Reduced susceptibility to waterlogging together with high-light stress is related to increases in superoxide dismutase and catalase activities in sweet potato

We investigated the changes in antioxidative enzyme activities of two sweet potato cultivars under waterlogging and high-light conditions in the growth chamber. The activities of antioxidative enzymes were measured from leaf crude extract of sweet potato during the first five days of the treatments. Activities of superoxide dismutase and catalase were consistently increased in Taoyuan 1 sweet potato over time under waterlogging and high-light conditions. However, decreases in both superoxide dismutase and catalase activities were observed for cultivar Yongtsai under waterlogging and high-light conditions. Waterlogging, together with high-light intensity, impairs superoxide dismutase and catalase activities in the cultivar Yongtsai indicating its greater susceptibility to waterlogging and high-light stress. In contrast, the increase in activities of superoxide dismutase and catalase in Taoyuan 1 indicated its greater ability to detoxify reactive oxygen species during the treatment and ensured its reduced susceptibility to waterlogging and high-light stress. The activities of peroxidase may be inactivated by high-light treatment and, therefore, may not be associated with tolerance of sweet potato plants to waterlogging and high-light stress. Differences in susceptibility to waterlogging and high-light conditions in the leafy vegetable Yongtsai and storage root Taoyuan 1 are discussed.     

QTL analyses of fiber components and crude protein in an annual × perennial ryegrass interspecific hybrid population

Annual (Lolium multiflorum Lam.) and perennial (Lolium perenne L.) ryegrasses are two important forage and turfgrass species. Improving the digestibility of forage by decreasing fiber content is a major goal in forage crop breeding programs. An annual × perennial ryegrass interspecific hybrid population was used to map quantitative trait loci (QTLs) for fiber components, neutral detergent fiber (NDF), acid detergent fiber (ADF), and acid detergent lignin (ADL), and crude protein (CP). Samples were harvested three times in August and September 2003 and August 2004, respectively. Simple interval mapping was used to detect QTLs from both the male and female parental maps previously developed for the population. Fiber components were all correlated positively with each other and were negatively correlated with CP. The largest correlations were between NDF and ADF with r = 0.86, 0.72, and 0.82 for each of the three harvests. All four traits showed intermediate broad-sense heritability values ranging from 0.35 to 0.72. A total of 63 QTLs were detected for the four traits measured over the three harvests from both the female and male maps. Coincident QTLs were detected on linkage groups (LGs) 2, 6, and 7 for NDF, LGs 1, 2, and 7 for ADF, LGs 6 and 7 for ADL, and LG 2 for CP, respectively. Coincident QTLs were also detected on LGs 2, 6, and 7 for NDF and ADF, providing evidence of the genetic basis of the observed high level of phenotypic correlation. The QTLs on LGs 2, 6, and possibly 7 for fiber components were co-located on the same LG as several lignin biosynthetic genes from perennial ryegrass.     

Construction of a primary RH panel of Italian ryegrass genome via UV-induced protoplast fusion

Symmetric and asymmetric somatic hybrids were produced via protoplast fusion between common wheat ( TRITICUM AESTIVUM L.) cv. "Jinan 177" and Italian ryegrass ( LOLIUM MULTIFLORUM Lam.). The ryegrass without or with UV irradiation was used as a donor, providing a small amount of chromatin. In these somatic hybrids, most ryegrass chromosomes have been confirmed preferential elimination and the somatic hybrid calli and plants showed wheat-like morphology. Some of the hybrid lines were used for the analysis of distribution and heredity of donor DNA in the hybrid genome and the possibility of establishing a radiation hybrid (RH) panel of the ryegrass in the present experiment. These hybrids, subcultured for two and three years, retained the ryegrass DNA examined by RFLP and GISH analysis, respectively. Distribution of the ryegrass DNA in the wheat genomes of 20 single-cell individuals, randomly selected from hybrid cell lines produced, were analyzed by 21 ryegrass genome specific SSR markers. The average frequencies of molecular marker retention in symmetric hybrid lines (UV 0), as well as asymmetric hybrid lines from UV 30 s and 1 min were 10.88, 15.48 and 33.86, respectively. It was suggested that the UV dose increased the introgression of donor DNA into wheat genome. The ryegrass SSR fragments in most asymmetric hybrid cell lines remained stable over a period of 2 approximately 3 years. This revealed that those asymmetric somatic hybrids are suitable for the introgression of ryegrass DNA into wheat, and for RH panel and RH mapping.     

小麦叶绿体psbA基因PCR扩增及其克隆

利用聚合酶链反应(Polymerase chain reaction)对小麦叶绿体的psbA基因进行特异性扩增,并以pBSD+质粒为载体将完整的psbA基因克隆到E.c oli中。通过分子杂交,PCR反应和酶切分析证明,重组质粒pTD1Ⅱ中含有完整的小麦叶绿体psbA基因。     

Taxonomic re-evaluation of the Azolla genus in Portugal

ABSTRACT

The Portuguese and the European Flora refer to the presence of two or three Azolla species in Portugal: A. filiculoides Lam., A. caroliniana Willd. and/or Azolla mexicana Presl., the latter included in the last edition of Flora Europaea. In the present work, the taxonomy of Azolla species is reviewed using the two most important characters that can distinguish between these two/three species: papillae in the dorsal leaf lobe and perine architecture of the megaspore apparatus. Other characteristics, such as the hyaline border cells of the dorsal leaf lobes and the number of glochidia septa in microsporangium massulae, are also used. All the Azolla specimens, collected from several locations in Portugal, were identified as Azolla filiculoides Lam. This identification disagrees with previous published reports on Azolla taxonomy in Portugal as well as with herbarium identification.     

Profiling of MicroRNAs under Wound Treatment in Aquilaria sinensis to Identify Possible MicroRNAs Involved in Agarwood Formation

Agarwood, a kind of highly valued non-timber product across Asia, is formed only when its resource trees -- the endangered genus Aquilaria are wounded or infected by some microbes. To promote the efficiency of agarwood production and protect the wild resource of Aquilaria species, we urgently need to reveal the regulation mechanism of agarwood formation. MicroRNAs (miRNAs) are a group of gene expression regulators with overwhelming effects on a large spectrum of biological processes. However, their roles in agarwood formation remain unknown. This work aimed at identifying possible miRNAs involved in the wound induced agarwood formation. In this study, the high-throughput sequencing was adopted to identify miRNAs and monitor their expression under wound treatment in the stems of A. sinensis. The miR171, miR390, miR394, miR2111, and miR3954 families remained at the reduced level two days after the treatment. 131 homologous miRNAs in the 0.5 h library showed over three-fold variation of read number compared with the control library, of which 12 exhibiting strong expression alterations were further confirmed by real-time quantitative PCR. Target prediction and annotation of the miRNAs demonstrated that the binding, metabolic process, catalytic activity, and cellular process are the most common functions of the predicted targets of these newly identified miRNAs in A.sinensis. The cleaveage sites of three newly predicted targets were verified by 5''RACE.     

白木香 3-羟基-3-甲基戊二酰辅酶 A 合酶(AsHMGS)基因的克隆与表达分析简

以白木香（Aquilaria sinensis(Lour.) Gilg）茎cDNA为模板,采用反转录PCR及RACE技术分离得到HMGS基因cDNA全长。序列分析表明该基因序列全长1 831 bp,共编码465个氨基酸,推导的蛋白质分子量为51.4 kD,理论等电点6.25,命名为AsHMGS。推导的AsHMGS蛋白质序列具有植物HMGS酶的典型结构,并预测出HMGS酶的活性中心。系统进化树分析表明,AsHMGS蛋白与拟南芥、琴叶拟南芥、芥菜的相应蛋白相似度最高,其次为人参、喜树和野茶树。荧光定量PCR结果显示,茉莉酸甲酯能诱导白木香AsHMGS的表达。     

沉香属植物研究进展

对土沉香的植物形态、生态学特性、迁地保护措施、沉香形成机理,造香、采收和加工分级进行了综述.通过分析其药用价值、园林绿化、香精等方面的开发利用价值,认为土沉香作为乡土树种,不仅经济和观赏价值较高,而且适应性强、繁殖简单、栽培容易、病虫害少,可大力推广种植土沉香.