Grain yield is a polygenic trait that can be influenced by environmental factors and genetic compositions at all plant growth stages. Currently, the molecular mechanisms behind the coordination of the interaction between grain yield-related traits remain unknown. In this study, we characterized the function of four STRESS_tolerance and GRAIN_LENGTH (OsSGL) Poaceae ortholog genes that are transcribed into DUF1645 domain-containing proteins in relation to the grain length, grain weight, and drought stress-tolerance of rice. The transgenic plants with overexpressing or heterologous high levels of Poaceae OsSGL ortholog genes exhibited longer grain size than the wild type plants. Larger cells were seen in panicles of the four transgenic lines with paraffin sectioning and scanning electron microscopy analyses. In addition, four Poaceae OsSGL ortholog genes positively affected the drought tolerance of rice. Four transgenic plants displayed higher resistance to drought stress at the seedling and vegetative stages. RNA-sequencing and qRT-PCR results indicated that over- or heterologous-expression of four Poaceae OsSGL ortholog genes also affected the transcriptome of rice plants. These genes may play a role in auxin and cytokinin biosynthesis and their transduction pathways. Taken together, these results suggested that the four OsSGL orthologs have a conserved function in the regulation of stress-tolerance and cell growth by modulating hormonal biosynthesis and signaling.

Starch biosynthesis during rice endosperm development is important for grain quality, as it influences grain size and physico-chemical properties, which together determine rice eating quality. Cereal starch biosynthetic pathways have been comprehensively investigated; however, their regulation, especially by transcriptional repressors remains largely unknown. Here, we identified a DUF1645 domain-containing protein, STRESS_tolerance and GRAIN_LENGTH (OsSGL), that participates in regulating rice starch biosynthesis. Overexpression of OsSGL reduced total starch and amylose content in the endosperm compared with the wild type. Chromatin immunoprecipitation sequencing and RNA-seq analyses indicated that OsSGL targets the transcriptional activity of several starch and sucrose metabolism genes. In addition, ChIP-qPCR, yeast one-hybrid, EMSA and dual-luciferase assays demonstrated that OsSGL directly inhibits the expression of SUCROSE SYNTHASE 1 (OsSUS1) in the endosperm. Furthermore, OsSUS1 interacts with OsSGL to release its transcriptional repression ability. Unexpectedly, our results also show that knock down and mutation of OsSGL disrupts the starch biosynthetic pathway, causing lower starch and amylose content. Therefore, our findings demonstrate that accurate control of OsSGL homeostasis is essential for starch synthesis and grain quality. In addition, we revealed the molecular mechanism of OsSGL in regulating starch biosynthesis-related genes, which are required for grain quality.

Grain quality is one of the key targets for rice breeding. Two-meter-high giant rice, Xiangju-1, is a new high-quality restorer line of hybrid rice. Here, the grain quality and storability of three varieties Jufeng 5 (JF5), Jufeng 6 (JF6), and Jufeng 8 (JF8) were studied. The grain sizes of three giant hybrid rice varieties (JFs) were larger than that of the control rice Jingliangyou 1212 (1212). With respect to nutritional value, the three JFs varieties had similar protein content (~8%) but much higher fat content (>0.8%) than 1212. In addition, JF6 had better storability than JF8 when assessed by controlled deterioration treatment (CDT). RNA-seq analysis revealed that the heatmaps of differentially expressed genes in JF6 and JF8 were similar after 20 days of CDT when compared with 0 days. Of particular interest were the different mRNA levels of several genes related to the pathways of DNA damage response and abscisic acid biosynthesis in JF6 and JF8 after 20 days of CDT. Taken together, the data suggested that JF6 had better grain quality and storability than the other hybrid varieties, and several candidate genes for seed storability were identified.

为建立‘翠玉’猕猴桃基因功能研究技术平台并通过生物技术改良‘翠玉’猕猴桃,本研究以‘翠玉’猕猴桃叶片为实验材料,利用农杆菌介导法将ACC氧化酶(ACO)基因的反义链导入‘翠玉’猕猴桃,共获得14株潮霉素抗性植株.PCR鉴定结果显示,其中8株扩增获得了目的条带,初步统计阳性植株约为57.1％.随机挑选其中4株进行实时荧光定量PCR检测,结果表明,ACO基因的相对表达量是野生型植株的22％～41％.本研究为利用分子生物学手段改良‘翠玉’猕猴桃品种提供了工作基础.

Copper is a mineral element essential for the normal growth and development of plants; however, excessive levels can severely affect plant growth and development. Oryza sativa L. multiple stress-responsive gene 3 (OsMSR3) is a small, low-molecular-weight heat shock protein (HSP) gene. A previous study has shown that OsMSR3 expression improves the tolerance of Arabidopsis to cadmium stress. However, the role of OsMSR3 in the Cu stress response of plants remains unclear, and, thus, this study aimed to elucidate this phenomenon in Arabidopsis thaliana, to further understand the role of small HSPs (sHSPs) in heavy metal resistance in plants. Under Cu stress, transgenic A. thaliana expressing OsMSR3 showed higher tolerance to Cu, longer roots, higher survival rates, biomass, and relative water content, and accumulated more Cu, abscisic acid (ABA), hydrogen peroxide, chlorophyll, carotenoid, superoxide dismutase, and peroxidase than wild-type plants did. Moreover, OsMSR3 expression in A. thaliana increased the expression of antioxidant-related and ABA-responsive genes. Collectively, our findings suggest that OsMSR3 played an important role in regulating Cu tolerance in plants and improved their tolerance to Cu stress through enhanced activation of antioxidative defense mechanisms and positive regulation of ABA-responsive gene expression.

从玉米中克隆了一个基因 ZmSGL ( Zea mays L. stress tolerance and grain length) ，该基因与水稻粒长基因 OsSGL 的编码序列一致性为 62.3% 。本工作在增加水稻粒长和粒重的功能方面对 ZmSGL 进行了初步研究。研究表明， ZmSGL 编码推定的 DUF1645 超家族蛋白。在水稻中表达玉米 ZmSGL 基因可引起水稻种子极显著增长增重。与野生型水稻相比，转基因水稻粒长增长 10.6% ，千粒重增重 8.4% 。转基因水稻小穗颖壳中的细胞数量和细胞大小增加，幼穗中 CDKA1 、 CYCA2 ; 1 和 CYCB2 ; 1 等细胞周期基因的表达水平升高。玉米基因 ZmSGL 作为谷粒大小调节因子，可应用于改善主要农作物的谷粒性状。

Grain weight is a major determining factor of rice (Oryza sativa L.) yield and the comprehensive embodiment of grain length, width, and thickness. Here, we describe the molecular and functional characterization of SbSGL (Sorghum bicolor L. stress tolerance and grain length), a sorghum gene that encodes a putative member of the DUF1645 protein family of unknown function. Expression of SbSGL in rice promoted cell division and grain filling, which affected an array of traits of rice, including grain length, grain weight, and seed setting rate. Expression of SbSGL also affected the expression of genes related to the plant cell cycle and grain size.

通过测定分析巨型稻(Oryza sativa)秸秆中营养成分含量,探讨两个巨型稻品种(巨丰5号和丰超6号)与超级稻Y两优1号的饲用价值.结果发现,1)巨型稻品种的单株生物量显著高于对照Y两优1号(P<0.05),分别是Y两优1号单株鲜重的2.74和2.15倍;2)3个水稻秸秆中,以丰超6号的粗蛋白含量最高,达到7.21％,比对照Y两优1号高约9.24％,但三者间的粗脂肪含量及总能值无显著差异(P>0.05);3)巨丰5号与丰超6号必需氨基酸的含量分别比Y两优1号高20.70％和7.72％,非必需氨基酸的含量分别比Y两优1号高10.96％和18.49％;4)丰超6号的粗纤维、中性洗涤纤维和酸性洗涤纤维的含量均显著高于巨丰5号与Y两优1号(P<0.05);5)Y两优1号的饲用价值及有机物质消化率显著高于两个巨型稻品种(P<0.05).综上所述,巨型稻秸秆的饲用价值虽低于Y两优1号,但其生物量、粗蛋白、氨基酸含量均较高.因此,巨型稻秸秆应用于动物生产实践中的潜力巨大.

Small signaling peptides play important roles in plant development and responses to abiotic and biotic stresses. We have identified a novel small peptide gene in rice, OsDSSR1, which is expressed mainly in the root, stem, node, leaf, and panicle. OsDSSR1 expression is also induced by drought, salinity, ABA, and H2O2 treatment. OsDSSR1 is localized in the nucleus and cytoplasm. Transgenic plants overexpressing OsDSSR1 exhibited enhanced drought stress tolerance and decreased ABA sensitivity as compared to the wild type. Overexpression of OsDSSR1 promoted the accumulation of compatible osmolytes, such as free proline and soluble sugars. OsDSSR1-overexpressing plants displayed enhanced OsSodCc2 and OscAPX expression and superoxide dismutase and ascorbate peroxidase activities under drought stress. RNA-sequencing data revealed that the expression of 72 abiotic stress-responsive genes was significantly altered in homozygous transgenic plants. These stress-responsive candidate genes will aid in expanding our understanding of the mechanisms by which small peptides mediate tolerance in crop species.

The MYB proteins play important roles in regulating plant responses to environmental stresses. We cloned and functionally characterized a novel MYB-related gene, OsMYBR1, from rice. Our microarray and qRT-PCR analyses showed that its expression was induced by drought and cold in different tissues at various developmental stages. This gene encodes a putative MYB-related protein of 463 amino acid residues. Compared with wild-type (WT) plants, transgenic plants over-expressing OsMYBR1 exhibited much greater tolerance to drought stress and decreased sensitivity to abscisic acid (ABA). Under drought treatment, levels of free proline and soluble sugar were higher in transgenic plants than in the WT. Furthermore, transcriptional expression of four stress-related genes -- OsP5CS1, OsProt, OsLEA3, and OsRab16 -- was significantly increased in transgenic plants under drought stressed conditions and ABA. Our results provide evidence that OsMYBR1 is involved in mediating plant responses to ABA and drought.

Autotetraploid Arabidopsis line esd and 4COL exhibit enhanced tolerance to Cu stress by enhancing activation of antioxidative defenses, altering expression of genes related to Cu transport, chelation, and ABA-responsive.

Calmodulin-like (CML) genes regulate plant growth, development, and responses to abiotic stresses such as salinity and drought. Many genes encoding CML proteins have been identified from rice (Oryza sativa), but their functions remain largely unknown. Our characterization of one putative CML gene, OsDSR-1 (O. sativa Drought Stress Response-1), showed that its protein binds Ca2+ and displays Ca2+-dependent conformational changes. In contrast to wild-type (WT) and OsDSR-1-RNA interference (OsDSR-1-Ri) plants, transgenic rice plants that overexpress OsDSR-1 were significantly more drought tolerant and had increased sensitivity to abscisic acid. Furthermore, their concentrations of free proline and soluble sugars and the activities of reactive oxygen species-scavenging enzymes as well as the transcript levels of many ROS-scavenging and stress-related genes were significantly enhanced under drought stress. Much less hydrogen peroxide and malondialdehyde accumulated in OsDSR-1-overexpressing (OsDSR-1-OE) plants than in either the Ri or WT plants. All of these results suggest that OsDSR-1 plays important roles in conferring tolerance to drought in rice by decreasing the occurrence of oxidative damage.

Drought is a major environmental factor that limits plant growth and crop productivity. Genetic engineering is an effective approach to improve drought tolerance in various crops, including rice (Oryza sativa). Functional characterization of relevant genes is a prerequisite when identifying candidates for such improvements. We investigated OsSGL (Oryza sativa Stress tolerance and Grain Length), a novel DUF1645 domain-containing protein from rice. OsSGL was up-regulated by multiple stresses and localized to the nucleus. Transgenic plants over-expressing or hetero-expressing OsSGL conferred significantly improved drought tolerance in transgenic rice and Arabidopsis thaliana, respectively. The overexpressing plants accumulated higher levels of proline and soluble sugars but lower malondialdehyde (MDA) contents under osmotic stress. Our RNA-sequencing data demonstrated that several stress-responsive genes were significantly altered in transgenic rice plants. We unexpectedly observed that those overexpressing rice plants also had extensive root systems, perhaps due to the altered transcript levels of auxin- and cytokinin-associated genes. These results suggest that the mechanism by which OsSGL confers enhanced drought tolerance is due to the modulated expression of stress-responsive genes, higher accumulations of osmolytes, and enlarged root systems.

Zinc nger proteins (ZFPs) play important roles in plant responses to biotic and abiotic stresses. Through microarray analysis, an Oryza sativa L. m ulti- s tress- r esponsive gene, OsMSR15 , was identied and subsequently cloned from rice Pei’ai 64S ( Oryza sativa L.). Expression of OsMSR15 was strongly up-regulated by cold, drought and heat stresses in different tissues at different developmental stages of rice. OsMSR15 contains two C2H2-type zinc nger motifs, a nuclear localization signal (B box), a Leu-rich domain (L-box) and a conserved EAR-motif close to its C-terminus. The OsMSR15-GFP fusion protein was localized to the nucleus. Yeast-one hybrid assay showed that OsMSR15 possesses transcriptional activation ability. Expression of OsMSR15 in Arabidopsis conferred drought tolerance, and transgenic plants showed hypersensitivity to exogenous ABA during the seed germination and post-germination stages. Transgenic plants also showed higher levels of free proline, less electrolyte leakage and increased expressions of a number of stress-responsive genes, including LEA3 , RD29A , DREB1A and P5CS1 under drought stress. The obtained results indicate that OsMSR15 is an important regulator involved in plant response to drought stress.

OsMsr16 (Oryza sativa L.multi-stress-responsive gene 16)是一个新的水稻植物同源结构域(PHD)-finger家族转录因子基因.之前研究显示,OsMsr16受到低温、高温和干旱胁迫的诱导表达.本研究中,qRT-PCR分析表明OsMsr16同样受到盐胁迫的诱导表达,推测该基因可能参与植物在高盐胁迫下的生理调控.苗期盐处理条件下,与对照相比,过表达OsMsr16的转基因水稻植株叶片失绿面积较少,存活率更高.盐胁迫条件下,转基因植株中积累更高含量的脯氨酸和可溶性糖,而丙二醛含量和双氧水含量明显降低.转基因植株中超氧化物歧化酶(superoxide dismutase,SOD)活性和过氧化氢酶(catalase,CAT)活性明显高于对照.以上结果说明OsMsr16基因可能在植物防御盐胁迫过程中发挥重要作用.

利用水稻基因芯片筛选到1个在水稻孕穗期和抽穗期穗中的相对表达量明显高于苗期、孕穗期和抽穗期叶片中相对表达量的基因OsMTG3,该基因在孕穗期穗中受低温、干旱诱导上调表达,而在抽穗期穗中受低温诱导下调表达.把该基因ATG密码子上游1.8kb左右的DNA片段预测为启动子区,并将其命名为pOsMTG3.用PCR技术克隆该启动子,并以GUS基因作为报告基因,在水稻中分析了该启动子在不同时期不同组织中的表达特性.GUS组织化学染色分析表明:pOsMTG3启动子能启动GUS基因在水稻根、芽、茎、穗中表达,而不能启动GUS基因在叶片中表达,是一个全新的叶片特异性不表达的启动子.

利用Affymetrix水稻表达芯片分析了超级稻两优培九母本培矮64S (Oryza sativa L.)在经过低温、干旱、高温等逆境条件胁迫处理后,不同组织器官在不同的生长发育时期全基因组的表达差异.筛选到一个在正常条件和逆境条件下均有较高表达水平的基因OsSG4 (GenBank登录号:AK068991.1),从水稻日本晴基因组中克隆得到其上游启动子区域Ospz4(1 625 bp),将其与GUS报告基因融合构建植物表达载体pCAM-BIA1301P4,并用农杆菌介导法转化台北309获得转基因植株.组织化学染色结果表明,Ospz4启动子可驱动GUS报告基因在转基因水稻植株的叶片,根、茎、颖花、胚乳及胚芽鞘中均有表达.在该启动子的基础上,构建了4个不同长度的5t端缺失片段启动子与GUS报告基因融合的植物表达载体,通过注射烟草(Nicotiana benthamiana)进行瞬时表达分析,结果表明,4个片段均可驱动GUS基因的表达,其中最短片段(492 bp)的表达活性最强.本研究表明Ospz4启动子可用于研究与遗传改良生产,具有重要的理论与实践价值,并有助于该启动子的改造.

Abiotic stress seriously affects the yield of rice (Oryza sativa L.). Grain yield in rice is multiplicatively determined by the number of panicles, number of grains per panicle, and grain weight. Here, we describe the molecular and functional characterization of STRESS_tolerance and GRAIN_LENGTH (OsSGL), a rice gene strongly up-regulated by a wide spectrum of abiotic stresses. OsSGL encodes a putative member of the DUF1645 protein family of unknown function. Overexpression of OsSGL significantly altered certain development processes greatly and positively affecting an array of traits in transgenic rice plants, including increased grain length, grain weight and grain number per panicle, resulting in a significant increase in yield. Microscopical analysis showed that the enhanced OsSGL expression promoted cell division and grain filling. Microarray and quantitative real-time PCR (qRT-PCR) analyses revealed that a large number of genes involved in stress-response, cell cycle and cytokinin signaling processes were induced or suppressed in OsSGL-overexpressing plants. Together, our results suggest that OsSGL may regulate stress-tolerance and cell growth by acting via a cytokinin signaling pathway. This study not only contributes to our understanding of the underlying mechanism regulating rice stress-tolerance and grain length, but also provides a strategy for tailor-made crop yield improvement.

Zinc (Zn) is an essential micronutrient for plants, but it becomes toxic when accumulated in excess. An autotetraploidArabidopsis thaliana treated with high concentration of Zn was found to be Zn-tolerant with-out Zn-hyperaccumulation. The root length and biomass of autotetraploid plants exhibited increases upon ex-cess Zn exposure, compared to wild-type plants, and the contents of total glutathione (GSH) were observed to be increased as well in autotetraploid plants. Quantitative real-time PCR (qRT-PCR) analysis of the expression proifles of autotetraploid plants revealed the alterations of some Zn stress-responsive genes in their expression levels. The obtained results suggested that altered expressions of Zn-responsive genes and increased GSH con-tent may play a major role in the Zn tolerance of autotetraploidArabidopsis.