Burkholderia ambifaria and B. caribensis Promote Growth and Increase Yield in Grain Amaranth (Amaranthus cruentus and A. hypochondriacus) by Improving Plant Nitrogen Uptake

Abstract

Grain amaranth is an emerging crop that produces seeds having high quality protein with balanced amino-acid content. However, production is restricted by agronomic limitations that result in yields that are lower than those normally produced by cereals. In this work, the use of five different rhizobacteria were explored as a strategy to promote growth and yields in Amaranthus hypochondriacus cv. Nutrisol and A. cruentus cv. Candil, two commercially important grain amaranth cultivars. The plants were grown in a rich substrate, high in organic matter, nitrogen (N), and phosphorus (P) and under greenhouse conditions. Burkholderia ambifaria Mex-5 and B. caribensis XV proved to be the most efficient strains and significantly promoted growth in both grain amaranth species tested. Increased grain yield and harvest index occurred in combination with chemical fertilization when tested in A. cruentus. Growth-promotion and improved yields correlated with increased N content in all tissues examined. Positive effects on growth also occurred in A. cruentus plants grown in a poor soil, even after N and P fertilization. No correlation between non-structural carbohydrate levels in roots of inoculated plants and growth promotion was observed. Conversely, gene expression assays performed at 3-, 5- and 7-weeks after seed inoculation in plants inoculated with B. caribensis XV identified a tissue-specific induction of several genes involved in photosynthesis, sugar- and N- metabolism and transport. It is concluded that strains of Burkholderia effectively promote growth and increase seed yields in grain amaranth. Growth promotion was particularly noticeable in plants grown in an infertile soil but also occurred in a well fertilized rich substrate. The positive effects observed may be attributed to a bio-fertilization effect that led to increased N levels in roots and shoots. The latter effect correlated with the differential induction of several genes involved in carbon and N metabolism and transport.

Culturable endophytic bacterial communities associated with field-grown soybean

“…Parra‐Cota et al . (), testing Burkholderia ambifaria and B. caribensis strains found that they are able to promote growth and yield of inoculated Amaranth.…”

“…Jiang et al (2012) found that inoculation of V. paradoxus in Pisum sativum promoted an increase in the biomass of roots and seedlings. Parra-Cota et al (2014), testing Burkholderia ambifaria and B. caribensis strains found that they are able to promote growth and yield of inoculated Amaranth.…”

Comparative analysis of sugarcane root transcriptome in response to the plant growth-promoting Burkholderia anthina MYSP113

“…Burkholderia genus abundantly proliferates in a broad range of ecological niches and wellknown plant-associated bacteria. Several species of Burkholderia were reported as PGPR in different plants viz., tomato [7], amaranthus [8], maize [9], rice [10], and sugarcane [11]. PGPR promote sugarcane growth through different mechanisms such as nitrogen fixation, production of plant hormone, antibiotic production, etc.…”

Physiological performance of quinoa (Chenopodium quinoa Willd.) under agricultural climatic conditions in Boyaca, Colombia

“…5). The protein of T1 could be higher because it does not contribute to the available nitrogen despite of the organic fertilizer supply; the population of diazotrophic bacterium existing in this kind of fertilizer influences its availability in the plant (Parra-Cota et al, 2014). Additionally, a balance in elements like phosphorus, magnesium and other microelements contribute to the synthesis of protein (Marschner, 2012).…”