小立碗藓新基因G4抗逆机制研究

	小立碗藓新基因G4抗逆机制研究; Mechanism of stress resistance of a novel gene G4 in Physcomitrium patens
	罗婷
导师	刘莉
摘要	The evolution of land plants was accompanied by the adaptation to the terrestrial environments. Frequent genome duplications, rearrangements and losses, and increased gene diversification gave rise to a complex regulatory network containing both ancient and neofunctionalized genes. However, little is known about gene neofunctionalization in land plants. Mosses occupy a phylogentic key position as the first colonized plant that transit from aquatic to terrestrial environment, and variously adversity adaptability which is mostly different from aquatic plant. Thus, mosses are very suitable experimental materials to investigate the relationship between new traits and new genes, which arising during the evolution. In the early stage, we sequenced the transcriptome of the drought and rehydrated plants materials of Physcomitrium patens (P. patens), and found some drought-responsive genes. Among these genes, we found an interesting gene G4. After drought treatment, the expression of G4 increased dozens of times, indicating that the gene has a strong response to drought. At the same time, in the previous DNA methylation sequencing data, it was also found that the methylation level of the upstream sequence of G4 in P. patens after drought treatment was significantly higher than that of the control group. Based on the above data, it is speculated that the expression of G4 gene may be regulated by changes in the methylation level of the G4 promoter region. Then using genetic and molecular experimental techniques and means to study the gene function and regulation mechanism of G4. The main results are summerized as following: 1. Bioinformatics analysis of amino acid sequence and nucleotide sequence of G4 revealed that its homologous amino acid sequence are only found in terrestrial plants. Among them, the similarity between the highest homology sequence and G4 only reached 32.7％. Domain analysis of this sequences, they have the same conservative motif. Based on the phylogenetic tree of G4, it can be seen that the most closely related species is Sphagnum fallax. 2.The CDS sequence of G4 (no stop codon) was fused with enhanced green fluorescent protein (EGFP) in the transient expression vector pm999, then we transformed the plasmids into protoplasts of P. patens and observed the fluorescence by laser confocal microscopy. This result can basically determine that the G4 protein is located in cell membrane and cytoplasm. 3.Construction of knockout and overexpression mutants of G4 gene in P. patens, then observing their phenotype and chlorophyll content under different stresses (drought, salt and high temperature). It was found that the chlorophyll content of the knockou mutants was significantly reduced under dehydration and salt treatment compared with the wild type, and the degree of albino was higher after rehydration treatment, while the overexpression plants were basically the same as the wild type. Based on the above results, we concluded that G4 plays an im
	2021-05
文献类型	学位论文
条目标识符	http://ir.kib.ac.cn/handle/151853/74608
专题	昆明植物所硕博研究生毕业学位论文
推荐引用方式 GB/T 7714	罗婷. 小立碗藓新基因G4抗逆机制研究, Mechanism of stress resistance of a novel gene G4 in Physcomitrium patens[D],2021.

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