ヤブコウジ科における葉粒菌垂直伝播の系統学的研究

细菌的叶瘤共生只在桃金娘亚科中进化过一次，但这一假说得到了部分证实，因为只强调了Ardisia(§Crispardisia)。这项研究通过包括三个节生属来测试桃金娘亚科植物叶结瘤的进一步进化，并确定了寄生在Amblyantus和Amblyanthopsis上的细菌共生体。并进行了寄主-共生体共生分析。在单独和/或组合的数据集分析中使用贝叶斯推论和最大似然法重建寄主和内共生菌的系统发育树。寄主(61个样本)和内生共生菌(167个样本)的系统发育分别基于nrITS、rpL32-trnL、trns-trnG和recA和gyrB。寄主-共生菌共发生分析采用Jane。在24个节生类群和3个非节生类群上进行了细菌共生菌的检测，发现寄主节生属及其内共生体不是单系的，形成两个类群(A)Amblyantus和(B)§Crispardisia+Amblyanthopsis。比较树显示寄主和内生共生体之间的不一致拓扑结构。系统发育分析表明，内共生菌的多样性主要是通过复制和寄主切换来实现的。从树叶结瘤共生体中扩增出的看家基因表明，它们在伯克霍尔德氏菌中形成了一个分支。聚合酶链式反应检测证实细菌共生体仅存在于根瘤部分和种子中，且仅限于节生类群。总体而言，本研究揭示了叶片结瘤的两次进化和独立起源。

Bacterial leaf-nodule symbiosis has been hypothesized evolved only once in Myrsinoideae but this hypothesis is partly confirmed because emphasizing only on Ardisia (§Crispardisia). This study tested further evolution of leaf nodulation within Myrsinoideae by including three nodulated genera and determine the bacterial symbionts that colonized Amblyanthus and Amblyanthopsis. Host-symbiont cophylogenetic analysis also conducted. Phylogenetic tree for both host and endosymbionts reconstructed using Bayesian inferences and maximum likelihood in separate and/or combined dataset analyses. The phylogeny of host (61 samples) and the endosymbionts (167 samples) are based on nrITS, rpL32-trnL, trnS-trnG and recA and gyrB, respectively. Host-symbiont cophylogenetic analysis was conducted using JANE. The presence of bacterial symbionts was tested on 24 nodulated and 3 non-nodulated taxa.The host nodulated genera and their endosymbionts were not monophyletic and formed into two groups (A) Amblyanthus and (B) §Crispardisia + Amblyanthopsis. Comparison tree shows incongruence topologies between the host and endosymbionts. Cophylogenetic analysis revealed that the diversification of endosymbionts is mainly by the duplication and host switching. The housekeeping genes amplified from the leaf nodulating symbionts suggested they form a clade within Burkholderia. PCR detection confirmed the present of bacterial symbionts only in nodule part and the seeds and restricted only to nodulated taxa. Overall, this study revealed that the leaf nodulation evolved twice and originated independently.