bioRxiv preprint doi: https://doi.org/10.1101/525964; this version posted January 21, 2019. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-NC-ND 4.0 International license. 1 Distribution and characterization of Aegilops cylindrica species from Iran 2 3 Behnam Bakhshi1*, Mohammad Jaffar Aghaei2, Eissa Zarifi2, Mohammad Reza Bihamta3 and 4 Ehsan Mohseni Fard4 5 1 6 Horticulture Crops Research Department, Sistan Agricultural and Natural Resources Research and 7 Education Center, Agricultural Research, Education and Extension Organization (AREEO), Zabol, 8 Iran 9 2Seed and Plant Improvement Institute, Agricultural Research, Education and Extension 10 Organization (AREEO), Karaj, Iran 11 3Department of Plant Breeding, The University of Tehran, Karaj, Iran 12 4Department of Agronomy and Plant Breeding, University of Zanjan, Zanjan, Iran 13 14 *Corresponding author’s email: [email protected] , [email protected] 15 16 Abstract 17 Jointed goatgrass (Aegilops cylindrica Host; 2n = 4x = 28, CcCcDcDc) is a tetraploid remote relative 18 of bread wheat (Triticum aestivum L; 2n=6x=42, AABBDD) with 2 genomes and 28 chromosomes. 19 The diversity center of this species is in the Fertile Crescent and in central Asia and could also be 20 found in many places in Iran. In this experiment, 359 accessions provided by National Plant Gene 21 Bank of Iran (NPGBI) were used. Based on the geographical distribution, the highest distribution of 22 Ae. cylindrica are from North, West and North West regions of Iran. The distribution data of Ae. 23 cylindrica showed that the distribution centers in Iran are more than those reported in previous 24 studies in Iran. Chromosome counting showed that all Ae. cylindrica accessions are tetraploid 25 (2n=4x=28). Results of factor analysis for 9 morphological chromosome traits showed that 26 karyotypic variation within accessions are related to the length of chromosomes and there is 27 difference between accessions for their total chromosome length, but the karyotype of different 1 bioRxiv preprint doi: https://doi.org/10.1101/525964; this version posted January 21, 2019. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-NC-ND 4.0 International license. 1 accessions were almost the same for the symmetry. Low coefficient of variation in morphological 2 traits as well as symmetric karyotypes of Ae. cylindrica species observed in this study could lead us 3 to more confidently say that Ae. cylindrica could be a recently evolved species among remote 4 relatives of bread wheat. 5 Key words: Remote relatives, Wheat, Cytogenetics, Chromosome, Genetic diversity. 6 7 1. Introduction 8 Jointed goatgrass, originated from two species, is native to the Mediterranean, Middle East, Asia, 9 and was also introduced to the Great Plains and the Pacific northwest of the United States (1, 2). It 10 is a winter annual grass weed that infests over 3 million ha of winter wheat in the Pacific 11 Northwest and Great Plains regions of the USA (3). It reduces winter wheat yields by interference 12 and lowers harvested grain quality. Average yield loss with moderate to dense Ae. cylindrica 13 infestations has been estimated to be 25% (4, 5) and it also has been estimated that the economic 14 cost of Ae. cylindrica to winter wheat producers in the western United States is $145 million 15 annually (6). Jointed goatgrass and winter wheat are closely related. Therefore, the development 16 of selective herbicides to control this weed in winter wheat has been problematic. 17 Aegilops cylindrica is a bush type plant with 20-40 centimeters. It is characterized by narrow leaves 18 (4-5 centimeters), none or very little hair, a narrow lanceolate spike (8 to 19 centimeters), almost 19 ended with two incomplete spikelet. Each spike consists of 6-11 spikelets and breaks off entirely or 20 disintegrates into segments. Each spikelet holds one to three seeds that are reddish-brown in color 21 and reach maturity in mid-summer which is when the spikelets are fragile (1, 2, 4, 7) (Figure 1). 2 bioRxiv preprint doi: https://doi.org/10.1101/525964; this version posted January 21, 2019. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-NC-ND 4.0 International license. 1 2 3 Figure 1. Spike and spikelet of Ae. cylindrica species. 4 The genomic constitution of Ae. cylindrica was determined by the analyses of chromosome pairiiring, 5 storage proteins, isozymes, and differences in restriction length patterns of repeated nucleoteotide 6 sequences (8). These studies identified the diploid species Ae. caudata L. (2n=2x=14, CC) andd Ae. 7 tauschii Coss. (2n=2x=14, DD) as the donor of the C and the D genome of Ae. cylindrica, respectivtively 8 (8). Previously, the cytoplasm of Ae. cylindrica was shown to be contributed by Ae. tauschii (9,9, 10)1 9 but, more recent analysis with chloroplast microsatellite markers has shown that both Ae. tauschii (D- 10 type cytoplasm) and Ae. markgrafii (C-type cytoplasm) have contributed their cytoplasms too Ae. 11 cylindrica (11). High genome homology shared between Ae. cylindrica and it's progenitor speciess anda 12 low intra-species polymorphism in Ae. cylindrica indicated it as a new species with little chromososome 13 changes. The D genome chromosomes of Ae. cylindrica species are more similar to Ae. tauschii 14 biotypes and Dcr2 genome of hexaploid cytotype of Ae. crassa species than D genome of bread wheatwh 3 bioRxiv preprint doi: https://doi.org/10.1101/525964; this version posted January 21, 2019. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-NC-ND 4.0 International license. 1 (12, 13). These results indicate that there are different versions of D genomes for both Ae. cylindrica 2 and T. aestivum species. 3 This species has wide distribution from Western Europe to East Asia and even North America. The 4 diversity center of this species is in the Fertile Crescent and in central Asia and could also be found 5 in many places in Iran (1). Ae. cylindrica has spread westward to Greece, Bulgaria, Romania, 6 Kosovo, Montenegro, Serbia, and Hungary. To the east, Ae. cylindrica is found in central Asia. 7 Northwards, it is present in the Caucasus region and along the Black Sea coast. Though rare, this 8 species is also present in the western arc of the Fertile Crescent involving Lebanon, Jordan, Syria, 9 northern Iraq, and northwestern Iran. Ae. cylindrica is also adventives in many parts of Europe, 10 Asia, and America (1). 11 The geographic distribution of Ae. cylindrica encompasses and extends beyond areas, where its 12 diploid progenitors, Ae. tauschii and Ae. markgrafii, can be found (Figure 2). 13 14 15 16 17 4 bioRxiv preprint doi: https://doi.org/10.1101/525964; this version posted January 21, 2019. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-NC-ND 4.0 International license. 1 2 Figure 2. Maps showing the distribution of collections of Ae. tauschii (a), Ae. markgrafii (b), and 3 Ae. cylindrica (c). The geographic coordinates were obtained from the system-wide information 4 network for genetic resources (SINGER; http://singer.cgiar.org/). 5 6 Throughout its range of distribution, Ae. cylindrica is considered a weedy species, particularly in 7 common wheat fields, where it chronically infests fields in the Mediterranean, the Middle East, 8 Europe, and the United States of America (USA) (1, 3, 14). Jointed goatgrass has also been 9 suggested as a source of genetic variation for wheat improvement (15-17) because it is a close 10 relative of common wheat—both species carry the D genome donated by Ae. tauschii (18, 19). In 11 addition, natural hybridization between wheat and jointed goatgrass suggests a potential for gene 12 flow between these species under field conditions (20, 21). Thus, there is considerable interest in 13 understanding various aspects of the evolution of Ae. cylindrica for its better management and use. 14 Cytogenetic and molecular-based analyses suggested that the D genomes of Ae. cylindrica and T. 15 aestivum were contributed by different biotypes of Ae. tauschii (12, 13). The D genome of hexaploid 16 wheat has been shown to be more closely related to the D genome of Ae. tauschii ssp. strangulata 17 than to Ae. tauschii ssp. Tauschii (22-24), whereas the D-type plastome and the D genome of Ae. 18 cylindrica are more closely related to Ae. tauschii ssp. tauschii than to Ae. tauschii ssp. strangulate 19 (11). 20 Although molecular genetic diversity and ploidy level of Ae. tauschii has been reported before 21 (25, 26), no extensive study has been done to identify cytogenetic and morphologic characteristics 22 of this species. We have collected many accessions from different regions of Iran that it could be 23 remarkable to identify potential genetic diversity among these accessions. In this study, we 24 analyzed chromosomes features of Ae. cylindrica as well as distribution and morphological 5 bioRxiv preprint doi: https://doi.org/10.1101/525964; this version posted January 21, 2019.