南京林业大学学报(自然科学版) ›› 2023, Vol. 47 ›› Issue (5): 80-86.doi: 10.12302/j.issn.1000-2006.202110046

• 研究论文 • 上一篇    下一篇

两个南方红豆杉天然居群的交配系统分析

罗芊芊1,2(), 李峰卿3, 肖德卿2, 邓章文1, 王建华1, 周志春2,*()   

  1. 1.抚州市林业科学研究所,江西 抚州 344000
    2.中国林业科学研究院亚热带林业研究所,浙江 杭州 311400
    3.中国林业科学研究院亚热带林业实验中心,江西 分宜 336600
  • 收稿日期:2021-10-23 修回日期:2022-05-12 出版日期:2023-09-30 发布日期:2023-10-10
  • 通讯作者: *周志春(zczhou_caf@163.com),研究员。
  • 作者简介:罗芊芊(luoqianqian617327@163.com),助理工程师。
  • 基金资助:
    百山祖国家公园科学研究项目(2021ZDLY02);中国林业科学研究院中央级公益性科研院所基本科研业务费专项资金项目(CAFYBB2018ZB010);抚州市科技计划项目(2018Tc06)

Mating system analyses of two natural populations of Taxus wallichiana var. mairei

LUO Qianqian1,2(), LI Fengqing3, XIAO Deqing2, DENG Zhangwen1, WANG Jianhua1, ZHOU Zhichun2,*()   

  1. 1. Forestry Research Institute of Fuzhou,Fuzhou 344000,China
    2. Research Institute of Subtropical Forestry,Chinese Academy of Forestry,Hangzhou 311400,China
    3. Experimental Center of Subtropical Forestry,Chinese Academy of Forestry,Fenyi 336600,China
  • Received:2021-10-23 Revised:2022-05-12 Online:2023-09-30 Published:2023-10-10

摘要:

【目的】研究南方红豆杉(Taxus wallichiana var. mairei)天然居群的交配系统,揭示浙江龙泉和江西分宜天然居群的交配机制以及亲代间的遗传多样性差异,为南方红豆杉的科学保育和遗传资源有效利用提供理论参考。【方法】以浙江龙泉和江西分宜天然居群亲代及其子代为研究对象,运用12对SSR引物对71个亲代及8个采种母株的104个子代进行分析。【结果】参试的浙江龙泉和江西分宜居群亲代的等位基因数(Na)皆为7,2个参试居群的有效等位基因数(Ne)分别为4.831和3.552,浙江龙泉居群较江西分宜居群高出1.279个有效等位基因。2个参试居群的观测杂合度(Ho)均小于期望杂合度(He),且固定指数(F)大于0。浙江龙泉居群的等位基因丰富度和私有等位基因丰富度(AR=4.195,PA=1.832)皆大于江西分宜居群(AR=3.576,PA=1.647)。2个参试居群的遗传多样性略有差异,但仍具有较高的遗传多样性。多位点交配系统分析(MLTR)结果表明,浙江龙泉和江西分宜居群中,南方红豆杉的异交率较高(tm=1.200)。单位点和多位点父本相关性的差值[rp(s)-rp(m)]为0.095,亲代居群内存在近交现象,但近交水平较低( C t m - t s=0.268)。有效花粉供体(Nep=1.5)数目较少,表明南方红豆杉自然交配时亲本(父本)来源非常有限。【结论】南方红豆杉属于高度异交树种,2个参试居群的异交率差异不明显且遗传多样性皆较高,居群内存在近交现象,但近交水平较低。

关键词: 南方红豆杉, 天然居群, 交配系统, 亲代, 子代, 微卫星DNA

Abstract:

【Objective】 The objective of this study is to examine the mating system of Taxus wallichiana var. mairei in natural populations located in Longquan City from Zhejiang Province and Fenyi City from Jiangxi Province. Furthermore, the study aims to elucidate the influence of mating mechanisms and variances in parental genetic diversity, to provide a theoretical basis for the scientific conservation and efficient utilization of the genetic resources of T. wallichiana var. mairei. 【Method】 A total of 71 parental plants and 104 progenies stemming from eight mother plants were meticulously analyzed using 12 pairs of the SSR primers, all of which were sourced from natural populations located in Longquan of Zhejiang Province (ZJLQ) and Fenyi of Jiangxi Province (JXFY). With the aid of GenAlEx 6.5, a number of genetic diversity measures such as the observed alleles and effective alleles, as well as observed heterozygosity, expected heterozygosity, Shannon index and fixed index were meticulously calculated. Furthermore, the team also utilized HP-Rare 1.1 to calculate allele richness and private allele richness, while FSTAT 2.9.3 was utilized to test the genetic diversity parameters for any potential differences among parents within each population through 1 000 simulations, along with the calculation of the inbreeding coefficient of the parental population. Lastly, we used MLTR 3.4 to estimate thoroughly the genetic parameters of T. wallichiana var. mairei’s mating system, which included single-locus population outcrossing rate, multilocus population outcrossing rate, number of effective pollen donors, multilocus correlation of paternity, singlelocus correlation of paternity, difference between the paternal correlation of single-locus and multilocus.【Result】 The average allele of the parental generation from Longquan and Fenyi populations was 7. Meanwhile, the effective allele number (Ne), Shannon index (I), allele richness (AR) and private allele richness (PA) of the two parental populations were 4.192, 1.508, 3.886 and 1.740, respectively. In comparison, the ZJLQ population displayed higher Ne, I, AR and PA values than the JXFY population, standing at 4.831, 1.620, 4.195 and 1.832, respectively. Both populations displayed an inbreeding coefficient greater than zero, with the ZJLQ population’s (Fis= 0.057) coefficient being significantly lower than that of the JXFY population (Fis= 0.171). Additionally, the observed heterozygosity (Ho) of the both populations was lower than that of the expected heterozygosity (He), with the fixed index (F) being greater than zero, indicating a loss of heterozygotes. The fixed index (F) of the ZJLQ population was 0.001, which did not differ from zero. The Longquan population exhibited higher values for both allele richness and private allele richness (AR= 4.195, PA= 1.832) in comparison to the Fenyi population (AR= 3.576, PA= 1.647). Despite a slight difference in the genetic diversity of the two populations, they both displayed high levels of genetic diversity. Results from the multi-locus mating system analysis (MLTR) revealed that the outcrossing rate of T. wallichiana var. mairei was higher (tm = 1.200) in the suitable populations of Longquan and Fenyi. Although the difference between paternal correlation of unit point and multilocus [rp(s) - rp(m)]equaled 0.095 and was greater than 0, indicating inbreeding in the parental population, the level of inbreeding was low (tm-ts = 0.268). The number of available pollen donors in both ZJLQ and JXFY populations was less than 2, and the paternal correlation and the number of effective pollen donors (Nep=1/rp(m)) were significantly different, suggesting that the parental sources were considerably limited during natural mating of T. wallichiana var. mairei. 【Conclusion】 T. wallichiana var. mairei is considered to be a highly outcrossing species, with both its single-locus population outcrossing rate and multilocus population outcrossing rate being high. However, there were no obvious differences in the outcrossing rate and genetic diversity between the two populations. Inbreeding was observed, but at low levels. The Longquan population is declining primarily due to the shortage of middle-aged and young plants and a high number of old trees. Despite the lower number of parental individuals in the ZJLQ population than the JXFY population, the former has a relatively high proportion of female individuals, which facilitates successful pollination rates and genetic exchange within the population. This advantageous characteristic results in the genetic diversity of the ZJLQ population not being inferior to that of the JXFY population. The Fenyi population has a larger number of young trees and seedlings, indicating that the habitat is suitable for the germination of T. wallichiana var. mairei seeds and the formation of seedlings. Therefore, with appropriate nurturing measures, this type of population has the potential to develop into an expanding population.

Key words: Taxus wallichiana var. mairei, natural population, mating system, parental generation, progeny, microsatellite(SSR)

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