Subjects: Biology >> Botany >> Applied botany submitted time 2024-05-15 Cooperative journals: 《广西植物》
HUANG Yanying
PENG Xiaohui
OU Guining
PENG Xiaoxue
GAN Li
HUANG Yuanhang
YANG Taiyi
QIN Fengyan
SHEN Zhangyou
WEI Maogui
Abstract： For revealing the mechanism of cassava continuous cropping obstacle formation, the current study planted cassava in a fixed field for three consecutive years, and applied high-throughput sequencing technology and bioinformatics to explore effects of continuous cropping on fungal community structure of both rhizosphere and non-rhizosphere of cassava soils. The results were as follows: (1) Continuous cropping caused significant effects on the α diversity and β diversity of rhizosphere and non-rhizosphere soils of cassava. (2) The dominant fungi phyla of cassava rhizosphere and non-rhizosphere soils were Ascomycota, SAR_k__norank, Basidiomycota, Mucoromycota, and unclassified _k __Fungi, while the main classes were Sordariomycetes, Eurotiomycetes, Dothideomycetes and Intramacronucleata. The composition of Ascomycota of the non-rhizosphere soils varied with the continuous cropping years significantly. In the rhizosphere, Hypocreales, Chaetothyriales, Myrothecium, Dothideomycetes, and Sordariomycetes were observed in 2019 and 2020, while Monosiga was found in 2021. (3) Soil pH, organic matter content, available nitrogen content, available phosphorus content, available potassium content, and urease activity significantly influenced the structure of fungal communities, especially for distributions of Ascomycota, SAR_k__norank, Basidiomycota, and Mucoromycota. In conclusion, continuous cropping of cassava influenced soil physicochemical properties through the accumulation of root exudates, thus altering the survival environment of fungi, leading to differences of the diversity and the abundance of fungal communities between cassava rhizosphere and non-rhizosphere soils. The relative abundance of Hypocreales, Myrothecium, and Sordariomycetes decreased with continuous cropping years, which may be one of main causes of the continuous cropping obstacles of cassava.
Subjects: Biology >> Botany >> Applied botany submitted time 2021-12-19 Cooperative journals: 《广西植物》
Abstract： The purpose of this study was to clone the RT genes of Ty1-copia-like retrotransposons, and to provide sequences basis for isolating the full-length sequences of Ty1-copia-like retrotransposons and studying their function in genus Arachis. Degenerate primers were designed according to the conserved region of RT genes, the genomic DNA of wild peanut species “Arachis duranensis” with AA genome was amplified by PCR using the degenerated primers. The amplified targeted bands were recovered, cloned and sequenced, and then sequences were analyzed through bioinformatics strategy. The results were as follows: (1) The amplified targeted bands were all about 260 bp in size. Forty-one and twenty-seven RT genes sequences were cloned from the two wild peanut species respectively. The length of sixty-eight sequences varied from 256 bp to 270 bp. The proportion of AT, AT/GC and the similarity between nucleotide sequences ranged from 55.86% to 68.42%, 1.27% to 2.17%, and 49.8% to 99.2% respectively, showing a higher heterogeneity. (2) The sixty-eight sequences were divided into six families, family I and family IV were the main components. (3) Nineteen of sixty-eight sequences had nonsense mutations, and Arachis duranensis (PI219823) had a higher nonsense mutations rate than Arachis duranensis (PI262133). (4) The similarity between amino acid sequences ranged from 4.7% to 100%, showing high heterogeneity. (5) The tertiary structures of proteins representing sequences in each family were basically similar in overall configuration, but there were great differences in the number of helix structures, folding structures, turns and hydrogen bonds. (6) The conserved motifs among sequences were generally consistent, but there were also some variations, showing a certain degree of heterogeneity. The phylogenetic tree divided sixty-eight sequences into ten classes. Most of sequences are clustered in A and B classes. (7) Some of RT genes sequences from two wild peanut species with AA genome were closely related to RT genes sequences from other plant species, which indicated that there might be transposon horizontal transmission between them. This study laid a foundation for the development and application of new molecular markers based on Ty1-copia-like retrotransposons in genus Arachis.
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