Biotechnological and agronomic potential of endophytic and rhizosferic bacteria associated with a Paspalum sp. germplasm bank

Abstract

The genus Paspalum is one of the most important from family Poaceae in the American continent. The genus comprises many species native to Brazil and Argentina with high forage value and potential to use as soil coverage. Paspalum species are one of the main components of native pastures from the south of Brazil and Argentina, and the introduction of its cultivation and genetic breeding is a road to diversify the forage cultivars offer, allowing more sustainable systems with the use of native grasses. However, in Brazil the commercial use of Paspalum cultivars as forage is still low. In countries such as The United States of America, New Zealand and other countries, many species of Paspalum are used with success. Endophytic microorganisms have been defined as those that reside at some phase of their life cycle within living plant tissues. These microorganisms include mutualistic symbionts species of bacteria, which could be used in the plant growth promotion and biological control of phytopathogens. Bacteria associated with the rhizosphere at different stages of plant development are termed rhizobacteria. Rhizospheric bacteria are able to positively influence plant growth and are generally referred to as plant growth-promoting rhizobacteria (PGPRs). Endophytic bacteria and rhizobacteria promote plant growth and yield either directly or indirectly. The direct growth promoting activities are as follows i) nitrogen fixation ii) solubulization of phosphorus and iii) production of phytohormones such as auxins, cytokinins, gibberellins. Second indirect mechanism of plant growth promotion by endophytes include biocontrol of phytopathogens. The potential role of PGPRs and endophytes as bio-fertilizers in agriculture offers an economically and environmentally beneficial way to reduce the use of chemical fertilizers, antibiotics, herbicides, pesticides and other agrochemicals. In recent years, interest in endophytic and rhizosferic microorganisms has increased, as they play a key role in agricultural environments and are promising because of their potential use in sustainable agriculture. The present project will select of plant growth promoting endophytic bacteria and rhizobacteria via their biochemical screening like nitrogen fixation, phosphate solubilization and indole acetic acid production. In addition, the biocontrol potential of the endophytic isolates will be tested against phytophatogen fungi by antagonist activity. Also, the diversity of endophytic and rhizosferic bacteria associated with a Paspalum sp. germplasm bank will be study by 16S rRNA gene and metagenomic analysis. (AU)