蒙古冰草苗期抗旱相关microRNA的差异表达分析及靶基因预测

为明确蒙古冰草抗旱相关microRNA(miRNA)的表达特征及其靶基因,利用实时荧光定量PCR技术,对前期测序筛选到的4个miRNA(amo-miR21、amo-miR44、amo-miR62、amo-miR82)在干旱胁迫下的苗期差异表达情况进行了定量验证,用Target Finder软件和psRNATarget数据库在线预测其靶基因,并用MegAlign软件对预测的靶基因进行了同源性比对分析。结果表明,干旱胁迫下,蒙古冰草中amo-miR21、amo-miR82和amo-miR62的表达量呈上调趋势,而amo-miR44的表达呈下调趋势,与前期测序结果相符;4个miRNA共预测出32个靶基因,其中,amo-miR44在玉米、水稻和小麦数据库中未发现同源的靶基因,在拟南芥、大麦、蒺藜苜蓿中发现的靶基因相似性较低;而amo-miR21、amo-miR82和amo-miR62的靶基因均与小麦中预测的靶基因存在较高同源性(68.6%~95.6%),推测这3个靶基因是参与干旱逆境胁迫响应的基因。     

Effects of short‐term starvation on the rhythmic expression of microRNAs in skeletal muscle of goldfish (Carassius auratus)

Molecular oscillators exist in peripheral tissues such as in skeletal muscles and diet is a dominant factor to affect Zeitgeber for peripheral clocks. MicroRNAs (miRNAs) play an important role in muscle cell proliferation and differentiation. However, the knowledge of starvation effects on miRNA rhythmic expression remains limited in teleost. In this study, the circadian expression pattern of miRNAs was investigated in goldfish muscle upon restricting feeding treatment. The data showed that 15 miRNAs exhibited a daily rhythmicity among the 70 miRNAs assayed in muscles of normally fed goldfish. While after 7‐day and 15‐day fasting treatment, 23 and 18 miRNAs showed circadian rhythmicity in goldfish muscles respectively. Only 4 miRNAs (miR‐23a, miR‐29, miR‐199a‐3p and miR‐455) exhibited a daily rhythmicity in all three groups of different nutrient treatments. Correlation analysis of the circadian‐miRNAs indicates different feeding stimulation could alter the circadian‐miRNA components and their expression profile in skeletal muscle upon short‐term feed deprivation. These miRNAs may play important roles in regulating circadian expression of genes involved in muscle cell differentiation and growth by nutritional alteration, thus having a potential application in fish aquaculture.     

水稻miR444b.2调控稻瘟病抗性及分蘖

microRNA(miRNA)是一类长度在20~24 bp的保守小RNA分子,广泛存在于真核生物中,参与调控生长发育及抗逆、抗病等反应。在前期研究中,我们对比感病和抗病水稻材料在接种稻瘟病菌前后miRNA的累积量,发现miR444b.2的累积量变化在抗病和感病材料间存在显著差异,但其在水稻对稻瘟病抗性中的作用尚不清楚。本文进一步对水稻感病和抗病材料接种稻瘟病菌,通过检测不同时间点miR444b.2及其靶基因的累积量来分析miR444b.2与水稻稻瘟病抗性的关系;同时,构建过表达miR444b.2的转基因水稻材料,对转基因材料进行了抗性分析及农艺性状分析。结果表明,在稻瘟病菌开始侵染水稻的24 h内,随着侵染时间的增加,miR444b.2在感病材料中的累积量也随之增加,而在抗病材料中的累积量则逐渐降低;相反,miR444b.2的靶基因中,MADS盒家族基因在感病材料中的转录受到抑制或变化不大,在抗病材料中的表达明显增加,与miR444b.2的累积量变化趋势相反,提示miR444b.2可能通过调节MADS盒家族基因的表达量来调控稻瘟病抗性。而且,过表达miR444b.2的转基因植株变得更加感病,主要表现为:与对照相比,叶片发病病斑数量增多、病斑面积增大、防御相关基因转录水平变低;而miR444b.2的靶基因在过表达miR444b.2的转基因植株中的转录水平显著降低。此外,miR444b.2过表达植株的分蘖数较对照减少。这些结果说明,miR444b.2通过调控MADS盒家族基因来负调控稻瘟病抗性及调节水稻分蘖。     

植物抗病研究进展与展望

植物在其整个生活史中随时经受多种病原的侵袭,在进化过程中植物发展出多种对抗病原的机制。植物抗病性研究是当前植物病理学研究的热点问题之一。培育具有广谱而持久抗性的植物品种是育种学家追求的目标。目前,关于植物非寄主抗性、抗病基因介导的抗性、microRNA相关的抗性、感病基因的研究以及基因编辑在植物抗病性中的应用等方面已取得了大量新的研究成果。本文就以上几个方面综述了近年来植物抗病研究中的最新进展,并提出今后研究和育种中的应用展望。     

调控动物表型microRNA在分子育种中新的重要标记

microRNA(miRNA)是一类由内源基因编码的长度约为21~22个核苷酸的非编码单链RNA分子,以基因沉默的方式来调控靶基因的表达。随着大规模转录组学研究的进行和深入,发现了大量与动物表型相关的microRNA。简要介绍了microRNA的基本特征,概述了近年来在动物性状决定及表型关联性分析方面的研究进展。越来越多的miRNA与多种动物的重要表型相关联,将为动物表型调控的研究提供一个新的思路。     

Effects of dietary Bacillus natto supplementation on growth performance and the growth‐related gene/microRNA expression in the skeletal muscle of grass carp (Ctenopharyngodon idella)

In this study, Bacillus natto NT was evaluated for use as a probiotic supplement in the feeds on the growth performance and the growth‐related genes' and microRNAs' (miRNAs) expression in the skeletal muscle of grass carp (Ctenopharyngodon idella). Grass carps (ave. wt. 43.96 ± 0.27 g) were fed diets supplemented with 1.87 × 10⁹ (Bn1), 3.73 × 10⁹ (Bn2), 5.60 × 10⁹ (Bn3), 7.47 × 10⁹ (Bn4) and 9.33 × 10⁹ (Bn5) B. natto NT cells per 100 g feed for 56 days. The control group (BnC) was not supplemented with the B. natto NT. The fish of Bn3, Bn4 and Bn5 groups displayed better growth performance and lower feed conversion ratio (FCR) than the other groups (P < 0.05). Compared with the fish of BnC group, miR‐1a, miR‐181a, miR‐23a and miR‐206 expressions increased (P < 0.05), and the myostatin and myocyte enhancer factor C (MEF2C) mRNAs were down‐regulated (P < 0.05) in the fish of Bn4 and Bn5 groups. The specific growth rate analysis and apparent expressional regulation of the growth‐related miRNAs and genes stimulated by B. natto suggest the potential application of B. natto in improving the growth performance on the grass carps.     

绿壳蛋鸡与白来航蛋鸡microRNA变异及其靶基因预测分析

本研究旨在分析绿壳蛋鸡与白来航蛋鸡microRNA变异及其靶基因,将已鉴定的microRNA与预测microRNA组成全基因组的microRNA,并通过与GGRS得到的两种鸡群体SNP位点进行映射,挖掘含SNP的microRNA。利用生物信息学的方法,对含SNP的microRNA进行靶基因预测,并对直接含有SNP的mature-microRNA进行聚焦。将这些靶基因进行富集,一共得到22个GO分类和10条KEGG信号通路与3个主要IPA调控网络,发现其在与生长相关的mTOR信号通路、Wnt信号通路、生长激素受体网络、胰岛素样生长因子Ⅰ受体网络得到了富集,与产蛋性状相关的卵母细胞减数分裂信号通路、黄体酮卵母细胞成熟信号通路得到了富集。此研究方法和结果可以给后期研究提供参考。     

越冬期体色变异红罗非鱼差异表达miRNA的鉴定

为了探究红罗非鱼越冬期体色变异的分子机制,实验构建了其2种体色(正常粉红体色和变黑体色)皮肤组织的小RNA文库,每组4个重复,组装后平均每组分别获得12 190 544和11 891 890条过滤后的读长(clean reads),获得miRNA成熟序列669个,其中337个是已知的miRNAs。鉴定出越冬期变黑体色相对于正常粉红体色鱼的差异表达miRNAs 26个,其中上调11个,下调15个,且12个为已知的miRNAs,可能在红罗非鱼越冬期体色变异过程中发挥重要作用。富集分析发现了大量代谢和体色调控相关的通路。研究表明,红罗非鱼越冬期的体色变异可能是色素细胞的增殖和迁移形成的,与代谢相关的调控通路在其中发挥重要作用,为解析红罗非鱼越冬期体色变异的机制奠定了基础。