First report of Fusarium solani species complex as a causal agent of Erythrina variegata decline and death after gall formation by Quadrastichus erythrinae on Okinawa Island, Japan
First report of Fusarium solani species complex as a causal agent of Erythrina variegata decline and death after gall formation by Quadrastichus erythrinae on Okinawa Island, Japan
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DOI：
10.1007/s10327-017-0738-3
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发表时间：
2017-11-01
影响因子：
1.2
通讯作者：
Kameyama, Norikazu
中科院分区：
文献类型：
--
作者：
Kuroda, Keiko;Chuma, Izumi;Kameyama, Norikazu
刺桐属植物的落叶和死亡。日本南部岛屿和台湾的数量正在增加。尽管瘿蜂Quadrastichus erythrinae的侵染已被认为是刺桐数量减少的原因，但其在宿主死亡中的作用从未被研究过。因此，我们研究了下降的原因，重点关注生理变化和微生物的贡献。来自衰败和落叶的树木，镰刀菌属 sp。主要在茄病菌复合体 (FSSC) 进化枝 3 中检测到，特别是从变色的木质部和有气味的坏死韧皮部中检测到。这种真菌属于豚草镰刀菌分支，这是一组豚草甲虫的共生体，其中包括牛油果上镰刀菌顶枯病的致病因子。在带有赤刺栎瘿的树枝和叶子中没有检测到特定的真菌。根据组织学观察，衰退 E. variegata 的内部症状与大豆猝死综合征相似，由 FSSC 2 支成员 F. virguliforme 引起。Fusarium sp. 的分离株之一。从斑叶桉中分离得到的菌株，人工接种后引起幼苗皮层和韧皮部枯萎、坏死，重新分离接种菌株。目前的结果表明，该分离株对斑叶刺桐具有致病性，并且可能是刺桐减少的原因。
The defoliation and mortality of Erythrina spp. are increasing on the southern islands of Japan as well as in Taiwan. Although infestation by the gall wasp Quadrastichus erythrinae has been accepted as the cause of Erythrina decline, its role in the death of hosts has never been investigated. We thus studied the cause of the decline, focusing on physiological changes and any contributions by microorganisms. From declining and defoliated trees, Fusarium sp. within F. solani species complex (FSSC) clade 3 was primarily detected, especially from discolored xylem and necrotic phloem that had an odor. This fungus belongs to the Ambrosia Fusarium clade, a group of symbionts of ambrosia beetles that includes the causal agent of Fusarium dieback on avocado. No specific fungi were detected from twigs and leaves with Q. erythrinae galls. According to histological observations, the internal symptoms of declining E. variegata are similar to those of sudden death syndrome in soybeans, which is caused by F. virguliforme, a member of FSSC clade 2. One of the isolates of the Fusarium sp. isolated from E. variegata induced wilt and necrosis of cortex and phloem in the seedlings after artificial inoculation, and the inoculated strain was reisolated. The present results demonstrated that the isolate was pathogenic to E. variegata and may be a causal agent of Erythrina decline.