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

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

Biocontrol opportunities to study microevolution in invasive populations

No abstract available.http://www.cell.com/trends/ecology-evolution/homehb201

Maternal effects on tree phenotypes : considering the microbiome

The biotic and abiotic environmental experience of plants can influence the offspring without any changes in DNA sequence. These effects can modulate the development of the progeny and its interaction with micro-organisms. This interaction includes fungal endophytic communities which have significant effects on trees and their associated ecosystems. We highlight potential maternal mechanisms through which endophytes could influence the progeny. We argue that a better understanding of these interactions might help predict the response of trees to stress conditions and to enhance the efficiency of tree breeding programs.Tree Protection Co-operative Programme, Genome Research Institute at the University of Pretoria.http://www.journals.elsevier.com/trends-in-plant-science2016-09-26hb201

Perception and knowledge of the Sirex woodwasp and other forest pests in South Africa

1. Sirex noctilio is one of the most serious invasive pests of pine. In South Africa, there has been a national effort to control S. noctilio, including an awareness campaign to increase awareness of the pest amongst the local forestry community. 2. We considered the impacts that the arrival of the pest and the awareness campaign has had on perceptions and knowledge of S. noctilio, as well as other forestry pests, amongst members of the forestry community. 3. For the data collection, a survey questionnaire was developed and used in telephone interviews. 4. Results of the study showed that the Sirex awareness campaign had increased knowledge of forestry pests in general. However, basic knowledge regarding the identification and symptoms of specific pests, such as S. noctilio, was poor. This will negatively influence monitoring efficacy. 5. Traditional paper-based media and personal contact contributed most to enhanced awareness. Electronic media were less effective and improvement would require a more focused effort. It was of concern that private farmers and contractors, as well as non-European first language speakers, were less well informed about forestry pests. 6. Clearly, a fragmented landscape in terms of ownership and language, presents challenges for effective communication of forestry pest threats.Forestry South Africa (FSA), the Department of Water Affairs and Forestry, the University of Pretoria and the THRIP initiative of the Department of Trade and Industry (DTI), South Africa.http://onlinelibrary.wiley.comab201

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

Maternal effects should be considered in the establishment of forestry plantations

Breeding strategies for plants focus on the genetic influence on their phenotypes. However, the phenotype is not only the outcome of the genotype or the environmental conditions under which plants grow. It is important to also recognise that the maternal environment has a significant effect on the phenotype of the offspring. These maternal effects represent a transgenerational form of phenotypic plasticity, transmitted to the progeny without modifications in the DNA sequence. These can influence the development, disease and pest resistance, and fitness of the offspring and subsequent development of the mature plant. In this review, we define and synthesize current understanding of maternal effects in plant reproduction and discuss evidence for the role of these effects in plants and more specifically in trees utilised for plantation forestry. We highlight the implications of the maternal environment in the management of forestry seed orchards and discuss approaches to study maternal effects in order to enhance the productivity of forestry plantations.The University of Pretoria, members of the Tree Protection Co-operative Programme and the Genome Research Institute at the University of Pretoria. M. Vivas received a post-doctoral grant from the Claude Leon Foundation.http://www.elsevier.com/locate/foreco2021-03-15hj2020BiochemistryForestry and Agricultural Biotechnology Institute (FABI)GeneticsMicrobiology and Plant Patholog

Sirex woodwasp : a model for evolving management paradigms of invasive forest pests

The Sirex woodwasp, Sirex noctilio, and its fungal mutualist, Amylostereum areolatum, together constitute one of the most damaging invasive pests of pine. Despite a century of research and well-established management programs, control remains unpredictable and spread continues to new areas. Variable success in managing this pest has been influenced by complex invasion patterns, the multilayered nature of biological interactions, the varying local ecologies, and microevolutionary population processes in both the biocontrol organisms and in the wasps. Recent research findings are challenging the historical perspectives on methods to manage the Sirex woodwasp, calling for management programs to incorporate the variable local dynamics affecting this pest complex. In this regard, the Sirex woodwasp provides a superb model to illustrate the need for a different approach to develop efficient and sustainable management tools to deal with the growing and global nature of pest invasions in forests and plantations.http://www.annualreviews.org/loi/entohb2016Forestry and Agricultural Biotechnology Institute (FABI)GeneticsZoology and Entomolog

Endophyte isolations from Syzygium cordatum and a Eucalyptus clone (Myrtaceae) reveal new host and geographical reports for the Mycosphaerellaceae and Teratosphaeriaceae

Speci e s of Mycosphaerellaceae and Teratosphaeriaceae (Ascomycetes) cause important leaf, shoot and canker diseases globally on a broad range of hosts, including Eucalyptus and other Myrtaceae. Recently, species of the Mycosphaerellaceae and Teratosphaeriaceae have been isolated as asymptomatic endophytes. In this study, endophytic species of Mycosphaerellaceae and Teratosphaeriaceae were isolated from samples taken from healthy native Syzygium cordatum (Myrtaceae) and related non-native Eucalyptus grandis x E. camaldulensis (hybrid clone) growing in Mtubatuba, KwaZulu Natal, South Africa. Multi-locus sequence analysis (MLSA) using the Internal Transcribed Spacer (ITS) region, the partial Large Subunit (LSU; 28S nrDNA) of the nuclear ribosomal DNA operon and Translation Elongation Factor-1α (TEF-1α) genes were used to correctly identify the 22 resulting isolates. The isolates grouped in five clades representing Readeriella considenianae that was isolated only from the Eucalyptus hybrid clone, Mycosphaerella marksii and M. vietnamensis from S. cordatum and Pseudocercospora crystallina from both S. cordatum and the Eucalyptus hybrid clone. Interestingly, the serious canker pathogen T. zuluensis was isolated from Eucalyptus leaves, although it is known only from stem and branch cankers. Of the species found, R. considenianae and M. vietnamensis were found in South Africa for the first time, while M. marksii, M. vietnamensis and P. crystallina were shown to naturally infect native S. cordatum for the first time. Despite the limited number of trees sampled, the new host and distribution reports show that more intensive sampling, especially following an endophyte approach, will reveal more complete patterns of host preference and geographical distribution for these fungi.Thutuka Funding programme of the National Research Foundation (NRF), members of the Tree Protection Co-operative Programme (TPCP) and the Department of Science and Technology (DST)/NRF Centre of Excellence in Tree Health Biotechnology (CTHB), South Africa.http://link.springer.com/journal/13313hb201