“中国灯笼”进化发育与适应环境的分子基础研究

The origin and selection of plant morphological novelty is a long-standing problem in evolutionary biology. A few genera within Solanaceae, like Physalis, the calyx is rapidly expanded after fertilization as berry develops, thus forming a balloon-like structure, which encapsulates the berry ultimately. The novel structure is called the "Chinese lantern". Obviously, it is a post-floral novelty from natural selection. It is an apparently simple but complicated trait. It is controlled by multiple components/genes, and their interaction with environments. The trait very likely provides a suitable microenvironment for the normal development of the fruit. The project is to aim at studying the effects of the Chinese lantern on the fitness in controlled conditions, the differential gene expression profiles at transcriptome level of the “Chinese lantern” in Physalis pubescens to characterize some key regulatory genes for development of the trait, followed by molecular evolution analysis and transgenic functional analysis. Comparative study between Physalis and its close relative Solanum without a lantern-like structure could reveal the molecular mechanisms of the development of the "Chinese lantern". These work, plus investigation of variation in fitness in different ecological environments, will identify the key genetic changes associated with phenotypic variation, and reveal the selective forces for “Chinese lantern”. As an important area of evolutionary biology, our efforts belong to microevolution.

植物创新结构的起源和选择是一个远没有解决的进化生物学难题。茄科酸浆属植物(Physalis)花萼在受精后随着浆果的发育而迅速膨大，形成气球状结构，包裹整个浆果，这种结构称为“中国灯笼”。显然，它是一个花后的创新结构，经过自然选择进化而来。它看似简单但实为一个复杂的性状，由多个因子控制。它的生态生物学功能之一可能是为浆果的正常发育提供一个合适的微环境。本项目拟在人工控制的环境下，研究“中国灯笼”对适合度的影响，从转录组水平上研究该器官中基因表达对环境的应答变化，对一些关键调控基因进行分子进化和转基因功能分析；并与酸浆属近缘的且不具该创新结构的茄属(Solanum)植物进行比较研究，揭示“中国灯笼”发育的分子机理。通过对“中国灯笼”在不同生态环境下对适合度的影响、在新旧环境间基因表达变异的分析，发现与表型变异相关的关键遗传改变，并揭示其进化的作用力，这是进化生物学在微进化层次上的重要研究内容。

形态创新的起源问题仍然是一个长期存在、悬而未决的进化生物学难题。茄科绝大多数属，如茄属具宿存果萼，但并不明显膨大，然而酸浆属具膨大的花萼症状（Inflated Calyx Syndrome, ICS），其形似灯笼，故这一性状被形象地称为“中国灯笼”。产生这种形态变异的分子遗传基础尚不清楚。本项目首次测定了酸浆属花果发育的转录组，并通过转录组的比较分析，揭示了茄属和酸浆属果实发育的遗传基础，锁定了一些参与“中国灯笼”发育的新基因；同时我们发现“中国灯笼”在多种环境下可以提高植物适合度，具体表现在它可以进行光合作用为果实生长提供物质积累，它形成的微环境不仅会影响果实的生长发育而且能够延长果实的保鲜期，而且有助种子借助于水流与风力实现远距离传播。这一研究结果揭示了茄科植物“中国灯笼”的进化发育的遗传基础和适应性，对理解植物器官的生物多样性具重要科学意义。