Genetic analysis and gene fine mapping for a rice novel mutant （rl9〈t）） with rolling leaf character

Much attention has been paid to leaf shape of rice in the process of ideotype breeding[1]. Several authors have reported that the rolling of leaf in some degree helps keep it erect, consequently optimizing canopy light transmission condition, which is good for dry matter accumulation and for high yield[2―6]. Rice as a polymorphic crop has many types of vari- ety with different morphologies. In terms of leaf shape, different cultivars with rolling leaf have been identifiedin rice germplasm. Le…     

Fine mapping of an incomplete recessive gene for leaf rolling in rice （Oryza sativa L.）

Genetic analysis and fine mapping of genes controlling leaf rolling were conducted using two backcrossed generations （BC4F2, BC4F3） derived from a cross between QMX, a non-rolled leaf cultivar as a recurrent parent, and JZB, a rolled leaf NIL of ZB as a donor parent. Results indicated that leaf rolling was mainly controlled by an incompletely recessive major gene, namely rl（t）, and at the same time, affected by quantitative trait loci （QTLs） and/or the environment. A genetic linkage map was constructed using MAPMAKER/EXP3.0 with eight polymorphic markers on chromosome 2, which were screened by BAS method from 500 SSR markers and 15 newly developed insertion/deletion （InDel） markers. The position of rl（t） was estimated with composite interval mapping （CIM） method using WinQTLcart2.5. Gene rl（t） was mapped between markers InDel 112 and RM3763, and 1.0 cM away from InDel 112 using 241 plants in BC4F2 population. To fine map r（t）, one BC4F3 line with 855 plants was generated from one semi-rolled leaf plant in BC4F2. Four new polymorphic InDel markers were developed, including InDel 112.6 and InDel 113 located between markers InDe1112 and RM3763. Based on the information of recombination offered by 191 rolled leaf plants and 185 non-rolled leaf plants from the BC4F3 line ,we mapped r（t） to a 137-kb region between markers InDel 112.6 and InDel 113. Homologous gene analysis suggested that r（t）was probably related to the process of leaf development regulated by microRNA.     

Obtaining transgenic rice resistant to rice fungal blast disease by controlled cell death strategy

The strategy of the two-component system,composed of Barnase and Barstar which encode RNase and a specific inhibitor to the RNase respectively, is adopted to obtain transgenic rice resistant to rice fungal blast disease. In this study, two chimeric promoters, induced by rice blast fungus pathogen (Magnaporthe grisea), are fused with Barnase respectively to construct two plant expression vectors, pWBNBS and pPBNBS together with the Barstar driven by CaMV 35S promoter. The resistance of the transgenic rice lines to rice blast fungus disease and rice blight disease are evaluated. The results show that (1) the expression of Barnase is induced in rice leaves when inoculated with the spores of Magnaporthe grisea; (2) the induced expression level of Barnase surpasses the level of Barstar, which elicits a similar hypersensitive response (HR) in the leaves, and the transgenic plant shows high resistance to the rice fungal blast disease; and (3) transgenic rice plants also show obvious resistance to rice bacterial blight disease. Taken together, these results suggest that the transgenic rice plants harboring this two-component system acquire relatively broad spectrum resistance against pathogens, especially high resistance to rice fungal pathogen.     

MiR-205 inhibits the invasion and migration of esophageal squamous cell carcinoma by modulating SMAD1 expression

Esophageal squamous cell carcinoma （ESCC） is one of the most lethal cancers worldwide. In this study, we aimed to investigate the underlying mechanisms of metastasis inhibition by miR-205 in ESCC. In microRNA （miRNA） array and quantitative RT-PCR analyses, we found that the expression level of miR-205 was significantly lower in patients with lymph node metastasis compared with that in patients without lymph node metastasis. After transfection of miR-205 mimics or inhibitors into ESCC cell lines, a significant negative correlation was observed between the expression level of miR-205 and Smad 1. In luciferase reporter assays, we revealed that miR- 205 inhibited the expression of SMAD1 by targeting the 3＇ untranslated region （3＇-UTR） of SMAD1 mRNA in ESCC cells. Furthermore, our results showed that miR-205 sup- pressed the invasion and migration of ESCC cells, whereas Smadl increased their invasion and migration. Taken together, our study demonstrates that miR-205 functions as a suppressor of tumor metastasis by regulating SMAD1 expression through targeting the 3＇-UTR of SMAD1 mRNAin ESCC. Therefore, miR-205 may be a potential therapeutic target for miRNA-based therapy of ESCC.     

Biomimetic fabrication and characterization of an artificial rice leaf surface with anisotropic wetting

In nature,rice leaves exhibit special anisotropic sliding capabilities.Although researchers have succeeded in fabricating artificial rice leaf structures and realizing the wettability function of the leaf surface,these methods used to date are complex and do not allow the fabrication of surfaces with large area.Herein,we adopted a simple technology—two steps soft transfer to fabricate biomimetic rice leaf.The fabricated surface well reproduced the structures of the rice leaf surface and exhibited a static superhydrophobic property similar to that of the real rice leaf surface.In terms of its dynamic wettability,it clearly exhibited an anisotropic sliding property.Systematic measurements showed that the sliding angles parallel and perpendicular with the vein direction were 25° and 40°,respectively.The method was simple and reliable,without the need for expensive instruments and complex technologies,which could be used for the rapid fabrication of large-area artificial rice leaf surfaces.We believe that the artificial rice leaf surface fabricated by this method has great potential applications in biomimetic functional surfaces,microfluidics,and so on.     

RNAi-mediated knockingdown of rlpk2 gene retarded soybean leaf senescence

Leaf senescence that occurs in the last stage of leaf development is a genetically programmed process. It is very significant to elucidate the molecular mechanisms that control the initiation and progression of leaf senescence and the way the senescence signal is transduced. In a previous study on artificially induced soybean leaf senescence, we cloned a novel gene designated rlpk2 (Genbank Accession No. AY687391) that encodes a leucine-rich repeat (LRR) receptor like protein kinase. The expression level of rlpk2 gene was shown to be strongly up-regulated during both the natural leaf senescence process in this report and the artificially induced primary-leaf-senescence process in our previous work. The RNA interference (RNAi)-mediated knocking-down of rlpk2 dramatically retarded both the natural and nutrient deficiency-induced leaf senescence in transgenic soybean. The transgenic leaves showed more cell-aggregated surface structure and higher content of chlorophyll.     

Genetic analysis and gene fine mapping of a rolling leaf mutant (<Emphasis Type="Italic">rl</Emphasis><Subscript><Emphasis Type="Italic">11(t)</Emphasis></Subscript>) in rice (<Emphasis Type="Italic">Oryza sativa</Emphasis> L.)

The exploration of new genes controlling rice leaf shape is an important foundation for rice functional genomics and plant archi-tecture improvement. In the present study, we identified a rolling leaf mutant from indica variety Yuefeng B, named rl_11(t), which exhibited reduced plant height, rolling and narrow leaves. Leaves in rl_11(t) mutant showed abnormal number and morphology of veins compared with those in wild type plants. In addition, rl_11(t) mutant was less sensitive to the inhibitory effect of auxin than the wild type. Genetic analysis suggested that the mutant was controlled by a single recessive gene. Gene Rl_11(t) was initially mapped between SSR markers RM6089 and RM124 on chromosome 4. Thirty-two new STS markers around the Rl_11(t) region were developed for fine mapping. A physical map encompassing the Rl_11(t) locus was constructed and the target gene was finally delimited to a 31.6 kb window between STS4-25 and STS4-26 on BAC AL606645. This provides useful information for cloning of Rl_11(t) gene.     

Genetic analysis and gene mapping of a narrow leaf mutant in rice ( Oryza sativa L.)

A narrow leaf mutant was obtained after T-DNA transformation conducted on a rice variety Zhonghua 11. Several abnormal morphological characteristics, including semi-dwarf, delayed flowering time, narrow and inward rolling leaves, and lower seed-setting, were observed. The rate of net photosynthesis (under saturate light) of flag leaves in the mutant was significantly lower than that of the wild type. Moreover, the leaf transpiration rate and stomatal conductance in the mutant flag leaf were lower than those of the wild type at the grain filling stage. It was found that the mutant phenotype was not caused by the T-DNA insertion. Genetic analysis showed that the mutant was controlled by a single recessive gene, designated as nal3(t). A genetic linkage map was constructed using a large F₂ mapping population derived from a cross between nal3(t) and an indica variety Longtefu B with 6 polymorphic markers on chromosome 12 identified from 366 SSR markers by the BAS method. Gene nal3(t) was mapped between the markers RM7018 and RM3331. Fine mapping of nal3(t) locus was conducted with 22 newly developed STS markers based on the sequence diversity around the region harboring nal3(t) between Nipponbare and 93–11, and nal3(t) was finally mapped to a 136-kb region between the STS markers NS10 and RH12-8. Supported by National High Technology Research and Development Program of China (863 Program) (Grant No. 2006AA10A102), National Natural Science Foundation of China (Grant No. 30600349) and Natural Science Foundation of Zhejiang Province (Grant No. Y306149)     

球面稳定同伦群的一族新元素G0(B1)4Γs

利用May谱序列的E₁^s,t,*项收敛于群E_A^s,t(Z_p,Z_p)以及Adams谱序列的E₂^s,t项收敛于球面稳定群π_t-s(S)_p的方法, 并结合谱的上纤维序列导出Ext群的正合序列, 发现了谱V(2)稳定同伦群中的一个非零元素g₀(b₁)⁴, 并且发现它在Adams谱序列中是一个永久循环. 运用Yoneda乘积, 得到了球面稳定同伦群中的一个非零元素g₀(b₁)⁴γ_s.     

Formation age and tectonic environment of the Gantaohe Group, North China Craton: Geology, geochemistry, SHRIMP zircon geochronology and Hf-Nd isotopic systematics

The Gantaohe Group is an important early Precambrian unit in the Trans-North China Orogen,North China Craton,and is mainly composed of greenschist-facies metabasalt,meta-sandstone and dolomitic marble.We report whole-rock geochemical compositions and SHRIMP zircon ages as well as LA-ICP-MS Hf-in-zircon isotopeic analyses for metabasalts from the Gantaohe Group.SHRIMP dating yielded a weighted mean 207Pb/206Pb age of 2087±16 Ma(MSWD=1.3) for magmatic zircons,but there are also abundant ca.2.5 Ga inherited zircon xenocrysts.The magmatic zircons shows a large Hf(t) variation in Hf(t) from 7.17 to +0.45,suggesting an isotopically highly heterogeneous source for the metabasalt.Chemically all samples show no distinct Zr or Hf anomalies,and some samples show no Nd or Ta anomalies in a primitive mantle-normalized trace element variation diagram,and their whole-rock Nd(t) values range from 4.0 to 0.8.We suggest that the basalt is formed by partial melting of a depleted mantle source,followed by significant crustal contamination.Field observations,the presence of abundant inherited zircon,as well as isotope and trace elements geochemistry support formation of the Gantaohe Group on top of a continental basement.These data and the regional geology lead us to conclude that the Trans-North China Orogen constituted an intracontinental rift during the Paleoproterozoic that was connected to the Eastern Block since the end of the Archean.     

The periodic solution for a kind odd order delay differential equation

In this paper, we use the coincidence degree theory to research the odd order delay differential equation a(t)χ(2n+1)(t)+b(t)χ(t)+g(t,-τ(t)))=p(t), and we obtain the sufficient conditions for the existence of periodic solutions, which improves and generalizes some related results in the literatures.     

Fine mapping of cisc(t), a gene for cold-induced seedling chlorosis, and identification of its candidate in rice

The seedlings of indica rice cultivar Dular are susceptible to chlorosis under low temperature conditions. Our previous studies indicated that low temperature-induced seedling chlorosis is controlled by a recessive gene, located between SSR markers RM257 and RM242, on the long arm of chromosome 9. We temporarily named the gene cisc(t). Using a large F₂ population derived from a cross between Dular and the japonica cultivar Lemont, which displays a normal green color at low temperatures, cisc(t) was fine mapped to within a 12-kb interval. There is only one annotated gene in this interval, which encodes a pentatricopeptide repeat (PPR) protein. Sequence analysis indicated that 8 bases were deleted at the 60th base in the Dular allele, resulting in a frame-shift mutation and loss of function of the gene. This is consistent with the chlorosis mutant phenotype of Dular. In addition, previous studies have shown that many chlorosis mutants of seedlings are related to PPR proteins. Hence, we presume that the PPR gene is the candidate for cisc(t).     

Gracefulness of several unconnected graphs with wheel

In the paper, we study the gracefulness of several unconnected graphs related to wheel. For natural number p ≥1,t ≥1, let n =2t +3, 2t +4, which proved W_n∪K_(p,t)~(1)∪K_(p,t)~(2) is graceful; for p ≥1, t ≥1,let n=2t+3,2t+4, then W_(n,2n+1)∪K_(p,t)~(1)∪K_(p,t)~(2) is graceful and for m≥1,r ≥1, let n =2m +5, W_(n,2n+1) ∪( C_3∨K m) U St( r)is graceful.     

Genetic analysis and fine mapping of the pubescence gene GL6 in rice (Oryza sativa L.)

The pubescence of the leaf blade surface is an important agronomic characteristic for rice morphology and significantly influences rice growth as well as physiological characteristics. This characteristic was analyzed in F1 and F2 plants derived by crossing cultivar 75-1-127 with the indica cultivar Minghui 63, as well as the glabrous cultivar Lemont and indica cultivar 9311. Results indicated that the pubescence of the leaf blade surface was a dominant trait and controlled by a single gene. The GL6 gene was primarily mapped on rice chromosome 6 with recessive F2 population derived from 75-1-127/Minghui 63 by combining bulked segregation analysis and recessive class analysis using the Mapmaker3.0/MapDraw software. The genetic distances between the simple sequence repeat markers RM20491 and RM20547 were 7.2 and 2.2 cM, respectively. The GL6 gene was fine mapped in the interval between InDel-106 and InDel-115 at genetic distances of 0.3 and 0.1 cM, respectively. The large, recessive F2 population was derived from 75-1-127/Minghui 63. A high-resolution genetic and physical map of GL6 was constructed. Derived from the map-based sequences published by the International Rice Genome Sequencing Project, the GL6 gene was localized at an interval of 79 (japonica) and 116.82 kb (9311) bracketed by InDel-106 and InDel-115 within the BAC accession numbers AP008403 and AP005760. Seven annotated genes (japonica) and eight annotated genes (9311) were present. The basis was further set for GL6 cloning and function analysis.     

Molecular evolution of rice S 5 n and functional comparison among different sequences

The wide compatibility gene, S ₅ ⁿ , can overcome embryo sac sterility between indica and japonica subspecies of rice. Therefore, it is very important to characterize the features of the S ₅ ⁿ sequence to reveal the origin and evolution of S ₅ ⁿ . In this paper, 26 cultivated rice haplotypes and 22 wild rice accessions harboring S ₅ ⁿ were used to sequence S ₅ ⁿ . The results showed that 15 genotypes among the 48 materials were fully consistent with control cultivar 02428 (CK). The other 33 accessions had different degrees of variation in the S ₅ ⁿ sequence. Variations in the coding region mainly occurred in the second exon and eight materials showed a 10-bp deletion at 1710?C1719 bp, including wild (O. nivara) and cultivated rice, such as IRW501 and Yuetai B. S ₅ ⁿ sequences were not biased and evolved neutrally. The 48 materials could be divided into 4 categories using a phylogenetic tree of the amino acid sequences. Most of the wild rice clustered together, and the cultivated rice clustered into another group. Eight cultivated rice and O. nivara (wild rice) clustered in another group, which were found to lack 10 consecutive bases in exon 2. Eight rice varieties with high numbers of differences in their S ₅ ⁿ coding regions were crossed with testers (typically indica and japonica) to produced test cross F₁ populations. The F₁s were examined for their ability to overcome indica-japonica hybrid sterility. The result showed that the embryo sac fertility of S ₅ ⁿ -containing hybrids increased significantly compared with control hybrids, but there were no differences among the materials with divergent sequences, indirectly proving that S ₅ ⁿ is a non-functional gene.