Role of the Arabidopsis thafiana NAC transcription factors ANAC019 and ANAC055 in regulating jasmonic acid-signaled defense responses

Jasmonic 酸(JA ) 是对草食动物攻击，病原体感染并且机械伤害调整植物防卫回答的重要植物激素。在这份报告，我们提供了生物化学、基因的证据证明 Arabidopsis thaliana NAC 家庭蛋白质 ANAC019 和 ANAC055 可能作为抄写使活跃之物工作调整辩护基因的导致 JA 的表示。在 JA 发信号的二 NAC 基因的角色与 anac019 anac055 被检验两倍异种并且与转基因的植物 overexpressing ANAC019 或 ANAC055。两倍变异的植物显示出的 anac019 anac055 稀释了导致 JA 的植物的存储 PROTEIN1 (VSP1 ) 和 LIPOXYGENASE2 (LOX2 ) 表示，而二 NAC 基因显示出的转基因的植物 overexpressing 提高了导致 JA 的 VSP1 和 LOX2 表示。二 NAC 基因的 导致JA 的表示取决于 COI1 和 AtMYC2 的功能和发现 ANAC019 的那 overexpression 部分救了 atmyc2-2 异种的JA相关的显型，带了我们到二 NAC 蛋白质 AtMYC2 下游地扮演调整 发信号JA 的防卫回答的一个假设。证实这个想法的进一步的证据来自观察到 necrotrophic 真菌的两倍异种高显示出的 anac019 anac055 的反应类似到 atmyc2-2 异种的。

Understanding the genetic and epigenetic architecture in complex network of rice flowering pathways

Although the molecular basis of flowering time control is well dissected in the long day （LD） plant Arabidopsis, it is still largely unknown in the short day （SD） plant rice. Rice flowering time （heading date） is an important agronomic trait for season adaption and grain yield, which is affected by both genetic and environmental factors. During the last decade, as the nature of florigen was identified, notable progress has been made on exploration how florigen gene ,expression is genetically controlled. In Arabidopsis expression of certain key flowering integrators such as FLOWERING LOCUS C （FLC） and FLOWERING LOCUS T （FT） are also epige- netically regulated by various chromatin modifications, however, very little is known in rice on this aspect until very recently. This review summarized the advances of both genetic networks and chromatin modifications in rice flowering time control, attempting to give a complete view of the genetic and epigenetic architecture in complex network of rice flowering pathways.

Ten Years of Gene Discovery for Meiotic Event Control in Rice

Meiosis is the crucial process by which sexually propagating eukaryotes give rise to haploid gametes from diploid cells. Several key processes, like homologous chromosomes pairing, synapsis, recombination, and segregation, sequentially take place in meiosis. Although these widely conserved events are under both genetic and epigenetic control, the accurate details of molecular mechanisms are continuing to investigate. Rice is a good model organism for exploring the molecular mechanisms of meiosis in higher plants. So far, 28 rice meiotic genes have been characterized. In this review, we give an overview of the discovery of rice meiotic genes in the last ten years, with a particular focus on their functions in meiosis.

Activation of gibberellin 2-oxidase 6 decreases active gibberellin levels and creates a dominant semi-dwarf phenotype in rice (Oryza sativa L.)

Gibberellin （GA） 2-oxidase plays a key role in the GA catabolic pathway through 2β-hydroxylation.In the present study,we isolated a CaMV 35S-enhancer activation tagged mutant,H032.This mutant exhibited a dominant dwarf and GA-deficient phenotype,with a final stature that was less than half of its wild-type counterpart.The endogenous bioactive GAs are markedly decreased in the H032 mutant,and application of bioactive GAs （GA3 or GA4） can reverse the dwarf phenotype.The integrated T-DNA was detected 12.8 kb upstream of the OsGA2ox6 in the H032 genome by TAIL-PCR.An increased level of OsGA2ox6 mRNA was detected at a high level in the H032 mutant,which might be due to the enhancer role of the CaMV 35S promoter.RNAi and ectopic expression analysis of OsGA2ox6 indicated that the dwarf trait and the decreased levels of bioactive GAs in the H032 mutant were a result of the up-regulation of the OsGA2ox6 gene.BLASTP analysis revealed that OsGA2ox6 belongs to the class III of GA 2-oxidases,which is a novel type of GA2ox that uses C20-GAs （GA12 and/or GA53） as the substrates.Interestingly,we found that a GA biosynthesis inhibitor,paclobutrazol,positively regulated the OsGA2ox6 gene.Unlike the over-expression of OsGA2ox1,which led to a high rate of seed abortion,the H032 mutant retained normal flowering and seed production.These results indicate that OsGA2ox6 mainly affects plant stature,and the dominant dwarf trait of the H032 mutant can be used as an efficient dwarf resource in rice breeding.

A strategy for generating rice apomixis by gene editing

Apomixis is an asexual reproduction way of plants that can produce clonal offspring through seeds.In this study,we introduced apomixis into rice(Oryza sativa)by mutating OsSPO11-1,OsREC8,OsOSD1,and OsMATL through a CRISPR/Cas9 system.The quadruple mutant showed a transformation from meiosis to mitosis and produced clonal diploid gametes.With mutated Osmatl,which gives rise to haploid induction in plants,the quadruple mutant is expected to be able to be produced apomictic diploid offspring.We named this quadruple mutant as AOP(Apomictic Offspring Producer)for its ability to produce apomictic offspring.

The Role of OsMSH5 in Crossover Formation during Rice Meiosis

MSH5, a meiosis-specific member of the MutS-homolog family, is required for normal level of recombination in budding yeast, mice, Caenorhabditis elegans, and Arabidopsis. Here, we report the identification and characterization of its rice homolog, OsMSH5, and demonstrate its function in rice meiosis. Five independent Osmsh5 mutants exhibited normal vegetative growth and severe sterility. The synaptonemal complex is well installed in Osmsh5, while the chiasma frequency is greatly reduced to approximately 10% of that observed in the wild-type, leading to the homologous non- disjunction and complete sterile phenotype. OsMSH5 is predominantly expressed in panicles. Immunofluorescence studies indicate that OsMSH5 chromosomal localization is limited to the early meiotic prophase I. OsMSH5 can be loaded onto meiotic chromosomes in Oszip4, Osmer3, and hellO. However, those ZMM proteins cannot be localized normally in the absence of OsMSH5. Furthermore, the residual chiasmata were shown to be the least frequent among the zmm mutants, including Osmer3, Oszip4, hellO, and Osmsh5. Taken together, we propose that OsMSH5 functions upstream of OsZIP4, OsMER3, and HEIl0 in class I crossover formation.

Identification of Chromosomes from Multiple Rice Genomes Using a Universal Molecular Cytogenetic Marker System

To develop reliable techniques for chromosome identification is critical for cytogenetic research, especially for genomes with a large number and smaller-sized chromosomes. An efficient approach using bacterial artificial chromosome （BAC） clones as molecular cytological markers has been developed for many organisms. Herein, we present a set of chromosomal arm-specific molecular cytological markers derived from the gene-enriched regions of the sequenced rice genome. All these markers are able to generate very strong signals on the pachytene chromosomes of Oryza sativa L. （AA genome） when used as fluorescence in situ hybridization （FISH） probes. We further probed those markers to the pachytene chromosomes of O. punctata （BB genome） and O. officinalis （CC genome） and also got very strong signals on the relevant pachytene chromosomes. The signal position of each marker on the related chromosomes from the three different rice genomes was pretty much stable, which enabled us to identify different chromosomes among various rice genomes. We also constructed the karyotype for both O. punctata and O. officinalis with the BB and CC genomes, respectively, by analysis of 10 pachytene cells anchored by these chromosomal arm-specific markers.

DsMTOPVIB Promotes Meiotic DNA Double-Strand Break Formation in Rice

Dear Editor,Meiotic recombination is initiated by the generation of DNA double-strand breaks （DSBs）, which are catalyzed by the Spo11 protein （de Massy, 2013）. Two key findings point to the role of Spo11 as the initiator of DSB formation in budding yeast： （1） Spo11 is linked to the 5＇ termini of the broken DNA molecules in rad50s mutants, whose meiosis has been blocked at the stage of the cleavaqe reaction （＇Keenev et al., 1997）.

Brassinosteroid Signaling and Application in Rice

Combined approaches with genetics, biochemistry, and proteomics studies have greatly advanced our understanding of brassinosteroid （BR） signaling in Arabidopsis. However, in rice, a model plant of monocot and as well an important crop plant, BR signaling is not as well characterized as in Arabidopsis. Recent studies by forward and reverse genetics have identified a number of either conserved or specific components of rice BR signaling pathway, bringing new ideas into BR signaling regulation mechanisms. Genetic manipulation of BR level or BR sensitivity to improve rice yield has established the great significance of BR research achievements.

Rice OsGL 1-1 Is Involved in Leaf Cuticular Wax and Cuticle Membrane

Cuticular wax forms a hydrophobic barrier on aerial plant organs; it plays an important role in protecting a plant from damage caused by many forms of environmental stress. In the present study, we characterized a rice leaf wax-deficient mutant osgll-1 derived from a spontaneous mutation, which exhibited a wax-deficient and highly hydro- philic leaf phenotype. We cloned the OsGLI-1 gene by the map-based cloning method and performed a complementation test to confirm the function of the candidate gene. Molecular studies revealed that OsGLI-1 was a member of the OsGL1 family, and contained regions that were homologous to some regions in sterol desaturases and short-chain dehydro- genases/reductases. Compared to the wild-type, the osgll-1 mutant showed decreased cuticular wax deposition, thinner cuticular membrane, decreased chlorophyll leaching, increased rate of water loss, and enhanced sensitivity to drought. OsGL 1-1 is expressed ubiquitously in rice. The transient expression of OsGLl-l-green fluorescent protein fusion protein indicated that OsGLI-1 is localized in the cytoplasm, plasma membrane, and nucleus.

From Basic Research to Molecular Breeding——Chinese Scientists Play A Central Role in Boosting World Rice Production

On November 18, 2018, the Future Science Prize Awarding Ceremony was held in Beijing. In the area of life science, Professors Jiayang Li, Longping Yuan, and Qifa Zhang shared the prize for their pioneering contributions in producing high-yield, superior-quality rice through systematic study of molecular mechanisms associated with speci?c rice features and application of novel approaches in rice breeding. The Future Science Prize is also touted as ‘‘China’s Nobel Prize", fully af?rming their achievements in rice basic research and breeding.