Production of viable male unreduced gametes in Brassica interspecific hybrids is genotype specific and stimulated by cold temperatures.
Production of viable male unreduced gametes in Brassica interspecific hybrids is genotype specific and stimulated by cold temperatures.
复制标题
DOI：
10.1186/1471-2229-11-103
复制
发表时间：
2011-06-12
影响因子：
5.3
通讯作者：
Cowling WA
中科院分区：
文献类型：
--
作者：
Mason AS;Nelson MN;Yan G;Cowling WA
未退化配子(具有体细胞染色体数目的配子)可能为异源多倍体的形成提供了一条进化物种形成的途径。我们研究了基因型和温度对甘蓝异源四倍体及其种间杂交种雄性未减数配子形成的影响。根据二分体或巨型四分体的频率在孢子体中估计减数分裂后未减少配子的频率，并根据可存活的巨型花粉与可存活的正常花粉的频率在花粉中估计未减少配子的频率。巨型四分体的体积是正常四分体的两倍，可能是减数分裂前染色体数量加倍的结果。巨型花粉被定义为直径大于正常直径的1.5倍以上的花粉，假设未减数配子中DNA含量翻倍将使花粉细胞体积增加约一倍。对5个甘蓝型油菜亲本、2个隆起甘蓝型油菜亲本和1个芥菜型油菜亲本以及13个种间杂交组合的遗传效应进行了研究。在高温(白天/夜间30℃/20℃)、温暖(25℃/15℃)、凉爽(18℃/13℃)和寒冷(10℃/5℃)处理中，对温度的影响进行了评估。根据孢子期的估计，一些种间杂交基因型产生未减数配子的频率(0.06%至3.29%)比亲本(0.00%至0.11%)高一个数量级以上。在9个产生可育成熟花粉的杂交种中，可育巨型花粉的出现频率(0.2%~33.5%)远高于亲本(0.0%~0.4%)。在杂交种中，巨大的花粉很可能是由未退化的配子形成的，比正常的花粉更有活力。两个甘蓝型油菜×隆起甘蓝型油菜杂交组合的减数分裂后孢子冷处理产生9%和23%的未减数配子，比亲本高两个数量级以上。这些结果表明，异源多倍体进化的三倍体桥梁假说所需的未还原配子的来源在一些油菜种间杂交基因型中很容易获得，特别是在低温下。
Unreduced gametes (gametes with the somatic chromosome number) may provide a pathway for evolutionary speciation via allopolyploid formation. We evaluated the effect of genotype and temperature on male unreduced gamete formation in Brassica allotetraploids and their interspecific hybrids. The frequency of unreduced gametes post-meiosis was estimated in sporads from the frequency of dyads or giant tetrads, and in pollen from the frequency of viable giant pollen compared with viable normal pollen. Giant tetrads were twice the volume of normal tetrads, and presumably resulted from pre-meiotic doubling of chromosome number. Giant pollen was defined as pollen with more than 1.5 × normal diameter, under the assumption that the doubling of DNA content in unreduced gametes would approximately double the pollen cell volume. The effect of genotype was assessed in five B. napus, two B. carinata and one B. juncea parents and in 13 interspecific hybrid combinations. The effect of temperature was assessed in a subset of genotypes in hot (day/night 30°C/20°C), warm (25°C/15°C), cool (18°C/13°C) and cold (10°C/5°C) treatments. Based on estimates at the sporad stage, some interspecific hybrid genotypes produced unreduced gametes (range 0.06 to 3.29%) at more than an order of magnitude higher frequency than in the parents (range 0.00% to 0.11%). In nine hybrids that produced viable mature pollen, the frequency of viable giant pollen (range 0.2% to 33.5%) was much greater than in the parents (range 0.0% to 0.4%). Giant pollen, most likely formed from unreduced gametes, was more viable than normal pollen in hybrids. Two B. napus × B. carinata hybrids produced 9% and 23% unreduced gametes based on post-meiotic sporad observations in the cold temperature treatment, which was more than two orders of magnitude higher than in the parents. These results demonstrate that sources of unreduced gametes, required for the triploid bridge hypothesis of allopolyploid evolution, are readily available in some Brassica interspecific hybrid genotypes, especially at cold temperatures.
登录
查看更多内容
影响因子：
3.8
作者：
DOWRICK, G. J.
通讯作者：
DOWRICK, G. J.
影响因子：
5.4
作者：
Mason, Annaliese S.;Nelson, Matthew N.;Cowling, Wallace A.
通讯作者：
Cowling, Wallace A.
影响因子：
7.4
作者：
De Storme, Nico;Geelen, Danny
通讯作者：
Geelen, Danny
DOI：
10.1111/j.1095-8312.2004.00332.x
发表时间：
2004-08-01
影响因子：
1.9
作者：
Mable, BK
通讯作者：
Mable, BK
影响因子：
5.4
作者：
Chèvre, AM;Eber, F;Renard, M
通讯作者：
Renard, M