Endophytic microorganisms: a review on insect control and recent advances on tropical plants

Abstract

In the past two decades, a great deal of information on the role of endophytic microorganisms in nature has been collected. The capability of colonizing internal host tissues has made endophytes valuable for agriculture as a tool to improve crop performance. In this review, we addressed the major topics concerning the control of insects-pests by endophytic microorganisms. Several examples of insect control are described, notably those involving the interactions between fungi and grazing grasses from temperate countries. The mechanisms by which endophytic fungi control insect attacks are listed and include toxin production as well as the influence of these compounds on plant and livestock and how their production may be affected by genetic and environmental conditions. The importance of endophytic entomopathogenic fungi for insect control is also addressed. As the literature has shown, there is a lack of information on endophytes from tropical hosts, which are more severely affected by pests and diseases. The natural and biological control of pests and diseases affecting cultivated plants has gained much attention in the past decades as a way of reducing the use of chemical products in agriculture. Biological control has been frequently used in Brazil, supported by the development of basic and applied research on this field not only in our country but also in South America as it can be found in several reviews (Lecuona, 1996;Alves, 1998;Melo and Azevedo, 1998). In fact, by having vast agriculturable areas and most of its territory in the tropical region, Brazil and all Latin America, show their agriculture severely affected by agricultural pests. The use of agrochemicals, although decreasing the attack of insects and phytopathogenic microorganisms, still represents a high risk to field workers and consumers. In addition, their use is, in certain cases, economically unviable. The control of pests and diseases by means of biological processes i. e., use of entomopathogenic microorganisms or those that inhibit/antagonise other microorganisms pathogenic to plants, is an alternative that may contribute to reduce or eliminate the use of chemical products in agriculture.

Biomimetic Synthesis of Silver Nanoparticles From an Endophytic Fungus and Their Antimicrobial Efficacy

“…Endophytes are microbes that inhabit plant tissues in their life cycle without causing any apparent harm to their host [2] . Their presence implied a symbiotic interaction, in all the plants investigated until now [3] . Metal nanoparticles show promising applications in the fields of medicine, electronics, agriculture, etc.…”

Colonization of rice and Spodoptera frugiperda J.E. Smith (Lepidoptera: Noctuidae) larvae by genetically modified endophytic Methylobacterium mesophilicum

“…The biotechnological progresses are allowing the identifi cation of endophytic microorganisms promising for insect biological control (Azevedo et al 2000). Azevedo & Araújo (2007) defi ned endophytes as all the microorganisms that inhabit the interior of the host plant, without causing apparent damages or visible external structure.…”

“…Azevedo & Araújo (2007) defi ned endophytes as all the microorganisms that inhabit the interior of the host plant, without causing apparent damages or visible external structure. The presence of endophytic microorganisms inside the host plant may increase the plant fi tness by protecting it against pest and pathogens, improving plant growth and increasing resistance in stressful environments (Azevedo et al 2000, Scherwinski et al 2007. Besides the natural occurrence of endophytes, many studies are being carried out with genetically modifi ed microorganisms (GMM) to evaluate host colonization (Germaine et al 2004, Ferreira et al 2008.…”

Endophytic fungi occurring in Ipomoea carnea tissues and their antimicrobial potentials

“…Studies have shown that fungal endophytes are neither incident residents nor merely latent pathogens of plant hosts but also exert several beneficial effect. Their functional roles may be attributed to protect the host from the insect pests (Azevedo et al 2000), fungal pathogens (Arnold et al 2003;Dingle and McGee 2003), or increase the host fitness in harsh environments (Redman et al 2002). Besides, endophytic fungi have been recognized as repository of biologically active substances (Tan and Zou 2001).…”