Djami-Tchatchou A T, Ntushelo K
Department of Agriculture and Animal Health, University of South Africa, Private Bag X6, 1710 Florida, South Africa.
Pak J Biol Sci. 2017;20(3):147-153. doi: 10.3923/pjbs.2017.147.153.
Pectobacterium carotovorum subsp. carotovorum (Pcc) is a soft rot bacterium which upon entry into the plant macerates plant tissues by producing plant cell wall degrading enzymes. It has a wide host range which includes carrot, potato, tomato, leafy greens, squash and other cucurbits, onion, green peppers and cassava. During plant-microbe interactions, one of the ways of plant response to pathogen infection is through the small RNA silencing mechanism. Under pathogen attack the plant utilizes microRNAs to regulate gene expression by means of mediating gene silencing at transcriptional and post-transcriptional level. This study aims to assess for the first time, the expression profile of some stress-responsive miRNA and differential expression pattern of their target genes in Arabidopsis thaliana inoculated with Pcc.
Leaves of five weeks old Arabidopsis thaliana plants were infected with Pcc and the quantitative real time-PCR, was used to investigate after 0, 24, 48 and 72 h post infection, the expression profiling of the stress-responsive miRNAs which include: miR156, miR159, miR169, miR393, miR396 miR398, miR399 and miR408 along with their target genes which include: Squamosa promoter-binding-like protein, myb domain protein 101, nuclear factor Y subunit A8, concanavalin A-like lectin protein kinase, growth regulating factor 4, copper superoxide dismutase, ubiquitin-protein ligase and plantacyanin respectively.
The findings showed that the overexpression of 6 miRNAs at 24, 48 and 72 h after infection resulted in the repression of their target genes and the expression of 2 miRNAs didn't affect their target genes.
These results provide the first indication of the miRNAs role in response to the infection of Pcc in A. thaliana and open new vistas for a better understanding of miRNA regulation of plant response to Pcc.
胡萝卜软腐果胶杆菌胡萝卜软腐亚种（Pcc）是一种软腐细菌，进入植物后通过产生植物细胞壁降解酶来浸解植物组织。它具有广泛的宿主范围，包括胡萝卜、马铃薯、番茄、叶菜类蔬菜、南瓜和其他葫芦科植物、洋葱、青椒和木薯。在植物 - 微生物相互作用过程中，植物对病原体感染的一种反应方式是通过小RNA沉默机制。在病原体攻击下，植物利用微小RNA通过在转录和转录后水平介导基因沉默来调节基因表达。本研究旨在首次评估接种Pcc的拟南芥中一些应激反应性微小RNA的表达谱及其靶基因的差异表达模式。
用Pcc感染五周龄拟南芥植株的叶片，并在感染后0、24、48和72小时，使用定量实时PCR来研究应激反应性微小RNA的表达谱，这些微小RNA包括：miR156、miR159、miR169、miR393、miR396、miR398、miR399和miR408，以及它们的靶基因，分别包括：鳞状启动子结合样蛋白、myb结构域蛋白101、核因子Y亚基A8、伴刀豆球蛋白A样凝集素蛋白激酶、生长调节因子4、铜超氧化物歧化酶、泛素 - 蛋白连接酶和植物蓝素。
研究结果表明，感染后24、48和72小时，6种微小RNA的过表达导致其靶基因受到抑制，而2种微小RNA的表达未影响其靶基因。
这些结果首次表明了微小RNA在拟南芥对Pcc感染的反应中的作用，并为更好地理解微小RNA对植物对Pcc反应的调控开辟了新的前景。
