APPLICATIONS OF ISSR MARKERS IN STUDIES OF GENETIC DIVERSITY OF Pityrocarpa moniliformis

ABSTRACT Pityrocarpa moniliformis (Benth.) Luckow & R. W. Jobson (Fabaceae) is a native brazilian species with high potential for economic development programs in semiarid regions, mainly related to the production of honey, animal food and firewood. Thus, the objective of this work was to select Inter-Simple Sequence Repeat (ISSR) molecular markers for genetic diversity studies, as well as to test the efficiency of this approach in quantifying the genetic diversity of a natural P. moniliformis population. For this, 28 ISSR molecular markers were tested, evaluating the total number of loci, polymorphism rate and the Polymorphism Information Content (PIC) for the selected primers, the “Marker Index”, and the “Resolving Power”. Genetic diversity parameters (Nei genetic distance and Shannon index) were evaluated for 30 individuals located in Macaíba, Rio Grande do Norte State, Brazil. Seven primers were selected, which provided 74 loci, with 82% being polymorphic, while the PIC value was 0.344. The Nei genetic distance was 0.244, and the Shannon index was 0.374. Therefore, ISSR molecular markers (UBC 827, 840, 844, 857, 859, 860 and 873) are considered efficient in studying the genetic diversity of populations for the selection of matrices and germplasm banks, and may contribute to the conservation and genetic improvement of P. moniliformis populations.摘要 链状银叶豆（Pityrocarpa moniliformis (Benth.) Luckow & R. W. Jobson，豆科Fabaceae）是巴西本土物种，在半干旱地区的经济开发项目中具备较高应用潜力，尤其可应用于蜂蜜生产、动物饲料制备及薪柴开发领域。为此，本研究旨在筛选简单序列重复区间（Inter-Simple Sequence Repeat，ISSR）分子标记用于遗传多样性研究，并验证该方法在量化天然P. moniliformis种群遗传多样性中的有效性。本次试验共测试28个ISSR分子标记，对筛选出的引物的总位点数、多态性比率、多态信息含量（Polymorphism Information Content，PIC）、标记指数（Marker Index）及分辨力（Resolving Power）进行了评估。研究对象为巴西北里奥格兰德州马卡伊巴地区的30个个体，对其奈氏遗传距离（Nei genetic distance）与香农指数（Shannon index）等遗传多样性参数进行了分析。最终筛选出7对引物，共扩增得到74个位点，多态性比率达82%，多态信息含量值为0.344。奈氏遗传距离为0.244，香农指数为0.374。综上，ISSR分子标记（UBC 827、840、844、857、859、860及873）在开展种群遗传多样性研究以用于优良母本筛选及种质资源库建设方面具备良好效能，可为P. moniliformis种群的遗传保护与遗传改良提供重要支撑。