Identifying pathogenicity genes in the rubber tree anthracnose fungus Colletotrichum gloeosporioides through random insertional mutagenesis

To gain more insight into the molecular mechanisms of Colletotrichum gloeosporioides pathogenesis, Agrobacterium tumefaciens-mediated transformation (ATMT) was used to identify mutants of C. gloeosporioides impaired in pathogenicity. An ATMT library of 4128 C. gloeosporioides transformants was generated. Transformants were screened for defects in pathogenicity with a detached copper brown leaf assay. 32 mutants showing reproducible pathogenicity defects were obtained. Southern blot analysis showed 60.4% of the transformants had single-site T-DNA integrations. 16 Genomic sequences flanking T-DNA were recovered from mutants by thermal asymmetric interlaced PCR, and were used to isolate the tagged genes from the genome sequence of wild-type C. gloeosporioides by Basic Local Alignment Search Tool searches against the local genome database of the wild-type C. gloeosporioides. One potential pathogenicity genes encoded calcium-translocating P-type ATPase. Six potential pathogenicity genes had no known homologs in filamentous fungi and were likely to be novel fungal virulence factors. Two putative genes encoded Glycosyltransferase family 28 domain-containing protein and Mov34/MPN/PAD-1 family protein, respectively. Five potential pathogenicity genes had putative function matched with putative protein of other Colletotrichum species. Two known C. gloeosporioides pathogenicity genes were also identified, the encoding Glomerella cingulata hard-surface induced protein and C. gloeosporioides regulatory subunit of protein kinase A gene involved in cAMP-dependent PKA signal transduction pathway.     

缅甸紫金牛属新记录

报道了缅甸克钦邦分布的报春花科(Primulaceae)紫金牛属(Ardisia Swtarz)的3 新记录种:伞形紫金牛(Ardisia corymbifera Mez)、珍珠伞(Ardisia maculosa Mez)和Ardisia interjacens C. M. Hu & J. E. Vidal。     

Development, characterization, genetic diversity and cross-species/genera transferability of ILP markers in rubber tree (Hevea brasiliensis)

To construct a linkage map enriched with tapping panel dryness (TPD)-related markers, we firstly utilized rubber tree ESTs associated with TPD to develop intron length polymorphism (ILP) markers. In this study, 52 new ILP markers were further developed. Together with the ILP markers previously reported, 102 ILP markers developed from TPD-related ESTs were analyzed within 39 Hevea germplasm in detail. The PCR success rate and polymorphism rate of ILP markers was 97.06 and 61.62 %, respectively. The results based on PCR amplification and sequence analyses provided the evidences on cross-species/genera transferability of rubber tree ILP markers. The average polymorphic information content (PIC) values of 39 Hevea germplasm were about 0.1719, indicating that the genetic base of Hevea germplasm selected in this study was very narrow. Among 39 Hevea germplasm, the PIC value of wild rubber tree accessions was the highest, followed by Hevea species and cultivated rubber tree clones. Based on the similarity coefficient of ILP markers, 39 Hevea germplasm were divided into three groups including cultivated clones, wild accessions and Hevea species, suggesting that the classification was generally related to the characterization of Hevea germplasm. The ILP markers developed in this study further enriches the number of molecular marker in rubber tree, and the ILP markers will have a wide application in DNA fingerprinting, genetic diversity, marker-assisted selection and genetic mapping, etc. Moreover, the ILP markers transferred cross-euphorbiaceae family might be utilized in cassava, castor bean and physic nut.     

植物源杀虫剂对槟榔红脉穗螟幼虫的致死效应

【背景】红脉穗螟是棕榈科植物的重要害虫,目前主要采用化学防治措施对其进行防控。【方法】采用药膜法和饲喂法研究了4种植物源杀虫剂对槟榔红脉穗螟幼虫的室内毒力。【结果】印楝素、烟碱、鱼藤酮和除虫菊素对红脉穗螟各龄幼虫均表现一定的杀虫活性。其中,采用药膜法处理后,除虫菊素和烟碱对槟榔红脉穗螟各龄幼虫的毒力最高,LC50分别为3.83~17.01 mg·L-1和3.75~24.78 mg·L-1,且其毒力随着幼虫龄期的增大而减弱。浸叶饲喂法结果表明,烟碱和鱼藤酮表现出较强的杀虫活性,LC50分别为7.72~20.69 mg·L-1和11.41~25.25 mg·L-1。【结论与意义】植物源杀虫剂不同处理方法对红脉穗螟的毒力存在差异,生产上应根据药剂的作用方式合理选择。     

Permanent Genetic Resources added to Molecular Ecology Resources Database 1 August 2012 – 30 September 2012

This article documents the addition of 83 microsatellite marker loci and 96 pairs of single‐nucleotide polymorphism (SNP) sequencing primers to the Molecular Ecology Resources Database. Loci were developed for the following species: Bembidion lampros, Inimicus japonicus, Lymnaea stagnalis, Panopea abbreviata, Pentadesma butyracea, Sycoscapter hirticola and Thanatephorus cucumeris (anamorph: Rhizoctonia solani). These loci were cross‐tested on the following species: Pentadesma grandifolia and Pentadesma reyndersii. This article also documents the addition of 96 sequencing primer pairs and 88 allele‐specific primers or probes for Plutella xylostella.     

A Miocene leaf fossil record of Rosa (R. fortuita n. sp.) from its modern diversity center in SW China

Roses (Rosa, Rosaceae) are arguably the most admired ornamental plants in the world. Southwestern China is the center of diversity for many extant native species of Rosa and fossils found in this region are critical for understanding the evolution of this genus. Herein, we report a leaf fossil record with good preservation from the late Miocene of Yunnan Province. The opposite and odd-pinnate leaf is composed of seven elliptical leaflets, with close, crenulate, and regular marginal teeth. The stipules are lanceolate and adnate to the petiole. Additionally, the secondary veins are semicraspedodromous, showing the same venation pattern as most living Rosa species in southwestern China. On the basis of the extensive morphological comparisons, we propose a new species, R. fortuita T. Su et Z.K. Zhou n. sp. This is the first confirmed Rosa leaf fossil record in China, and the discovery of R. fortuita n. sp. indicates that Rosa existed in southwestern China by the late Miocene. It suggests that Rosa was distributed in subtropical or temperate forests and shared a similar ecological niche as Rosa in Europe during the Oligocene and Miocene. The modern diversification of Rosa in southwestern China is thought to have been closely associated with the continuous uplift of the Qinghai-Tibet Plateau since the late Miocene, creating complex topography and a variety of climate conditions.     

Bacillus thuringiensis Crystal Protein Cry6Aa Triggers Caenorhabditis elegans Necrosis Pathway Mediated by Aspartic Protease (ASP-1)

Cell death plays an important role in host-pathogen interactions. Crystal proteins (toxins) are essential components of Bacillus thuringiensis (Bt) biological pesticides because of their specific toxicity against insects and nematodes. However, the mode of action by which crystal toxins to induce cell death is not completely understood. Here we show that crystal toxin triggers cell death by necrosis signaling pathway using crystal toxin Cry6Aa-Caenorhabditis elegans toxin-host interaction system, which involves an increase in concentrations of cytoplasmic calcium, lysosomal lyses, uptake of propidium iodide, and burst of death fluorescence. We find that a deficiency in the necrosis pathway confers tolerance to Cry6Aa toxin. Intriguingly, the necrosis pathway is specifically triggered by Cry6Aa, not by Cry5Ba, whose amino acid sequence is different from that of Cry6Aa. Furthermore, Cry6Aa-induced necrosis pathway requires aspartic protease (ASP-1). In addition, ASP-1 protects Cry6Aa from over-degradation in C. elegans. This is the first demonstration that deficiency in necrosis pathway confers tolerance to Bt crystal protein, and that Cry6A triggers necrosis represents a newly added necrosis paradigm in the C. elegans. Understanding this model could lead to new strategies for nematode control.     

Honey Bee Inhibitory Signaling Is Tuned to Threat Severity and Can Act as a Colony Alarm Signal

Alarm communication is a key adaptation that helps social groups resist predation and rally defenses. In Asia, the world’s largest hornet, Vespa mandarinia, and the smaller hornet, Vespa velutina, prey upon foragers and nests of the Asian honey bee, Apis cerana. We attacked foragers and colony nest entrances with these predators and provide the first evidence, in social insects, of an alarm signal that encodes graded danger and attack context. We show that, like Apis mellifera, A. cerana possesses a vibrational “stop signal,” which can be triggered by predator attacks upon foragers and inhibits waggle dancing. Large hornet attacks were more dangerous and resulted in higher bee mortality. Per attack at the colony level, large hornets elicited more stop signals than small hornets. Unexpectedly, stop signals elicited by large hornets (SS _{large hornet}) had a significantly higher vibrational fundamental frequency than those elicited by small hornets (SS _{small hornet}) and were more effective at inhibiting waggle dancing. Stop signals resulting from attacks upon the nest entrance (SS _nest) were produced by foragers and guards and were significantly longer in pulse duration than stop signals elicited by attacks upon foragers (SS _forager). Unlike SS _forager, SS _nest were targeted at dancing and non-dancing foragers and had the common effect, tuned to hornet threat level, of inhibiting bee departures from the safe interior of the nest. Meanwhile, nest defenders were triggered by the bee alarm pheromone and live hornet presence to heat-ball the hornet. In A. cerana, sophisticated recruitment communication that encodes food location, the waggle dance, is therefore matched with an inhibitory/alarm signal that encodes information about the context of danger and its threat level.     

液体植物保护膜防治瓜实蝇的效果评价

【背景】瓜实蝇是一种重要的世界性检疫害虫,广泛分布在我国的热带、亚热带地区。在室内和田间测定了液体植物保护膜对瓜实蝇的控制效能,并初步探索了该保护膜的作用方式,以期为瓜实蝇的绿色防控提供一定的技术支撑。【方法】测定了应用保护膜后瓜实蝇的产卵、存活以及对苦瓜的为害率。【结果】保护膜显著影响了瓜实蝇产卵、存活以及选择性。随着保护膜浓度的升高,瓜实蝇的存活率和在供试苦瓜段上的产卵量逐渐下降,但300和400倍保护膜之间的差异不显著。当浓度达到400倍时产卵量最低,为0.33粒,死亡率最高,约为50%;室内研究发现保护膜可持续影响瓜实蝇产卵5 d;此外,通过将保护膜应用在损伤的苦瓜上,发现保护膜并没有抑制瓜实蝇产卵。在田间,研究发现苦瓜的果长影响了保护膜的应用效能,2种果长的苦瓜应用保护膜后12~14 cm苦瓜的被害率显著低于6~8 cm苦瓜的被害率。【结论与意义】400倍的植物液体保护膜是防治瓜实蝇的最佳浓度,应用时间建议每4 d一次。保护膜最合适的应用时期为果长发育至12~14 cm时,即生长后期。施用保护膜时一定均匀,且在寄主果实受到损伤时不宜喷施保护膜。