Exploitation of new endophytic bacteria and their ability to promote sugarcane growth and nitrogen nutrition

Abstract

Few studies have evaluated endophytic bacteria in relation to plant growth promotion, nitrogen uptake and biological control. The aim of this study was to molecularly and physiologically characterize thirteen endophytic bacteria strains, evaluate their biological control properties and their ability to promote plant growth and plant N nutrition. All the strains produced indole acetic acid and promoted increase of plant biomass, N accumulative amount and N-use efficiency index. None of the strains carries the nifH gene. Four strains stimulated plant nitrate reductase activity, four solubilized phosphate, nine produced siderophores and none produced HCN. Seven strains inhibited Bipolaris sacchari growth and one was antagonistic to Ceratocystis paradoxa. The pathogens were inhibited by the production of diffusible and volatile metabolites by the bacterial strains. Moreover, this is the first study to demonstrate the effect of Delftia acidovorans on sugarcane plant growth, nitrogen metabolism improvement and antagonism to B. sacchari. The most efficient strains in promoting plant growth and exhibiting antagonistic activities towards fungal pathogens were Herbaspirillum frinsingense (IAC-BECa-152) and three Pantoea dispersa strains (IAC-BECa-128, IAC-BECa-129, and IAC-BECa-132). These bacteria show potential to be used as inoculants for sustainable agricultural management, mainly at the seedling production phase.

Experimental evidence of microbial inheritance in plants and transmission routes from seed to phyllosphere and root

“…Species in this genus were reported to be a common endophyte in plant seeds (López‐López et al ., 2010; Huang et al ., 2017; Liu et al ., 2017). Delftia species are seed bacterial endophytes known for their antagonistic activity against several plant pathogens, growth‐promotion, and nitrogen‐fixing properties (Han et al ., 2005; da Silveira et al ., 2019; Chen et al ., 2020).…”

Experimental Evidence of Microbial Inheritance in Plants and Transmission Routes from Seed to Phyllosphere and Root

“…Species in this genus were reported to be a common endophyte in Phaseolus vulgaris seeds [84], Ferula sinkiangensis seeds [85] and Arachis hypogaea seeds and sprouts [72], as well as several other crops [86]. Delftia species are seed bacterial endophytes known for their antagonistic activity against several plant pathogens, growthpromotion, and nitrogen-xing properties [87][88][89]. Rahnella is a bacterium present in oak stems and is suggested to play a role in the pathobiome of acute oak decline [90,91].…”

Plant-Growth Endophytic Bacteria Improve Nutrient Use Efficiency and Modulate Foliar N-Metabolites in Sugarcane Seedling

“…N uptake from soil can occur either in the nitrate or ammonia forms or be provided by diazotrophic bacteria in the form of ammonium (NH 4 + ). Thus, N assimilation enzymes, such as nitrate reductase (NR) and glutamine synthetase, have been assessed to evaluate endophytic bacteria influence on N uptake and use efficiency, indicating activation of N metabolism and a higher uptake from soil [5][6][7]. Plant receptors of bacterial signals are known to recognize phytopathogenic bacteria or be involved in the identification of beneficial microorganisms by plants [8,9].…”