Packard Holly, Kernell Burke Alison, Jensen Roderick V, Stevens Ann M
Department of Biological Sciences, Virginia Polytechnic Institute and State University (Virginia Tech), Blacksburg, VA, United States.
PeerJ. 2017 Apr 27;5:e3237. doi: 10.7717/peerj.3237. eCollection 2017.
subsp. is a bacterial phytopathogen that causes Stewart's wilt disease in corn. It uses quorum sensing to regulate expression of some genes involved in virulence in a cell density-dependent manner as the bacterial population grows from small numbers at the initial infection site in the leaf apoplast to high cell numbers in the xylem where it forms a biofilm. There are also other genes important for pathogenesis not under quorum-sensing control such as a Type III secretion system. The purpose of this study was to compare gene expression during an infection versus either a pre-inoculum liquid culture or an agar plate culture to identify genes specifically expressed that may also be important for colonization and/or virulence. RNA was purified from each sample type to determine the transcriptome via RNA-Seq using Illumina sequencing of cDNA. Fold gene expression changes in the data set in comparison to the two grown samples were determined and a list of the most differentially expressed genes was generated to elucidate genes important for plant association. Quantitative reverse transcription PCR (qRT-PCR) was used to validate expression patterns for a select subset of genes. Analysis of the transcriptome data via gene ontology revealed that bacterial transporters and systems important for oxidation reduction processes appear to play a critical role for as it colonizes and causes wilt disease in corn plants.
亚种是一种细菌性植物病原体，可导致玉米的斯图尔特枯萎病。随着细菌群体从叶片质外体初始感染部位的少量数量增长到木质部中形成生物膜的高细胞数量，它利用群体感应以细胞密度依赖的方式调节一些与毒力相关基因的表达。也有其他对致病作用很重要的基因不受群体感应控制，例如III型分泌系统。本研究的目的是比较感染期间与接种前液体培养或琼脂平板培养期间的基因表达，以鉴定特异性表达的基因，这些基因可能对定殖和/或毒力也很重要。从每种样品类型中纯化RNA，通过对cDNA进行Illumina测序的RNA-Seq来确定转录组。确定数据集中与两种生长样品相比的基因表达变化倍数，并生成差异表达最显著的基因列表，以阐明对植物关联重要的基因。使用定量逆转录PCR（qRT-PCR）来验证选定基因子集的表达模式。通过基因本体分析转录组数据表明，对氧化还原过程重要的细菌转运蛋白和系统在其定殖并导致玉米植株枯萎病时似乎起着关键作用。
