Department of Plant Pathology.
Department of Chemistry.
Plant Dis. 2018 Nov;102(11):2170-2179. doi: 10.1094/PDIS-01-18-0143-RE. Epub 2018 Sep 10.
Volatile organic compounds (VOC) produced by green residues for the management of plant-parasitic nematodes are poorly studied for oilseed plants and some Brassica spp. To investigate the activity of VOC in vitro and as biofumigants, dry and aqueous macerates of broccoli (Brassica oleracea var. italica) shoots and sunflower (Helianthus annuus) seed were used against the root-knot nematode Meloidogyne incognita. VOC produced by sunflower seed caused higher mortality of M. incognita second-stage juveniles (J) than VOC produced by broccoli shoots but both plant species were equally effective in decreasing the infectivity and reproduction of this nematode. The number of galls and eggs produced by the nematode in tomato roots was reduced by 89 and 95%, respectively, on average, at the highest concentrations of broccoli and sunflower seed macerates tested as biofumigants. When nematodes were placed in water exposed to broccoli VOC, J immobility increased and the number of galls and eggs produced by the nematode in tomato roots decreased 80 and 96%, respectively. Water exposed to sunflower seed VOC had no effect on the viability of the nematode. Gas chromatography was used to identify five and six chemical groups in broccoli and in sunflower seed macerates, respectively, but only alcohols, sulfurated VOC, and terpenes were detected in the water exposed to these plant macerates. Sulfurated VOC from the water exposed to broccoli macerates were found to be involved in its activity against M. incognita. The purified VOC dimethyl disulfide (DMDS) and 3-pentanol were tested directly against J and showed a lethal concentration of 176 and 918 µg/ml (ppm), respectively, whereas dimethyl sulfide had no effect against M. incognita. Furthermore, DMDS and 3-pentanol retained in water killed J and reduced gall formation and the number of eggs of M. incognita on tomato roots. Both these plant species produced toxic VOC to M. incognita, whereas only VOC retained in water exposed to broccoli had activity against M. incognita.
植物寄生线虫治理中绿肥产生的挥发性有机化合物（VOC）在油料作物和某些芸薹属植物中的研究较少。为了研究 VOC 的体外活性和生物熏蒸特性，使用干燥和水浸的西兰花（ Brassica oleracea var. italica ）嫩枝和向日葵（ Helianthus annuus ）种子的浸提液来防治根结线虫 Meloidogyne incognita 。与西兰花嫩枝相比，向日葵种子产生的 VOC 使二龄幼虫（J）的死亡率更高，但这两种植物在降低这种线虫的感染力和繁殖力方面同样有效。在作为生物熏蒸剂测试的最高浓度下，用西兰花和向日葵种子浸提液处理番茄根系后，根结线虫产生的根瘤和卵的数量分别平均减少了 89%和 95%。当线虫置于暴露于西兰花 VOC 的水中时，J 变得不活动，并且线虫在番茄根系中产生的根瘤和卵的数量分别减少了 80%和 96%。暴露于向日葵种子 VOC 的水对线虫的活力没有影响。气相色谱法分别鉴定了西兰花和向日葵种子浸提液中的 5 种和 6 种化学物质组，但仅在暴露于这些植物浸提液的水中检测到醇类、含硫 VOC 和萜烯。从暴露于西兰花浸提液的水中发现的含硫 VOC 参与了其对线虫的活性。直接测试了从水中分离出的挥发性有机化合物二甲基二硫（DMDS）和 3-戊醇对 J 的致死浓度分别为 176 和 918 µg/ml（ppm），而二甲基硫对 M. incognita 没有影响。此外，保留在水中的 DMDS 和 3-戊醇可杀死 J，并减少番茄根系上的根瘤形成和卵的数量。这两种植物都产生了对线虫有致命毒性的 VOC，而只有暴露于水中的西兰花 VOC 对线虫有活性。
