
烟粉虱内共生菌Rickettsia在植物体内的形态及动态变化
The morphology and spatiotemporal dynamics of the Rickettsia endosymbiont transmitted by the whitefly Bemisia tabaci to host plants
师沛琼 谢丽珠 徐 进 刘 媛 邱宝利
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DOI:10.7679/j.issn.2095-1353.2021.071
作者单位:广东海洋大学滨海农业学院,湛江 524088;广东省生物农药创制与应用重点实验室,广州 510640; 广东省农业害虫生物防治工程技术研究中心,广州 510640
中文关键词:烟粉虱;内共生菌;Rickettsia;水平传播;宿主昆虫;宿主植物
英文关键词:Bemisia tabaci; endosymbiont; Rickettsia; horizontal transmission; insect host; plant host
中文摘要:
【目的】 通过研究烟粉虱 Bemisia tabaci取食传入植物体内的昆虫内共生菌种类,探明其在不同植物中的分布形态及时空动态。【方法】 以B型烟粉虱、棉花、番茄、豇豆为实验材料,利用常规PCR检测烟粉虱取食后传入植物体内的共生菌种类;利用透射电镜(Transmission electron microscope,TEM)检测Rickettsia传入植物后的分布及形态;利用q-PCR技术检测豇豆叶片中Rickettsia含量的动态变化。 【结果】 B型烟粉虱体内含有原生共生菌Portiera、次生共生菌Rickettsia,Hamiltonella和Hemipteriphilus,但只检测到Rickettsia可经烟粉虱传入棉花、番茄、豇豆植物体内,并可在植物体内存活、转移。在3种植物体内Rickettsia均分布于叶片韧皮部的筛管细胞中。烟粉虱、棉花、番茄组织内的Rickettsia形态基本一致,但豇豆中Rickettsia在形态上较小而钝圆。相同数量的烟粉虱取食,在豇豆体内最先检测到Rickettsia。随着烟粉虱取食时间的增加,豇豆体内的Rickettsia含量先增加后下降;而当无烟粉虱持续取食时,一定时间段内豇豆体内的Rickettsia先下降再小幅度上升,并可以在一定时间内保持不变。基于16S rDNA序列的系统发育分析表明,传入棉花、番茄、豇豆叶片中的Rickettsia与B型烟粉虱体内的Rickettsia高度同源。【结论】 Rickettsia可经烟粉虱取食传入植物体内,分布并存活于韧皮部的筛管细胞中,并可在植物不同叶片之间转移;在不同植物宿主中,Rickettsia的形态会发生轻微变化;烟粉虱对Rickettsia的传播效率受到植物种类的影响。
英文摘要:
[Objectives] To detect endosymbiont species transmitted to
plants by the feeding behavior of the whitefly Bemisia tabaci, and the morphology and
spatiotemporal dynamics of Rickettsia in different host plants. [Methods] The transmission of endosymbionts by the B. tabaci B biotype into cotton, tomato
and cowpea plants was investigated. Endosymbionts were detected by PCR and the
location and morphology of Rickettsia in plants observed with TEM. Dynamic changes in Rickettsia titers in cowpea leaves was detected with q-PCR. [Results] The B.
tabaci B biotype is infected with the obligate endosymbiont Portiera and the facultative
endosymbionts Rickettsia, Hamiltonella and Hemipteriphilus. Only Rickettsia was transmitted to cotton, tomato and cowpea plants by B. tabaci feeding activity. Rickettsia can move between different plant leaves and TEM revealed that it is located in the sieve tube cells of
plant phloem. The morphology of Rickettsia in B. tabaci, cotton and tomato
leaves was similar, but it was relatively smaller and slight rounder in cowpea
leaves. The titers of Rickettsia in
cowpea plants first increased, then decreased, with increased duration of
continuous feeding by B. tabaci.
However, in cowpea plants that had been fed on by whiteflies for only 7 days it
first decreased, then increased slightly, then remained basically unchanged.
Phylogenetic analysis based on variation in the 16S rDNA sequence indicates
that Rickettsia found in cotton,
tomato and cowpea leaves is identical to Rickettsia in B. tabaci. [Conclusion] Rickettsia can be transmitted to host
plants by the feeding activity of B.
tabaci after which it becomes localized in the sieve tube cells of phloem
and can move between different leaves. The morphology of Rickettsia may vary slightly in different hosts, and the efficiency
of transmission of Rickettsia varies
with host plant species.