Identification and characterization of genes involved in the jasmonate biosynthetic and signaling pathways in mulberry(Morus notabilis)

Jasmonate （JA） is an important phytohormone regulating growth, development, and environmental response in plants, particularly defense response against herbivorous insects. Recently, completion of the draft genome of the mulberry （Morus notabilis） in conjunction with genome sequencing of silkworm （Bombyx mori） provides an opportuni-ty to study this unique plant-herbivore interaction. Here, we identified genes involved in JA biosynthetic and signaling pathways in the genome of mulberry for the first time, with the majority of samples showing a tissue-biased expression pattern. The analysis of the representative genes 12-oxophy-todienoic acid reductase （OPRs） and jasmonate ZIM-domain （JAZs） was performed and the results indicated that the mulberry genome contains a relatively smal number of JA biosynthetic and signaling pathway genes. A gene encoding an＆amp;nbsp;important repressor, MnNINJA, was identified as an alternative splicing variant lacking an ethylene-responsive element binding factor-associated amphiphilic repression motif. Having this fundamental information wil facilitate future functional study of JA-related genes pertaining to mulberry-silkworm interactions.

Genome-wide identification and expression analyses of cytochrome P450 genes in mulberry(Morus notabilis)

Cytochrome P450 S play critical roles in the biosynthesis of physiologically important compounds in plants.These compounds often act as defense toxins to prevent herbivory.In the present study,a total of 174 P450 genes of mulberry（Morus notabilis C.K.Schn） were identified based on bioinformatics analyses.These mulberry P450 genes were divided into nine clans and 47 families and were found to be expressed in a tissue-preferential manner.These genes were compared to the P450 genes in Arabidopsis thaliana.Families CYP80,CYP92,CYP728,CYP733,CYP736,and CYP749 were found to exist in mulberry,and they may play important roles in the biosynthesis of mulberry secondary metabolites.Analyses of the functional and metabolic pathways of these genes indicated that mulberry P450 genes may participate in the metabolism of lipids,other secondary metabolites,xenobiotics,amino acids,cofactors,vitamins,terpenoids,and poiyketides.These results provide a foundation for understanding of the structures and biological functions of mulberry P450 genes.

桑树PHR家族基因的鉴定及生物信息学分析

磷是植物生长发育的主要矿质营养元素之一,磷饥饿响应(phosphate starvation response, PHR)基因在调节植物磷素吸收中起着重要作用。鉴定桑树磷饥饿响应转录因子家族成员,分析其生物信息学特征,为桑树PHR家族基因的功能研究提供基础。从桑树基因组数据库中获得桑树PHR转录因子序列,利用GSDS、ExPASy、MEGA、MEME、psRNATarget、STRING等软件和网上转录组数据,对桑树PHR家族成员的基因结构、蛋白理化性质、保守基序、系统进化、基因组织表达、调控miRNA和蛋白互作网络进行分析。从桑树基因组中共鉴定出12个PHR基因家族成员,氨基酸数介于256~1 529之间,83.3%的成员属于酸性蛋白,所有成员均为亲水性蛋白。进化分析显示,MnPHR转录因子归为9个聚类组,各聚类组含有1~2个MnPHR成员。外显子数为6、7、8、19的MnPHR编码基因成员分别有7个、3个、1个、1个,同一聚类组中的基因结构类似。发现4个保守性较强的基序,所有MnPHR转录因子均含有基序1~4,聚类组Ⅰ~Ⅳ的MnPHR转录因子缺少基序6。基因组织表达分析发现10个桑树PHR基因在不同组织中有表达,且存在组织特异性,部分基因转录可能受miRNA的调控。MnPHR1的蛋白互作网络分析发现,其主要参与了纤维素合成和转录因子表达调控等生物学过程。桑树PHR家族基因结构和氨基酸序列具有较强的保守性,其组织表达和蛋白互作网络结果表明该家族基因在植物的生长发育和营养吸收过程中发挥作用。本研究结果为深入开展桑树磷吸收和转运相关基因的克隆和功能验证提供了基础。