Key Laboratory of Marine Biotechnology of Zhejiang Province, Ningbo University, Ningbo, Zhejiang 315211, China; Li Dak Sum Yip Yio Chin Kenneth Li Marine Biopharmaceutical Research Center, Ningbo University, Ningbo 315211, China.
Key Laboratory of Marine Biotechnology of Zhejiang Province, Ningbo University, Ningbo, Zhejiang 315211, China; Li Dak Sum Yip Yio Chin Kenneth Li Marine Biopharmaceutical Research Center, Ningbo University, Ningbo 315211, China.
J Photochem Photobiol B. 2019 May;194:76-83. doi: 10.1016/j.jphotobiol.2019.03.009. Epub 2019 Mar 16.
The toxic dinoflagellate Karlodinium veneficum is widely distributed in cosmopolitan estuaries and is responsible for massive fish mortality worldwide. Intraspecific biodiversity is important for the spread to various habitats, interspecific competition to dominate a population, and bloom formation and density maintenance. Strategies for light adaptation may help determine the ecological niches of different ecotypes. However, the mechanism of phenotypic biodiversity is still unclear. In this study, intraspecific differences in genetic regulatory mechanisms in response to varied light intensities and qualities were comparatively researched on two different strains isolated from coastal areas of the East China Sea, namely, GM2 and GM3. In GM2, the expression of genes in the Calvin cycle, namely, rbcL and SBPase, and a light-related gene that correlated with cellular motility, rhodopsin, were significantly inhibited under high light intensities. Thus, this strain was adapted to low light. In contrast, the gene expression levels were promoted by high light conditions in GM3. These upregulated genes in the GM3 strain probably compensated for the negative effects on the maximum quantum yields of PSII (Fv/Fm) under high light stress, which inhibited both strains, enabling GM3 to maintain a constant growth rate. Thus, this strain was adapted to high light. Compared with white light, monochromatic blue light had negative effects on Fv/Fm and the relative electron transfer rate (ETR) in both strains. Under blue light, gene expression levels of rbcL and SBPase in GM2 were inhibited; in contrast, the levels of these genes, especially rbcL, were promoted in GM3. rbcL was significantly upregulated in the blue light groups. Monochromatic red light promoted rhodopsin gene expression in the two strains in a similar manner. These intraspecific diverse responses to light play important roles in the motor characteristics, diel vertical migration, interspecific relationships and photosynthetic or phagotrophic activities of K. veneficum and can determine the population distribution, population maintenance and bloom formation.
毒性甲藻卡多利毒素广泛分布于世界性的河口，并导致全球范围内大量鱼类死亡。种内生物多样性对于向各种栖息地的传播、种间竞争以主导种群以及形成和维持水华至关重要。对光的适应策略可能有助于确定不同生态型的生态位。然而，表型生物多样性的机制仍不清楚。在这项研究中，比较研究了从东海沿海地区分离的两个不同菌株 GM2 和 GM3 对不同光照强度和质量的遗传调控机制的种内差异。在 GM2 中，卡尔文循环中的基因表达，即 rbcL 和 SBPase，以及与细胞运动相关的光相关基因视紫红质，在高光强下显著受到抑制。因此，该菌株适应于低光。相比之下，GM3 中的基因表达水平受到高光条件的促进。GM3 菌株中这些上调的基因可能补偿了高光胁迫下 PSII（Fv/Fm）最大量子产量的负效应，抑制了两个菌株，使 GM3 能够保持恒定的生长率。因此，该菌株适应于高光。与白光相比，单色蓝光对 Fv/Fm 和两个菌株的相对电子传递率（ETR）都有负面影响。在蓝光下，GM2 中 rbcL 和 SBPase 的基因表达水平受到抑制；相反，这些基因，特别是 rbcL，在 GM3 中被促进。rbcL 在蓝光组中显著上调。单色红光以相似的方式促进了两个菌株视紫红质基因的表达。这些种内对光的不同反应在卡多利毒素的运动特性、昼夜垂直迁移、种间关系以及光合作用或吞噬作用中起着重要作用，并可以决定种群分布、种群维持和水华形成。
