Tree invasions and biosecurity: eco-evolutionary dynamics of hitchhiking fungi

201

Insect gallers and their plant hosts : From omics data to systems biology

Gall-inducing insects are capable of exerting a high level of control over their hosts’ cellular machinery to the extent that the plant’s development,metabolism,chemistry,and physiology are all altered in favour of the insect. Many gallers are devastating pests in global agriculture and the limited understanding of their relationship with their hosts prevents the development of robust management strategies. Omics technologies are proving to be important tools in elucidating the mechanisms involved in the interaction as they facilitate analysis of plant hosts and insect effectors for which little or no prior knowledge exists. In this review,we examine the mechanisms behind insect gall development using evidence from omics-level approaches. The secretion of effector proteins and induced phytohormonal imbalances are highlighted as likely mechanisms involved in gall development. However,understanding how these components function within the system is far from complete and a number of questions need to be answered before this information can be used in the development of strategies to engineer or breed plants with enhanced resistance

Complex patterns of global spread in invasive insects: eco-evolutionary and management consequences

The advent of simple and affordable tools for molecular identification of novel insect invaders and assessment of population diversity has changed the face of invasion biology in recent years. The widespread application of these tools has brought with it an emerging understanding that patterns in biogeography, introduction history and subsequent movement and spread of many invasive alien insects are far more complex than previously thought. We reviewed the literature and found that for a number of invasive insects, there is strong and growing evidence that multiple introductions, complex global movement, and population admixture in the invaded range are commonplace. Additionally, historical paradigms related to species and strain identities and origins of common invaders are in many cases being challenged. This has major consequences for our understanding of basic biology and ecology of invasive insects and impacts quarantine, management and biocontrol programs. In addition, we found that founder effects rarely limit fitness in invasive insects and may benefit populations (by purging harmful alleles or increasing additive genetic variance). Also, while phenotypic plasticity appears important post-establishment, genetic diversity in invasive insects is often higher than expected and increases over time via multiple introductions. Further, connectivity among disjunct regions of global invasive ranges is generally far higher than expected and is often asymmetric, with some populations contributing disproportionately to global spread. We argue that the role of connectivity in driving the ecology and evolution of introduced species with multiple invasive ranges has been historically underestimated and that such species are often best understood in a global context

Internet access constrains science development and training at South African universities

The original publication is available at http://www.sajs.co.za/As a group of young scientists whose future careers depend increasingly on access to Internet resources, we are extremely concerned by the apparent lack of understanding of the stranglehold that current approaches to Internet pricing are placing on the development of science in South Africa.Lette

Prediction of the body weight of Nguni goats

(South African J of Animal Science, 2000, 30, Supplement 1: 127-128

Small science : view from developing nations

No abstracthttp://www.sciencemag.org/magazinehb201

The plant disease pyramid : the relevance of the original vision of plant pathology in 2020

In 1926, Professor Paul A. van der Bijl made an address to the South African Association for the Advancement of Science in his capacity as President of Section C of the Association, entitled ‘Landmarks in the development of the science of plant pathology and of disease control’.1 The talk itself marks a key moment in the development of plant pathology as a discipline in South Africa, as Van der Bijl had been appointed 5 years earlier as the first Professor of Plant Pathology and Mycology in South Africa, at Stellenbosch University. The field was just being established, not only in South Africa, but in many parts of the world, and its distinction from other disciplines was a matter of pride.http://www.sajs.co.zaam2021BiochemistryForestry and Agricultural Biotechnology Institute (FABI)GeneticsMicrobiology and Plant Patholog

Stedelike Afrikaanssprekende verbruikers se houding, voorkeur en selfgelding ten opsigte van Afrikaanse bemarkingskommunikasie (Afrikaans)

AFRIKAANS: Afrikaans, as een van 11 amptelike landstale, bevind homself in ’n unieke posisie as ’n belangrike bemarkingskommunikasietaal. Die assosiasie tussen Afrikaans en die apartheidsregering het die beeld van Afrikaans, oor jare, groot skade berokken. Afrikaanssprekendes is egter vir baie jare reeds die taalgroep met die grootste besteebare inkomste en ʼn teikengroep wat maklik bereikbaar is. Tog word Afrikaans dikwels nie ernstig deur die reklame-industrie opgeneem nie. Weinig is egter bekend oor wat Afrikaanssprekende verbruikers se houding teenoor bemarkingskommunikasie in Afrikaans is, of hulle dit hoegenaamd verkies en of hulle bereid is om daarvoor te vra. Die primêre navorsingsdoel van die studie was om stedelike Afrikaanssprekende verbruikers se houding, voorkeur en selfgelding ten opsigte van Afrikaanse bemarkingskommunikasie te bepaal en verder te ondersoek. Primêre data is met behulp van rekenaargesteunde telefoononderhoude ingesamel. Die teikenpopulasie was stedelike Afrikaanssprekende verbruikers in Suid-Afrika van 19 jaar en ouer. ’n Verteenwoordigende steekproef van 306 voltooide onderhoude is op ’n nie-ewekansige wyse met behulp van ʼn kwotasteekproef verkry. Die studie het bevind dat stedelike Afrikaanssprekende verbruikers ’n positiewe houding ten opsigte van Afrikaanse bemarkingskommunikasie het; dat hulle tot ’n baie groot mate ’n voorkeur vir Afrikaanse bemarkingskommunikasie bo Engelse bemarkingskommunikasie het, maar dat hulle tot ’n mindere mate bereid is om waarskynlik selfgeldend ten opsigte van Afrikaanse bemarkings-kommunikasie op te tree. Die resultate dui ook aan dat daar, met die uitsondering van verskillende ouderdomsgroepe, verskeie beduidende verskille in stedelike Afrikaanssprekende verbruikers se houding, voorkeur en selfgelding ten opsigte van Afrikaanse bemarkingskommunikasie voorkom, wat betref: demografiese profiel (inkomste, ras en geslag); Engelse taalvaardigheid; taalgroepidentiteit; die bemarkingskommunikasiemedium (kontakpersoneel, tasbare kommunikasie, reklame en verpakking); produkbetrokkenheid (ooreenkomstig die FCB-matriks); en produkte se posisie op die goedere-dienstekontinuum (suiwer diens, goedere-dienstekruising en suiwer produk). Onder meer toon die resultate dat vroulike respondente ’n positiewer houding het, ’n groter voorkeur het en meer waarskynlik selfgeldend sal optree ten opsigte van Afrikaanse bemarkingskommunikasie as manlike respondente. Die resultate toon ook dat, waar dienste en kontakpersoneel ter sprake is, stedelike Afrikaanssprekende verbruikers by uitstek Afrikaanse bemarkingskommunikasie verkies. Aspekte soos hierdie behoort in ag geneem te word wanneer ’n bemarkingskommunikasieplan, wat hierdie teikengroep insluit, ontwikkel word. Bemarkers en maatskappye wat daarin belangstel om met stedelike Afrikaanssprekende verbruikers ’n verhouding te bou, behoort ongetwyfeld die moeite te doen om met hierdie teikengroep in Afrikaans te kommunikeer. ENGLISH: Afrikaans, as one of the country’s 11 official languages, finds itself in a unique position as an important marketing communication language. The association between Afrikaans and the apartheid government, over years caused much damage to the image of Afrikaans. Afrikaans speakers, however, have for many years been the language group with the largest disposable income and are a target group that is easily reached. In spite of this, Afrikaans is frequently not being taken seriously by the advertising industry. Little is however known about the attitude of Afrikaans-speaking consumers towards marketing communication in Afrikaans, whether it is at all preferred by them and if they are prepared to ask for it. The primary research goal of the study was to determine and further investigate the attitude, preference and assertiveness of urban Afrikaans-speaking consumers in terms of Afrikaans marketing communication. Primary data was collected by means of computer-assisted telephone interviews. The target population was urban Afrikaans-speaking consumers in South Africa aged 19 years and older. A representative test sample of 306 completed interviews was obtained by means of a nonprobability quota sample. The study found that urban Afrikaans-speaking consumers have a positive attitude towards Afrikaans marketing communication; that they, to a very large extent, prefer Afrikaans marketing communication to English marketing communication, but that they are to a lesser extent prepared to likely act assertively with regards to Afrikaans marketing communication. The results further show that, with the exception of different age groups, various significant differences exist in urban Afrikaans-speaking consumers’ attitudes, preferences and assertiveness with regards to Afrikaans marketing communication concerning: demographic profile (income, race and gender); English language proficiency; language group identity; the marketing communication medium (contact personnel, tangible communication, advertising and packaging); product involvement (according to the FCB grid); and products’ position on the goods-services continuum (pure service, goods-services hybrid; pure tangible goods). Amongst other things, the results show that female respondents have a more positive attitude, a greater preference and are more likely to act assertively with regards to Afrikaans marketing communication than male respondents. The results also show that, especially where services and contact personnel are concerned, urban Afrikaans-speaking consumers prefer Afrikaans marketing communication. Aspects like these should be taken into consideration when a marketing communication plan, which includes this target group, is developed. Marketers and companies, who are interested in building a long-term relationship with urban Afrikaans-speaking consumers, should undoubtedly make the effort to communicate with this target group in Afrikaans.Thesis (PhD)--University of Pretoria, 2009.Communication ManagementPhDUnrestricte

Foliar fungi of the enigmatic desert plant Welwitschia mirabilis show little adaptation to their unique host plant

Foliar fungi, especially endophytic fungi, constitute an important part of the microbiome of plants. Yet little is known about the composition of these communities. In this study, we isolated fungi from leaf tissues of the desert plant Welwitschia mirabilis to determine the culturable diversity of the foliar fungal community. The isolated fungal taxa, which grouped into 17 distinct lineages, were identified by sequencing elongation factor 1 alpha, beta-tubulin 1, beta-tubulin 2 and the internal transcribed spacer region. The culturable community was mainly composed of cosmopolitan fungal genera despite the unique taxonomic position of the plant and its geographic isolation. To test for endemism in two of the common fungal genera, Alternaria and Aureobasidium, we built haplotype networks using a global data set. Even this broad data set showed little evidence for specialisation within this unique host or its geographical location. The data suggest that the culturable members of communities of leaf-associated fungi in habitats with little plant coverage, such as the Namib Desert, are mainly established by long-distance aerially distributed fungal inocula and few of these taxa co-evolve with the host within the habitat.Significance: The culturable members of fungal communities associated with an ecological and evolutionary isolated plant have not co-speciated with their hosts, but to a large extent are composed of globally distributed fungal species. Harsh environmental conditions and the geographic isolation of host plants seem to favour ubiquitous fungal species over more specialist fungal species