Comparative Chloroplast Genome Analysis of New-Green Tide Causative Species in China: Ulva laetevirens [我国新记录绿潮物种Ulva laetevirens的比较叶绿体基因组学研究]

作者：Wang J.; Wang Y.-C.; Wang H.-S.; Liu F.; Chen N.-S.

来源：海洋与湖沼, 2021, 52(5): 1201-1213.

DOI：10.11693/hyhz20210200045

• Chloroplast
• Local green tide
• Molecular evolution
• Ulva

Green tides caused by Ulva species have occurred for many years in the world. Some of them are large in scale across different ocean regions, while others are local. A green tide event occurred in early November, 2020 in the No.1 Bathing Beach, Yantai, Shandong, East China was investigated. Twelve algae samples were randomly collected, of which 11 were identified as Ulva laetevirens according to the molecular marker tufA. The full-length chloroplast genome of U. laetevirens CNS00533 was constructed. The genome is 110 889 bp in size, containing 71 protein coding genes, 27 tRNA genes, and 3 rRNA genes (rrl, rrn, and rrn5). The chloroplast genome of CNS00533 and the U. laetevirens MT179351 genome have high sequence identity (99.8%). They also have identical number of genes and perfect colinearity, and showed substantial differences of genome between two U. laetevirens strains. The chloroplast genome of CNS00533 had five type-I introns and one type-Ⅱ intron that are absent in the Irish strain, resulting in an increase of 7 kb in chloroplast genome length difference in-between. In contrast, the chloroplast genome of CNS00533 and the U. rigida MT179352 chloroplast genome had low sequence identity (93.1%) and large number of long insertion/delection (ranging 763-2 346 bp). Large genomic differences were observed between the chloroplast genome of CNS00533 and U. australis (MT179348), including an inversion that covered 45 genes. In the phylogenetic tree based on 71 protein coding genes of Ulva species, CNS00533 and U. laetevirens MT179351 joined in one cluster, while U. rigida MT179352, and U. australis MT179348 were clearly in another clade, indicating that U. laetevirens, U. rigida, and U. australis are three different species of the Ulva genera. Therefore, U. laetevierens was found to be a new green-tide causative species in China ocean regions. The molecular evolution analysis of this species presented in this paper enriched our findings and shall help effective monitoring green tides in coastal waters of China.

• 单位
  中国科学院; 中国科学院大学