Applied Biodiversity Laboratory, Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Assam, 781 039, India.
Mol Biotechnol. 2020 Jan;62(1):31-42. doi: 10.1007/s12033-019-00223-0.
Pongamia pinnata (also called Millettia pinnata), a non-edible oil yielding tree, is well known for its multipurpose benefits and acts as a potential source for medicine and biodiesel preparation. Due to increase in demand for cultivation, understanding of genetic diversity is an important parameter for further breeding and cultivation programme. Transposable elements (TEs) are a major component of plant genome but still, their evolutionary significance in Pongamia remains unexplored. In view to understand the role of TEs in genome diversity, Pongamia unigenes were screened for the presence of TE cassettes. Our analysis showed the presence of all categories of TE cassettes in unigenes with major contribution of long terminal repeat-retrotransposons towards unigene diversity. Interestingly, the insertion of some TEs was also observed in both organellar genomes. The study of insertion of TEs in coding sequence is of great interest as they may be responsible for protein diversity thereby influencing the phenotype. The present investigation confirms the exaptation phenomenon in pyruvate decarboxylase (PDC) gene where the entire exon sequence was derived from Ty3-gypsy like retrotransposon. The study of PDC protein revealed the translation of gypsy element into protein. Furthermore, the phylogenetic study confirmed the diversity in PDC gene due to insertion of the gypsy element, where the PDC genes with and without gypsy insertion were clustered separately.
麻疯树（也称为 Millettia pinnata）是一种非食用产油树种，以其多种用途而闻名，是医药和生物柴油制备的潜在来源。由于对种植的需求增加，了解遗传多样性是进一步进行繁殖和种植计划的重要参数。转座元件（TEs）是植物基因组的主要组成部分，但它们在麻疯树中的进化意义仍未被探索。为了了解 TEs 在基因组多样性中的作用，对麻疯树的 unigenes 进行了 TE 盒的存在筛选。我们的分析表明，unigenes 中存在所有类别的 TE 盒，长末端重复逆转录转座子对 unigene 多样性的贡献最大。有趣的是，一些 TEs 的插入也在细胞器基因组中观察到。研究 TEs 在编码序列中的插入非常有趣，因为它们可能负责蛋白质多样性，从而影响表型。本研究证实了丙酮酸脱羧酶（PDC）基因中的适应现象，其中整个外显子序列都来自 Ty3-gypsy 样逆转录转座子。对 PDC 蛋白的研究表明，gypsy 元件被翻译成蛋白。此外，系统发育研究证实了 PDC 基因因插入 gypsy 元件而产生的多样性，具有和不具有 gypsy 插入的 PDC 基因分别聚类。
