Key Laboratory of Experimental Marine Biology, Center for Ocean Mega-Science, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China.
Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China.
J Phycol. 2021 Feb;57(1):160-171. doi: 10.1111/jpy.13073. Epub 2020 Nov 24.
The red macroalga Pyropia yezoensis is an economically important seaweed widely cultured in Asian countries and is a model organism for molecular biological and commercial research. This species is unique in that it utilizes both phycobilisomes and transmembrane light-harvesting proteins as its antenna system. Here, one of the genes of P. yezoensis (PyLHCI) was selected for introduction into its genome to overexpress PyLHCI. However, the co-suppression phenomenon occurred. This is the first documentation of co-suppression in algae, in which it exhibits a different mechanism from that in higher plants. The transformant (T1) was demonstrated to have higher phycobilisomes and lower LHC binding pigments, resulting in a redder color, higher sensitivity to salt stress, smaller in size, and slower growth rate than the wildtype (WT). The photosynthetic performances of T1 and WT showed similar characteristics; however, P700 reduction was slower in T1. Most importantly, T1 could release a high percentage of carpospores in young blades to switch generation during its life cycle, which was rarely seen in WT. The co-suppression of PyLHCI revealed its key roles in light harvesting, stress resistance, and generation alternation (generation switch from gametophytes to sporophytes, and reproduction from asexual to sexual).
条斑紫菜是一种具有经济重要性的大型红藻，广泛分布于亚洲国家，是分子生物学和商业研究的模式生物。该物种的独特之处在于，它同时利用藻胆体和跨膜光捕获蛋白作为其天线系统。在这里，我们选择了条斑紫菜的一个基因（PyLHCI）导入其基因组以过表达 PyLHCI。然而，发生了共抑制现象。这是藻类中首次记录到共抑制现象，其机制与高等植物中的不同。转化体（T1）表现出更高的藻胆体和更低的 LHC 结合色素，导致颜色更红、对盐胁迫更敏感、体型更小、生长速度更慢，与野生型（WT）相比。T1 和 WT 的光合作用性能表现出相似的特征；然而，T1 中的 P700 还原更慢。最重要的是，T1 可以在其生命周期中在年轻叶片中释放出高比例的果孢子，以进行世代交替（从配子体到孢子体的世代转换，以及从无性到有性的繁殖）。共抑制 PyLHCI 揭示了其在光捕获、抗逆性和世代交替（配子体到孢子体的世代转换，无性到有性的繁殖）中的关键作用。
