The pine wood nematode (PWN) Bursaphelenchus xylophilus is the pathogen that causes pine wilt disease (PWD), a devastating forest disease. PWN-associated bacteria may play a role in PWD. However, little is known about the endo-bacteria in PWN. We analyzed the diversity of endo-bacteria in nine isolates of PWNs from Pinus massoniana Lamb. in nine epidemic areas from three Chinese provinces by high-throughput sequencing of 16S rDNA and isolated and identified culturable endo-bacteria through construction of a 16S rDNA phylogenetic tree and Biolog microbial identification. We also examined the effects of endo-bacteria on PWN fecundity, antioxidant capacity, and virulence using sterile nematodes as a control. While the dominant endo-bacteria in PWNs from different regions exhibited no significant difference in the classification levels of class and genus, their proportions differed. Pseudomonas and Stenotrophomonas were highly abundant in all PWN isolates. A total of 15 endo-bacterial strains were successfully isolated and identified as six species: Stenotrophomonas maltophilia, Pseudomonas fluorescens, Kocuria palustris, Microbacterium testaceum, Rhizobium radiobacter, and Leifsonia aquatica. We also found that P. fluorescens significantly increased the egg production of PWN, and that both P. fluorescens and S. maltophilia enhanced the mobility of PWN under oxidative stress and reduced the content of reactive oxygen species by increasing antioxidant enzyme activity in PWN. These strains also accelerated the development of PWD, and P. fluorescens had a more beneficial effect on PWN than S. maltophilia. Diversity exists among the endo-bacteria in PWNs from different regions, and some endo-bacteria can promote PWN infestation by enhancing the fecundity and antioxidant capacity of the nematode. Our study contributes to clarifying the interaction between endo-bacteria and PWN.

Loquat [Eriobotrya japonica (E. japonica)], a small genus of the subtribe Malinae that consists of ≈30 species, is an evergreen rosaceous fruit tree that is native to southeastern China, and some wild species that possess novel, favorable traits have excellent breeding potential. For example, Eriobotrya bengalensis blooms in late spring and ripens in early autumn in Guizhou Province, China, which prevents cold injury in winter by breeding spring-flowering cultivars using the special characters. Therefore, in the present study, the pollination treatments of cut-style pollination were evaluated that may promote successful distant hybridization in Eriobotrya japonica ‘Dawuxing’ × Eriobotrya deflexa and E. japonica ‘Dawuxing’ × E. bengalensis. The results indicated that the impairment of the pollen tube growth in the upper third of the style after pollen germination is an important factor leading to the failure of distant hybridization between the species tested in E. japonica, and that cut-style pollination can effectively overcome prefertilization barriers of the distant hybridization combination. Furthermore, the results of allele-specific polymerase chain reaction (AS-PCR) showed that S-genotypes, in accordance with the S-RNase heredity to separate the rule completely in offspring, should be both parents' S-RNase, and that the random 50 seedlings of Eb-2 and Ed-2 are true hybrids.

Abstract. Based on the current research value of biomass and terpenoids, in this paper, the terpenoids contented in the different organizational of the camphor tree were analyzed by SDE extract method and GC-MS analysis method. The results showed that the contents of terpenoids contained in camphor leaves were the richest. The highest content of terpenoids in three tissues was camphor, especially the relative content of camphor in leaves got to 71.96%.In addition, except camphor, the higher terpeneoid compounds of the leaves respectively were carypohyllene (5.29%), α-pinene (4.06%) and limonene (2.87%). The higher terpeneoid compounds of the branches respectively were α-pinene (2.33%) and carypohyllene (1.78%). The terpenoids contained in the flowers were ketone terpenes, respectively, 2, 3-acetylacetone (1.33%) and propyl methyl ketone (1.25%). This paper provides the basis for the extraction and utilization of terpenoids in camphor trees, which lays a foundation for the further study of the application value of natural terpenoids in camphor trees.

Centranthera grandiflora, a kind of traditional Chinese medicinal materials in Yunnan Province, has very high medicinal value. However, constant expansion of the plantation has resulted in worsening root diseases, an obstacle of continuous cropping. From 2018 to 2019, the author investigated the parasitic nematodes in the rhizosphere of Centranthera grandiflora in Pingbian County, Yunnan province, and identified them according to their morphological characteristics. The results showed that there were two kinds of parasitic nematodes harmful to Centranthera grandiflora root in Pingbian County, Yunnan: Tylenchorhynchus capitatus Allen, 1955 and Helicotylenchus dihystera (Cobb, 1893) sher, 1961.