微囊藻毒素生物降解过程mlr基因功能和mRNA转录水平响应机制的研究

项目名称： 微囊藻毒素生物降解过程mlr基因功能和mRNA转录水平响应机制的研究

项目编号： No.31300434

项目类型： 青年科学基金项目

立项/批准年度： 2014

项目学科： 生物科学

项目作者： 李洁明

作者单位： 中国农业大学

项目金额： 23万元

中文摘要： 在微囊藻毒素-LR (MC-LR)的生物降解过程中，mlrA、mlrB、mlrC、mlrD基因mRNA转录水平随不同共存营养基质的响应机制，以及mlrD基因发挥的功能，目前尚不清楚。本项目拟进行如下研究：（i）构建MCs降解菌的mlrD基因缺失突变株、突变株的mlrD基因互补菌株，并在不同种类和浓度营养基质共存条件下，比较突变株、互补株和野生型MCs降解菌的MC-LR及其降解产物（线型MC-LR、四肽、Adda）的降解活性，以及各降解过程中mlr基因mRNA转录水平的动态变化；（ii）比较mlrA、mlrB、mlrC三基因缺失的mlrD互补菌株在不同种类和浓度营养基质共存条件下，对MC-LR及其降解产物的吸收富集效能差异。本项目旨在揭示mlr基因mRNA转录水平对不同共存营养基质的响应差异，弄清MlrD对MC-LR及其降解产物的转运特性，及mlrD基因缺失、互补对MC-LR降解过程的影响。

中文关键词： 微囊藻毒素；生物降解；基因表达；基因敲除与互补；定量PCR

英文摘要： During the biodegradation of microcystin-LR (MC-LR), the mRNA transcription status of mlrA、mlrB、mlrC、mlrD genes responsed to various nutrient conditions in the culture, and the functions of mlrD gene still remain unclear. The research of this project can be specified as: (i) to construct a mlrD-deficited mutant derived from MC-degrading bacteria of wild type and a mlrD-complemented strain, and in the presence of the wild-type MCs-degrading strain, the mlrD-deficited mutant,or the mlrD-complemented strain, to compare the biodegrading activity of MC-LR and its degradative products（linear MC-LR, tetrapeptide and Adda）, and concurrent dynamics in mRNA transcription levels of mlr genes under various nutrient conditions;(ii) to compare the uptake efficiency of the mlrD-complemented strain with mlrA、mlrB、mlrC-deficit for MC-LR and its degradative products under various nutrient conditions. This project aims to reveal the difference in mechanisms for mRNA transcription of mlr genes responsed to different nutrient conditions, and to elucidate the MlrD's transportation potential for MC-LR and its degradative products, as well as the effects of mlrD-deletion and -complementation on the biodegradation of MC-LR.

英文关键词： microcystins；biodegradation；gene expression；gene knock-out and complementation；quantative PCR