Departamento de Biotecnologia e Produção Vegetal e Animal, Centro de Ciências Agrárias, Universidade Federal de São Carlos, Araras, São Paulo, Brasil.
PLoS One. 2020 May 22;15(5):e0233211. doi: 10.1371/journal.pone.0233211. eCollection 2020.
Sugarcane is an important crop for food and energy security, providing sucrose and bioethanol from sugar content and bioelectricity from lignocellulosic bagasse. In order to evaluate the diversity and genetic structure of the Brazilian Panel of Sugarcane Genotypes (BPSG), a core collection composed by 254 accessions of the Saccharum complex, eight TRAP markers anchored in sucrose and lignin metabolism genes were evaluated. A total of 584 polymorphic fragments were identified and used to investigate the genetic structure of BPSG through analysis of molecular variance (AMOVA), principal components analysis (PCA), a Bayesian method using STRUCTURE software, genetic dissimilarity and phylogenetic tree. AMOVA showed a moderate genetic differentiation between ancestors and improved accessions, 0.14, and the molecular variance was higher within populations than among populations, with values of 86%, 95% and 97% when constrasting improved with ancestors, foreign with ancestors and improved with foreign, respectively. The PCA approach suggests clustering in according with evolutionary and Brazilian breeding sugarcane history, since improved accessions from older generations were positioned closer to ancestors than improved accessions from recent generations. This result was also confirmed by STRUCTURE analysis and phylogenetic tree. The Bayesian method was able to separate ancestors of the improved accessions while the phylogenetic tree showed clusters considering the family relatedness within three major clades; the first being composed mainly by ancestors and the other two mainly by improved accessions. This work can contribute to better management of the crosses considering functional regions of the sugarcane genome.
甘蔗是粮食和能源安全的重要作物，其糖分可用于生产蔗糖和生物乙醇，其木质纤维素蔗渣可用于生产生物电能。为了评估巴西甘蔗基因型核心种质资源库（BPSG）的多样性和遗传结构，本研究选用了甘蔗复合体中的 254 份材料，利用 8 个锚定在蔗糖和木质素代谢基因上的 TRAP 标记进行分析。共鉴定到 584 个多态性片段，用于通过 AMOVA、PCA、STRUCTURE 软件的贝叶斯分析、遗传距离和系统发育树分析来研究 BPSG 的遗传结构。AMOVA 显示，祖先和改良品种之间存在中等程度的遗传分化，为 0.14；群体内的分子方差高于群体间，分别为改良品种与祖先、外国品种与祖先、外国品种与改良品种对比时的 86%、95%和 97%。PCA 方法表明，聚类与甘蔗的进化和巴西育种历史相吻合，因为较老世代的改良品种与祖先的距离比较新世代的改良品种更接近。这一结果也得到了 STRUCTURE 分析和系统发育树的证实。贝叶斯方法能够将改良品种的祖先分离出来，而系统发育树则根据三个主要分支内的亲缘关系显示出聚类，第一个分支主要由祖先组成，另外两个分支主要由改良品种组成。这项工作可以为考虑甘蔗基因组功能区域的杂交提供更好的管理。
