Research Area Gene Technology and Applied Biochemistry, Institute of Chemical Engineering, Vienna University of Technology, Getreidemarkt 9/166, A-1060 Vienna, Austria.
BMC Genomics. 2009 Nov 30;10:567. doi: 10.1186/1471-2164-10-567.
Combating the action of plant pathogenic microorganisms by mycoparasitic fungi has been announced as an attractive biological alternative to the use of chemical fungicides since two decades. The fungal genus Trichoderma includes a high number of taxa which are able to recognize, combat and finally besiege and kill their prey. Only fragments of the biochemical processes related to this ability have been uncovered so far, however.
We analyzed genome-wide gene expression changes during the begin of physical contact between Trichoderma atroviride and two plant pathogens Botrytis cinerea and Rhizoctonia solani, and compared with gene expression patterns of mycelial and conidiating cultures, respectively. About 3000 ESTs, representing about 900 genes, were obtained from each of these three growth conditions. 66 genes, represented by 442 ESTs, were specifically and significantly overexpressed during onset of mycoparasitism, and the expression of a subset thereof was verified by expression analysis. The upregulated genes comprised 18 KOG groups, but were most abundant from the groups representing posttranslational processing, and amino acid metabolism, and included components of the stress response, reaction to nitrogen shortage, signal transduction and lipid catabolism. Metabolic network analysis confirmed the upregulation of the genes for amino acid biosynthesis and of those involved in the catabolism of lipids and aminosugars.
The analysis of the genes overexpressed during the onset of mycoparasitism in T. atroviride has revealed that the fungus reacts to this condition with several previously undetected physiological reactions. These data enable a new and more comprehensive interpretation of the physiology of mycoparasitism, and will aid in the selection of traits for improvement of biocontrol strains by recombinant techniques.
自二十年前以来，利用真菌寄生菌来对抗植物病原微生物的作用已被宣布为替代化学杀真菌剂的一种有吸引力的生物方法。木霉属真菌包括许多能够识别、对抗并最终包围和杀死其猎物的分类群。然而，迄今为止，仅揭示了与这种能力相关的生化过程的片段。
我们分析了厚垣轮枝菌与两种植物病原菌灰葡萄孢和立枯丝核菌在物理接触初期的全基因组基因表达变化，并分别与菌丝体和分生孢子培养的基因表达模式进行了比较。从这三种生长条件中，分别获得了约 3000 个 EST，代表约 900 个基因。在寄生作用开始时，有 66 个基因（代表 442 个 EST）特异性和显著过表达，其中一部分的表达通过表达分析进行了验证。上调的基因包括 18 个 KOG 组，但最丰富的是代表翻译后加工和氨基酸代谢的组，其中包括应激反应、对氮缺乏的反应、信号转导和脂类分解代谢的成分。代谢网络分析证实了氨基酸生物合成基因和参与脂质和氨基糖分解代谢的基因的上调。
对厚垣轮枝菌寄生作用开始时过表达基因的分析表明，真菌对此条件的反应伴随着几种以前未检测到的生理反应。这些数据使我们能够对寄生生理学进行新的、更全面的解释，并有助于通过重组技术选择改善生物防治菌株的特性。
