Euphyllophyte evolution and defense
Ferns are close relatives of seed plants, and together they form the euphyllophyte clade, which contains almost all vascular plants. The genome of the maidenhair fern (Adiantum capillus-veneris L.) provides a window on the evolution of both groups and on their pathogen resistance mechanisms.
PLANT PHYSIOLOGY:中科院揭示生物钟系统对水稻ABA信号转导调控的分子机制
植物生物钟系统对于其在干旱及盐渍条件下的生存至关重要。本研究证实水稻生物钟系统的核心组分CIRCADIAN CLOCK ASSOCIATED1 (OsCCA1)在水稻对盐渍、渗透以及干旱胁迫的响应过程中发挥重要作用。
DNA affinity purification sequencing结合转录组分析发现了692个直接受OsCCA1调控的基因，其中包括了ABA信号途径中的 group A protein phosphatase 2C基因以及basic region and leucine zipper 46 (OsbZIP46)。
此外，作者证实 OsCCA1可以直接结合到OsPP108 and OsbZIP46的启动子上来激活它们的表达。水稻的oscca1无义突变体呈现对ABA的超敏感表型。
小结：本研究揭示了水稻生物钟核心组分OsCCA1通过调控ABA信号转导影响植物对非生物胁迫耐受性的分子机制。
Figure 8 A proposed molecular model of OsCCA1 orchestrating ABA signaling to confer multiple abiotic stress tolerance. Under stress condition in the WT (left), endogenous ABA levels increase rapidly, and OsCCA1 orchestrates ABA signaling by binding to the rCBS motifs within the promoters of multiple components of ABA signaling, such as OsPP108, regulating their expression and thereby negatively modulating the ABA signaling pathway. OsCCA1 also directly activates the transcription of OsbZIP46, a well-established key positive regulator of abiotic stress tolerance, which allows OsCCA1 to modulate a wide spectrum of stress-responsive genes by forming a transcriptional cascade, in both ABA dependent or independent manner. In the absence of OsCCA1 (right), the dual regulations disappeared, resulting in the enhanced sensitivity to ABA signaling and correspondingly the abiotic stresses.
原文信息：Rice CIRCADIAN CLOCK ASSOCIATED 1 transcriptionally regulates ABA signaling to confer multiple abiotic stress tolerance
