Entomopathogenic nematodes induce components of systemic resistance in plants: Biochemical and molecular evidence

Antagonism between entomopathogenic nematodes (EPNs) and plant-parasitic nematodes (PPNs) has been documented over the past two decades but its mechanism and ecological significance remain elusive. We investigated the effects of Steinernema carpocapsae and its symbiotic bacterium, Xenorhabdus nematophila applied to the potting medium on pyrogallol peroxidase (P-peroxidase), guaiacol peroxidase (G-peroxidase) and catalase activities in Hosta sp. and Arabidopsis thaliana leaves as components of induced systemic resistance. We found that P-peroxidase activity was significantly higher in the leaves from hosta plants treated with S. carpocapsae infective juveniles (IJs) and S. carpocapsae infected insect cadavers than in the leaves from the control plants 2 weeks after treatment. The G-peroxidase activity was significantly higher in S. carpocapsae infected cadaver and X. nematophila treatments 10 and 15 days after treatment (DAT) and in S. carpocapsae IJs treatment 5 and 15 DAT. The catalase activity in hosta leaves was significantly higher in S. carpocapsae infected cadaver and X. nematophilus treatments compared with the control 5 and 15 DAT and in S. carpocapsae IJs treatment 5 and 10 DAT. Further, the catalase activity in A. thaliana leaves was significantly higher in S. carpocapsae IJs treatment than in the control 7 DAT. We also determined the effects of S. carpocapsae infected cadavers and S. carpocapsae IJs on PR1-gene expression in transgenic A. thaliana leaves through GUS (β-glucuronidase) activity assay and found that the PR1-gene was expressed in leaves from all treatments except the control. Thus, we conclude that the EPNs and their symbiotic bacteria can induce systemic resistance in plants which may explain the elusive antagonistic effect of EPNs on PPNs.     

控释氮肥对紫萼玉簪（Hosta ventricosa）生长和光合特性的影响

以紫萼玉簪（Hosta ventricosa）盆栽苗为材料,研究了50%遮荫条件下控释氮肥对玉簪不同生长发育时期生长和光合特性的影响,结果表明：N₁处理（4 g控释氮肥）和N₂处理（8 g控释氮肥）能够提高或显著提高玉簪不同生长发育时期干物质量;能够显著提高形态建成期叶绿素b（Chlb）含量,抽葶期和开花期叶绿素a（Chla）、Chlb及类胡萝卜素（Car.）含量;且显著提高各生长发育时期净光合速率（P_n）。在抽葶期和开花期,N₁处理最大光能转化效率（F_v/F_m）、PSⅡ电子传递量子效率（Φ_PSⅡ）、PSⅡ有效光化学量子产量（F′_v/F′_m）显著高于对照, 在形态建成期和开花期,N₂处理F_v/F_m、Φ_PSⅡ、F′_v/F′_m显著高于对照,且抽葶期F_v/F_m显著高于对照。除形态建成期N₁处理外,各施氮处理qP在不同时期与对照无显著差异。各施氮处理NPQ在形态建成期与对照无显著差异,而在抽葶期和开花期显著低于对照。     

玉簪属品种DUS测试中数量性状的测定方法探索

利用74份玉簪品种对19个数量性状进行筛选和分级研究,并对不同性状的测量时期和部位进行了探讨。结果表明:叶柄宽度的测试方式采取自然状态下直接测量,花序梗长度测量从基部到第1花苞片着生处的长度,苞片性状全部观测第1花苞片,花相关性状以1~3花中的完全开放花为观测对象;所有候选性状均符合DUS测试指南性状选用的条件,可分为3~9个连续的分级;植株、叶片的观测可改在开花期观测,花序相关性状则在末花期观测。     

Comparative phylogeographic study of Hosta sieboldiana and Hosta albomarginata (Asparagaceae) in Japan

We analyzed variations in chloroplast DNA (cpDNA) in the widespread herbaceous species Hosta sieboldiana and Hosta albomarginata across large portions of their geographic ranges in the Japanese archipelago. Our objective was to compare the phylogeographic histories and phylogeographic structures of the two congeneric species in the Japanese archipelago. The location of the study is Japanese archipelago. We sequenced 1380 bp of noncoding cpDNA from 45 populations of H. sieboldiana (n = 362) and 55 populations of H. albomarginata (n = 436) to assess genetic variations within and among populations across almost the entire distributions of the species in Japan. Extant patterns of geographic structure were analyzed using statistical parsimony networks and spatial analysis of molecular variance (SAMOVA). We also used Monmonier's algorithm to detect genetic barriers between regions. Relationships between the populations were examined using a neighbor‐joining (NJ) method. Four haplotypes were found for H. sieboldiana, whereas eight haplotypes were identified for H. albomarginata. Total genetic haplotype diversity (hT) and within‐population haplotype diversity (hS) for H. sieboldiana were 0.352 and 0.040, respectively, while the values for H. albomarginata were 0.529 and 0.085, respectively. The population differentiations (GST) for H. sieboldiana and H. albomarginata were 0.839 and 0.886, respectively. The SAMOVA analysis revealed two clusters in H. sieboldiana and four clusters in H. albomarginata. Differentiations between and among the clusters were supported by the BARRIER analysis and the NJ tree. We detected differences in the population genetic structure between the two species. We found that H. sieboldiana had lower haplotype diversity than H. albomarginata. These results may be partially explained by the difference in ecological habitats and geographic distributions between the species. Hosta albomarginata is more widely distributed than H. sieboldiana in East Asia including Russia, and this large distribution range would enable more chances to intraspecific gene flow.     

Plant regeneration from suspension cultures of Hosta sieboldiana

Systems for establishing suspension cultures and for inducing plant regeneration from these cultures for the Liliaceous ornamental plant, Hosta sieboldiana (Lodd.) Engl. have been developed. Pale-yellow and nodular calluses were induced from more than 20% of scape segments on MS medium containing 1 mg l^–1 picloram (PIC), 30 g l^–1 sucrose, and 2 g l^–1 gellan gum. Upon transfer of calluses to the same medium lacking gellan gum, stably-growing suspension cultures were established after 1 month. Suspension cell clusters regenerated a large number of adventitious shoots following transfer to MS media containing 0.1 mg l^–1 NAA in combination with either BA or TDZ. Over 20 shoots per 0.3 g FW of cell clusters were obtained on media containing 0.1 mg l^–1 NAA and either 1 or 5 mg l^–1 TDZ. Shoots rooted easily on plant growth regulator (PGR)-free MS medium, and plantlets were successfully transferred to soil. Plants showed no visible morphological alterations and maintained the diploid level as indicated by flow cytometric analysis.     

安徽玉簪属一新种

<正> 多年生草本,全株有白粉。叶基生,4—5枚,簇生,卵形或狭卵形,长13—20厘米,宽6—9厘米,先端急尖,基部下延成楔状,被白粉,叶背尤甚,叶脉每侧5—7条,叶柄长14—20厘米。花葶高40—44厘米。总状花序,具花10朵左右。总苞1—2枚,叶状,长5—10厘米,宽1—1.5厘米,基部抱茎,苞片绿白色,有白粉,卵形或披针形,长1.5—3.5匣米,宽0.6—1.1厘米。花不俯垂,排列紧密,无香味;花梗长约1厘米;花被白色,长约5.5厘米,径达4.1厘米,开放时呈喇叭状,裂片平展,每裂片有5条紫色条纹,花被管内有18条紫色条     

Visualization of Actin Filament Patterns in Pollen Tubes of Hosta caerulea Tratt. with a Non-Fixation and TRITC-Phalloidin Method

Actin filament patterns during pollen germination in Hosta caerulea Tratt. were visualized with a simple method in which there was no pre-fixation, with dimethylsulphoxide (DMSO) as a permeabilising agent and staining with TRITC-Phalloidin. The cytoplasm of the vegetative cell of the ungerminated pollen grain contained numerous crystalline fusiform bodies to constitute a storage form of actin. These bodies were transferred to the emerging pollen tube after the germination of the pollen grain. Following the growth of pollen tube, the fusiform bodies were gradually dissociated, branched, slenderized and formed a cross-linked actin network. During the further growth of the pollen tube, the preponderance of longitudinally-oriented thin actin filaments with some anastomoses to form a more complex network present always in the long pollen tube. This was the typical pattern of actin filaments in most cases. In some conditions, actin filaments were assembled to form thick actin cables near the proximate part of the pollen tube tip. The branching and connecting of the cables were probably also seen in some parts. Actin filaments were always entering to the apical region of a tube tip. The significance of the non-fixation and fluorescence-phalloidin (FI-Ph) method and the problems in the future studies are discussed     

大驳骨化学成分研究

通过对大驳骨(Gendarussa uentricosa)提取物的乙酸乙酯溶解部分进行分离纯化,发现了两个已知成分β-谷甾醇(1)和西米杜鹃醇(2),并对其低级性组分进行了GC/MS分析,共鉴定出21个化合物。该植物成分为首次报道。     

Relationships between floral morphology and pollinator fauna in insular and main island populations of Hosta longipes (Liliaceae)

We compared the floral morphologies and pollinator fauna and morphologies of Hosta longipes var. longipes on the main Japanese island of Honshu and var. latifolia on the Izu Islands to examine the differentiation processes of H. longipes in the island system. The corolla length was shorter on the southern Izu Islands than on the main island and northern Izu Islands. However, the size of other flower parts of H. longipes did not simply decrease across main island Honshu and the Izu Islands, unlike other Izu endemic plant species studied previously. Instead, the floral morphology showed a complicated variation pattern. Pollinator fauna of H. longipes on the Izu Islands varied more widely than those on the main island. The diverse pollinator fauna may have influenced the morphological differentiation of H. longipes on these islands.     

用非固定的荧光探针方法观察紫萼花粉管肌动蛋白纤丝的形式

用非固定的、二甲基亚砜作为渗透剂的、异硫氰四甲基罗丹明标记的鬼笔环肽染色方法,观察了紫萼(Hosta caerulea Tratt.)未萌发的花粉粒及不同生长时期的花粉管中的肌动蛋白纤丝的形式。显示未萌发的花粉粒中具有结晶状的梭状体,为肌动蛋白的一种贮藏形式。花粉萌发时,这种梭状体转移到短的花粉管中,逐渐松解、分支和形成肌动蛋白纤丝交错的网络。在花粉管迅速生长和达到一定长度时,肌动蛋白纤丝形成以与花粉管长轴平行的细丝占优势的网络系统,这是在大多数情况中紫萼花粉管典型的肌动蛋白纤丝的形式。在某些条件下,在花粉管接近顶端的前部,肌动蛋白纤丝可集合成长的粗束,这种粗束也常有分支和并合。肌动强白纤丝一直分布到花粉管的末端。讨论了研究肌动蛋白纤丝的非固定方法的重要性和进一步研究花粉管肌动蛋白纤丝值得注意的问题。