Zhao Ang, Yang Zujing, Wang Haoran, Wang Hao, Zhong Shuai, Li Chenhui, Zhang Yuehuan, Hu Jingjie, Bao Zhenmin, Huang Xiaoting
MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, 266003, China.
Academy of Future Ocean, Ocean University of China, Qingdao, 266100, China.
Mar Biotechnol (NY). 2024 Dec 27;27(1):24. doi: 10.1007/s10126-024-10406-9.
Triploids are widely used to rapidly achieve genetic improvements of organisms due to their fast growth and enhanced environmental adaptability. Artificially induced triploids are generally considered to be infertile owing to the obvious inhibition of gonadal development. Recently, some fertile individuals with reduced advantages have been found in triploid bivalves, which is a notable deviation from the original intention of artificially inducing triploids. This study utilized dwarf surf clams (Mulinia lateralis), a promising model organism of bivalves, to develop a model for exploring the potential mechanism of triploid reproduction. The results showed that the optimal induction condition for triploid M. lateralis, determined by orthogonal experiments, was 0.5 mg/L cytochalasin B (CB) to inhibit PB2 for 20 min, resulting in a triploidy rate of 95.57% and a hatching rate of 60.25%. By tracking the development of M. lateralis, we found that the induced triploids could develop normally to maturity and exhibited significant growth and survival advantages post-metamorphosis. Although the triploidy rate exhibited a slight decline overtime, it remained high, with a ratio of 90.63% at 120 dpf. Histological observation confirmed that the gonadal development pattern of triploid M. laterali was similar to that of diploids, but it also showed characteristics such as developmental retardation, few mature gametes, and gamete gigantism. The dynamic expression of genes related to gonadal development provided further molecular evidence for this phenomenon. Additionally, 82.6% of triploid M. laterali exhibited normal spawning behavior, produced fewer but larger viable gametes, and could generate offspring with full developmental potential. Flow cytometry analysis revealed that sperm of triploid M. laterali was aneuploid, with a DNA content of about 1.5 times that of diploid sperm, and the ploidy levels of mating offspring were 2N (DD, diploid female × diploid male), 2.5N (DT, diploid female × triploid male), 2.5N (TD, triploid female × diploid male), and 3N (TT, triploid female × triploid male), respectively. Overall, the artificially induced triploid M. laterali has been confirmed to be bisexually fertile, which will provide a unique model for exploring the underlying mechanisms of advantageous trait formation and fertility regulation in triploids, and offer a valuable platform for the study of ploidy control and polyploidization in bivalves. Please check and confirm that the authors and their respective affiliations have been correctly identified and amend if necessary. Yes, i have checked and it is OK.
由于三倍体生长迅速且环境适应性增强，它们被广泛用于快速实现生物体的遗传改良。人工诱导的三倍体通常被认为是不育的，因为性腺发育受到明显抑制。最近，在三倍体双壳贝类中发现了一些优势减弱但可育的个体，这与人工诱导三倍体的初衷明显背离。本研究利用矮滨蛤（Mulinia lateralis）这一双壳贝类中有前景的模式生物，建立了一个模型来探索三倍体繁殖的潜在机制。结果表明，通过正交实验确定的三倍体矮滨蛤的最佳诱导条件是0.5 mg/L细胞松弛素B（CB）抑制第二极体20分钟，三倍体率为95.57%，孵化率为60.25%。通过追踪矮滨蛤的发育过程，我们发现诱导产生的三倍体能够正常发育至成熟，并在变态后表现出显著的生长和存活优势。尽管三倍体率随时间略有下降，但仍保持较高水平，在120日龄时为90.63%。组织学观察证实，三倍体矮滨蛤的性腺发育模式与二倍体相似，但也表现出发育迟缓、成熟配子少和配子巨大等特征。性腺发育相关基因的动态表达为这一现象提供了进一步的分子证据。此外，82.6%的三倍体矮滨蛤表现出正常的产卵行为，产生的可存活配子数量较少但体积较大，并且能够产生具有完全发育潜力的后代。流式细胞术分析显示，三倍体矮滨蛤的精子是非整倍体，其DNA含量约为二倍体精子的1.5倍，交配后代的倍性水平分别为2N（DD，二倍体雌性交配二倍体雄性）、2.5N（DT，二倍体雌性交配三倍体雄性）、2.5N（TD，三倍体雌性交配二倍体雄性）和3N（TT，三倍体雌性交配三倍体雄性）。总体而言，人工诱导的三倍体矮滨蛤已被证实具有双性可育性，这将为探索三倍体有利性状形成和育性调控的潜在机制提供一个独特的模型，并为双壳贝类的倍性控制和多倍体化研究提供一个有价值的平台。请检查并确认作者及其各自的单位是否已正确识别，如有必要请进行修改。是的，我已检查，没问题。
