Page 138 - 《水产学报》2023年第1期

郑卫卫，等 水产学报, 2023, 47(1): 019109

Genome-wide identification of the MKK gene family in Scophthalmus maximus
and its involvement in abiotic and biotic stress responses

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ZHENG Weiwei , XU Xiwen , CHEN Songlin 1,2,3 , E Zechen , LIU Yingjie 1,4*
(1. College of Fisheries and Life Science, Shanghai Ocean University, Shanghai 201306, China;
2. Laboratory for Marine Fisheries Science and Food Production Processes, Yellow Sea Fisheries Research Institute,
Chinese Academy of Fishery Sciences, Qingdao 266071, China;
3. Shandong Key Laboratory of Marine Fisheries Biotechnology and Genetic Breeding, Qingdao 266071, China;
4. Chinese Academy of Fishery Sciences, Beijing 100141, China)

Abstract: Mitogen-activated protein kinase kinases (MAPKKs or MKKs) are essential components of the highly
evolutionarily conserved mitogen-activated protein kinase (MAPK) cascade, which play crucial roles in response
to a variety of biotic and abiotic stresses and immune responses. However, very little information is available about
the MKKs in S. maximus. In order to detect the roles of the MKKs in response to biotic and abiotic stresses in Sco-
phthalmus maximus, we first identified the MKKs of S. maximus at the whole genome level through bioinformat-
ics methods, and then analyzed the expression patterns of MKKs in different tissues and under different biotic and
abiotic stresses using multiple stress-related RNA-seq datasets. As a result, a total of 9 MKKs of S. maximus
(SmMKKs) were identified, and they were unevenly distributed on 7 chromosomes. Physicochemical characterist-
ics, secondary structure and subcellular localization of the proteins they encode were predicted, respectively.
Phylogenetic analysis revealed that SmMKKs were classified into 5 subfamilies. Conserved motifs, intron-exon
structure and multiple sequence alignment not only provided evidences for the classification of MKK subfamilies,
but also revealed high levels of conservation in evolution within and between subfamilies. Expression patterns of
SmMKKs in distinct tissues and under diverse abiotic and biotic stresses were examined using multiple published
RNA-seq datasets. As a result, SmMKKs showed obviously tissue-specific expression. In addition, SmMKK6a was
extremely significant differentially expressed after infection with both Enteromyxum scophthalmi and Megalocyt-
ivirus. After heat stress, SmMKK6a also showed extremely significant differential expression. Furthermore,
SmMKK4a, SmMKK4b, SmMKK6a and SmMKK7 were extremely significant differentially expressed after high- or
low- salinity stresses. Among these candidate stress-responsive MKK genes, SmMKK6a showed extremely signi-
ficant response to both abiotic and biotic stresses, demonstrating its potential functions in comprehensive anti-
stress. This study may be the first to systematically identify and analyze the MKK gene family in turbot. The res-
ults not only demonstrate that SmMKKs play crucial roles in response to various biotic and abiotic stresses, but also
provide important theoretical support for the development of molecular selective breeding for comprehensive stress-
resistance in S. maximus.

Key words: Scophthalmus maximus; mitogen-activated protein kinase kinases (MKK); gene family; biotic stress;
abiotic stress

Corresponding author: LIU Yingjie. E-mail: lyj@cafs.ac.cn
Funding projects: Central Public-interest Scientific Institution Basal Research Fund, CAFS (2020TD20); Taishan
Scholar Climbing Project of Shandong Province

中国水产学会主办 sponsored by China Society of Fisheries https://www.china-fishery.cn
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