Root nematode infection enhances leaf defense against whitefly in tomato
Root nematode infection enhances leaf defense against whitefly in tomato
复制标题
根线虫感染增强番茄叶片对粉虱的防御能力
DOI：
10.1007/s11829-016-9462-8
复制
发表时间：
2017-02-01
影响因子：
1.6
通讯作者：
Ge, Feng
中科院分区：
文献类型：
--
作者：
Guo, Honggang;Ge, Feng
植物对同一寄主不同食草动物的叶片反应是植物-昆虫相互作用研究的一个重要课题。植物进化出局部和系统的抗性策略来应对食草动物。许多研究人员已经描述了叶片对昆虫侵染的反应机制；然而，根作为系统对叶片食草动物的抗性调节器这一事实被广泛忽视。在这里，我们报道了感染南方根结线虫(根结线虫)的番茄(Solanum Lycopersicum)植物--这种线虫以根部为食形成根瘤--增强了叶片对地上攻击者的防御能力，特别是烟粉虱(Bomesia Tabaci)。我们的结果表明，与未感染线虫的番茄相比，线虫侵染提供了更强的SA依赖的防御途径，从而降低了烟粉虱的种群丰度。同时，侵染线虫的番茄植株在烟粉虱侵染后4h也激活了叶片JA依赖的防御途径。然而，在烟粉虱单独侵染下，叶片对茉莉酸的依赖防御受到抑制，茉莉酸含量比同时感染线虫和烟粉虱的番茄植株低近30%。此外，线虫侵染显著降低了植物叶片和根部的氮素浓度。因此，线虫侵染通过增强叶片SA依赖防御、激活JA依赖防御和降低氮素营养来减少烟粉虱的数量。我们的结果表明，地下线虫的侵染显著提高了番茄植株对粉虱的防御能力。
The foliar response to different herbivores sharing the same hosts is an important topic for the study of plant-insect interactions. Plants evolve local and systemic resistant strategies to cope with herbivores. Many researchers have characterized the mechanisms of leaf responses to insect infestation; however, the fact that roots serve as systemic resistance modulators to leaf herbivores has been widely ignored. Here, we report that tomato (Solanum lycopersicum) plants infected with southern root-knot nematodes (Meloidogyne incognita)-which feed on the roots to form nodules-enhanced leaf defenses against aboveground attackers, specifically, the whitefly (Bemisia tabaci). Our results show that nematode infection reduced the whitefly population abundance because of conferring a stronger SA-dependent defense pathway against whitefly than in tomato plants without nematode infection. Meanwhile, nematode-infected tomato plant also activated the foliar JA-dependent defense pathway at 4 h after whitefly infestation. However, the foliar JA-dependent defense under whitefly infestation alone was suppressed, with the JA content being nearly 30 % lower than that in tomato plants co-infected with nematodes and whiteflies. Furthermore, nematode infection significantly decreased the plant nitrogen concentration in leaves and roots. As a result, nematode infection reduced the number of whiteflies by enhancing foliar SA-dependent defense, activating JA-dependent defense and decreasing nitrogen nutrition. Our results suggest that underground nematode infection significantly enhances the defense ability of tomato plants against whitefly.