poplar-adventitious-roots-induced-stem-canker-pathogens-an

Poplar Adventitious Roots Induced by Stem Canker Pathogens: An Experimental System for Studying Roots Biology and Light Response-Related Processes

Valsa sordida and Botryosphaeria dothidea are two crucial necrotrophic fungal pathogens that damage many plant hosts, particularly species in the genus ...

in-vivo-leaf-inoculation-an-alternative-method-to-assess-disease

In Vivo Leaf Inoculation: An Alternative Method to Assess the Disease Resistance of Hybrid Clones in Poplar Breeding of Stem Canker Disease

Stem canker diseases caused by the pathogen Cytospora chrysosperma (Pers.) Fr.) and Botryosphaeria dothidea (Moug. ex Fr.) Ces. &#38; de Not. are the two ...

chinese academy of forestry

Comprehensive Experimental Center in Yellow River Delta of Chinese Academy of Forestry

 is fatal to the pine trees around the world. The production of the pine tree secondary metabolite gradually increases in response to a  infestation, via a stress reaction mechanism(s). α-pinene is needed to combat the early stages of  infection and colonization, and to counter its pathogenesis. Therefore, research is needed to characterize the underlying molecular response(s) of  to resist α-pinene. We examined the effects of different concentrations of α-pinene on the mortality and reproduction rate of  in vitro. The molecular response by which  resists α-pinene was examined via comparative transcriptomics of the nematode. Notably,  genes involved in detoxification, transport, and receptor activities were differentially expressed in response to two different concentrations of α-pinene compared with control. Our results contribute to our understanding of the molecular mechanisms by which  responds to monoterpenes in general, and the pathogenesis of .

Comparative Transcriptome Analysis of the Pinewood Nematode  Reveals the Molecular Mechanism Underlying Its Defense Response to Host-Derived α-pinene.

The pine wood nematode (PWN; ) is the causal agent of pine wilt disease, which results in severe ecological and economic losses in coniferous forests. During overwintering, PWNs undergo morphological and physiological changes to adapt to low temperature environments. Here, the physiological changes of the PWN populations sampled in the summer and winter were compared to analyze the role of low temperatures in their response. The PWN overwinters as third-stage dispersal juveniles, which showed significantly greater survival rates than summer populations (propagative forms) at sub-zero temperatures. The major biochemical compounds in the populations were analyzed by gas chromatography. Eight dominant fatty acids, with stearic acid being the most important, were identified from PWN propagative stage and third-stage dispersal stage. Compared with the propagative stage, the dispersal stage showed significant increases in the fatty acid content and the proportion of unsaturated fatty acids. Three carbohydrates, trehalose, glycerol and glucose, were detected in the PWN. Compared with the summer population, the levels of trehalose and glycerol increased significantly, while glucose decreased, in the winter population. The modifications in fatty acid composition and cryoprotectant levels, as elements of its changing physiology, play important roles in the overwintering success of the PWN.

Cold adaptive potential of pine wood nematodes overwintering in plant hosts.

Pinewood nematode, Bursaphelenchus xylophilus, a pine parasitic nematode, poses a serious threat to its host pine forests globally. When dispersal-stage larvae 4 (dauer, DL4) of B. xylophilus enters the new pine, it moults into propagative adult (dauer recovery) and reproduces quickly to kill the host pine. Here, we found pine chemical volatiles, rather than the common dauer recovery factors of nematodes (e.g. suitable temperatures, nutrient availability or density), promote B. xylophilus dauer recovery. The results showed that volatilization of chemicals in host pines could attract DL4 and promote DL4 recovery. To identify which chemicals promote this process, we determined the stimulated activity of the main volatiles of pines including six monoterpenes and two sesquiterpenes. Results showed that all the six monoterpenes promoted dauer recovery, especially β-pinene and β-myrcene, but the two sesquiterpenes have no effect on the transformation. Furthermore, β-pinene performed gradient effects on dauer recovery. We hypothesized that when DL4 infect pine trees, the pine volatiles released from the feeding wounds are used as chemical signals for DL4 transformation to adult to reproduce and rapidly kill the pines. Our study identified the B. xylophilus dauer recovery chemical signal and may contribute to preventing pine wilt disease.

Pine chemical volatiles promote dauer recovery of a pine parasitic nematode, .

Nematodes can enter cryptobiosis by dehydration as an adaptation to low-temperature environments and recover from cryptobiosis by rehydration after environmental improvement. In this work, the survival of  third-stage dispersal juveniles was studied in response to low-temperature treatment. The average survival rates were 1.7% after -80 °C treatment for 30 d and 82.2% after -20 °C treatment for 30 d. The changes of water content and inorganic salt ions that occur in pine trees during winter gradually alter the osmotic pressure in the liquid environment to dehydrate  juveniles, resulting in improved survival after low-temperature treatment. The survival rate at -20 °C improved to 92.1% when the juveniles entered cryptobiosis by osmotic regulation. The results of this study demonstrate that  third-stage dispersal juveniles can resist low-temperature stress through cryptobiosis, providing the theoretical basis for the identification of areas potentially vulnerable to  in the mid-temperature and cold temperature zones of China.

Third-Stage Dispersal Juveniles of  Can Resist Low-Temperature Stress by Entering Cryptobiosis.

A key step in the study of tree pathology is the identification of an appropriate method for inoculating pathogens of diseases in branches and trunks. Pathogens of diseases in branches and trunks are commonly inoculated through punching, burning, and toothpick inoculation. However, there is a lack of comparative analyses of the inoculation outcomes of these three methods. In this work, six-year-old  var.  were inoculated with  using punching, burning, and toothpick techniques to investigate the differences in the effectiveness of these inoculation methods. Results reveal that the incidence rate was 93.55% in the toothpick inoculation group, significantly higher than the 80.65% in the burning inoculation group (chi-square,  = 90,  = 0.007), while punching inoculation exhibited significant pathological responses in the early stages, with spontaneous healing in the later stage. Additionally, toothpick inoculation was more efficient in inducing  canker when inoculating the pathogen at the bottom of the tree, with lower intra- and inter-row spacing (stand density) providing better outcomes than higher intra- and inter-row spacing. The results of this study demonstrate that toothpick inoculation is an optimal option for studying the artificial inoculation of  in six-year-old  var. , providing technical support for research on poplar diseases and offering a theoretical basis for the inoculation of other diseases in the branch and trunk.

ArticleTotal : 2	Year
Publication title	2024
Publication title Cited by 1	2024

Article	Year
Comparative Transcriptome Analysis of the Pinewood Nematode Reveals the Molecular Mechanism Underlying Its Defense Response to Host-Derived α-pinene. International journal of molecular sciences\| PubMed ID: 30791528	2019
Cold adaptive potential of pine wood nematodes overwintering in plant hosts. Biology open\| PubMed ID: 31023716	2019
Pine chemical volatiles promote dauer recovery of a pine parasitic nematode, . Parasitology\| PubMed ID: 31455450	2020
Third-Stage Dispersal Juveniles of Can Resist Low-Temperature Stress by Entering Cryptobiosis. Biology\| PubMed ID: 34440018	2021
Comparative Study on the Effectiveness of Three Inoculation Methods for in var. . Biology\| PubMed ID: 38666863	2024

Long Pan

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