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| Author(s): |
Natália Oliveira de Araujo
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | Campinas, SP. |
| Institution: | Universidade Estadual de Campinas (UNICAMP). Instituto de Biologia |
| Defense date: | 2021-08-31 |
| Examining board members: |
Juliana Velasco de Castro Oliveira;
Maria Carolina Quecine;
Alessandra Alves de Souza
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| Advisor: | Juliana Velasco de Castro Oliveira |
| Abstract | |
Plant growth-promoting bacteria (PGPBs) have been used in the agricultural system as an eco-friendly option to increase the productivity of economically important crops, as an alternative to chemical inputs. One of the positive mechanisms of PGPBs for plants is the emission of volatile organic compounds (VOCs), which are small gaseous molecules that signal plant growth and antagonism to phytopathogens. In most research, the effects of VOCs are investigated in Arabidopsis thaliana, a dicotyledonous model plant, with no added commercial value. Hence, further research is required in monocotyledons and crops of economic relevance, such as rice (Oryza sativa) and sugarcane (Saccharum sp.). In addition, there are not many studies of VOCs on the antagonist action of phytopathogens from the last crop, such as the fungus Fusarium moniliforme, the causal agent of pokkah-boeng disease. Therefore, the objectives of this research were to evaluate the effects of bacterial VOCs on the model plants and crops growth promotion, as well as to evaluate the VOCs potential on the phytopathogens growth inhibition. On investigating the effect of VOCs on A. thaliana, five out 20 bacterial isolates caused a significant increase in dry shoot and root biomass, up to 288 and 423%, respectively, whereas by up to 72% in rice. To investigate the molecular mechanisms involved in this growth promotion, 28 and 37 metabolites present in significantly different concentrations in shoots of A. thaliana and rice were identified, respectively, when grown in contact with bacterial VOCs, and several metabolic pathways related to growth were enriched. In addition, 73 and 58 VOCs produced by bacteria relevant to the growth of A. thaliana and rice, respectively, were identified. The chemical classes benzene, ketone, alcohol, and sulfide were the most found in volatilomes. The functional analysis of synthetic VOCs allowed the validation of 2-Butanone and Phenethyl alcohol, in vitro, as capable of increasing the total biomass of A. thaliana by up to 237%. In the case of rice, the mix containing Dimethyl disulfide, 2-Heptanone, and 2-Nonanol promoted an increase in total dry biomass by up to 115%. In vivo, the VOCs of one of the isolates were able to significantly increase (87%) the dry biomass accumulation of rice. There is still a need for standardization in co-cultivation trials with micropropagated sugarcane, mainly because it is a non-model plant. Finally, four bacteria were able to inhibit the mycelial growth of F. moniliforme by up to 67%. All the knowledge acquired about VOCs and their influence on the growth and health of plants will enable the development of agricultural bioproducts, aiming to increase the productivity and sustainably of crops (AU) | |
| FAPESP's process: | 19/08522-2 - Identification and characterization of volatiles as crop growth inducers |
| Grantee: | Natália Oliveira de Araujo |
| Support Opportunities: | Scholarships in Brazil - Master |