Liang Cheng’s research while affiliated with State Key Laboratory of Integrated Management of Pest Insects and Rodents and other places

Background Chenopodium album L. is one of the most important threat weeds affecting crops productivity in the fields. Control of this weed is complex and currently, lies in the use of chemical methods, although this method has not proven to be fully effective. The utilization of microorganisms has emerged as a means of simultaneously controlling this weed with high-efficiency, and friendly to the environment. In this regard, this study used LC-MS/MS and RNA-Seq technology to gain insights into the molecular herbicidal mechanisms underlying strain Aureobasidium pullulans PA-2 on C. album. Results Physiological and biochemical tests showed that compared with the control group (CK), the content of chlorophyll, soluble protein, soluble sugar and phenylalanine ammonia-lyase (PAL) activity in C. album leaves in the pot show a decreasing trend under the infection of PA-2. Transmission electron microscopy (TEM) observation revealed that abnormal shapes of chloroplast, incomplete intracellular structure and gradual disintegration of the outer membrane in the cells of C. album are observed at the third day after inoculation. A total of 69,404 unigene was obtained, among which 35,950 were differentially expressed genes (DEGs), and most of them were enriched plant secondary metabolite biosynthesis, phytohormone signaling, and carotenoid biosynthesis. Moreover, the analysis of 8 candidate genes showed that the content of photosynthesis indices was significantly decreased, which was resulted from the down-regulation of photosynthesis-related genes expression levels after PA-2 infection. During the PA-2 infection phase, a total of 14,521 and 13,211 differentially accumulated metabolites (DAMs) were identified using the ESI⁺ and ESI⁻ modes, respectively. Significant differences were observed in the content of DAMs at the five stages of PA-2 infection, especially photosynthesis, purine metabolism, and carotenoid biosynthesis. Further correlation analysis of major DAMs and DEGs showed that 19 key DEGs were involved in photosynthesis, 10 key DEGs in carotenoid biosynthesis, and 3 key DEGs in purine metabolism. Conclusion These findings have paved way in further functional characterization of candidate genes and subsequently can be better understanding of molecular mechanism of PA-2 infection on C. album.

Rhizosphere microorganisms exert a significant influence in counteracting diverse external stresses and facilitating plant nutrient uptake. While certain rhizosphere microorganisms associated with Salix species have been investigated, numerous rhizosphere microorganisms from various Salix species remain underexplored. In this study, we employed high-throughput sequencing to examine the rhizosphere bacterial and fungal communities composition and diversity of three Salix species: Salix zangica (SZ), Salix myrtilllacea (SM), and Salix cheilophila (SC). Furthermore, the BugBase and FUNGuild were utilized to predict the functional roles of bacterial and fungal microorganisms. The findings revealed notable variations in the alpha and beta diversities of bacterial and fungal communities among the three Salix species exhibited significant differences ( p < 0.05). The relative abundance of Flavobacterium was highest in the SZ samples, while Microvirga exhibited significant enrichment in the SM samples. Microvirga and Vishniacozyma demonstrate the highest number of nodes within their respective bacterial and fungal community network structures. The functions of bacterial microorganisms, including Gram-positive, potentially pathogenic, Gram-negative, and stress-tolerant types, exhibited significant variation among the three Salix species ( p < 0.05). Furthermore, for the function of fungal microbe, the ectomycorrhizal guild had the highest abundance of symbiotic modes. This results demonstrated the critical role of ectomycorrhizal fungi in enhancing nutrient absorption and metabolism during the growth of Salix plants. Additionally, this findings also suggested that S. zangica plant was better well-suited for cultivation in stressful environments. These findings guide future questions about plant-microbe interactions, greatly enhancing our understanding of microbial communities for the healthy development of Salix plants.

Elsholtzia densa and Avena fatua are known as two of the most aggressive weeds, causing severe economic, environmental, human and animal health problems in China and around the world. In this study, seven strains of pathogenic fungi (i.e. DT-YSB1, DT-04A2, DT-DYLC, DT-XRKA, DT-08C, DT-14A2, and DT-QKBD004A) were isolated from weeds plants with infections symptoms. Pathogenicity test was performed and found that strain DT-XRKA exhibited strong herbicidal activity against E. densa, while strain DT-QKBD004A was highly pathogenic to A. fatua. On the basis of cultural, morphological and molecular characteristics, these two strains were identified as Alternaria alternata and Fusarium avenaceum, respectively. The safety assessment indicated that the spore suspension (10⁴ spore/ml) of strain DT-XRKA was generally safe for rapeseed, cabbage, tomato, cucumber, and pepper among the 12 tested crop species, though some non-target infections were observed. Strain DT-QKBD004A with same concentration was found to be safe for broad beans, corn, cabbage, tomato, cucumber, and pepper. Therefore, A. alternata and F. avenaceum can be selected for further studies to development mycoherbicides for control of these two weeds in rapeseed and broad bean fields.

Aims Stipa purpurea is one of the dominant grass species in alpine grassland and plays a crucial role in safeguarding the ecosystem and restoring degraded grassland. To enhance the population dominance of S. purpurea and effectively prevent further grassland degradation. In this study, we screened high-efficiency plant growth-promoting rhizobacteria (PGPR) from rhizosphere soil samples, with the aim of improving the growth activity of S. purpurea through spraying PGPR. Methods and results We selected functional medium for the isolation of PGPR from the rhizosphere soils of five distinct sampling sites in the alpine grasslands surrounding Qinghai Lake. Nitrogenase activity, phosphorus-solubilization, carbon-fixation, indole acetic acid (IAA)-like compounds production, and 1-aminocyclopropane-1-carboxylate deaminase production were used to assess the growth-promoting capability of the PGPR. Additionally, the ecological adaptability of PGPR was examined. Finally, the growth promotion effect of high-efficiency PGPR on S. purpurea was determined using pot experiments. The results of this study showed that 136 strains were isolated and were categorized into 18 genera based on the 16S rRNA sequences. Among these, seven strains exhibited multiple characteristics of promoting growth, and meanwhile, strains GD-1-1, YD-2-4, GD-3-9, and HD-1-1 exhibited strong resistance to drought, cold, UV, and oxidation. The strains GD-1-1 and YD-2-4 had growth-promoting effects on the growth of S. purpurea, which significantly enhance the seed germination rate, facilitate the growth of the above-ground part of seedlings, and the formation of lateral roots. Additionally, the results of the principal component analysis indicated that the interaction effect of high-efficiency PGPRs with young roots was more beneficial than that with young sprout. Conclusions The results of this study provide outstanding strain resources and a theoretical foundation for the restoration of alpine degraded grassland. The findings further provide the basis for research and development of microbial fertilizer.

In screening biocontrol strains with broad-spectrum and high-efficiency herbicidal activities, a strain with strong pathogenicity, HY-021, was isolated from the leaves of Rumex acetosa, which was identified as Botrytis fabiopsis based on morphology and molecular biology. The herbicidal activities of the fermentation filtrate of strain HY-021 against nine weeds, including Chenopodium album L., Elsholtzia densa Benth., Malva verticillata L. var. Crispa, Polygonum lapathifolium L., Amaranthus retroflexus L., Avena fatua L., Thlaspi arvense L., Polygonum aviculare L., and Galium spurium L., were determined in vitro and in vivo. The results showed that the pathogenicity of strain HY-021 to the different weeds in vitro was as follows: E. densa > A. retroflexus > P. aviculare > P. lapathifolium > M. verticillata > T. arvense > G. spurium > A. fatua > C. album. Seven days after inoculation with the HY-021 strain, the incidences in nine weeds were in the range of 32.9–87.23%, and the disease index values of the nine weeds were 41.73–94.57%. The pathogenic effects from high to low were A. retroflexus > E. densa > A. fatua > G. spurium > C. album > M. verticillata > T. arvense > P. aviculare > P. lapathifolium. The crop safety test showed that the biocontrol strain HY-021 was safe to V. faba, P. sativum, H. vulgare, and T. aestivum, but had a slight effect on B. napus. Scanning electron microscopy showed that the mycelium of strain HY-021 invaded the tissue through the stomata of C. album leaves, parasitized and reproduced in the tissue, and gradually destroyed the tissue. The results of this study provide a basis for the development and utilization of new and efficient microbial source herbicides.

This study used the ITS approach based on Illumina MiSeq sequencing to assess the endosphere and rhizosphere fungal communities in healthy and diseased faba bean plants. The findings indicate that the most predominant phyla in all samples were Ascomycota (49.89–99.56%) and Basidiomycota (0.33–25.78%). In healthy endosphere samples, Glomeromycota (0.08–1.17%) was the only predominant phylum. In diseased endosphere samples, Olpidiomycota (0.04–1.75%) was the only predominant phylum. At the genus level, Penicillium (0.47–35.21%) was more abundant in rhizosphere soil, while Paraphoma (3.48–91.16%) was predominant in the endosphere roots of faba bean plants. Significant differences were observed in the alpha diversity of rhizosphere samples from different germplasm resources (p < 0.05). The fungal community structures were clearly distinguished between rhizosphere and endosphere samples and between healthy and diseased endosphere samples (p < 0.05). Saccharomyces was significantly enriched in diseased endosphere samples, whereas Apiotrichum was enriched in healthy endosphere samples. Vishniacozyma and Phialophora were enriched in diseased rhizosphere samples, while Pseudogymnoascus was enriched in healthy rhizosphere samples. Diseased samples displayed more strongly correlated genera than healthy samples. Saprotrophs accounted for a larger proportion of the fungal microbes in rhizosphere soil than in endosphere roots. This study provides a better understanding of the composition and diversity of fungal communities in the rhizosphere and endosphere of faba bean plants as well as a theoretical guidance for future research on the prevention or control of faba bean root rot disease.