Crutcher Frankie K, Puckhaber Lorraine S, Bell Alois A, Liu Jinggao, Duke Sara E, Stipanovic Robert D, Nichols Robert L
USDA, Insect Control and Cotton Disease Research Unit, Southern Plains Agricultural Research Center, Agricultural Research Service, USDA , 2765 F&B Road, College Station, Texas 77845, United States.
Cotton Incorporated, 6399 Weston Parkway, Cary, North Carolina 27513, United States.
J Agric Food Chem. 2017 Jun 21;65(24):4989-4992. doi: 10.1021/acs.jafc.7b01655. Epub 2017 Jun 7.
Fusarium oxysporum f. sp. vasinfectum race 4 (VCG0114), which causes root rot and wilt of cotton (Gossypium hirsutum and G. barbadense), has been identified recently for the first time in the western hemisphere in certain fields in the San Joaquin Valley of California. This pathotype produces copious quantities of the plant toxin fusaric acid (5-butyl-2-pyridinecarboxylic acid) compared to other isolates of F. oxysporum f. sp. vasinfectum (Fov) that are indigenous to the United States. Fusaric acid is toxic to cotton plants and may help the pathogen compete with other microbes in the soil. We found that a laboratory strain of the fungus Mucor rouxii converts fusaric acid into a newly identified compound, 8-hydroxyfusaric acid. The latter compound is significantly less phytotoxic to cotton than the parent compound. On the basis of bioassays of hydroxylated analogues of fusaric acid, hydroxylation of the butyl side chain of fusaric acid may affect a general detoxification of fusaric acid. Genes that control this hydroxylation may be useful in developing biocontrol agents to manage Fov.
尖孢镰刀菌萎蔫专化型4号生理小种（VCG0114）可引发棉花（陆地棉和海岛棉）根腐病和枯萎病，最近在加利福尼亚州圣华金谷的某些田地中首次在西半球被发现。与美国本土的其他尖孢镰刀菌萎蔫专化型（Fov）分离株相比，该致病型产生大量的植物毒素镰刀菌酸（5-丁基-2-吡啶羧酸）。镰刀菌酸对棉花植株有毒，可能有助于该病原菌与土壤中的其他微生物竞争。我们发现，鲁氏毛霉的一个实验室菌株可将镰刀菌酸转化为一种新鉴定出的化合物，8-羟基镰刀菌酸。后一种化合物对棉花的植物毒性明显低于母体化合物。基于镰刀菌酸羟基化类似物的生物测定，镰刀菌酸丁基侧链的羟基化可能影响镰刀菌酸的一般解毒作用。控制这种羟基化的基因可能有助于开发用于防治Fov的生物防治剂。
