Abstract Detail

Molecular Ecology and Evolution

Du, Zhaokui [1], Li, Junmin [2], Jin, Zexin [1], Shi, Yongbin [1].

Transcriptomic and proteomic comparisons reveal mechanisms of growth inhibition of Arabidopsis thaliana by the parasitism of Cuscuta australis.

Parasitic plants commonly occur in many natural and seminatural ecosystems in the world, where they play key roles in determining community structure and function and are considered keystone species. To better understand the roles of parasitic plants in the development and maintain of ecosystem, understanding the genetic basis of the inter-specific interactions between parasitic plants and their host plants are indispensible. Using Arabidopsis thaliana as a model plant, we compared the photosynthetic rate of A. thaliana before and after the parasitism of C. australis, and analyzed the gene differential expression using Affymetrix gene-chip arrays and proteomic profile differences using 2D-electrophoresis and mass spectrometry. The net photosynthetic rate of A. thaliana significantly decreased after 72 hours parasitization of C. australis. In the leaves of A. Thaliana, 1594 genes were up-regulated and 696 genes were down-regulated more than 5-fold. Pathway and gene ontology term enrichment analyses revealed that genes involved in light reaction, dark reaction, light respiration and tricarboxylic acid cycle were up-regulated, but the expression of transketolase gene was significantly down-regulated. Proteomics profile revealed that the key enzymes involved in calvin cycle, such as ribulose bisphosphate carboxylase, phosphoribulokinase and glyceraldehyde 3-phosphate dehydrogenase, were significantly down-regulated, which in turn inhibited the photosynthesis rate and reduced the production of organic matters. Proteomics profile also revealed that the key enzymes involved in tricarboxylic acid cycle, such as aldolase and phosphoglyceate kinase, were significantly up-regulated, which in turn consume more organic matters. Both of the two kinds of effect might contribute to the inhibition of growth of A. Thaliana parasitized by C. australis. We also find that genes express involved in dark reaction were up-regulated at mRNA level, but the protein of these genes were down-regulated, which might be due to the positive feedback of the inhibition of photosynthesis induced by the shortage of these key enzymes involved in the photosynthetic pathway. Further researches should be focused on the gene differential expression at different development stages in order to reveals the turning point when the positive feed back happened.

1 - Taizhou University, Institute of Ecology, 1139# Shifu Road, Jiaojiang District, Taizhou City, Zhejiang Province, 318000, China
2 - Taizhou University, Insitute Of Ecology, 1139 Shifu Road, Jiaojiang, Taizhou, Zhejiang, N/A, 318000, China

Keywords:
Transcriptomic 
proteomic 
parasitism 
Arabidopsis thaliana
Photosynthesis.

Presentation Type: Poster:Posters for Topics
Session: P
Location: Hall D/The Shaw Conference Centre
Date: Monday, July 27th, 2015
Time: 5:30 PM
Number: PME003
Abstract ID:982
Candidate for Awards:None