RESUMO
Grazing, as an important land use method in grassland, has a significant impact on the morphological and physiological traits of plants. However, little is known about how the molecular mechanism of plant responds to different grazing intensities. Here, we investigated the response of Taraxacum mongolicum to light grazing and heavy grazing intensities in comparison with a non-grazing control. Using de novo transcriptome assembly, T. mongolicum leaves were compared for the expression of the different genes under different grazing intensities in natural grassland. In total, 194,253 transcripts were de novo assembled and comprised in nine leaf tissues. Among them, 11,134 and 9058 genes were differentially expressed in light grazing and heavy grazing grassland separately, with 5867 genes that were identified as co-expression genes in two grazing treatments. The Nr, SwissProt, String, GO, KEGG, and COG analyses by BLASTx searches were performed to determine and further understand the biological functions of those differentially expressed genes (DEGs). Analysis of the expression patterns of 10 DEGs by quantitative real-time RT-PCR (qRT-PCR) confirmed the accuracy of the RNA-Seq results. Based on a comparative transcriptome analysis, the most significant transcriptomic changes that were observed under grazing intensity were related to plant hormone and signal transduction pathways, carbohydrate and secondary metabolism, and photosynthesis. In addition, heavy grazing resulted in a stronger transcriptomic response compared with light grazing through increasing the of the secondary metabolism- and photosynthesis-related genes. These changes in key pathways and related genes suggest that they may synergistically respond to grazing to increase the resilience and stress tolerance of T. mongolicum. Our findings provide important clues for improving grassland use and protection and understanding the molecular mechanisms of plant response to grazing.
RESUMO
The plants Feicai (Sedum aizoon L.) and dandelion(Taraxacum mongolicum Hand.-Mazz.) have good salt tolerance, and can improve soil quality and the micro-ecological environment. Coastal saline-soil plots planted with S. aizoon and T. mongolicum and bare plots were used to explore their effects on the microbial community structure of coastal saline soil. The diversity and function of soil bacterial communities were analyzed using Illumina MiSeq high-throughput sequencing technology. The results showed that the α-diversity of soil bacterial communities were higher in planted than in bare plots, in the following order: T. mongolicum plot > S. aizoon plot > bare plot. The soil bacterial communities also changed after planting S. aizoon and T. mongolicum. The LDA effect size analysis showed that there were 37 indicator species among the three plot types. Correlation analysis of environmental factors showed that EC, AP, and OM were the main factors influencing bacterial community composition in this coastal saline soil. The PICRUSt functional prediction showed that the numbers of metabolic functions of bacterial communities were in the following order: T. mongolicum plot > S. aizoon plot > bare plot. The results provide a theoretical basis and plant species for developing salt-tolerant bacterial resources and phytoremediation of coastal saline soil.
This study investigated the changes of soil bacterial α-diversity and community structures in coastal saline soil after planting the medicinal and edible plants coastal feicai (Sedum aizoon L.)and dandelion "Binpu No. 1" (Taraxacum mongolicum Hand.-Mazz.). It also identified the biomarkers and differential metabolic functions of soils among different plots. Our findings revealed that planting S. aizoon and T. mongolicum significantly improved bacterial diversity, and altered composition and metabolic function in coastal saline soils. This study makes a significant contribution to the literature because it offers an insight into novel strategies for vegetation restoration and ecological reconstruction of saline soils.