文蛤不同生活阶段适应酸化胁迫的传递机制及基因效应

Ocean acidification is one of the most important issues for global climate change. Intertidal zone is regarded as an important marine extreme environment, which is alternately under the impact of air and seawater. Intertidal shellfish is an excellent model for studying stress adaptation. As a typical calcifying invertebrate, shellfish exhibit short life cycles and complex life histories. The transfer effect of adaptation to stress environment between different generations and different developmental stages is an important driving force in the evolution of shellfish. This research aims to study the effect of long-term acidification stress on the different life stages of hard clam (Meretrix meretrix) and its carry-over effect. We want to explore the adaptation process and gene effects of different life stages to ocean acidification. To study the long-term acidification ocean acidification effect on the health status and gonad development of Meretrix meretrix; to analyze the stress mechanism of ocean acidification on reproductive performance. To compare the fitness of offspring from parents raised in the acidification group and control group, to investigate the effects of parents exposure on their offspring. To study the ocean acidification stress effect on the growth and calcification of juveniles, to clarify the carry-over effect of planktonic exposure to ocean acidification on the juveniles. To extract RNA to construct the transcriptome and microRNA libraries for both acidification group and control group; to screen acidification response genes, and construct the gene network and regulation network based on the difference of gene expression level between the acidification group and control group. To establish ♀10×♂10 hybridized families to explicit the genetic background of experimental materials; to compare polymorphic loci from transcriptome sequences, calculate the changes of allele frequencies between different developmental stages, and extract quantitative trait loci for acidification resistance on cDNA level. This project provides a new idea for the study of stress adaptation for the organisms living in the intertidal zone.

海洋酸化是全球气候变化的核心问题之一。潮间带交替受到空气和海水淹没的影响，生境类型多样，是重要的海洋极端环境。作为典型钙化无脊椎生物，贝类生命周期短、生活史复杂，不同世代、不同发育阶段适应逆境的传递效应是适应进化的重要驱动力。本项目研究长期酸化对文蛤不同生活阶段的影响及其延迟效应，探讨文蛤不同生活阶段对酸化胁迫的适应过程和基因效应。研究长期酸化对亲贝健康状况和性腺发育的影响，解析海水酸化对文蛤繁殖性能的胁迫机制。比较酸化组和对照组子代在酸化胁迫下的适合度差异，探讨亲本酸化暴露对幼虫耐酸性的影响。研究幼虫酸化胁迫对稚贝生长钙化的影响，阐明幼虫酸化胁迫对稚贝的延迟效应。利用高通量测序技术，在基因转录和调控水平研究不同生活阶段响应酸化胁迫的分子机制；利用♀10×♂10群体杂交家系，研究酸化胁迫对文蛤群体遗传变异的选择机制，评价文蛤适应海洋酸化的进化潜力。本研究为潮间带生物逆境胁迫研究提供新思路。

海洋酸化是全球气候变化的核心问题之一。潮间带交替受到空气和海水淹没的影响，生境类型多样，是重要的海洋极端环境。作为典型钙化无脊椎生物，贝类生命周期短、生活史复杂，不同世代、不同发育阶段适应逆境的传递效应是适应进化的重要驱动力。本项目研究长期酸化对文蛤不同生活阶段的影响及其延迟效应，探讨文蛤不同生活阶段对酸化胁迫的适应过程和基因效应。研究长期酸化对亲贝健康状况和性腺发育的影响，解析海水酸化对文蛤繁殖性能的胁迫机制。比较酸化组和对照组子代在酸化胁迫下的适合度差异，探讨亲本酸化暴露对幼虫耐酸性的影响。研究幼虫酸化胁迫对稚贝生长钙化的影响，阐明幼虫酸化胁迫对稚贝的延迟效应。利用高通量测序技术，在基因转录和调控水平研究不同生活阶段响应酸化胁迫的分子机制；利用♀10×♂10群体杂交家系，研究酸化胁迫对文蛤群体遗传变异的选择机制，评价文蛤适应海洋酸化的进化潜力。海洋酸化对文蛤和菲律宾蛤仔成体长期酸化的实验结果表明：在水温较低的情况下，海洋酸化对文蛤和菲律宾蛤仔死亡率影响不大，随海水温度的升高，酸化条件下培养的文蛤和菲律宾蛤仔死亡率呈现明显上升的趋势。两种贝类相比，文蛤受到的影响更大。文蛤的代谢率、氨氮排泄率和壳长增长率在酸化条件下显著降低，表明其生理活动在酸化条件下受到抑制。氧氮比的增加表明其更多的以碳水化合物作为底物进行代谢活动。酸化条件下培养的亲本产生的子代对酸化的耐受性更差。以上现象表明文蛤是对酸化较为敏感的物种，并且子代不会产生酸化的耐受性。菲律宾蛤仔的上述指标受酸化影响较小，菲律宾蛤仔为近岸广温广盐物种，其栖息环境本身就具有相当大的变动范围，因而在进化过程中已经对环境因子包括pH的变化具有一定的适应性，且相对于其早期生命阶段，成体的适应性更强。在这种较强选择和耐受的作用下，最终存活的菲律宾蛤仔可能都是环境适应性较强的个体，因此其子代也表现出对酸化较强的适应性。