Influence of feeding silkmoth (Bombyx mori L.) hybrid larvae with leaves of old local Hungarian and Slovenian mulberry (Morus alba L.) genotypes on the development and health status of larvae
Project number: N1-0041
Duration: 1. 1. 2016 – 31. 12. 2018
Project leaders:
Hungarian partner: dr. Rebeka Lucijana Berčič
Slovenian partner: dr. Andreja Urbanek Krajnc
Lead research agencies:
University of Maribor, Faculty of Agriculture and Life Sciences
University of Veterinary Medicine Budapest
Project is financed by:
Nemzeti kutatási fejlesztési és innovációs hivatal, NKFIH (lead agency)
Javna agencija za raziskovalno dejavnost Republike Slovenije, ARRS
Summary
Silk is a nature’s gift to mankind produced by silkworms, which secrete this natural fibre for the protection of pupae in the process of completing their life cycle. Among silkworm the most commercially exploited one is the mulberry silkworm Bombyx mori L. The larvae are monophagous and feed only on mulberry (Morus spp. L., Moraceae). More than 68 species of Morus have been recognized, of which the white mulberry (Morus alba) is preferentially grown to feed the caterpillars. It has been domesticated over thousands of years and adapted to the wide area of tropical, subtropical, and temperate zones including Asia, Europe, the Americas, and Africa. The classification of mulberries is very difficult and unreliable when based solely on morpho-phenological traits due to their naturalization and adaptation to areas far away from their origin. Mulberry bears different sex types, is monoecious or dioecious, with sex expression varying among species and varieties due to their cross fertilization. The biodiversity of wild populations and the genetic structure of different mulberry cultivars have been studied extensively in Asia. The molecular characterization revealed a wide variation in genetic distance among different genotypes.
In a number of European countries, mulberry trees became over centuries an integral part of the landscaping bearing witness to the sericulture past activity. Since the Hungarian and Slovenian cultural landscape, particularly in the period after the 2th World War, did not changed radically, both countries retain a number of centuries-old mulberry varieties, which are outstanding for the natural heritage bearing the former Austro-Hungarian Monarchy’s socio-economic and political history. The old varieties are further a valuable genetic resource best adapted to specific climate conditions, which can significantly contribute to the sustainable mulberry cultivation to meet the increasing demand of the silk industry. To our knowledge, the information on the number of remaining old mulberry varieties belonging to the genus M. alba and M. nigra in Hungary and Slovenia is incomplete and the genetic structure has not been studied, as yet. Therefore, the Slovenian part of proposed project main research priorities are sampling, molecular characterization, conservation and propagation of old local mulberry genotypes from different eco-geographic regions of Hungary and Slovenia, which coincided with the sericulture industry in the past. Among major types of molecular markers, amplified fragment length polymorphism (AFLP) and simple sequence repeats (SSR), have the most resolving potential and will be used to study the genetic diversity of mulberries.
In the last 5,000 years of selective breeding for larger cocoons and better silk, the silkmoth. became completely dependent on humans for feeding and reproduction. Additionally, the larva of B. mori became vulnerable to many environmental factors and prone for various types of diseases, especially in connection to quality of silkworm’s food. After establishing a collection of old local Hungarian and Slovenian mulberry trees and describing their phylogeny, one of the main objectives of the proposed project will be to screen biochemical content of important primary (sugars, proteins and amino acids) and secondary metabolites (phenolics, ascorbate, glutathione) in leaves of local mulberry varieties and, as a Hungarian part of a project, to test their relevance on development and health status of larvae. The quantitative analysis of bacterial loads in clinically healthy and diseased insects with special emphasize on possible infection with mycoplasma will be done first. Development of model systems using B. mori and their specific bacteria would help us to investigate the effects of basic environmental factors (temperature, humidity, feed) on bacteria multiplication, and on the expression of certain, innate immunity related genes. In addition, the possible effects of neuraminidase of specific bacteria on various silkworm tissues will be tested in the aforementioned model systems.
In the end of the project the nutritively richer and for the silkworm’s health status more suitable varieties of local mulberry trees will be taken and propagated as highly recommendable feed for silkworm to increase their silk productivity. The results of the proposed project may be of great benefit for re-establishing sustainable organic sericulture in Central Europe.
Problem, hypothesis questions
Bacterial diseases significantly influence the efficacy of silkworm rearing and silk production, but several aspects of bacterial infections (i.e. species compositions) and bacterial diseases of silkworm (i.e. impact of bacterial neuraminidase activity) are not fully characterised yet. Nutrition plays a significant role in the vitality and immune-reactivity of silkworm in general; however, little is known about the effects of feed quality on the resistance to bacterial diseases. Our hypothesis is that feeding silkmoth hybrid larvae with nutritively richer leaves of selected, old local Hungarian and Slovenian mulberry genotypes has a positive effect on development, general health status of larvae, immune reactivity and silk production. The old varieties of mulberry are valuable genetic resources best adapted to specific climate conditions with significant qualitative and quantitative composition of important metabolites, but information on the number of remaining old mulberry varieties in Hungary and Slovenia, and the taxonomic classification at the species and subspecies level is unreliable and incomplete. The cooperative research could answer the questions whether the old, local mulberry varieties differ in their primary and secondary metabolite content, and whether these differences has detectable, significant effect on larval development, silk rope production, and resistance of B. mori to bacterial diseases. The studies could also provide answers, whether neuraminidase activity of bacteria involved in the Flacherie disease of silkworm has impact on the development of clinical signs and pathological lesions.
The aims of the project
1: Qualitative and quantitative analysis of bacterial infections and loads in clinically healthy and diseased silkworm. Special emphasize will be put on detection of mycoplasmas.
2: Determination of neuraminidase activity of pathogenic bacteria isolated from B. mori.
3: Development of a model system using B. mori and their specific bacteria to investigate the effects of feed on bacterial multiplication, development of clinical signs and expression of immunity related genes.
4: Collection data regarding locations of mulberry plants and creation of digital map and digital library.
5: Propagation and conservation of old local mulberry genotypes from different eco-geographic regions of Hungary and Slovenia, which coincided with the sericulture industry in the past.
6: Molecular analyses (AFLP, SSR) to identify genetic variation of available local Hungarian and Slovenian mulberry genotypes.
7: Qualitative and quantitative screening of important primary (sugars, proteins and amino acids) and secondary metabolites (phenolics, ascorbate, glutathione) in leaves of different local mulberry varieties in different developmental stages to test their relevance on development (nutrient digestion, growth, survival rate of young larvae, silk synthesis activity, cocoon yield and filament quality) and health status (resistance against specific pathogens, improved innate immunity) of larvae.
Realization of project’s tasks
According to the project’s aims, the following activities have been implemented:
T1 Recording and sampling of local mulberry varieties:
The geographical locations of old mulberry trees have been identified in Hungary as well as in Slovenia and digital distribution maps were created, which are available on http://murve.um.si/en/maps/. In Slovenia we recorded locations of 645 mainly historical mulberry trees (>180 cm). The highest density of trees was recorded in Coastal-Karst and Gorizia region, followed by Prekmurje and Southeast Slovenian region.
The hughest Slovenian white mulberry tree and, at the same time, the widest fruit tree is the historical mulberry at the Fabiani homestead in Kobdilj. It has more than 710 cm of circumference. There are some beautiful mulberry avenues in Lokev, next to Školj Castle at the Famlje village and near the monastery on Krog, not far from the village of Sečovlje.
In Hungary, there are many avenues preserved along Pannonian villages and cemeteries, as well as plantations of the kolkhoz era. We sampled most of the historical mulberry trees in the former sericultural counties Csongrád (226), Bács-Kiskun (206), Somogy (180), Baranya (169), Veszprém (200), Zala (146), Hajdú-Bihar (128), Győr-Moson-Sopron (120), Szabolcs-Szatmár-Bereg (97), Tolna (83). The widest tree was sampled in Tolna couty (561 cm, Paks, Városi Múzeum)
fabijani
Former sericultural regions retained a number of centuries-old mulberry trees, which represent both, a valuable natural heritage and outstanding monuments of the very early attempts of industrial societies in Europe, mainly reflecting the socio-economic and political history of the former Austro-Hungarian Monarchy.
zemljevid
Morphological leaf analyzes have shown that yearly pruned trees form leaves of larger dimensions, and that pruning also increases the tendency towards heterophylly. By applying the multivariate analysis PCA, two morphotypes were confirmed in the Goriška region.
The results were presented in scientific article: »Morphometric and Biochemical Screening of Old Mulberry Trees (Morus alba L.) in the Former Sericulture Region of Slovenia”, Acta Societalis Botanicorum Poloniae, Vol.1, 2019 (DOI is: 10.5586/asbp.3614).
The monograph written by Sfiligoj-Smole et al. 2019: »Surface properties of non-conventional cellulose fibres« published by Springer (22157590) reviews the potential use of mulberry as a source of bast fibers and its use in the textile and paper industry as well as for new technical applications.
The diploma thesis Korez J. (4231724) presents the morphological characteristics of the mulberries from Vipava region. The results were presented at two international symposiums [4476460, 4427564] and within the society’s lectures (Botanical Society of Slovenia, 4376876, Naturwissenschaftliches Verein fuer Steiermark, 4398892).
T2 Vegetative propagation and conservation of mulberries:
Approximately 2000 plantlets were obtained by vegetative propagation comprising Hungarian and Slovenian historical mulberries. Mulberry gene bank (Moretum) was established at the Faculty of Agriculture and Life Sciences, University of Maribor (lat. 46.508459, long. 15.622440). The collection is divided into three parts: First part contains old high yielded mulberry varieties (8 varieties, N=80) brought from Sericultural Institute in Padua, Italy. In sericulture most commonly, used varieties are ‘Morettiana’ (origins from India) and ‘Kokusou’ (origins from Japan), ‘Florio’ and ‘Giazzola’.
Second part is collection of old local Hungarian (N=250) and Slovenian mulberry varieties (N=145). Rooting of cuttings took place in nursery, however cuttings were planted in the collection when they reach about 70 cm height. The collection is still in establishment.
Third part of collection contains mulberry varieties for fruit production. Until now 19 fruit trees were planted by obtaining the grafting material from different European gene banks and collectors. They are mostly crossbreeds between white and red mulberries (Morus alba × M. rubra) from different origin (Romania, Ukraine, Bulgaria, France, Austria). In the collection there also two black mulberry trees (Morus nigra) derived from historical trees, one originates from eastern Austrian Styria and the other from Albania (village Boboshtice, mother plants are believed to be 1000 years old but probably between 400-500 years).
The collection will be used for screening of the metabolites with respect to the seasonal variation, pruning and production techniques and used for the feeding experiments on silk worms. Several trees were also identified as suitable for silk worm feed as they are characterized by large leaves and superior composition of metabolites.
T3 Molecular characterization of local mulberry genotypes:
The genetic diversity of selected mulberry specimen was tested with genomic DNA simple sequence repeat (SSR) analysis. The genetic characterization has been found sophisticated, mainly due to the different ploidy levels, sexual dimorphism, distribution in the past and natural genetic recombination among trees of different origins. Considering the traditional varieties, the clustering method grouped the genotypes into 7 main clusters. The relatively high level of polymorphism reflects that in the past mulberries were mainly propagated generatively, and that they were distributed throughout the Austro-Hungarian countries. The study enabled us to reconstruct the origin and spread of mulberries among the silkworm rearers in the past.
M. alba, M. nigra
T4 Biochemical analyses of the main metabolites in leaves:
During the field excursions, we collected the representative samples of leaves of old mulberry genotypes for analysis of total proteins, amino acids, total and individual phenols and thiols.
Mulberry leaves were characterized by a high content of proteins and amino acids, which are an important factor of the quality of feed. In some genotypes, protein content exceeded 20 g / 100 mg DW. We have found that high protein contents have a beneficial effect on the growth of larvae, the size and mass of cocoons. Pruning has a positive effect on the protein concentration. The highest protein content was determined in the yearly pruned trees of the SE Slovenian region and in Hungary within genotypes of the Csongrád county.
Free amino acids are dominated by threonine, arginine, asparagine, serine and glutamine, which have are known to have an antibacterial activity and are important for the growth and development of silkworms. Yearly pruned trees have higher asparagine, alanine and serine contents compared to unpruned trees.
The average content of total phenols (tPH) in Slovenian genotypes ranged from 1.0 to 1.7 g / 100 g SS. Pruning has a statistically significant negative effect on the tPH content. The highest content of tPH was determined in the SE and central region trees. The individual phenolic compounds were precisely determined by HPLC-MS. The main phenolic compounds were identified as caffeoylquininic acid derivatives, quercetin malonyl-hexoside, rutin, kaempferol acetyl-hexoside, quercetin-3-glucoside and p-coumaric acid derivatives. Multivariate analyzes of biochemical parameters have proved to be supportive in the geographical distribution of samples and the characterization of certain chemotypes in terms of the individual amino acids and phenols.
All genotypes included in these morphometric and biochemical analysis are part of a broader study aimed at defining high yielding and nutritive richer mulberry trees from the local gene pool, which are selected and propagated as highly recommendable feed for silkworms.
Summary of the research project
The joint Hungarian-Slovenian project was based on the evaluation of the existing genetic resources of historical mulberries in Slovenia and Hungary, collection establishment, identification of important metabolites in leaves (SI priorities) and testing their relevance on the development and health of silkworms( HU priorities).
White mulberry (Morus alba L.) was brought to Europe from SE Asia, not later than in the 12th century in order to establish a sustainable European sericulture. The determination of domesticated mulberries and their wild relatives based on morphological traits is difficult, especially due to the tendency towards heterophylly and the variations in fruit colour. During the field research, we recorded 645 locations of historical trees in Slovenia and 1498 locations in Hungary. The widest mulberry (circumference 710 cm) is located at Fabiani’s homestead in Kobdilj, and in Hungary in Tolna county (Paks, 561 cm). The highest density of individuals was recorded in the submediterranean region, whereas in Hungary in the former sericultural counties Czongrad and Bacs-Kiskun. We have established a herbarium collection, database and distribution maps that are accessible on the website. Pruning recordings revealed that base cutting is traditionally practiced in SM region. It has a positive effect on the leaf size and increases the tendency towards heterophylly. The multivariate analysis revealed two divided leaf morphotypes.
We established a collection of local historical trees, by including old sericultural and new fruit varieties. The genetic variability was evaluated by analysing morphological traits and, at the molecular level, by using microsatellite markers. The genetic characterization has been found sophisticated, mainly due to the different ploidy levels, sexual dimorphism, distribution in the past and natural genetic recombination among trees of different origins. Considering the traditional varieties, the clustering method grouped the genotypes into 7 main clusters. The relatively high level of polymorphism reflects that in the past mulberries were mainly propagated generatively, and that they were distributed throughout the Austro-Hungarian countries. The study enabled us to reconstruct the origin and spread of mulberries among the silkworm rearers in the past.
By reviewing the metabolites, we confirmed that pruning has a significant effect on the protein and amino acid contents, while it has a negative effect on phenolics. The multivariate analyses enabled us to define 7 distinct chemotypes, which are crucial for selection and propagation of superior varieties.
By reviewing the existing genetic resources and collection establishment, we highlighted the natural, cultural and scientific value of the white mulberry. The project underlines the necessity of preserving the historical remains of sericulture, particularly mulberries in the context of genetic erosion, which represents a general tendency among cultivated plants.
Significance of scientific development
The joint sericultural history of both countries justifies the need for multidisciplinary basic research covering the inventory of the mulberry genetic resources as well as the involvement of veterinary microbiology in the silkworm production with the aim to re-establish sericulture. Determination of mulberries based on morphological traits is difficult, especially due to the tendency towards heterophylly. In the project, multivariate analyzes of morphological traits have proved to be supportive in defining certain morphotypes. The results were published in scientific paper and on symposiums. In the previous year, the Italian scientists (La Bianco and Mirabella 2018, doi: 10.3390) published the first such morphological study on sericultural varieties in Italy by using a multivariate analysis.
The use of SSR has demonstrated a high degree of genetic variability (C3), which is influenced by the historical distribution and the natural recombination between trees. The current state of genetic characterization of mulberries in the world is relatively modest. Most studies use a combination of RAPD, ISSR and ITS markers for defining the genetic variability of mulberries and originate from Asian research groups. The confusion over the classification of Morus into species and on lower taxonomic levels remains a major bottleneck. From more than 60 Morus species that were recognized in the past, molecular analyses now enabled to redefine the taxonomy of Morus into eight species: four Asian (M. alba, M. serrata, M. nigra, M. notabilis), three American (M. celtidifolia, M. insignis, M. rubra), and one African species (M. mesozygia) (Zeng et al. 2015, doi: 10.1371/journal.pone.0135411).
The most important field gene collection in Europe is located at the Institute for Sericulture (CRA-API), Padua, Italy, with which we closely collaborate. So far, they carried out molecular studies of most common sericultural varieties by using RAPD and APLP, which did not prove to be sufficiently supportive. In the presented project, the selection of SSR markers was based on previously developed SRRs by Mathithumilan et al. 2013 (http://www.biomedcentral.com/1471-2229/13/194). In this comprehensive study over hundred M. alba specific SSR markers have been generated that have proved to be supportive on lower taxonomic levels.
Compared to other horticultural plants, where great progress is made in the cultivation of new varieties using genetic knowledge, research on mulberries on a worldwide scale is insufficient. The approaches of omics, molecular breeding, plant tissue cultures and genetic engineering techniques that are used to genetically improve mulberries were currently reviewed by Sarkar et al. 2017 (Biotech, DOI 10.1007 / s13205-017-0829-z), but they are far from being realized.
Furthermore, relatively few studies address the characteristics of mulberries regarding important metabolites and this results in deficient selection criteria. It has been previously confirmed that high protein content in leaves has a direct impact on the growth of larvae and cocoon production. With the help of multivariate analyzes of single amino acids and phenolics, we were able to define 7 chemotypes as well certain superior genotypes. The qualitative and quantitative composition of phenolics in the mulberry leaves varies among authors, due to the deficiency of the analytical methods. Until now, the identification of phenolics in mulberry leaves with UPLC-MS has been the subject of only two recent studies (Ju et al., 2017, 2018; https://doi.org/10.5338/KJEA.2017.36.4.39, https://doi.org/10.1007/s13197-018-3093-2).
The sharing of mulberry germplasm information and utilization of genetic resources at global level is hitherto running at slow pace due to non-coherence on the level of national strategies. There is an urgent need to establish the International Networking on Mulberry Germplasm Management and Utilization at global level (http://www.fao.org/3/AD107E/ad107e0o.htm).
Significance for Slovenia
First attempts to promote sericulture and the cultivation of mulberry trees (moriculture) in Slovenia date back to the 16th century. Following economic reasons, the 18th century was known as the “golden age” of Gorizian sericulture. Despite the tradition of hundreds of years, the silk production in Europe was decreasing and became irrelevant at the middle of the 20th century because of the introduction of artificial silk (http://murve.um.si/sl/zgodovina/).
By reviewing the existing genetic resources (C1), the importance of the project in terms of preserving the natural and cultural heritage associated with sericulture was underlined. We have demonstrated a high degree of genetic variability (C3), which is mainly influenced by various historical factors associated with the distribution of varieties and natural genetic recombination among trees of different origins. We found that white mulberry is subjected to dramatic genetic erosion due to the abandonment of sericulture and farmlands, reconstruction of agroecosystems, and associated reforestation of agricultural landscapes as well as abandonment of certain cultural monuments (the town of Školj, Dragatuš, Benedictine monastery Krog). The establishment of a mulberry collection (C2) is important in terms of conserving local genetic resources and for reintegration of moriculture and sericulture in Slovenia and Hungary.
Sample expeditions and online applications (http://murve.um.si/sl/prijav-murvo/) enabled us to establish a direct contact with owners of historical mulberries for ongoing cooperation. Historical mulberries were tested for the silk production with the European genetic lines of silkworms that were used in the past (obtained during the intensive collaboration with the Sericultural Institute CRA-API in Padua). Furthermore, we performed a pilot experiment by distributing a small number of silkworms in the 2nd larval stage to the interested owners of historical mulberries in SI (Fabiani’s mulberry, Školj, Kobjeglava, Krog, Goričko, Ptujsko polje, Litija) and HU (Pest, Vezsprém, Tolna). By analysing the cocoons and silk rope, we confirmed the ability to produce silk of the highest quality based on the existing genetic sources of mulberries. In the light of the local interest and the increased demand of European silk, a private research institute (non-profit institution, Institute of Sericulture and Silk Processing) was established in 2018 aimed at disassembling the sericulture, providing healthy genetic source of silkworms and mulberries and establishing a link between rearers and silk processors.
We donated a few trees to local communities, in order to raise awareness of the natural and cultural heritage associated with sericulture. So far, we have organized several professional guides and a sericultural consultation. The project has been disseminated by professional articles, interviews, radio and television articles, lectures and symposia.
Screening of the metabolites in leaves (A4) enabled us to define superior genotypes from the point of view of important amino acids and phenols. The nutritive composition of leaves already demonstrates potential as a feed additive in animal nutrition, especially for pigs, sheeps and poultry (Latin America, Thailand, India, Spain). Mulberry also demonstrates the potential for intensive forage production in form of silvopastural systems, alley crops, live fences, and fodder banks. Research on the effect of pruning is also crucial from the point of view of the introduction of new cultivation forms, smaller planting distances, which are among the first measures that would significantly increase the hectare yields of mulberries.
All parts of mulberries have been recognized for the human pharmacological potential since 700 A.D. (Chinese medicine, Pliny, Hildegard of Bingen) and have been the subject of numerous studies over the last decade. Antioxidative, neuroprotective, immune-stimulatory, anti-glycaemic and anti-cancerous effects of all parts have been proven. Mulberry leaves and fruits are today recognized as supernutrients. The leaves are used to prepare tea, spirits. Modern varieties give the potential of fruit processing (jam, liqueur, brandy, vinegar, dried fruits). Fruits of dark genotypes which have a strong staining activity are used as dyes in food and textile industries, white genotypes as sweetener.
The wood is very solid and durable. It can be used in civil engineering, casks making and joinery. Due to its acoustic properties, it is appreciated material for producing musical instruments. Bark fibres were traditionally used for paper production (native Americans since 300 BC, Chinese) and textiles. The recognized good physical properties of cellulose fibres open up the possibility to use mulberry braches as by-/waste product of sericulture as inexpensive source of natural fibres as well for advanced technical applications. The first attempts to use mulberry bark for textile fibre in Italy trace back to 19. century. Today, a small plant in Porcia di Pordenone, is preparing fibre out of mulberry bark called gelsofil (Sfiligoj-Smole et al. 2019, 22157590).
Within the framework of the established collection, the project “Taking a Creative Path Towards Knowledge” was carried out usage analysis of local products with high added value from different mulberry parts. Students from different study programs FALS and FNM UM participated in the project, which was presented at the event “Meeting New Challenges “.
The project has opened up permanent possibilities for using mulberries and for re-integration of sericulture. We have established cooperation with experts from Italy, Hungary, Austria and Croatia.
The project’s objectives are in line with the European Common Agricultural Policy and the European 2020 Strategy, which emphasizes the importance of smart, sustainable economic growth, and supports the sustainable social-market economy. It also seeks to pursue the objectives of the Rural Development Program aimed in promoting small and family farms, innovative agricultural technologies and social inclusion as well as preservation of rural areas in the direction of sustainable agriculture. The widespread use of mulberries demonstrates the need for further agronomic research and the development of conditions for the restoration of moriculture and associated sericulture in Slovenia. The purpose is to incorporate the mulberry collection into the Plant Gene Bank National Programme (SRGB). FALS already participates in this programme with the genera Prunus, Vitis, Rubus.
The project also represents an important contribution to the conservation of plant genetic resources on farms, which coincides with the objectives of the International Treaty on Plant Genetic Resources for Food and Agriculture (FAO).
The long-term goal is to re-establish the entire silk rearing and processing operations in Slovenia and to create silk products with high added value by the development of a trademark with protected geographical origin. With the priority goals of the project, we have already re-introduced the knowledge of sericulture and contributed significantly to the preservation of the old genetic resources of mulberries and silkworms, thus establishing new possibilities for a modern and sustainably European sericulture.
Significance of veterinary researches
The pathogenesis of bacterial diseases of higher vertebrates (mammalians and birds) is in the focus of veterinary and medical microbiology research. However, much less is known about bacterial infections and diseases of insects, the host’s defence mechanisms, and the effects of environmental factors on the vitality of insects and their resistance to bacterial infections. The most significant scientific outcome of the proposed research could be that it may provide new data on certain aspects of the pathogenesis of bacterial infections (i.e. the role of neuraminidase activity) in Bombyx mori model, and could reveal details of the effects of nutrition, particularly primary and secondary metabolite content, on the development, immunity and antibacterial resistance of the silkworm. The results could be compared with the findings in vertebrates, and general conclusions could be drawn, which may open further perspectives in the research of host-pathogen-environment interfaces.
Silk production is a significant part of the economy in some Far-Eastern countries (China and India). Nowadays intensive, industrial methods are used with severe environmental abuse and application of chemical treatments (antibiotics, pesticides) or genetically modified silkworms. Due to the increasing problems connected to intensive rearing technologies, and the changes in the social structure (urbanisation), the silk production is stagnating or decreasing in several regions of China, while the demand on silk at international markets is increasing. In Central Europe silk production has a history of hundreds of years, but it became extinct in the second half of the XXth century. The results of the proposed research may provide scientific basis on the revival of sustainable, ecological silk production in Central Europe. Establishment and characterisation of old, local mulberry trees in Hungary and Slovenia would also contribute to the conservation of genetic diversity of this species in the cooperating countries. Re-introduction of silkworm rearing and raw silk production could provide additional income to several families, and diversify the agricultural productivity of the countries.
For public
The natural silk is produced by the larva of the silkmoth, the silkworm. Millions of silkworms are reared to supply the demands on silkrope world-wide. Infectious diseases damage silkworms and threaten silk production. Bacteria are important infectious agents causing certain diseases of silkworms; however scientific data on several details of bacterial infections and diseases of this insect host is not available yet. Silkworms are eating the leaves of the white mulberry. Mulberry trees are very diverse and they also differ in the nutritive contents of leaves. The quality of the leaves influences the development, immunological reactions and anti-bacterial defence mechanisms of silkworms. The proposed research project aims to discover the diversity of bacteria involved in certain diseases of silkworms, and would like to describe details of the development of disease signs and lesions. In Hungary and in Slovenia silkworms had been were reared for hundreds of years, but the activity was stopped several decades ago. However, many of the old, local mulberry trees are still available in the countries. Another aim of the research is to find and maintain these trees and investigate the nutritive contents of their leaves. Silkworms would be experimentally infected with bacteria and fed with leaves of different mulberries to see the effect on the development of larvae and resistance against bacteria. The results of the studies may provide new data on the development of bacterial diseases of the silkworm, and characterisation of the nutritive values and effects of the leaves of local mulberry varieties could be useful if silkworm rearing would be re-introduced in Central Europe.
Project members:
Hungarian partner
Project leader: dr. Rebeka Berčič
Department of Microbiology and Infectious Diseases
University of Veterinary Medicine Budapest
Hungária krt. 23-25., 1147 Budapest, Hungary
bercic.rebeka.lucijana@aotk.szie.hu
Research field: Biotechnical sciences, animal production and processing
dr. Tamás Bakonyi
tamas.bakonyi@vetmeduni.ac.at
Research field: Biotechnical sciences, animal production and processing
Slovenian partner
Project leader: dr. Andreja Urbanek Kranjc
Chair of Botany and Plant Physiology
Faculty of Agriculture and Life Sciences
University of Maribor
Pivola 10, 2311 Hoče, Slovenia
andreja.urbanek@um.si
Research field: Biology, plant physiology
Researchers
dr. Vesna Bukovac
vesna.bukovac@um.si
Research field: Chemistry, Analitical chemistry
Mateja Felicijan, mag. kmet.
mateja.felicijan@um.si
Research field: Biology, botany
dr. Mario Lešnik
mario.lesnik@um.si
Research field: Plant production and processing, phytomedicine
dr. Andrej Paušič
andrej.pausic@um.si
Research field: Biology, botany
dr. Stanislav Tojnko
stanislav.tojnko@um.si
Research field: Plant production and processing, agricultural plants
Technical associates
Anja Ivanuš, dipl. inž. kmet. un
anja.ivanus@um.si
Research field: Biology, botany
Johannes Rabensteiner, mag. rer. nat.
jj.rabenstein@gmail.com
Research field: Biology, botany
Polona Sušnik, mag. ekol. biod.
Research field: Biology, botany
polona.susnik@um.si
Bojana Žiberna, univ. dipl. ing. kem. tehn.
bojana.ziberna21@gmail.com
Research field: Chemical engeneering, processing systemic engeneering