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：念珠状扁荚树（Pityrocarpa moniliformis (Benth.) Luckow & R. W. Jobson）隶属于豆科（Fabaceae），是巴西本土物种，在半干旱地区的经济开发项目中具备极高应用潜力，尤其可应用于蜂蜜生产、动物饲料制备及薪柴开发领域。本研究旨在筛选适用于遗传多样性研究的简单序列重复区间（Inter-Simple Sequence Repeat，ISSR）分子标记，并验证该技术量化自然种群遗传多样性的有效性。实验共测试28条ISSR引物，评估所选引物的总位点数、多态性比率、多态性信息含量（Polymorphism Information Content，PIC）、标记指数（Marker Index）与分辨力（Resolving Power）。研究对象为巴西里约格兰德州马卡伊巴地区的30个个体，对其遗传多样性参数——奈氏遗传距离（Nei genetic distance）与香农指数（Shannon index）进行分析。最终筛选出7条有效引物，共扩增得到74个位点，多态性比率为82%，PIC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）可有效用于种群遗传多样性研究，为育种亲本选择与种质资源库建设提供支撑，同时可为念珠状扁荚树种群的遗传保护与遗传改良工作贡献参考价值。