Santos R X, Melo S C O, Cascardo J C M, Brendel M, Pungartnik C
Departamento de Ciências Biológicas, Universidade Estadual de Santa Cruz, Rodovia Ilhéus-Itabuna, km 16, Ilhéus, CEP 45662-000 Brasil, BA, Brazil.
Fungal Genet Biol. 2008 Jun;45(6):851-60. doi: 10.1016/j.fgb.2008.02.005. Epub 2008 Feb 29.
The basidiomycete Moniliophthora perniciosa causes Witches' Broom disease in Theobroma cacao. We studied the influence of carbon source on conditioning hyphae to oxidative stress agents (H(2)O(2), paraquat, 4NQO) and to UVC, toward the goal of assessing the ability of this pathogen to avoid plant defenses involving ROS. Cells exhibited increased resistance to H(2)O(2) when shifted from glucose to glycerol and from glycerol to glycerol. When exposed to paraquat, cells grown in fresh medium were always more resistant. Apparently glycerol and/or fresh media, but not old glucose media, up-regulate oxidative stress defenses in this fungus. For the mutagens UVC and 4NQO, whose prime action on DNA is not via ROS, change of carbon source did not elicit a clear change in sensitivity/resistance. These results correlate with expression of fungal genes that protect against ROS and with biochemical changes observed in infected cacao tissues, where glycerol and high amounts of ROS have been detected in green brooms.
担子菌可可丛枝病菌（Moniliophthora perniciosa）可引发可可树的丛枝病。我们研究了碳源对菌丝适应氧化应激剂（过氧化氢、百草枯、4-硝基喹啉-N-氧化物）及紫外线C的影响，旨在评估该病原体规避植物中涉及活性氧（ROS）防御机制的能力。当从葡萄糖培养基转至甘油培养基以及从甘油培养基转至甘油培养基时，细胞对过氧化氢的抗性增强。暴露于百草枯时，在新鲜培养基中生长的细胞始终具有更强的抗性。显然，甘油和/或新鲜培养基，而非陈旧的葡萄糖培养基，可上调该真菌的氧化应激防御机制。对于诱变剂紫外线C和4-硝基喹啉-N-氧化物，其对DNA的主要作用并非通过活性氧，碳源的改变并未引起敏感性/抗性的明显变化。这些结果与真菌中抵御活性氧的基因表达以及在受感染可可组织中观察到的生化变化相关，在绿色丛枝中已检测到甘油和大量活性氧。
