郑肖兰 刘先宝 李博勋 郑行恺 时涛 冯艳丽 黄贵修

摘  要：天然橡胶是四大工业原料中唯一的可再生资源，由炭疽病菌侵染引起的橡胶树炭疽病是当前我国橡胶生产上最为严重的两大叶部病害之一。本研究以分离自云南保山的喀斯特炭疽病菌MeCkYN1705为对照，对海南新发炭疽病菌喀斯特炭疽菌HCkHNQZ1736进行抗药性评价。结果表明，菌株HCkHNQZ1736对苯并咪唑类杀菌剂多菌灵表现出高抗药性，EC50达1107.2654 ?g/mL，而MeCkYN1705的EC50仅为0.0554 ?g/mL。克隆了菌株HCkHNQZ1736的tub2基因，序列分析发现其所编码的第198个氨基酸位点由谷氨酸（Glu-E）突变为丙氨酸（Ala-A），推测该氨基酸位点突变是导致该菌株产生多菌灵抗性的原因。此外生物学特性测定发现，该菌株最适生长温度为28 ℃，致死温度为35 ℃;最适生长pH为6;光暗交替利于菌落生长;果胶、蛋白胨分别为最适碳源和氮源。

关键词：橡胶树炭疽病;喀斯特炭疽病菌;β-TUB2;抗药性

Abstract： Rubber tree （Hevea brasiliensis） is the only renewable resource among the four major industrial raw materials. Rubber tree anthracnose which infected by the Colletotrichum spp. is one of the most serious foliar disease of rubber production in China. In this paper， a new strain of C. karstii was identified and analyzed for carbendazim （2-benzo imidazole methyl carbamate） resistance. The carbendazim sensitivity test of HCkHNQZ1736 and MeCkYN1705， HCkHNQZ1736 showed high resistance to benzimidazole fungicides carbendazim， the EC50 was 1107.265 ?g/mL， while MeCkYN1705 had only 0.0554 ?g/mL. After the HCkHNQZ1736 tub2 gene was cloned， sequence analysis showed that the 198th amino acid locus was mutated from glutamic acid （Glu-E） to alanine （Ala-A）. This paper speculated that the mutation of the amino acid locus was the cause of carbendazim resistance of the strain. Combining morphological observation and polygenic phylogenetic analysis found that the optimum temperature was 28 ℃， the lethal temperature was 35 ℃， and the optimum pH was 6. The study also found that the alternation of light and dark was beneficial to colony growth， and pectin and peptone were the optimum carbon and nitrogen sources.

Keywords： rubber tree anthracnose; Colletotrichum karstii; β-TUB2; resistance

天然橡胶、钢铁、煤炭、石油并称为世界四大工业原料，天然橡胶是其中唯一的可再生资源。1906年斯里兰卡的Peteh首次报道橡膠树炭疽病，我国该病最早于1962年在海南大丰农场开割林段爆发流行[1-2]。到目前为止，橡胶树炭疽病几乎遍布全球所有植胶地，其中非洲中部、南美洲、亚洲南部和东南部等植胶国家最为严重[2-3]。苯并咪唑类杀菌剂是一种内吸性杀菌剂，其开发已有近50 a的历史，以高效和广谱著称，是植物病害化学防治的里程碑，极具历史意义[4-5]。其中多菌灵是应用最普遍的一种。在化学防治仍是目前橡胶树炭疽病的主要应对方法的大环境下，长期施药除了污染环境以外，还极易使病原菌产生抗药性，这一现状为炭疽病防治加大了难度。……