Advancement in Endophytic Microbes from Medicinal Plants

This overview firstly highlights biology of endophytic microbes from medicinal plants as well as their chemistry with emphasis on the important merging of microbiology and natural products chemistry and its role in improving our current knowledge of endophytic associations in medicinal plants. Secondary metabolites of medicinal plants-derived endophytes reported in recent years are grouped according to their bioactive properties including antitumor, antimicrobial, growth-promoting, antioxidant, antithrombotic, insecticide and other functions. New insights on distributing characteristics and biodiversity of these endophytes including bacteria, actinomycetes and fungi are also presented. It suggested that endophytic microbe from medicinal plant is a treasure trove of bioactive natural products with a good and potential application prospect in pharmacy and agriculture. INTRODUCTION: The term ‘endophyte’ is a kind of microbes which reside in the intracellular or intercellular area of healthy plant tissues during their periods of life or the whole, and don't cause any obvious symptoms or distinct negative effects in their plant hosts 1 . Endophytes are the normal organism in plant tissues and shown to be an important part of microecosystem 2 . Investigation of endophytes had not become a hot spot globally until a taxol and taxane producing endophyte, Taxomyces andreanae, isolated from Taxus brevifolia was reported in 1993 3 . Nowadays, more attention is being worldwide paid to endophytic microbes by microbiologists and natural product chemists because of their abundant biological and chemical diversity. Endophytes originated from the formation of higher plants or vascular plants on the earth 4, 5 . During the long period of co-evolution with host plants, endophytes had adapted themselves to the niches and formed a completely compatible symbiont via gene regulation 2 . In this micro-ecoenvironment, host plants provide endophytes with photosynthetic products and minerals for their normal growth while `endophytes promote the growth and chemical defense of host plants by directly providing with valuable metabolites or transferring the corresponding genes to the host genome 6, 7 . So, endophytic microbes can improve the resistance of their hosts to adverse biotic factors (such as plant pathogens, herbivore, insects, etc.)