Leeggangers Hendrika A C F, Folta Adam, Muras Aleksandra, Nap Jan-Peter, Mlynarova Ludmila
Laboratory of Molecular Biology, Plant Sciences Group, Wageningen University and Research Centre, Wageningen, The Netherlands.
Physiol Plant. 2015 Feb;153(2):318-26. doi: 10.1111/ppl.12231. Epub 2014 Jun 27.
In the life of flowering plants, seed germination is a critical step to ensure survival into the next generation. Generally the seed prior to germination has been in a dormant state with a low rate of metabolism. In the transition from a dormant seed to a germinating seed, various epigenetic mechanisms play a regulatory role. Here, we demonstrate that the over-expression of chromatin remodeling ATPase genes (AtCHR12 or AtCHR23) reduced the frequency of seed germination in Arabidopsis thaliana up to 30% relative to the wild-type seeds. On the other hand, single loss-of-function mutations of the two genes did not affect seed germination. The reduction of germination in over-expressing mutants was more pronounced in stress conditions (salt or high temperature), showing the impact of the environment. Reduced germinations upon over-expression coincided with increased transcript levels of seed maturation genes and with reduced degradation of their mRNAs stored in dry seeds. Our results indicate that repression of AtCHR12/23 gene expression in germinating wild-type Arabidopsis seeds is required for full germination. This establishes a functional link between chromatin modifiers and regulatory networks towards seed maturation and germination.
在开花植物的生命周期中，种子萌发是确保其存活至下一代的关键步骤。一般来说，萌发前的种子处于休眠状态，新陈代谢速率较低。在从休眠种子到萌发种子的转变过程中，各种表观遗传机制发挥着调节作用。在此，我们证明，与野生型种子相比，染色质重塑ATP酶基因（AtCHR12或AtCHR23）的过表达使拟南芥种子的萌发频率降低了30%。另一方面，这两个基因的单功能缺失突变并不影响种子萌发。过表达突变体在胁迫条件（盐或高温）下萌发率的降低更为明显，显示出环境的影响。过表达导致的萌发率降低与种子成熟基因转录水平的增加以及干种子中储存的mRNA降解减少相一致。我们的结果表明，拟南芥野生型种子萌发时AtCHR12/23基因表达的抑制对于完全萌发是必需的。这建立了染色质修饰因子与种子成熟和萌发调控网络之间的功能联系。
