Kovács Zsófia, Mlinarec Jelena, Höhn Mária
Institute of Agronomy, Department of Botany, Hungarian University of Agriculture and Life Sciences, Villányi Út 29-43, Budapest, 1118, Hungary.
Department of Zoology, Plant Protection Institute, Centre for Agricultural Research, ELKH, Budapest, Hungary.
Bot Stud. 2023 Jan 24;64(1):2. doi: 10.1186/s40529-022-00365-6.
The analysis of genetic diversity of protected plant species can greatly support conservation efforts. Plantago maxima Juss. ex Jacq. is a perennial species distributed along the Eurasian steppe. The westernmost range edge of the species' distribution is located in the Pannonian basin, in Hungary where it is represented by a few, fragmented and highly endangered populations. We studied population diversity of all Hungarian range edge, natural populations, and one established ex situ population. One population from the centre of distribution (Kazakhstan) was implemented in the cpDNA haplotype study to compare the peripheral vs. central populations. We performed morphometric trait-based analysis, chromosome studies (morphometric analyses and FISH) and genetic diversity evaluations using inter simple sequence repeats (ISSR) and cpDNA trnL-trnF to evaluate differences between the in situ and ex situ populations as well as central vs. peripheral populations.
Our results showed no obvious morphological differences among the in situ and ex situ populations in the period between 2018 and 2020. One ex situ subpopulation develops flowers three years in a row from 2019, which is a favourable indicator of the introduction success. Hungarian populations are exclusively diploids (2n = 2x = 12). The karyogram consists of 5 metacentric and 1 acrocentric chromosome pair. Plantago maxima has one 35S and two 5S rDNA loci, located on the acrocentric chromosome pair. Eight variable ISSR primers yielded 100 fragments, of which 74.6% were polymorphic (mean H = 0.220). A high level of genetic variation within population was observed (92%) while the genetic differentiation among the populations was only 8%. STRUCTURE analysis revealed that the largest Kunpeszér population separated from the rest of the Hungarian populations, indicating a high rate of admixture among the other ones. Based on the trnL-trnF sequence analysis the Hungarian populations represent a single haplotype, which can indicate a reduced diversity due to isolation and recent population decline. By contrast, Kazakh population represents a distinct haplotype compared to the Hungarian samples.
The present study draws the attention to the high conservation value of the Plantago maxima populations from the westernmost range edge of the species' distribution.
对受保护植物物种的遗传多样性进行分析能够极大地助力保护工作。大车前（Plantago maxima Juss. ex Jacq.）是一种分布于欧亚草原的多年生植物。该物种分布最西端的边缘位于匈牙利的潘诺尼亚盆地，那里仅存在少数零散且极度濒危的种群。我们研究了匈牙利所有分布边缘自然种群以及一个已建立的迁地保护种群的种群多样性。在叶绿体DNA单倍型研究中纳入了一个来自分布中心（哈萨克斯坦）的种群，以比较边缘种群与中心种群。我们进行了基于形态特征的分析、染色体研究（形态分析和荧光原位杂交）以及使用简单序列重复区间（ISSR）和叶绿体DNA的trnL - trnF进行遗传多样性评估，以评估原位种群与迁地种群之间以及中心种群与边缘种群之间的差异。
我们的结果表明，在2018年至2020年期间，原位种群和迁地种群之间没有明显的形态差异。一个迁地亚种群从2×19年起连续三年开花，这是引种成功的一个良好指标。匈牙利种群均为二倍体（2n = 2x = 12）。核型由5对中着丝粒染色体和1对近端着丝粒染色体组成。大车前有一个35S和两个5S核糖体DNA位点，位于近端着丝粒染色体对上。8个可变的ISSR引物产生了100个片段，其中74.6%是多态性的（平均H = 0.220）。观察到种群内存在高水平的遗传变异（92%），而种群间的遗传分化仅为8%。结构分析表明，最大的昆佩斯泽尔种群与其他匈牙利种群分离，这表明其他种群间的混合率很高。基于trnL - trnF序列分析，匈牙利种群代表单一单倍型，这可能表明由于隔离和近期种群数量下降导致多样性降低。相比之下，哈萨克种群与匈牙利样本代表不同的单倍型。
本研究提请人们注意大车前分布最西端边缘种群的高保护价值。
