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121.
Auxin imbalance was suggested as a key factor in phytoplasma symptom development. Furthermore, remission of the symptoms of phytoplasma‐infected shoots can be promoted by culturing them in vitro in high‐auxin‐containing media. Therefore, effect of spraying 1‐naphthaleneacetic acid (NAA) on infected periwinkle (Catharanthus roseus) with periwinkle leaf yellowing (PLY) phytoplasma was examined. 1‐Naphthaleneacetic acid stimulated symptom development in phytoplasma‐inoculated shoots. Accelerated symptom development was associated with early accumulation of phytoplasmas. Two PATHOGENESIS‐RELATED (PR) genes, CrPR1a and CrPR1b, were induced by PLY phytoplasma infection, and the induction was suppressed by NAA. Therefore, the accelerated symptom development may be due to the suppression effect of NAA on PR‐related defence. However, while NAA promoted symptom development on shoots inoculated with phytoplasma, more non‐symptomatic shoots containing no phytoplasma were observed, suggesting that NAA prevents phytoplasma colonisation in non‐symptomatic shoots. The expression of two genes encoding jasmonic acid (JA) biosynthesis key enzymes, lipoxygenase and allene oxide cyclase, was downregulated in non‐symptomatic shoots of infected plants, and remained downregulated after auxin treatment. Therefore, the auxin‐promoted resistance should be JA independent. Because auxin may promote symptom development of PLY phytoplasma‐infected periwinkles, it may not link to plant resistance to phytoplasma infection. 相似文献
122.
Sébastien Rioux Paquette Sandra M. Behncke Susan H. O’Brien Rick A. Brenneman Edward E. LouisJr. François-Joseph Lapointe 《Conservation Genetics》2007,8(4):797-807
The radiated tortoise (Geochelone radiata) is an endangered species endemic to Madagascar. It inhabits the semiarid spiny forest of the southern part of the island,
an ecosystem heavily affected by habitat destruction. Furthermore, illegal harvesting greatly threatens this species. The
main objective of our study was to acquire better knowledge of its genetic structure, in order to take appropriate management
decisions concerning, for instance, the reintroduction of confiscated individuals. Our hypothesis was that rivers represent
effective barriers to tortoise dispersal despite the fact that they are dry most of the year. We used 13 polymorphic microsatellite
markers to compare samples from six populations across the range of the species. All analyses (Fisher’s exact tests, F
ST values, AMOVA) indicated that the radiated tortoise exhibits moderate levels of genetic structure throughout its range. In
addition, we used a multiple regression approach that revealed the importance of rivers to explain the observed structure.
This analysis supported the role of the Menarandra and Manambovo Rivers as major barriers to the dispersal of most radiated
tortoises, but Markov chain Monte Carlo simulations revealed that low levels of recurrent gene flow may explain why F
ST values were not higher. We identified three distinct conservation units with relatively high assignments rates (87%), which
should be valuable for the management of the species. This is the first study to report the genetic structure of a species
sampled throughout the Malagasy spiny forest. 相似文献
123.
124.
Suk Weon Kim Sung Hee Ban Soon-Chun Jeong Hwa-Jee Chung Suk Min Ko Ook Joon Yoo Jang R. Liu 《Biotechnology and Bioprocess Engineering》2007,12(6):646-652
When whole cell extracts are subjected to proton nuclear magnetic resonance spectroscopy (1H NMR), metabolite profiles are generated that contain overlapping signals of the majority of compounds within the extract.
In order to determine whether pattern recognition based on the metabolite profiles of higher plants is able to genetically
discriminate between plants, we analyzed leaf samples of eight cultivars ofCatharanthus roseus by1H NMR. Hierarchical dendrograms, based on the principal component analysis of the1H NMR total, aliphatic carbohydrate and aromatic region data, revealed possible relationships between the cultivars. The dendrogram
based on the aromatic region data was in general agreement with the genetic relationships determined by conventional DNA fingerprinting
methods. Secologanin and polyphenols were assigned to the signals of the1H NMR spectra, and contributed most profoundly to the discrimination between cultivars. The overall results indicate that
the genetic relationships betweenC. roseus cultivars are reflected in the differences of the aromatic compounds in the leaves. 相似文献
125.
In this study we revise the taxonomy of the genus Prionopelta for the Malagasy region, treating seven species, six of which are newly described (Prionopelta
laurae
sp. n., Prionopelta
seychelles
sp. n., Prionopelta
subtilis
sp. n., Prionopelta
talos
sp. n., Prionopelta
vampira
sp. n., Prionopelta
xerosilva
sp. n.), and one redescribed (Prionopelta
descarpentriesi Santschi). One species, Prionopelta
seychelles, is restricted to Seychelles, while the six remaining species treated are endemic to Madagascar. 相似文献
126.
127.
The Afrotropical Cynipoidea are represented by 306 described species and 54 genera in four families: Cynipidae, Figitidae, Liopteridae and Ibaliidae, the latter represented by a single introduced species. Seven of these genera are only represented by undescribed species in the region. Seven new genus-level synonymies, one genus resurrected from synonymy, 54 new combinations, one combination reinstated, and one new replacement name are presented. We provide identification keys to the families, subfamilies and genera of cynipoid wasps occurring in the Afrotropical region (Africa south of the Sahara, including Madagascar and southern Arabian Peninsula). Online interactive Lucid Phoenix and Lucid matrix keys are available at: http://www.waspweb.org/Cynipoidea/Keys/index.htm. An overview of the biology and checklists of species for each genus are provided. This paper constitutes the first contributory chapter to the book on Afrotropical Hymenoptera. 相似文献
128.
In this study we provide an update to the taxonomy of the ant genus Tetramorium Mayr in Madagascar. We report the first record of the Tetramorium
setigerum species group in Madagascar and describe the only Malagasy representative as Tetramorium
cavernicola
sp. n., which is known only from a cave in Ankarana. In addition, we provide an overview of the 19 proposed Malagasy species groups, and discuss their zoogeography and relationships to other groups and larger lineages within the hyper-diverse genus Tetramorium. At present, we recognise a highly unique Malagasy Tetramorium fauna with 113 species endemic to the island of Madagascar out of a total of 125 translating into an endemism rate of 93%. We hypothesise that this fauna is based on one or a few colonisation events from the Afrotropical region, with subsequent adaptive radiation in Madagascar. Furthermore, we present an updated and illustrated identification key to the Tetramorium species groups in the Malagasy region. 相似文献
129.
Rasoloharijaona S Randrianambinina B Braune P Zimmermann E 《American journal of physical anthropology》2006,129(4):591-600
Dispersed pair-living primates provide a unique model for illuminating the evolution of mechanisms regulating spacing and cohesiveness in permanently cohesive groups. We present for the first time data on the spatiotemporal distribution and loud-calling behavior of the Milne Edwards' sportive lemur, known to forage solitarily during the night, but to form stable male-female sleeping groups during the day. Data include radio-tracking observations of sleeping associations, and focal follows of pair partners during dispersal in the evenings and reunions in the mornings. Male-female pairs forming stable sleeping associations during the day were pair-bonded. They used sleeping sites and home ranges exclusively, and exchanged loud calls at potentially restricted resources during dispersal in the evenings and during reunion in the mornings. Direct agonistic conflicts between pairs and others were rare. The acoustic analysis of loud calls revealed nine major call types. They carry signatures for sex and pair identity, and provide the substrate for signaling and the potential for recognizing pair ownership. Thus, pairs use loud call exchanges as a vocal display for signaling territory ownership, thus limiting direct aggressive encounters between neighbors and strangers. Altogether, our findings provide the first empirical evidence for the hypothesis that loud calling has evolved as a key mechanism for regulating space use and cohesiveness in dispersed pair-living primates. 相似文献
130.
A. B. R. Witt A. J. McConnachie W. A. Palmer E. Grobbelaar 《Biocontrol Science and Technology》2006,16(8):859-869
The biology and host range of a leaf-beetle, Rhembastus sp. (Coleoptera: Chrysomelidae: Eumolpinae) from Madagascar, was studied under quarantine laboratory conditions in South Africa to determine its potential as a biological control agent of Bryophyllum delagoense (Ecklon & Zeyher) Schinz (Crassulaceae) in Australia. Favourable attributes of the beetle include relative ease of culturing, multiple generations per year, and high levels of damage inflicted by adults, which feed on the plantlets produced at the end of each leaf, and root feeding larvae. The adults therefore have an impact on the reproductive potential of the plant and larval feeding on the roots hampers the uptake of water and may even facilitate secondary infections by pathogens. Despite indications from field surveys in Madagascar that Rhembastus sp. has a narrow host range, preliminary no-choice and multiple-choice trials in quarantine revealed that it could complete its development on five non-target species in the family Crassulaceae. Extensive host range trials still have to be undertaken in Australia before the beetle can be considered for release. 相似文献