College of Horticulture, China Agricultural University, Beijing, 100193, China.
Institute of Laboratory Animal Science, Guizhou University of Traditional Chinese, Guiyang, 550025, China.
Protoplasma. 2020 Sep;257(5):1333-1344. doi: 10.1007/s00709-020-01505-0. Epub 2020 May 5.
Root-knot nematodes (RKNs) are highly invasive plant parasites that establish permanent feeding sites within the roots of the host plant. Successful establishment of the feeding site is essential for the survival of RKN. The formation and development of the feeding cell, also called giant cell, involve both cell division and endoreduplication. Here, we examined giant cell development and endoreduplication in Prunus sogdiana infected with the RKN. We found that feeding sites were established 3-5 days post inoculation (dpi) and matured at 21-28 dpi. The giant cells began to form 5 dpi and continued to increase in size from 7 to 21 dpi. The large numbers of dividing nuclei were observed in giant cells from 7 to 14 dpi. However, nuclear division was rarely observed after 28 days. RT-PCR and in situ hybridization analyses revealed that PsoCCS52A was abundantly expressed at 7-21 dpi and the PsoCCS52A signal observed in giant cell nucleus at 7-14 dpi. The PsoCCS52B is highly expressed at 14 dpi, and the hybridization signal was mainly in the cytoplasm of giant cells. The PsoDEL1 expression was lowest 7-21 dip, with negligible transcript detected in the giant cells. This indicates that the PsoCCS52A plays a role in the process of cell division, while the CCS52B plays a role in the development of giant cells. The PsoDEL1 plays a negative regulatory role in megakaryocyte nuclear replication. These data suggest that an increased expression of PsoCCS52A promotes nuclear division and produces a large number of polyploid nuclei, the area of giant cells and feeding sites increase, ultimately leading to the formation of galls in Prunus sogdiana.
根结线虫（RKNs）是高度侵袭性的植物寄生虫，它们在宿主植物的根部建立永久性的取食部位。取食部位的成功建立对于 RKN 的生存至关重要。取食细胞（也称为巨型细胞）的形成和发育既涉及细胞分裂，也涉及内复制。在这里，我们研究了受 RKN 感染的沙枣中巨型细胞的发育和内复制。我们发现，取食部位在接种后 3-5 天建立，并在 21-28 天成熟。巨型细胞在接种后 5 天开始形成，并从 7 天到 21 天持续增大。在 7 到 14 天的巨型细胞中观察到大量分裂核。然而，在 28 天后很少观察到核分裂。RT-PCR 和原位杂交分析表明，PsoCCS52A 在 7-21 天大量表达，并且在 7-14 天的巨型细胞核中观察到 PsoCCS52A 信号。PsoCCS52B 在 14 天高度表达，杂交信号主要在巨型细胞的细胞质中。PsoDEL1 的表达在 7-21 天最低，在巨型细胞中检测到的转录本可忽略不计。这表明 PsoCCS52A 在细胞分裂过程中发挥作用，而 CCS52B 在巨型细胞的发育中发挥作用。PsoDEL1 在核复制中起负调节作用。这些数据表明，PsoCCS52A 的表达增加促进了核分裂，并产生了大量的多倍体核，巨型细胞和取食部位的面积增加，最终导致沙枣形成虫瘿。
