Plant Beneficial Microbes: An Overview

Abstract

Use of harmful chemical fertilizers and pesticides that have large negative impacts on environmental and human health have generated increasing interest in the use of beneficial microorganisms for the development of sustainable agri-food systems. A successful microbial inoculant has to colonize the root system, establish a positive interaction and persist in the environment in competition with native microorganisms living in the soil through rhizo competence traits. Recently, several approaches based on culture-dependent, microscopic and molecular methods have been developed to follow bio inoculants in the soil and plant surface over time. Culture-dependent methods are commonly used to estimate the persistence of bio inoculants; it is difficult to differentiate inoculated organisms from native populations based on morphological characteristics. Therefore, these methods should be used complementary to culture-independent approaches. Microscopy-based techniques (bright-field, electron and fluorescence microscopy) allow to obtain a picture of microbial colonization outside and inside plant tissues also at high resolution, but it is not possible to always distinguish living cells from dead cells by direct observation as well as distinguish bio inoculants from indigenous microbial populations living in soils. The present paper deals with the study of beneficial microbes benefit to plants growth and development.