Nutritional constituents of mulberry and their potential applications in food and pharmaceuticals: A review

Mulberry is a fast growing deciduous plant found in wide variety of climatic, topographical and soil conditions, and is widely distributed from temperate to subtropical regions. Due to presence of valuable phytochemical constituents, mulberry as a whole plant has been utilized as a functional food since long time. Mulberry fruits are difficult to preserve as they have relatively high water content. Therefore for proper utilization, different value-added products like syrups, squashes, teas, pestil sand köme, pekmez (turkuish by-products), yogurts, jams, jellies, wines, vinegar, breads, biscuits, parathas, and many more are made. In overseas, these value-added products are commercially sold and easily available, though in India, this versatile medicinal plant is still missing its identity at commercial and industrial scale. Leaves of mulberry are economically viable due to their important role in the sericulture industry since ancient times. Mulberries or its extracts exhibit excellent anti-microbial, anti-hyperglycaemic, anti-hyperlipidemic, anti-inflammatory, anti-cancer effects and is used to combat different acute and chronic diseases. Different parts of Morus species like fruits, leaves, twigs, and bark exhibit strong anti-tyrosinase inhibition activity that makes it a suitable candidate in cosmetic industries as a whitening agent. The current review provides a comprehensive discussion concerning the phytochemical constituents, functionality and nutraceutical potential of mulberry and as a common ingredient in various cosmetic products.     

桑叶不同化学成分的降血糖作用

桑叶是一种重要的降血糖药用植物资源。以秋桑叶中提取的六种活性化学成分为材料,研究了六种提取物对四氧嘧啶诱导的糖尿病小鼠的降血糖效果。结果显示,各提取物均有一定的降血糖作用,其中以桑叶总多糖的功效最为显著,桑叶生物碱及桑叶黄酮苷类效果次之。     

桑及菌根桑在库区消落带的生态重建功能及应用潜力

三峡工程在提供丰富水电资源造福人类的同时,也引发了一些生态环境问题,对库区环境、生物、气候以及人们的生活都产生了不同程度的影响。桑树休眠和生长发育节律与库区水体涨落规律的反向偶联,桑的菌根结构在改善根际土质量,促进桑树水分和养分吸收,增强桑树对盐碱、干旱、重金属的耐受性,提高幼苗的存活率,促进桑苗生长,促进植物群落正向演替等生态过程中发挥着重要的作用。分析了三峡库区消落带周期性水淹的生态特征和岸生植物生态恢复障碍,综述了桑及菌根桑在消落带的生态特性和应用潜力,最后提出了菌根桑生物技术的应用所面临的新课题和挑战。     

Advances in mulberry tissue culture

The mulberry (Morus spp.) is an important tree in the sericultural industry because its leaves constitute the sole source of food for the Mori silkworm (Bombyx mori). Qualitative and quantitative improvements in mulberry varieties play a vital role in industrial advances. However, the perennial nature of the plants, coupled with the species prolonged juvenile period, slows this process. Plant tissue-culture techniques have been used extensively for stock improvement During the last thirty years, several researchers have reported success in plant regeneration from different expiants types. This review describes the major findings in mulberry tissue-culture research.     

Genetic diversity among mulberry genotypes from seven countries

Mulberry (Morus alba) is an economically and ecologically important, widespread woody plant. It has served human beings for over hundreds of years, and it is still widely used in pharmaceuticals, food industry and farming nowadays. Using modern techniques, deeper understanding in classification and conservation resources of mulberry leads to higher-efficiency hybrids among populations. Genetic polymorphisms among 42 mulberry genotypes from seven countries over Asia and South America were detected using 17 inter simple sequence repeat (ISSR) primers. A dendrogram was constructed using the similarity matrix among genotypes and a principal component analysis (PCA) was carried out to further identify and cluster the mulberry genotypes. In the 42 genotypes, 175 distinct bands were displayed, among which 169 were polymorphic bands (96.57%). The polymorphic information content of 17 ISSR primers ranged from 0.2921 to 0.3746 with the mean of 0.3494. And Nei’s index and Shanon’s information index averaged 0.116 and 0.174, respectively, indicating low diversity of mulberry. For further study, cluster analysis and PCA were carried out and the results were similar. 42 genotypes were grouped, showing some hybridized combinations. Additionally, a connection between mulberry diseases and their genotypes was noted, which indicates possible application for ISSR in studying disease resistance of mulberry.     

Molecular distinction amongst varieties of Mulberry using RAPD and DAMD profiles

Background  

Mulberry trees are the most important host for rearing mulberry silkworms in sericulture. Improved varieties of mulberry tree have been developed through traditional breeding procedures. Not much work, however, has been carried out on the molecular characterization of these varieties. Random Amplified Polymorphic DNA (RAPD) and Directed Amplification of Minisatellite DNA (DAMD) methods based on Polymerase Chain Reaction are important tools to analyze genetic diversity of mulberries. These have been used to determine variation amongst nine varieties of Morus spp. maintained at Banthra Research Station of National Botanical Research Institute, Lucknow.     

Selection of suitable reference genes for quantitative real-time PCR gene expression analysis in Mulberry (Morus alba L.) under different abiotic stresses

Molecular Biology Reports - Mulberry (Morus alba L.) is the sole food source for the mulberry silkworm, Bombyx mori and therefore important for sericulture industry. Different abiotic stress...     

Shotgun proteomic analysis of mulberry dwarf phytoplasma

Background  

Mulberry dwarf (MD), which is caused by phytoplasma, is one of the most serious infectious diseases of mulberry. Phytoplasmas have been associated with diseases in several hundred plant species. The inability to culture phytoplasmas in vitro has hindered their characterization at the molecular level. Though the complete genomes of two phytoplasmas have been published, little information has been obtained about the proteome of phytoplasma. Therefore, the proteomic information of phytoplasmas would be useful to elucidate the functional mechanisms of phytoplasma in many biological processes.     

Genetic relationships of Japanese and Indian mulberry (Morus spp.) genotypes revealed by DNA fingerprinting

Mulberry (Morus spp.), a deciduous tree, originated at the foothills of the Himalayas and is used in sericulture for its leaf to feed the silkworm Bombyx mori L. Species differentiation among the genotypes of the genus Morus has never been out of debate as inter-specific hybridization events are often fertile. In the present study attempts were made to elucidate the genetic relationships among 18 mulberry genotypes collected from India and Japan using 15 Inter Simple Sequence Repeat (ISSR) and 15 Random Amplified Polymorphic DNA (RAPD) primers. The ISSR primers generated 81.13% polymorphism while the RAPDs generated 71.78% polymorphism. The polymorphic index of the primers identified UBC-812, UBC-826, UBC827, UBC-881, OPA-01, OPA-02, OPA-04 and OPH-17 as informative primers in mulberry. The genetic similarity coefficients and the dendrograms showed considerable genetic similarity among the genotypes. However, using the DNA markers, these genotypes were discriminated into two major groups in accordance with their geographic origin and species status. Distribution of the genotypes on a two-dimensional figure on the basis of the ALSCAL algorithm using Euclidean distance further confirmed the genetic divergence between these two groups. From the study it can be concluded that though morphologically Japanese and Indian mulberry genotypes show little divergence, genetic analysis using DNA markers could unravel significant genetic variation between these two groups. Similarly, while the species status of Japanese mulberry genotypes agrees with the genetic analysis, the same does not apply to Indian genotypes, in agreement with many earlier reports. The information generated in this study is of much use for taxonomical grouping and also for utilization in breeding and conservation programs.     

Groupwise sampling: a strategy to sample core entries from RAPD marker data with application to mulberry

Key message

A strategy for effective utilization of RAPD marker data for sampling diverse entries was suggested and utilized for the development of mulberry core collection.

Abstract

Mulberry (Morus spp.) is a perennial tree cultivated mainly for its foliage in sericulture industry and also known for its edible fruits, fodder, and valued timber. In recent years, mulberry cultivation is confronted with several abiotic and biotic stresses due to inimical climatic factors and this has necessitated the genetic improvement of the crop. Core collection is an efficient way of harnessing the trait variation and novel genes available in a natural gene pool for the development of improved elite lines. In this study, we analyzed 850 mulberry accessions assembled from 23 countries with separate sets of polymorphic RAPD markers along with a limited number of ISSR, SSR, and phenotypic markers. A total of 75 accessions were duplicated in 20 clusters among five natural groups. The limitations of the RAPD marker system like problem in cross gel comparison were tackled by adopting a novel “Groupwise sampling” approach. A mulberry core collection with 100 diverse entries was selected using maximization method implemented in MSTRAT software. The mean Dice dissimilarity coefficient computed from marker data was 0.308 among core entries. Indigenous and exotic entries were not discriminated in cluster and principal component analysis supporting the spread of mulberry far from the place of origin. Accessions belonging to two wild mulberry species from Andaman Islands and Himalayan region formed separate clusters indicating the geographical, reproductive, and taxonomic distinction. The identified core collection will be available for researchers for intensive mining of desirable alleles in mulberry improvement as well as in genome resequencing program.     

Morphological and molecular characterization of Diplodia seriata,the causal agent of canker and twig dieback disease on mulberry in Iran

Mulberries are cultivated for different purposes: for feeding larvae of silkworm, Bombyx mori, as fresh and dry food resources, in wood instrument industry, in pharmaceutical industry and as outdoor ornamental trees in Iran. In recent years, twig and branch canker disease symptoms have been noticed on mulberry trees in northwestern parts of Iran. Diplodia isolates were repeatedly recovered from symptomatic tissues. Based on cultural and morphological features, the isolates were identified as Diplodia seriata. The identity of the isolates was further confirmed using sequence data from internal transcribed spacer (ITS)-rDNA and ef-1α gene. A phylogenetic analysis using ITS sequence data clustered the isolates obtained in this study together with known Diplodia seriata isolates of other woody hosts from GenBank. Inoculation studies carried out on white mulberry twigs using an excised shoot method revealed that the isolates are pathogenic on this host. D. seriata have been reported from other woody host plant species such as Juglans nigra and Vitis vinifera in Iran, however, to the best of our knowledge, the occurrence of D. seriata on mulberry trees is new for Iran. The distribution and reaction of different Morus spp. to D. seriata remain to be studied.     

SEM studies on the leaf surface of promising mulberry (Morus spp.) genotypes

Mulberry (Moms spp.) leaf quality has a great role in silkworm rearing which in turn affects the overall silk yield. In the recent past, many varieties of mulberry have been evolved considering the morphological characters, growth, yield, and quality parameters based on bioassay. The present investigation was carried out on ten promising mulberry genotypesviz. Tr-10, K-2, S-36, S-54, S-1, V-1, Mysore local, S-13, S-34, and RFS-135 to characterize stomatal size and frequency, trichomes and idioblasts using SEM. These new parameters will provide useful information for cultivars identification as well as for selecting mulberry genotypes adapted to different eco-climatic conditions and assessing the feeding quality of leaf for silkworm rearing.     

Isolation and characterization of six novel microsatellite markers for mulberry (Morus indica)

Genetic characterization of germplasm resources is necessary for their effective management and efficient utilization, especially for species like mulberry in which the available germplasm exhibits rich phenotypic diversity with almost no information about its genetic base. Here we present the first report on the isolation of six novel microsatellite markers of mulberry, developed from an enriched genomic library of Morus indica. These markers revealed a high degree of polymorphism (14–26 alleles per locus; polymorphic information content, 0.85–0.90) and a broad cross‐species affinity when tested on a set of 43 elite genotypes including 13 related Morus species. The data thus demonstrate their utility as potentially efficient genetic markers for germplasm characterization, crop improvement and molecular systematics of mulberry.     

Colonization of <Emphasis Type="Italic">Morus alba</Emphasis> L. by the plant-growth-promoting and antagonistic bacterium <Emphasis Type="Italic">Burkholderia cepacia</Emphasis> strain Lu10-1

Background  

Anthracnose, caused by Colletotrichum dematium, is a serious threat to the production and quality of mulberry leaves in susceptible varieties. Control of the disease has been a major problem in mulberry cultivation. Some strains of Burkholderia cepacia were reported to be useful antagonists of plant pests and could increase the yields of several crop plants. Although B. cepacia Lu10-1 is an endophytic bacterium obtained from mulberry leaves, it has not been deployed to control C. dematium infection in mulberry nor its colonization patterns in mulberry have been studied using GFP reporter or other reporters. The present study sought to evaluate the antifungal and plant-growth-promoting properties of strain Lu10-1, to clarify its specific localization within a mulberry plant, and to better understand its potential as a biocontrol and growth-promoting agent.     

NaCl induced morpho-biochemical and anatomical changes in mulberry (<Emphasis Type="Italic">Morus</Emphasis> spp.)

Mulberry is an economically important tree, used for feeding the silkworm Bombyx mori L. Effect of different levels of NaCl on growth and development of mulberry has been studied using five mulberry genotypes selected on the basis of their performance under in vitro salinity. The study while endorsing the efficacy of in vitro screening of axillary buds of mulberry for salt tolerance, showed genotypic variability in its response to salinity. Salinity reduced growth and development of all genotypes. However, the putative tolerant genotypes showed better performance than the putative susceptible genotypes. Under low salinity (<0.5% NaCl) salt tolerant genotypes showed an increase in chlorophyll and protein concentrations, while in susceptible genotypes both were reduced by 3–58% at 0.5% NaCl and 50–64% at 1.00% NaCl. Leaf thickness increased by 16% at 1.00% NaCl in C776 and reduced by 1.0% in Mandalaya. The increase in chlorophyll concentration and leaf thickness under high salinity can be considered as preliminary selection parameters for salt tolerance in mulberry. The study confirmed the efficacy of in vitro method for screening of large number of genotypes for salt tolerance in mulberry.