pine wood nematode (PWN) is little known. Here, we tested how ECMF/DSE may improve resistance to PWD by quantifying microbial carbon biomass and soil enzymatic activity among different treatments at 6 and 9 months after PWN infection. Denaturing gradient gel electrophoresis (DGGE) was used to study the microbial community structure at 3, 6, and 9 months after PWN infection in the rhizosphere of P. tabulaeformis seedlings inoculated with ECMF/DSE. The results showed that exogenous ECMF/DSE inoculation reduced the disease severity caused by PWN infection. After PWN infection, the rhizosphere microbial carbon of seedlings inoculated with Amanita vaginata, Suillus bovinus, Gaeumannomyces cylindrosporus, and Paraphoma chrysanthemicola was 38.16, 49.67, 42.11, and 96.05% higher than that of the control group, respectively. Inoculation of ECMF/DSE inhibited the decrease of rhizosphere microbial biomass caused by PWN infection. The richness and diversity of P. tabulaeformis rhizosphere fungi at 9 months were reduced by PWN infection but partially recovered by the exogenous fungi (ECMF/DSE) inoculation except for P. chrysanthemicola, which indicates a role of ECMF/DSE in maintaining stability of the microbial community. Inoculation with ECMF/DSE increased the beneficial bacterial (Thauera sp., Mesorhizobium sp., etc.) and fungal groups (Tomentella ellisii, Wilcoxina mikolae, etc.) of in the rhizosphere. In summary, exogenous ECMF/DSE inoculation could increase P. tabulaeformis resistance to PWD probably by improving the rhizosphere microenvironment.

Download Full-text

The Dark Septate Endophytes and Ectomycorrhizal Fungi Effect on Pinus tabulaeformis Carr. Seedling Growth and their Potential Effects to Pine Wilt Disease Resistance

Forests ◽

10.3390/f10020140 ◽

2019 ◽

Vol 10 (2) ◽

pp. 140 ◽

Cited By ~ 5

Author(s):

Honglong Chu ◽

Chuyan Wang ◽

Zhumei Li ◽

Haihua Wang ◽

Yuguo Xiao ◽

...

Keyword(s):

Ectomycorrhizal Fungi ◽

Growth Traits ◽

Pine Wilt Disease ◽

Wilt Disease ◽

Pinus Tabulaeformis ◽

Conifer Forest ◽

Cumulative Mortality ◽

Pine Wilt ◽

Pinus Tabulaeformis Carr ◽

The Relationship

Pine wilt disease (PWD), a worldwide threat to pine forests, has caused tremendous damage to conifer forest in the world. However, little research has been conducted on the relationship between symbiosis functions of root associated fungi and pine wilt disease. In this study, we assessed the influence of seven ectomycorrhizal fungi (ECMF) and five dark septate endophytic fungi (DSE) on the growth traits and root morphology as well as the correlation of these parameters to the cumulative mortality and the morbidity rates in Pinus tabulaeformis Carr.showed the lowest cumulative mortality rates. We propose that the ECMF/DSE symbiosis enhanced the resistance of pine wilt disease via mitigation the dysfunction of water caused by PWN infection. Our research provided evidence that inoculation of ECMF/DSE could be a potential way for pine wilt disease prevention. To find highly efficient fungi for pine wilt disease management, more ECMF and DSE species should be tested.

Download Full-text

Bacterial Communities and Virulence Associated with Pine Wood Nematode Bursaphelenchus xylophilus from Different Pinus spp.

International Journal of Molecular Sciences ◽

10.3390/ijms20133342 ◽

2019 ◽

Vol 20 (13) ◽

pp. 3342 ◽

Cited By ~ 6

Author(s):

Qi Xue ◽

Yang Xiang ◽

Xiao-Qin Wu ◽

Ming-Jie Li

Keyword(s):

Bacterial Communities ◽

Bacterial Species ◽

Pine Wilt Disease ◽

Bursaphelenchus Xylophilus ◽

Wilt Disease ◽

Sequencing Analysis ◽

Culturable Bacteria ◽

Pine Wilt ◽

Pinus Spp ◽

Pine Species

Bursaphelenchus xylophilus, the causal agent of pine wilt disease, is a destructive threat to pine forests. The role of bacteria associated with B. xylophilus in pine wilt disease has attracted widespread attention. This study investigated variation in bacterial communities and the virulence of surface-sterilized B. xylophilus from different Pinus spp. The predominant culturable bacteria of nematodes from different pines were Stenotrophomonas and Pseudomonas. Biolog EcoPlate analysis showed that metabolic diversity of bacteria in B. xylophilus from P. massoniana was the highest, followed by P. thunbergii and P. densiflora. High-throughput sequencing analysis indicated that bacterial diversity and community structure in nematodes from the different pine species varied, and the dominant bacteria were Stenotrophomonas and Elizabethkingia. The virulence determination of B. xylophilus showed that the nematodes from P. massoniana had the greatest virulence, followed by the nematodes from P. thunbergii and P. densiflora. After the nematodes were inoculated onto P. thunbergii, the relative abundance of the predominant bacteria changed greatly, and some new bacterial species emerged. Meanwhile, the virulence of all the nematode isolates increased after passage through P. thunbergii. These inferred that some bacteria associated with B. xylophilus isolated from different pine species might be helpful to adjust the PWN’s parasitic adaptability.

Download Full-text

Microbial carbon use and associated changes in microbial community structure in high-Arctic tundra soils under elevated temperature

Soil Biology and Biochemistry ◽

10.1016/j.soilbio.2021.108419 ◽

2021 ◽

pp. 108419

Author(s):

Aline Frossard ◽

Lotte De Maeyer ◽

Magdalene Adamczyk ◽

Mette Svenning ◽

Elie Verleyen ◽

...

Keyword(s):

Community Structure ◽

Elevated Temperature ◽

Microbial Community ◽

Microbial Community Structure ◽

Arctic Tundra ◽

High Arctic ◽

Tundra Soils ◽

Microbial Carbon

Download Full-text

Insights into the Role of Fungi in Pine Wilt Disease

Journal of Fungi ◽

10.3390/jof7090780 ◽

2021 ◽

Vol 7 (9) ◽

pp. 780

Author(s):

Cláudia S. L. Vicente ◽

Miguel Soares ◽

Jorge M. S. Faria ◽

Ana P. Ramos ◽

Maria L. Inácio

Keyword(s):

Complex Disease ◽

Pine Wilt Disease ◽

Wilt Disease ◽

Host Tree ◽

Fungal Communities ◽

Insect Vector ◽

Pinewood Nematode ◽

Management Actions ◽

Pine Wilt ◽

Pinus Spp

Pine wilt disease (PWD) is a complex disease that severely affects the biodiversity and economy of Eurasian coniferous forests. Three factors are described as the main elements of the disease: the pinewood nematode (PWN) Bursaphelenchus xylophilus, the insect-vector Monochamus spp., and the host tree, mainly Pinus spp. Nonetheless, other microbial interactors have also been considered. The study of mycoflora in PWD dates back the late seventies. Culturomic studies have revealed diverse fungal communities associated with all PWD key players, composed frequently of saprophytic fungi (i.e., Aspergillus, Fusarium, Trichoderma) but also of necrotrophic pathogens associated with bark beetles, such as ophiostomatoid or blue-stain fungi. In particular, the ophiostomatoid fungi often recovered from wilted pine trees or insect pupal chambers/tunnels, are considered crucial for nematode multiplication and distribution in the host tree. Naturally occurring mycoflora, reported as possible biocontrol agents of the nematode, are also discussed in this review. This review discloses the contrasting effects of fungal communities in PWD and highlights promising fungal species as sources of PWD biocontrol in the framework of sustainable pest management actions.

Download Full-text

Characterization of bacterial communities associated with the pine wilt disease insect vectors Monochamus alternatus Hope and host trees Pinus massoniana

10.21203/rs.2.14055/v1 ◽

2019 ◽

Author(s):

Yajie Guo ◽

Qiannan Lin ◽

lvyi Chen ◽

Carballar-Lejarazú Rebeca ◽

Ensi Shao ◽

...

Keyword(s):

Microbial Community ◽

Pine Wilt Disease ◽

Pinus Massoniana ◽

Wilt Disease ◽

Microbial Flora ◽

Pinewood Nematode ◽

Monochamus Alternatus ◽

Transmission Cycle ◽

Pine Wilt ◽

Monochamus Alternatus Hope

Abstract Background Pine wilt disease (PWD) is a destructive disease caused by the pinewood nematode Bursaphelenchus xylophilus . Monochamus alternatus Hope is the main vector of this disease. The symbiotic microorganisms can play an important role in the transmission cycle mechanism. However, the role of bacterial microorganisms in the transmission of pine wood nematode by M. alternatus is not clear currently. The main purpose of this study is to reveal the composition and diversity of microbial flora in the gut of M. alternatus , as well as healthy and infected Pinus massoniana and its peripheral environment to discover the important microbial flora contributing to the transmission cycle.Methods In this study, total DNA was extracted from 60 samples, including 20 samples of M. alternatus gut from different larval instars, healthy P. massoniana , nematode-infected P. massoniana and their peripheral environment (needles, bark, phloem, xylem, root, surface soil and rhizosphere soil), by triplicate. Samples were used for 16S rDNA Amplicon sequencing to determine the composition and diversity of microbial flora in each sample.Results Infection of pinewood nematode resulted in an increase of the microbial community in the nematode-infected P. massoniana and its peripheral environment when compared with healthy P. massoniana , the microbial community in different tissues changed. Among them, Gryllotalpicola and Cellulomonas showed to be endemic microorganisms in nematode-infected P. massoniana , which can be used as indicators to detect the disease. Serratia was shown as an opportunistic pathogen, and was found to be enriched in M. alternatus gut and was also detected in the host plant tissues.Conclusions This study clarified the change of microbial community in the transmission of pine wilt disease by M. alternatus . An important theoretical basis for the prevention of pine wilt disease was structured by our research.

Download Full-text