细胞分裂素基因(T-cyt)启动子驱动下的GUS基因在烟草和马铃薯中的表达

构建了来自根癌农杆菌（Ａｇｒｏｂａｃｔｅｒｉｕｍ ｔｕｍ ｅｆａｃｉｅｎｓ） Ｔ－ＤＮＡ 的细胞分裂素基因（Ｔ－ｃｙｔ）启动子驱动下的ＧＵＳ基因的表达质粒，并用以转化烟草（Ｎｉｃｏｔｉａｎａ ｔａｂａｃｕｍ ｃｖ． Ｗ ３８）和马铃薯（Ｓｏｌａｎｕｍ ｔｕｂｅｒｏ－ｓｕｍ Ｌ． ｃｖ． Ｄｅｓｉｒｅｅ），研究其在转基因植物中表达的定位。结果表明，Ｔ－ｃｙｔ启动子在转基因植株的根、茎、叶、块茎和萌发的种子中均可表达。其中在茎和块茎中的表达是不均一的：在维管束部分表达较强，在侧芽或叶柄的生长点及块茎的芽生长点表达活性较高。此外，在培养基中加入０．１ ｍ ｇ／ＬＢＡＰ，转基因烟草茎中ＧＵＳ基因的表达活性增强，而对ＮＡＡ 没有明显的反应。

对生叶序与互生叶序玉米细胞分裂素调控基因差异分析

在明晰对生叶序玉米生长点的3大类内源细胞分裂含量不仅显著高于互生叶序玉米,而且随互生到对生到螺旋畸形叶序逐渐增大,以及CTK/IAA值是控制玉米叶序分化类型关键因素的基础上,搜索玉米细胞分裂素调控基因ZmRR1,ZmRR2,ZmRR3,ZmRR4,ZmRR5,ZmRR6,ZmRR7,ZmRR8,ZmRR9,ZmRR10的基因序列及其cDS序列,设计特异性上下游引物,通过对对生叶序玉米及其近等基因系的互生叶序玉米基因组进行PCR扩增、测序,证实了对生叶序玉米、互生叶序玉米在ZmRR1,ZmRR2,ZmRR3,ZmRR4,ZmRR5,ZmRR6,ZmRR7,ZmRR8,ZmRR9,ZmRR10基因序列结构上未见差异。RT-PCR分析结果证实ZmRR1,ZmRR2是根特异性表达基因,ZmRR3在根和叶中不表达,而ZmRR6在茎尖中不表达,对生叶序玉米与互生叶序玉米在不同时期、不同发育组织中其ZmRR1,ZmRR2,ZmRR3,ZmRR4,ZmRR5,ZmRR6,ZmRR7,ZmRR8,ZmRR9,ZmRR10基因的表达均未见差异,表明安徽农业大学作物生物学实验室的对生叶序玉米突变体的形成机制与冷泉港实验室关于ZmRR3基因的Mu转座子插入突变导致对生叶序玉米突变体形成的机制不同。

植物细胞分裂素氧化酶基因研究进展

通过梳理已有的研究文献,综述了植物细胞分裂素氧化酶基因的生理功能及其表达调控研究进展。目前,关于CKX基因在农作物方面的研究报道较多,而在木本植物和观赏植物方面的研究却较少。今后可利用生物信息学软件以及基因编辑技术如CRISPR/Cas9系统加强此方面的研究,以加强对木本植物、观赏植物等植物中CKX基因的表达调控研究,更好地调控植物生长发育进程以及响应逆境胁迫,充分挖掘生物资源的潜力。

6-苄基腺嘌呤对水稻颖花分化影响机制的研究

以常规籼稻品种扬稻6号为材料,在盆栽条件下,于生长锥伸长期外喷6-苄基腺嘌呤(6-BA)后,定期取样,测量穗部细胞分裂素(cytok in ins,CKs)含量,同时采用RT-PCR检测水稻穗分化过程中细胞分裂素氧化酶基因(O sCKX2)的表达模式,考察水稻穗部性状。结果发现:6-BA处理促进水稻穗长发育并显著提高每穗枝梗和颖花数,分化枝梗数和总颖花数分别为60和255.4,比对照分别提高了10%和30.5%。穗部细胞分裂素含量的增加,刺激了更多颖花分化。6-BA处理的水稻穗部O sCKX2表达时间提前,但表达量下降。认为:水稻穗分化始期喷施6-BA可降低穗部O sCKX2的表达强度,提高穗部细胞分裂素含量,对枝梗和颖花分化产生促进作用,为形成大穗提供了先决条件。

Genome-wide comparative analysis of type-A Arabidopsis response regulator genes by overexpression studies reveals their diverse roles and regulatory mechanisms in cytokinin signaling

Cytokinin is a critical growth regulator for various aspects of plant growth and development. In Arabidopsis, cytokinin signaling is mediated by a two-component system-based phosphorelay that transmits a signal from the receptors, through histidine phosphotransfer proteins, to the downstream response regulators （ARRs）. Of these ARRs, type-A ARR genes, whose transcription can be rapidly induced by cytokinin, act as negative regulators of eytokinin signaling. However, because of functional redundancy, the function of type-A ARR genes in plant growth and development is not well understood by analyzing loss-of-function mutants. In this study, we performed a comparative functional study on all ten type-A ARR genes by analyzing transgenic plants overexpressing these ARR genes fused to a MYC epitope tag. Overexpression of ARR genes results in a variety of cytokinin-associated phenotypes. Notably, overexpression of different ARR transgenes causes diverse phenotypes, even between phylogenetically closely-related gene pairs, such as within the ARR3-ARR4 and ARR5-ARR6 pairs. We found that the accumulation of a subset of ARR proteins （ARR3, ARR5, ARR7, ARR16 and ARR17; possibly ARR8 and ARR15） is increased by MG132, a specific proteasomal inhibitor, indicating that stability of these proteins is regulated by proteasomal degradation. Moreover, similar to that of previously characterized ARR5, ARR6 and ARR7, stability of ARR16 and ARR17, possibly including ARR8 and ARR15, is regulated by cytokinin. These results suggest that type-A ARR proteins are regulated by a combinatorial mechanism involving both the cytokinin and proteasome pathways, thereby executing distinctive functions in plant growth and development.

Bioinformatics Analysis of Upland Cotton Gene GhCRE1

Cytokinin plays a very important role in plants growth and development,and CRE1 has been identified as a cytokinin receptor.However,the biological function of CRE1 in cotton remains unclear.In this paper,GhCRE1 gene was cloned and its sequence was analyzed by bioinformatics.The results revealed that GhCRE1 had 11 exons and 10 introns,and its molecular weight,theoretical isoelectric point(pI)and number of amino acids differed from those of the homologous gene in Theobroma cacao and Arabidopsis thaliana,with three different protein domains.15 unidentified proteins were found in potential interaction with CRE1 protein and 2 phosphorylation sites on CRE1 protein sequence were predicted by mutiple bioinformatics websites.Additionally,8 cis-acting regulatory elements were detected on CRE1 promoter sequence,and found related to light signal and hormone.These results were conducive to unfolding the function of GhCRE1 in upland cotton.

玉米CKXs基因组编辑载体的构建

植物细胞分裂素氧化酶(CKX)能够降解细胞分裂素,在植物生长和发育过程中发挥重要作用。本研究从玉米B73基因组数据库中筛选到3个玉米细胞分裂素氧化酶基因(CKXs),通过在线工具e-crisp,设计sg RNA。利用一套密码子优化的CRISPR/Cas9载体系统,构建ZmCKX基因的p3301-U6P-sgRNA-Ubi-Cas9植物表达载体,为获得稳定的突变体提供技术基础。