甘蔗割手密种LRRII-RLK基因家族演化和表达分析

Evolution and relative expression pattern of LRRII-RLK gene family in sugarcane Saccharum spontaneum

LRRII-RLK是一种类受体激酶(receptor-likekinase,RLK),该基因家族在植物中广泛存在,在植物的生长发育和生物胁迫中发挥着重要的作用,但目前在甘蔗中未见对该基因家族的系统鉴定和分析。本研究对甘蔗的LRRII-RLK基因进行分类,并研究了其结构和功能。结合割手密种基因组和发育组织、叶片发育梯度、昼夜节律和生物胁迫反应转录组数据,在甘蔗割手密种中共鉴定到27个LRRII-RLK基因,分布在17条染色体上。系统进化分析发现,它们分别属NIK、SERK和LRRII-C分支,其中处于LRRII-C分支的SsLRRII-RLK基因出现了显著扩增。顺式元件分析显示,它们的启动子共包含32类顺式元件,其主要参与植物光反应、响应胁迫反应、调控植物激素和植物生长发育。这些基因共有35对共线性基因对,具有多个保守基序,主要通过片段复制的方式进行扩增,且根据Ka/Ks比率发现,它们在演化过程中经历了严格的纯化选择作用。此外,SsLRRII-RLK基因表达分析显示,它们在甘蔗不同组织中表达量不同,其中部分基因在昼夜不同时期表达量呈现差异,这表明它们参与了植物生长和光合作用的调节。值得注意的是,SsLRRII-RLK基因的表达模式在不同病害(甘蔗梢腐病和花叶病)胁迫下呈现差异,因此,我们认为这些基因在病毒复制和发病机制过程中发挥作用。本研究结果有助于深入了解甘蔗LRRII-RLK基因的演化过程,且为LRRII-RLK基因在甘蔗生长发育、光合作用以及在病害胁迫中的功能研究提供初步的理论基础。

It is well-known that LRRII-RLK gene family widely exists in plants.These genes are receptor like kinase(RLK),which play a significant role in plant development and biological stress.Up till now,there is no systematic identification and analysis of the LRRII-RLK gene family in sugarcane.Here,we identified 27 LRRII-RLK genes in Saccharum spontaneum,which were distributed on 17 chromosomes.Phylogenetic tree showed the classification of these genes into three different branches including NIK,SERK,and LRRII-C.Furthermore,we observed the significant amplification in the LRRII-C branch.Next,we characterized the cis-regulatory elements,which identified 32 different types of cis elements in the gene promoters,primarily involved in light response,stress response,regulation of hormone mechanism,and plant growth.Interestingly,SsLRRII-RLK genes were detected to be conserved with 35 collinear gene pairs and multiple conserved motifs.These genes were mainly amplified by segmental replication and had undergone strict purification selection during the evolution,according to their Ka/Ks ratios.Furthermore,the relative expression level of SsLRRII-RLK genes varied in different tissues of sugarcane.Additionally,some genes expressed differently during distinct periods of day and night,suggesting that they were associated with plant growth regulation and photosynthesis.Noticeably,the relative expression pattern of SsLRRII-RLK genes varied significantly under different disease conditions(sugarcane pokkah boeng disease and mosaic disease).In conclusion,these genes might play a role in pathogenesis and viral replication.The results of this study are helpful to further understand the evolutionary process of LRRII-RLK gene in sugarcane.This data provides a preliminary theoretical basis for the functional study of LRRII-RLK gene during photosynthesis,growth and development,and disease conditions in sugarcane.