Karrikins enhance light responses during germination and seedling development in Arabidopsis thaliana
Karrikins enhance light responses during germination and seedling development in Arabidopsis thaliana
复制标题
DOI：
10.1073/pnas.0911635107
复制
发表时间：
2010-04-13
影响因子：
11.1
通讯作者：
Smith, Steven M.
中科院分区：
文献类型：
--
作者：
Nelson, David C.;Flematti, Gavin R.;Smith, Steven M.
Karrikins是在野火烟雾中发现的一类种子发芽刺激剂。对吸胀的拟南芥种子进行微阵列分析，以鉴定萌发前对KAR（1）的转录响应。鉴定出一小部分基因受KAR（1）调控，即使在赤霉素生物合成或光照缺乏而阻止发芽的情况下也是如此。在KAR（1）上调基因中，光诱导基因、推测的HY5结合靶基因和ABRE样启动子基序过多。KAR（1）瞬时诱导光信号转导转录因子基因HY5和HYH。当用KAR处理时，在较低的红光通量下触发后熟拟南芥种子的萌发（1）。光依赖性子叶扩张和抑制下胚轴伸长的萌发活性karrikins的存在下得到加强。HY5在拟南芥下胚轴伸长过程中起重要作用，但对karrikins诱导的种子萌发无影响。这些结果揭示了karrikins在引发光反应中的新兴幼苗的作用，并表明karrikins对火灾后生态的影响可能不仅限于发芽招聘。
Karrikins are a class of seed germination stimulants identified in smoke from wildfires. Microarray analysis of imbibed Arabidopsis thaliana seeds was performed to identify transcriptional responses to KAR(1) before germination. A small set of genes that are regulated by KAR(1), even when germination is prevented by the absence of gibberellin biosynthesis or light, were identified. Light-induced genes, putative HY5-binding targets, and ABRE-like promotermotifs were overrepresented among KAR(1)-up-regulated genes. KAR(1) transiently induced the light signal transduction transcription factor genes HY5 and HYH. Germination of afterripened Arabidopsis seed was triggered at lower fluences of red light when treated with KAR(1). Light-dependent cotyledon expansion and inhibition of hypocotyl elongation were enhanced in the presence of germination-active karrikins. HY5 is important for the Arabidopsis hypocotyl elongation, but not seed germination, response to karrikins. These results reveal a role for karrikins in priming light responses in the emerging seedling, and suggest that the influence of karrikins on postfire ecology may not be limited to germination recruitment.