Molecular Phylogeny of Palestinian Date Palm Cultivars by Microsatellite Simple Sequence Repeats and Inter Simple Sequence Repeats Markers

Abstract

Date palm (Phoenix dactylifera L.) is considered one of the major fruit crops in Palestine and one of the oldest cultivated plants. Date crops contribute to the economical, industrial, and religious concepts in the Middle East and North Africa. Since studies on the genetic diversity and relatedness of date palm germplasm are limited in Palestine, the aim of this study is to analyze the genetic relatedness among twelve cultivars collected from the Jericho City area in Palestine using Simple Sequence Repeat (SSR) and Inter- Simple Sequence Repeat (ISSR). These cultivars are Zahidi, Hayani, Hejazi, Khadrawy, Barhy, Majool, Dejlet Noor (Deek Noor), Amery, Ibrahemi, and three cultivars known as Baladi. DNA was extracted and purified from the young leaves by applying a phenol-chloroform extract followed by DNeasy DNA extraction kit. Microsatellites (Simple Sequence Repeats; SSR) and Inter Simple Sequence Repeats (ISSR) were amplified by PCR using 3 SSR and 9 ISSR primers, respectively. The size of the amplicons of the SSR and ISSR products ranged between 180-240bp and 140 - 3100bp, respectively. A matrix representing the banding profiles was used to establish a phylogenetic tree of the twelve cultivars using the Fingerprint Analysis with Missing Data (FAMD) software and the Neighbor Joining method. The phylogram obtained by SSR and ISSR encompasses three clusters. The first cluster contained one cultivar Ameri. The second cluster included 5 cultivars, which was further divided into two sub-clusters; the first sub-cluster contained one cultivar; Baladi 3, and the second sub-cluster encompasses four cultivars, Ibrahimi, Khadrawi, Dejlat Noor and Hayani. The third cluster was divided into two sub-clusters; the first one contains Majool and Berhy, while the other one holds Balady 2, Zuhadi, Hijazi, and Baladi 1. The fidelity of the phylogram was assured by the bootstrapping and Principal Coordinate of Analysis (PCoA) methods. Despite the well-known morphological differences among some cultivars, they were closely related in this phylogram. Examples include Ibrahemy and Khadrawi, Dejlat Noor and Hayani, as well as Hijazi and Baladi 1. The phylogram differentiates among three cultivars that are known as Baladi. These three cultivars were named as Baladi1-3 to facilitate their use in this study. To the best of my knowledge, this is the first study done in Palestine with emphasis on the genetic relatedness among date palms cultivars using SSR and ISSR.