Dpto. Biología de Organismos y Sistemas, Área de Fisiología Vegetal, Universidad de Oviedo 33071, Oviedo, Asturias, Spain.
Ann Bot. 2011 Sep;108(3):485-98. doi: 10.1093/aob/mcr185. Epub 2011 Jul 28.
Recent papers indicated that epigenetic control is involved in transitions in bud dormancy, purportedly controlling gene expression. The present study aimed to identify genes that are differentially expressed in dormant and non-dormant Castanea sativa buds.
Two suppression subtractive hybridization cDNA libraries were constructed to characterize the transcriptomes of dormant apical buds of C. sativa, and buds in which dormancy was released.
A total of 512 expressed sequence tags (ESTs) were generated in a forward and reverse subtractive hybridization experiment. Classification of these ESTs into functional groups demonstrated that dormant buds were predominantly characterized by genes associated with stress response, while non-dormant buds were characterized by genes associated with energy, protein synthesis and cellular components for development and growth. ESTs for a few genes involved in different forms of epigenetic modification were found in both libraries, suggesting a role for epigenetic control in bud dormancy different from that in growth. Genes encoding histone mono-ubiquitinase HUB2 and histone acetyltransferase GCN5L were associated with dormancy, while a gene encoding histone H3 kinase AUR3 was associated with growth. Real-time RT-PCR with a selection of genes involved in epigenetic modification and stress tolerance confirmed the expression of the majority of investigated genes in various stages of bud development, revealing a cyclical expression pattern concurring with the growth seasons for most genes. However, senescing leaves also showed an increased expression of several of the genes associated with dormancy, implying pleiotropy. Furthermore, a comparison between these subtraction cDNA libraries and the poplar bud dormancy transcriptome and arabidopsis transcriptomes for seed dormancy and non-dormancy indicated a common basis for dormancy in all three systems.
Bud dormancy and non-dormancy in C. sativa were characterized by distinct sets of genes and are likely to be under different epigenetic control.
近期的研究表明，表观遗传控制参与芽休眠的转变，据称可控制基因表达。本研究旨在鉴定休眠和非休眠板栗芽中差异表达的基因。
构建了两个抑制性消减杂交 cDNA 文库，以描述板栗休眠顶芽和解除休眠芽的转录组。
正向和反向消减杂交实验共产生了 512 个表达序列标签（EST）。这些 EST 分类为功能组表明，休眠芽主要以与应激反应相关的基因为特征，而非休眠芽以与能量、蛋白质合成以及细胞发育和生长相关的基因为特征。在两个文库中均发现了几个涉及不同形式表观遗传修饰的基因的 EST，表明表观遗传控制在芽休眠中的作用不同于生长。编码组蛋白单泛素酶 HUB2 和组蛋白乙酰转移酶 GCN5L 的基因与休眠有关，而编码组蛋白 H3 激酶 AUR3 的基因与生长有关。对涉及表观遗传修饰和应激耐受的几个基因的实时 RT-PCR 证实了大多数基因在芽发育的不同阶段表达，揭示了与大多数基因的生长季节一致的周期性表达模式。然而，衰老叶片中也表现出与休眠相关的几个基因的表达增加，暗示多效性。此外，将这些消减 cDNA 文库与杨树芽休眠转录组和拟南芥种子休眠和非休眠转录组进行比较，表明这三个系统的休眠具有共同的基础。
板栗芽的休眠和非休眠以不同的基因集为特征，可能受到不同的表观遗传控制。
