Deciphering the role of bacterial volatile organic compounds in the promotion of maize (Zea mays L.) growth and health and in the modulation of its microbial community

Abstract

Volatile organic compounds (VOCs) are signaling molecules produce during the microbial metabolism. Interestingly, it is known that these gaseous metabolites can promote plant growth as well as inhibit the growth of phytopathogens. So far, there are several studies with Arabidopsis thaliana (mainly), lettuce (Lactuca sativa), alfalfa (Mendicago sativa), Nicotiana attenuata, cucumber (Cucumis sativus), cabbage (Brassica rapa), soybean (Glycine max L.), sorghum (Sorghum bicolor), tobacco (Nicotiana tabacum) and tomato (Solanum lycopersicum L.); however, few studies were carried out with maize (Zea mays L.), an important agricultural crop. Therefore, we propose to establish a collection of VOC-producers bacteria capable of promoting plant growth and with antagonistic effect on phytopathogens of maize, as well as to understand the molecular mechanisms involved in these processes. The bacteria will be selected from rhizospheric soil (free-living) and maize plant tissues (endophytic). As main objectives, we propose: (i) Isolate and identify VOC-producer bacteria that promote maize growth and inhibit the growth of phytopathogens; (ii) Identify which bioactive volatiles are responsible for the phenotypes of interest investigated in (i); (iii) Evaluate the gene expression of maize plants that had their growth induced by VOCs and/or phytopathogen which growth was inhibited in (i); and (iv) Evaluate the rhizosphere microbial community of maize in the presence or absence of VOCs, as well as of the neighboring maize plants. This proposal consists of a multidisciplinary approach involving areas of chemistry, microbiology, agronomy, and molecular biology, and it is based on biology data from the scientific literature, as well as data from FAPESP projects (PITE -Agilent 2017/20521-6 and BIOEN 2017/24395-5). Few groups in Brazil have a focus on this important topic, and the objective of our group, included in this project, is the characterization of new bioactive molecules and the molecular understanding of how they act. This is the first step to enable, in the future, the development of bioproducts aiming a sustainable agriculture. (AU)