Mulberry (Morus spp.) of Moraceae family is regarded as a unique plant on this earth due to its broader geological distribution across the continents; ability to be cultivated in different forms; multiple uses of leaf foliage and its positive impact in environmental safety approaches such as ecorestoration of degraded lands, bioremediation of polluted sites, conservation of water, prevention of soil erosion and improvement of air quality by carbon sequestering. Mulberry is also used as a medicinal plant in improving and enhancing the life of human beings by utilizing the biologically active pharmacokinetic compounds found in leaf, stem and root parts. Further industrial exploitation of mulberry through preparation of various products in pharmaceutical, food, cosmetic and health care industries has gained the attention of industrialists. As mulberry is being exploited by sericulture, pharmaceutical, cosmetic, food and beverage industries along with its utilization in environmental safety approach; it is appropriate to call it as a most suitable plant for sustainable development. Through this review paper, all the important characteristics of mulberry were put together for considering it as an ideal plant in providing sustainable future.

Mulberry (Morus spp.): An ideal plant for sustainable development

Intensive investigations have been conducted on the effect of sole drought or salinity stress on the growth of plants. However, there is relatively little knowledge on how plants, particularly woody species, respond to a combination of these two stresses although these stresses can simultaneously occur in the field. In this study, mulberry, an economically important resource for traditional medicine, and the sole food of domesticated silkworms was subjected to a combination of salt and drought stress and analyzed by physiological methods and TMT-based proteomics. Stressed mulberry exhibited significant alteration in physiological parameters, including root/shoot ratio, chlorophyll fluorescence, total carbon, and ion reallocation. A total of 577 and 270 differentially expressed proteins (DEPs) were identified from the stressed leaves and roots, respectively. Through KEGG analysis, these DEPs were assigned to multiple pathways, including carbon metabolism, photosynthesis, redox, secondary metabolism, and hormone metabolism. Among these pathways, the sucrose related metabolic pathway was distinctly enriched in both stressed leaves and roots, indicating an important contribution in mulberry under stress condition. The results provide a comprehensive understanding of the adaptive mechanism of mulberry in response to salt and drought stress, which will facilitate further studies on innovations in terms of crop performance.

https://www.mdpi.com/1422-0067/20/10/2486/pdf

Physiological and Proteomic Responses of Mulberry Trees (Morus alba. L.) to Combined Salt and Drought Stress.

Abiotic stresses negatively influence the survival, biomass production, and yield of crops. Tolerance to diverse abiotic stresses in plants is regulated by multiple genes responding differently to various stress conditions. Genetic engineering approaches have helped develop transgenic crops with improved abiotic stress tolerance including yields. The dehydration-responsive element binding protein (DREB) is a stress-responsive transcription factor that modulates the expression of downstream stress-inducible genes, which confer simultaneous tolerance to multiple stresses. This review focuses on advances in the development of DREB transgenic crops and their characterization under various abiotic stress conditions. It further discusses the mechanistic aspects of abiotic stress tolerance, yield gain, the fate of transgenic plants under controlled and field conditions and future research directions toward commercialization of DREB transgenic crops.

Advances in the development and use of DREB for improved abiotic stress tolerance in transgenic crop plants.

Superoxide dismutase (SOD) plays a vital role in the removal of active oxygen in plant In this study, bioinformatics research and expression analysis of SOD gene family under drought and salt stress has been done in barley (Hordeum vulgare L, Hv) Seven SOD genes were identified, including four Cu/Zn-SODs, two Fe-SODs and one Mn-SOD Those three kinds of SOD genes were distributed in 2, 4 and 7 chromosomes, respectively Phylogenetic analysis revealed that SODs of barley, rice and Arabidopsis thaliana can be divided into three subfamilies (A–C) Motif analysis founded six conservative motifs Most SOD genes had relatively conservative intron/exon and motif composition, but the number of intron/exons varied greatly among different genes Based on RNA-seq data and qRT-PCR analysis of expression changes of barley SOD family gene under stress, HvCSD1, HvCSD4 and HvFSD1 were more valuable for in-depth research due to their significant changes in their expression after stress treatment These outcomes help to lay the foundation for studying the gene function of barley SOD family and provide the improvement of drought and salt tolerance barley genetic breeding

Genome-wide identification of the SOD gene family and expression analysis under drought and salt stress in barley

Mulberry (Morus alba L.) is the sole food source for the mulberry silkworm, Bombyx mori and therefore important for sericulture industry. Different abiotic stress conditions like drought, salt, heat and cold stress adversely affect the productivity and quality of mulberry leaves. Quantitative real time PCR (qPCR) is a reliable and widely used method to identify abiotic stress responsive genes and molecular mechanism in different plant species. Selection of suitable reference genes is important requirement for normalizing the expression of genes through qRT-PCR study. In the present study, we have selected eight candidate reference genes in mulberry for analyzing their expression stability in different abiotic stress treatments including drought, salt, heat and cold stresses. The expression stability of these reference genes was determined using geNorm, NormFinder and RefFinder statistical algorithms. The results showed that Ubiquitin and protein phosphatase 2A regulatory subunit A (PP2A) were the most stable genes across all the treatment samples. However, analysis of individual stresses revealed different expression profiles and stability of reference genes. Actin3 and PP2A were most stable in drought and salt conditions respectively. RPL3 most preferred in heat stress and Ubiquitin was most stable in cold stress. We propose the ubiquitin and PP2A are the preferred reference genes for normalization of gene expression data from abiotic stresses. In addition, Actin3 are preferred for drought stress, PP2A for salt stress, RPL3 for heat stress and Ubiquitin for cold stress studies.

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

Mulberry (Morus spp.), being an economically important tree, is cultivated in China, India, Thailand, Brazil, Uzbekistan and other Countries across the globe, for its leaves to feed monophagous mulberry silkworm (Bombyx mori). The sustainability of silk industry is directly correlated with the production and continuous supply of high-quality mulberry leaves. In India, it is cultivated on large scale in tropical, sub-tropical and temperate regions under irrigated conditions for silkworm rearing. Drought, low temperature, high salinity and alkalinity, being experienced in widespread areas, are the major abiotic stresses, causing reduction in its potential foliage yield and quality. Further, climate change effects may worsen the productivity of mulberry in near future, not only in India but also across the globe. Although traditional breeding methods contributed immensely towards the development of abiotic stress-tolerant mulberry varieties, still there is lot of scope for implementation of modern genomic and molecular biology tools for accelerating mulberry genetic improvement programmes. This review discusses omics approaches, molecular breeding, plant tissue culture and genetic engineering techniques exploited for mulberry genetic improvement for abiotic stress tolerance. However, high-throughput biotechnological tools such as RNA interference, virus-induced gene silencing, epigenomics and genome editing tools need to be utilized in mulberry to accelerate the progress of functional genomics. The application of genomic tools such as genetic engineering, marker-assisted selection and genomic selection in breeding programmes can hasten the development of climate resilient and productive mulberry varieties leading to the vertical and horizontal expansion for quality silk production.

Improvement of abiotic stress adaptive traits in mulberry (Morus spp.): an update on biotechnological interventions.

Mulberry (Morus spp.) is an important crop in the sericulture industry, as the leaves constitute the primary feed for the silkworm. The availability of diverse genetic sources of resistance to root...

Genetic Diversity, Identification, and Utilization of Novel Genetic Resources for Resistance to Meloidogyne incognita in Mulberry (Morus spp.)

Mulberry (Morus spp.) is a woody, perennial, highly heterozygous, fast-growing plant and grown mainly for its foliage worldwide under various agroclimatic zones (tropical, subtropical and temperate) of Asia, Africa and the Americas. Mulberry leaves are the sole food source for monophagous and domesticated mulberry silkworm, Bombyx mori L. Moreover, mulberry fruits are fleshy, succulent and delicious berries. The fruits are low in calories and contain health-promoting phytonutrients such as polyphenols, minerals and vitamins having medicinal importance for its antioxidant, antitumor, neuroprotective activities and hypo-lipidemic/macrophage activating effects. Genetic improvement of mulberry is mainly aimed for improving productivity and quality of leaf for silk production. Conventional plant breeding techniques including tissue culture and molecular biology methods are employed in mulberry genetic improvement programmes to develop varieties for improved leaf productivity and biotic/abiotic stress tolerance. This review focuses on various tissue culture approaches such as in vitro regeneration, micropropagation, genetic transformation, somaclonal variation, in vitro selection, suspension culture, and much more which often supplement the traditional breeding methods. Further, characterization and production of secondary metabolites from mulberry tissues through suspension culture which are becoming a blooming option for commercial exploration of bioactive compounds have been discussed.

Tissue Culture in Mulberry (Morus spp.) Intending Genetic Improvement, Micropropagation and Secondary Metabolite Production: A Review on Current Status and Future Prospects

Thallapally Mogili

Papers

Improvement of abiotic stress adaptive traits in mulberry (Morus spp.): an update on biotechnological interventions.

Genetic Diversity, Identification, and Utilization of Novel Genetic Resources for Resistance to Meloidogyne incognita in Mulberry (Morus spp.)

Tissue Culture in Mulberry (Morus spp.) Intending Genetic Improvement, Micropropagation and Secondary Metabolite Production: A Review on Current Status and Future Prospects