Meyer Susan L F, Everts Kathryne L, Gardener Brian McSpadden, Masler Edward P, Abdelnabby Hazem M E, Skantar Andrea M
USDA, ARS, Nematology Laboratory, Northeast Area, Henry A. Wallace Beltsville Agricultural Research Center (BARC)-West, Beltsville, MD 20705.
University of Maryland College Park/University of Delaware, The Lower Eastern Shore Research and Education Center, Salisbury, MD 21801.
J Nematol. 2016 Mar;48(1):43-53.
Pseudomonas fluorescens isolates Clinto 1R, Wayne 1R, and Wood 1R, which produce the antibiotic 2,4-diacetylphloroglucinol (DAPG), can suppress soilborne diseases and promote plant growth. Consequently, these beneficial bacterial isolates were tested on watermelon plants for suppression of Meloidogyne incognita (root-knot nematode: RKN) and Fusarium oxysporum f. sp. niveum (Fon). In a greenhouse trial, Wayne 1R root dip suppressed numbers of RKN eggs per gram root on 'Charleston Gray' watermelon by 28.9%. However, in studies focused on 'Sugar Baby' watermelon, which is commercially grown in Maryland, a Wayne 1R root dip did not inhibit RKN reproduction or plant death caused by Fon. When all three isolates were applied as seed coats, plant stand in the greenhouse was reduced up to 60% in treatments that included Fon ± P. fluorescens, and eggs per gram root did not differ among treatments. In a microplot trial with Clinto 1R and Wayne 1R root dips, inoculation with P. fluorescens and/or Fon resulted in shorter vine lengths than treatment with either P. fluorescens isolate plus RKN. Root weights, galling indices, eggs per gram root, and second-stage juvenile (J2) numbers in soil were similar among all RKN-inoculated treatments, and fruit production was not affected by treatment. Plant death was high in all treatments. These studies demonstrated that the tested P. fluorescens isolates resulted in some inhibition of vine growth in the field, and were not effective for enhancing plant vigor or suppressing RKN or Fon on watermelon.
荧光假单胞菌菌株Clinto 1R、Wayne 1R和Wood 1R能够产生抗生素2,4-二乙酰基间苯三酚（DAPG），可抑制土传病害并促进植物生长。因此，对这些有益细菌菌株在西瓜植株上进行了测试，以抑制南方根结线虫（根结线虫：RKN）和尖孢镰刀菌西瓜专化型（Fon）。在温室试验中，Wayne 1R浸根处理使‘查尔斯顿灰’西瓜每克根上的RKN卵数量减少了28.9%。然而，在针对马里兰州商业化种植的‘甜心宝贝’西瓜的研究中，Wayne 1R浸根处理并未抑制RKN繁殖或由Fon引起的植株死亡。当将所有三种菌株用作种衣剂时，在包括Fon±荧光假单胞菌的处理中，温室中的植株成活率降低了60%，各处理之间每克根上的卵数量没有差异。在使用Clinto 1R和Wayne 1R浸根的微区试验中，接种荧光假单胞菌和/或Fon导致的藤蔓长度比单独使用荧光假单胞菌菌株加RKN的处理要短。在所有接种RKN的处理中，根重、瘿瘤指数、每克根上的卵数量和土壤中的二龄幼虫（J2）数量相似，且果实产量不受处理影响。所有处理中的植株死亡率都很高。这些研究表明，所测试的荧光假单胞菌菌株在田间导致了一些藤蔓生长抑制，并且在增强西瓜植株活力或抑制RKN或Fon方面无效。
