Ploidy dynamics in aphid host cells harboring bacterial symbionts
Ploidy dynamics in aphid host cells harboring bacterial symbionts
复制标题
含有细菌共生体的蚜虫宿主细胞的倍性动力学
DOI：
10.1101/2021.12.03.471054
复制
发表时间：
2021
期刊：
影响因子：
--
通讯作者：
Shigenobu Shuji
中科院分区：
文献类型：
--
作者：
Nozaki Tomonari;Shigenobu Shuji
蚜虫已经进化出细菌细胞或共生宿主细胞，这些细胞具有专性互惠细菌--蚜虫生布赫纳氏菌（Buchnera aphidicola）。由于细菌细胞的大细胞尺寸（直径约100 μm）及其在营养共生中的关键作用，研究人员认为这些细胞是高度多倍体的，并假设细菌细胞多倍性可能是蚜虫和细菌之间共生关系所必需的。然而，对蚜虫细菌细胞的倍性水平和动力学知之甚少。在这里，我们定量分析了豌豆蚜的细菌细胞的倍性水平。基于图像的荧光测定法揭示了细菌细胞在整个生命周期中的超多倍性，范围从16倍体到256倍体。成年孤雌生殖胎生雌虫的细菌细胞分布在64 ~ 128 C DNA水平之间，而有性变异体（卵生雌虫和雄虫）的细菌细胞分别由64 C和32- 64 C细胞组成。在胎生雌性的胚胎后发育过程中，细菌细胞的倍性水平显著增加，从出生时的16 - 32 C增加到活跃繁殖的成年体的128- 256 C。这些结果表明，倍性水平之间的表型和发育过程中动态调节。本研究为进一步了解昆虫细菌细胞多倍体的功能作用和生物学意义奠定了基础。
Aphids have evolved bacteriocytes or symbiotic host cells that harbor the obligate mutualistic bacteriumBuchnera aphidicola. Because of the large cell size (approximately 100 μm in diameter) of bacteriocytes and their pivotal role in nutritional symbiosis, researchers have considered that these cells are highly polyploid and assumed that bacteriocyte polyploidy may be essential for the symbiotic relationship between the aphid and the bacterium. However, little is known about the ploidy levels and dynamics of aphid bacteriocytes. Here, we quantitatively analyzed the ploidy levels in the bacteriocytes of the pea-aphidAcyrthosiphon pisum. Image-based fluorometry revealed the hyper polyploidy of the bacteriocytes ranging from 16- to 256-ploidy throughout the lifecycle. Bacteriocytes of adult parthenogenetic viviparous females were ranged between 64 and 128C DNA levels, while those of sexual morphs (oviparous females and males) were comprised of 64C, and 32–64C cells, respectively. During post-embryonic development of viviparous females, the ploidy level of bacteriocytes increased substantially, from 16 to 32C at birth to 128–256C in actively reproducing adults. These results suggest that the ploidy levels are dynamically regulated among phenotypes and during development. Our comprehensive and quantitative data provides a foundation for future studies to understand the functional roles and biological significance of the polyploidy of insect bacteriocytes.