Enhancing Growth and Lignocellulosic-Biomass Yield Through the Use of Naturally Occurring Growth-Promoting Microbial Endophytes in Sorghum
Currently, ~2.5% of the world’s transportation fuels are produced from crop plants including maize, sugarcane, and vegetable oils. However, extensive use of both maize and sugarcane as biofuel feedstock will pose a threat to food security, as they will compete with other food crops for irrigation and arable land resources. For this reason, in the United States of America (USA), Sweet Sorghum [Sorghum bicolor (L.) Moench], is considered a leading candidate for lignocellulosic biofuel feedstock, partly because of its high biomass production, wide adaptation, low agronomic input requirements, and accumulation of sugars in its stalks. Other agronomic traits, like the short life cycle of about four months, low cost of cultivation, and C4 photosynthesis are especially helpful for its adoption as a biofuel feedstock; however, sorghum itself is recalcitrant to genetic manipulation and is threatened by various diseases, limiting its growth. To address these issues, we used naturally-occurring, growth-promoting rhizobacteria—Biological Control Agents (BCAs) to enhance sorghum growth and its biomass traits. Four BCAs will be investigated: Bacillus thuringiencis (IMC8), Bacillus subtilis (PRT), Bacillus vallismortis (PS), and Bacillus amyloliquefaciens (PSL). Specifically, we investigated the biochemical mechanisms that underlie the beneficial interactions between BCAs and sorghum by evaluating BCAs’ impacts on two varieties of sorghum: Dale and Topper 76-6, well known to be cultivated in the state of Tennessee through three objectives: (i) Evaluation of the effects of BCAs in sorghum seed germination and growth. (ii) Phenotypical characterization of BCA-host sorghum plants interaction (iii) Evaluation of biochemical mechanisms underlying BCA-host sorghum plants interaction. Results show that none of the BCAs were harmful to sorghum plants, and they all promote germination and overall growth. However, these BCAs may provide other benefits that are subject to further analyses. Overall, our studies indicate that BCAs naturally and safely promote sorghum growth, suggesting that they can be used as a replacement of chemical products that are harmful for plants or humans.
"Enhancing Growth and Lignocellulosic-Biomass Yield Through the Use of Naturally Occurring Growth-Promoting Microbial Endophytes in Sorghum"
ETD Collection for Tennessee State University.