高粱光敏色素A基因的克隆、蛋白结构与长短日照诱导表达模式

光敏色素是一类红光/远红光受体,对植物光形态建成、外部形态和生理功能等方面起着重要的调节作用。为明晰光敏色素A在调控高粱光形态建成发育过程中的作用,本研究比较分析光温敏感程度不同的高粱品种Btx623、Rio、Tx430和LH645的PhyA基因序列和PHYA蛋白的保守结构域,利用qRT-PCR明确长短日照条件处理下PhyA基因的表达模式。结果表明,Btx623、Rio和Tx430之间PhyA基因序列存在非同义突变,LH645在PhyA基因的第7个外显子上插入了5 bp碱基序列;高粱PhyA蛋白中含有1个PAS-2结构域、1个GAF结构域、1个Phytochrome结构域、2个PAS结构域、1个组氨酸激酶A结构域和1个类似组氨酸激酶的ATP激酶结构;遗传进化树分析表明,单子叶和双子叶植物PhyA蛋白明显聚为2大类,高粱PhyA、谷子PhyA和玉米PhyA1、PhyA2聚为一个亚类,相互间亲缘关系较近,与水稻PhyA同源性相对较远;在短日照(SD)条件下各时期PhyA基因转录水平变化显著,Rio PhyA基因转录水平较Btx623和Tx430变化明显,LH645 PhyA基因转录变化不显著,在长日照(LD)条件下Rio PhyA基因转录水平低于Btx623和Tx430,LH645 PhyA基因转录水平变化不显著。以上结果表明,PhyA受光周期诱导,推测其在高粱光形态建成中起重要调控作用。本研究为进一步解析PhyA基因功能及其在调控高粱光形态建成发育过程中的作用提供理论基础。

Cloning of Protein Structures and Expression Patterns Responding to Long/Short Light of Phytochrome A Gene in Sorghum

The phytochrome is a kind of red/far red light receptor,which plays an important role in regulating the photomorphogenesis,external morphology and physiological functions of plants.In order to clarify the role of phytochrome A in the regulation of morphogenesis in sorghum,this study compared with the PhyA gene sequences and the conserved domain of PhyA protein of sorghum varieties Btx623,Rio,Tx430 and LH645 in different light temperature sensitivity,analyzed the expression pattern of the PhyA gene under long/short light conditions by qRT-PCR.The results showed that there were a non-synonymous mutation in the PhyA gene sequence between Btx623,Rio and Tx430,and LH645 inserted a 5 bp base sequence in the seventh exon of the PhyA gene.The sorghum PhyA protein contains a PAS-2 domain,a GAF domain,a Phytochrome domain,two PAS domains,a histidine kinase A domain,and a histidine kinase-like ATPase domain.Phylogenetic tree analysis indicated that the PhyA proteins of monocotyledonous and dicotyledonous plants were significantly clustered into two broad categories.Sorghum PhyA,millet PhyA and maize PhyA1 and PhyA2 clustered into one subclass,which were closely related to each other and shared with rice PhyA relatively far.Under the condition of short daylight(SD),the transcript level of PhyA gene changed significantly in each period.The transcription level of Rio PhyA gene was significantly changed compared with Btx623 and Tx430,and the transcriptional change of LH645 PhyA gene was not significant.The transcription level of the Rio PhyA gene was lower than that of Btx623 and Tx430 under long-day(LD)conditions,and the transcription level of LH645 PhyA gene was not significantly changed.The above results indicated that PhyA is induced by photoperiod,which is presumed to play an important regulatory role in the light formation of sorghum.This study provides a theoretical basis for further analysis of PhyA gene function and its role in regulating of the morphological forms in sorghum.