Pandey Ajay K, Jain Preti, Podila Gopi K, Tudzynski Bettina, Davis Maria R
Department of Biological Sciences, University of Alabama, Huntsville, AL 35899, USA.
Mol Genet Genomics. 2009 Feb;281(2):135-46. doi: 10.1007/s00438-008-0397-3. Epub 2008 Nov 15.
Botrytis cinerea is a necrotrophic fungal plant pathogen that can survive, grow and infect crops under cold stress. In an attempt to understand the molecular mechanisms leading to cold tolerance of this phytopathogen, we identified an enolase, BcEnol-1. BcEnol-1 encodes a 48 kDa protein that shows high identity to yeast, Arabidopsis and human enolases (72, 63 and 63%, respectively). Northern analysis confirms that an increase in transcript abundance of BcEnol-1 was observed when B. cinerea mycelium was shifted from 22 to 4 degrees C. In order to understand its regulation during cold stress, BcEnol-1 expression was studied in B. cinerea mutants viz Deltabcg1 (mutant of B. cinerea for bcg1), Deltabcg3 (mutant of B. cinerea for bcg3) and Deltabac (mutant of B. cinerea for adenylate cyclase). A decrease in enolase expression in these mutants was observed during cold stress suggesting enolase activation by a cAMP mediated cascade. Expression of enolase was restored with the exogenous addition of cAMP to the Deltabac mutant. Recombinant enolase protein was also found to bind to the promoter elements of transcripts belonging to the Zinc-C(6) protein family and calpain like proteases. Based on these results we conclude that enolase from Botrytis is cold responsive, influenced by cAMP and acts putatively as a transcriptional regulator.
灰葡萄孢是一种坏死型真菌植物病原体，能够在冷胁迫下存活、生长并感染作物。为了了解这种植物病原体产生耐寒性的分子机制，我们鉴定出一种烯醇酶，即BcEnol-1。BcEnol-1编码一种48 kDa的蛋白质，与酵母、拟南芥和人类的烯醇酶具有高度同源性（分别为72%、63%和63%）。Northern分析证实，当灰葡萄孢菌丝体从22℃转移至4℃时，观察到BcEnol-1的转录本丰度增加。为了了解其在冷胁迫期间的调控机制，我们在灰葡萄孢突变体（即Deltabcg1，灰葡萄孢bcg1基因的突变体；Deltabcg3，灰葡萄孢bcg3基因的突变体；以及Deltabac，灰葡萄孢腺苷酸环化酶基因的突变体）中研究了BcEnol-1的表达。在冷胁迫期间，这些突变体中烯醇酶的表达下降，这表明烯醇酶是由cAMP介导的级联反应激活的。向Deltabac突变体中外源添加cAMP可恢复烯醇酶的表达。还发现重组烯醇酶蛋白可与锌-C(6)蛋白家族和钙蛋白酶样蛋白酶转录本的启动子元件结合。基于这些结果，我们得出结论，灰葡萄孢中的烯醇酶对冷有响应，受cAMP影响，并可能作为一种转录调节因子发挥作用。
