Cotton LIM domain‐containing protein GhPLIM1 is specifically expressed in anthers and participates in modulating F‐actin

As one form of actin binding protein (ABP), LIM domain protein can trigger the formation of actin bundles during plant growth and development. In this study, a cDNA (designated GhPLIM1) encoding a LIM domain protein with 216 amino acid residues was identified from a cotton flower cDNA library. Quantitative RT‐PCR indicated that GhPLIM1 is specifically expressed in cotton anthers, and its expression levels are regulated during anther development of cotton. GhPLIM1:eGFP transformed cotton cells display a distributed network of eGFP fluorescence, suggesting that GhPLIM1 protein is mainly localised to the cell cytoskeleton. In vitro high‐speed co‐sedimentation and low co‐sedimentation assays indicate that GhPLIM1 protein not only directly binds actin filaments but also bundles F‐actin. Further biochemical experiments verified that GhPLIM1 protein can protect F‐actin against depolymerisation by Lat B. Thus, our data demonstrate that GhPLIM1 functions as an actin binding protein (ABP) in modulating actin filaments in vitro, suggesting that GhPLIM1 may be involved in regulating the actin cytoskeleton required for pollen development in cotton.     

陆地棉SUPERMAN类似锌指蛋白基因的克隆与表达分析

锌指蛋白是生物体内数量最多的转录调控因子,它在动植物的生长发育中都起到十分重要的作用。SUPERMAN类锌指蛋白只含有1个锌指结构。我们根据这类蛋白的保守结构域设计简并引物,通过RT-PCR从棉花中获得了3个这个家族成员的EST,得到1个锌指蛋白基因的全长序列,该基因的编码区长744 bp,编码长248个氨基酸的多肽,其氨基酸序列与GenBank中登录的一个拟南芥RBE蛋白有40%的同源性。此基因被命名为GZFP。它含有保守的锌指结构并在多肽链的C-端具有富含亮氨酸的保守结构域,GZFP含有核定位信号并且没有内含子。GZFP基因在棉花花蕾、子房、花瓣和根中的表达量要高于木质部、韧皮部、叶片、纤维和种子。GZFP基因的表达量很低,在GenBank中没有任何和它同源的EST序列存在。对GZFP 5′侧翼区进行分析发现有数个花粉和根特异表达相关元件,4个与Dof蛋白作用的核心序列,4个与光诱导相关的元件。      

Cotton AnnGh3 Encoding an Annexin Protein is Preferentially Expressed in Fibers and Promotes Initiation and Elongation of Leaf Trichomes in Transgenic Arabidopsis

The annexins are a multifamily of calcium-regulated phospholipid-binding proteins. To investigate the roles of annexins in fiber development, four genes encoding putative annexin proteins were isolated...     

陆地棉类谷氧还蛋(GhGRL)基因家族生物信息学分析

谷氧还蛋白(glutaredoxin, GRX)是一类小分子氧化还原蛋白,可以调节蛋白质的氧化还原状态从而维持蛋白质的功能,在生物的生长发育及抗氧化反应中起着重要的作用。类谷氧还蛋白蛋白(glutaredoxin-like, GRL)是新划分的GRX类型,本研究为深入探究GRL基因家族在陆地棉中功能,对GhGRL基因家族进行生物信息学及表达分析。研究结果表明,32个GhGRL基因主要定位于细胞核,它们均具有GRX-GRX-Like保守结构域。GhGRL基因所编码的氨基酸的多重序列比对和保守序列分析发现,该家族成员序列相似性约为31.31%,大部分包含4个保守基序,同时这4个保守基序与保守结构域重叠;根据GhGRL基因的系统进化树可将32个GhGRL基因分为3亚组,基因结构分析发现该家族基因大部分无内含子;染色体定位分析显示GhGRL基因分散在19个染色体上,每条染色体上的GhGRL基因数目有很大的差别;表达谱数据分析表明,大部分GhGRL基因在根、茎、雄蕊、雌蕊、子房、叶片和花等7个组织器官中均有表达,并且有差异。以上结果有利于了解棉花GhGRL基因家族的基本情况,为深入研究该基因家族在生物学功能提供基础。     

A gene encoding a novel anti-adhesive protein is expressed in growing cells and restricted to anterior-like cells during development of Dictyostelium

The Dictyostelium gene ampA, initially identified by the D11 cDNA, encodes a novel anti-adhesive-like protein. The ampA gene product inhibits premature cell agglutination during growth and modulates cell-cell and cell-substrate adhesion during development. Analysis of the promoter indicates that cap site-proximal sequence directs ampA expression during both growth and early development. Expression following tip formation is controlled by more distal sequence, which contains TTGA repeats known to regulate prestalk cell gene expression in other promoters. Comparison of reporter gene expression and endogenous mRNA accumulation indicates that during growth the ampA gene is expressed in an increasing number of cells as a function of density. The number of cells expressing the ampA gene drops as development initiates, but the cells that continue to express the gene do so at high levels. These cells are initially scattered throughout the entire aggregate. By the tip formation stage, however, the majority of ampA-expressing cells are localized to the mound periphery, with only a few cells remaining scattered in the upper portion of the mound. In the final culminant, ampA is expressed only in the upper cup, lower cup, and basal disc. Although reporter expression is observed in cells that migrate anteriorly to a banded region just posterior to the tip, expression is rarely observed in the extreme tip. AmpA protein however, is localized to the tip as well as to ALCs during late development. The results presented here suggest that ampA gene expression is shut off in ALCs that continue along the prestalk differentiation pathway before they are added to the primordial stalk.     

陆地棉皱缩叶突变体基因wr3的初步定位

陆地棉皱缩叶突变体是本项目组自主发现的一种自然突变体。前期对其表型性状的观察发现该突变体的农艺性状有别于前人已报道的皱叶突变体;通过陆陆杂交世代群体对其遗传规律的研究表明, 皱缩叶突变性状是受一对完全隐性基因wr3控制的质量性状。文章以皱叶突变自交系L037和海7124为亲本配置组合得到的海陆杂交F2为作图群体, 利用本实验室遴选的平均覆盖棉花26对染色体上的234对SSR引物(每染色体相对等距离分布9对引物), 通过对双亲以及近等基因池的筛选, 共得到12对多态性引物。用这些引物检测F2作图群体每个单株的标记基因型, 经Join Map 4.0分析显示, 位于Chr.21的引物BNL3279与目的基因连锁, 二者间的遗传距离为28.7 cM。随后对Chr.21上的其他引物进一步筛选, 共得到16对与目的基因连锁的标记, 其中与目的基因距离最近的标记NAU3740的遗传距离为4.8 cM, 另一侧标记cgr5428的遗传距离为10.4 cM。由此推定, 皱缩叶突变体基因wr3在棉花第21染色体上。     

Response of the enzymes to nitrogen applications in cotton fiber (Gossypium hirsutum L.) and their relationships with fiber strength

To investigate the response of key enzymes to nitrogen (N) rates in cotton fiber and its relationship with fiber strength, experiments were conducted in 2005 and 2006 with cotton cultivars in Nanjing. Three N rates 0, 240 and 480 kgN/hm2, signifying optimum and excessive nitrogen application levels were applied.The activities and the gene expressions of the key enzymes were affected by N, and the characteristics of cellulose accumulation and fiber strength changed as the N rate varied. Beta-1,3-glucanase activity in cotton fiber declined from 9 DPA till boll opening, and the beta-1, 3-glucanase coding gene expression also followed a unimodal curve in 12—24 DPA. In 240 kgN/hm² condition, the characteristics of enzyme activity and gene expression manner for sucrose synthase and beta-1,3-glucanase in developing cotton fiber were more favorable for forming a longer and more steady cellulose accumulation process, and for high strength fiber development.