Fatty Acid Biosynthesis in Eukaryotic Photosynthetic Microalgae: Identification of a Microsomal Delta 12 Desaturase in Chlamydomonas reinhardtii

Xiaoyuan Chi,Xiaowen Zhang,Xiangyu Guan,Ling Ding,Youxun Li,Mingqing Wang,Hanzhi Lin,Song Qin 한국미생물학회 2008 The journal of microbiology Vol.46 No.2

Polyunsaturated fatty acids (PUFAs) are important components of infant and adult nutrition because they serve as structural elements of cell membranes. Fatty acid desaturases are responsible for the insertion of double bonds into pre-formed fatty acid chains in reactions that require oxygen and reducing equivalents. In this study, the genome-wide characterization of the fatty acid desaturases from seven eukaryotic photosynthetic microalgae was undertaken according to the conserved histidine-rich motifs and phylogenetic profiles. Analysis of these genomes provided insight into the origin and evolution of the pathway of fatty acid biosynthesis in eukaryotic plants. In addition, the candidate enzyme from Chlamydomonas reinhardtii with the highest similarity to the microsomal Δ12 desaturase of Chlorella vulgaris was isolated, and its function was verified by heterologous expression in yeast (Saccharomyces cerevisiae).

Transcriptome analysis reveals salt-stress-regulated biological processes and key pathways in roots of peanut (Arachis hypogaea L.)

Shanlin Yu,Na Chen,Maowen Su,Xiaoyuan Chi,Zhimeng Zhang,Lijuan Pan,Mingna Chen,Tong Wang,Mian Wang,Zhen Yang 한국유전학회 2016 Genes & Genomics Vol.38 No.6

The cultivated peanut is important oil crop and salt stress seriously influences its development and yield. Tolerant varieties produced using transgenic techniques can effectively increase peanut plantation area and enhance its yields. However, little is known about how gene expression is regulated by salt stress in peanut. In this study, we screened genes regulated by salt stress in peanut roots using microarray technique. In total, 4828 up-regulated and 3752 down-regulated probe sets were successfully identified in peanut roots subjected to 3 and 48 h of salt stress. Data analysis revealed that different response groups existed between the up and down-regulated probe sets. The main up-regulated biological processes involved in salt stress responses included transcription regulation, stress response, and metabolism and biosynthetic processes. The main down-regulated biological processes included transport processes, photosynthesis and development. The Kyoto encyclopedia of genes and genomes pathway analysis indicated that metabolic pathway, biosynthesis of unsaturated fatty acids and plant–pathogen interaction, were mainly up-regulated in peanut under salt stress. However, photosynthesis and phenylalanine metabolism were mainly down-regulated during salt stress. The function of some probe sets in salt stress regulation was not clarified (e.g., protein functioning in cell cycle regulation and xylem development). Many of the genes we identified lacked functional annotations and their roles in response to salt stress are yet to be elucidated. These results identified some candidate genes as potential markers and showed an overview of the transcription map, which may yield some useful insights into salt-mediated signal transduction pathways in peanut.

Influence of Peanut Cultivars and Environmental Conditions on the Diversity and Community Composition of Pod Rot Soil Fungi in China

Wang, Mian,Chen, Mingna,Yang, Zhen,Chen, Na,Chi, Xiaoyuan,Pan, Lijuan,Wang, Tong,Yu, Shanlin,Guo, Xingqi The Korean Society of Mycology 2017 Mycobiology Vol.45 No.4

Peanut yield and quality are seriously affected by pod rot pathogens worldwide, especially in China in recent years. The goals of this study are to analyze the structure of fungal communities of peanut pod rot in soil in three peanut cultivars and the correlation of pod rot with environmental variables using 454 pyrosequencing. A total of 46,723 internal transcribed spacer high-quality sequences were obtained and grouped into 1,706 operational taxonomic units at the 97% similarity cut-off level. The coverage, rank abundance, and the Chao 1 and Shannon diversity indices of the operational taxonomic units were analyzed. Members of the phylum Ascomycota were dominant, such as Fusarium, Chaetomium, Alternaria, and Sordariomycetes, followed by Basidiomycota. The results of the heatmap and redundancy analysis revealed significant variation in the composition of the fungal community among the three cultivar samples. The environmental conditions in different peanut cultivars may also influence on the structure of the fungal community. The results of this study suggest that the causal agent of peanut pod rot may be more complex, and cultivars and environmental conditions are both important contributors to the community structure of peanut pod rot fungi.

Influence of Peanut Cultivars and Environmental Conditions on the Diversity and Community Composition of Pod Rot Soil Fungi in China

( Mian Wang ),( Mingna Chen ),( Zhen Yang ),( Na Chen ),( Xiaoyuan Chi ),( Lijuan Pan ),( Tong Wang ),( Shanlin Yu ),( Xingqi Guo ) 한국균학회 2017 Mycobiology Vol.45 No.4

Peanut yield and quality are seriously affected by pod rot pathogens worldwide, especially in China in recent years. The goals of this study are to analyze the structure of fungal communities of peanut pod rot in soil in three peanut cultivars and the correlation of pod rot with environmental variables using 454 pyrosequencing. A total of 46,723 internal transcribed spacer high-quality sequences were obtained and grouped into 1,706 operational taxonomic units at the 97% similarity cut-off level. The coverage, rank abundance, and the Chao 1 and Shannon diversity indices of the operational taxonomic units were analyzed. Members of the phylum Ascomycota were dominant, such as Fusarium, Chaetomium, Alternaria, and Sordariomycetes, followed by Basidiomycota. The results of the heatmap and redundancy analysis revealed significant variation in the composition of the fungal community among the three cultivar samples. The environmental conditions in different peanut cultivars may also influence on the structure of the fungal community. The results of this study suggest that the causal agent of peanut pod rot may be more complex, and cultivars and environmental conditions are both important contributors to the community structure of peanut pod rot fungi.

Long-term continuously monocropped peanut significantly disturbed the balance of soil fungal communities

Chen Mingna,Zhang Jiancheng,Liu Hu,Wang Mian,Pan LiJuan,Chen Na,Wang Tong,Jing Yu,Chi Xiaoyuan,Du Binghai 한국미생물학회 2020 The journal of microbiology Vol.58 No.7

Balancing soil microbial diversity and abundance is critical to sustaining soil health, and understanding the dynamics of soil microbes in a monocropping system can help determine how continuous monocropping practices induce soil sickness mediated by microorganisms. This study used previously constructed gradient continuous monocropping plots and four varieties with different monocropping responses were investigated. The feedback responses of their soil fungal communities to short-term and long-term continuous monocropping were tracked using high-throughput sequencing techniques. The analyses indicated that soil samples from 1 and 2 year monocropped plots were grouped into one class, and samples from the 11 and 12 year plots were grouped into another, regardless of variety. At the species level, the F. solani, Fusarium oxysporum, Neocosmospora striata, Acrophialophora levis, Aspergillus niger, Aspergillus corrugatus, Thielavia hyrcaniae, Emericellopsis minima, and Scedosporium aurantiacum taxa showed significantly increased abundances in the long-term monocropping libraries compared to the short-term cropping libraries. In contrast, Talaromyces flavus, Talaromyces purpureogenus, Mortierella alpina, Paranamyces uniporus, and Volutella citrinella decreased in the long-term monocropping libraries compared to the shortterm libraries. This study, combined with our previous study, showed that fungal community structure was significantly affected by the length of the monocropping period, but peanut variety and growth stages were less important. The increase in pathogen abundances and the decrease in beneficial fungi abundances seem to be the main cause for the yield decline and poor growth of long-term monocultured peanut. Simplification of fungal community diversity could also contribute to peanut soil sickness under long-term monocropping. Additionally, the different responses of peanut varieties to monocropping may be related to variations in their microbial community structure.