Banca de DEFESA: SUEIDE KARINA DA SILVA
Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.STUDENT : SUEIDE KARINA DA SILVA
DATE: 01/08/2022
TIME: 09:00
LOCAL: Defesa remota pelo Google Meet
TITLE:
Endophytic rhizobia in sugarcane (RB92579) intercropped with grain legumes in soil with a long history of sugarcane exploitation
KEY WORDS:
Endophytic bacteria. Energy crops. Plant growth-promoting, Rhizobacteria. Sacharum spp
PAGES: 119
BIG AREA: Ciências Agrárias
AREA: Agronomia
SUBÁREA: Ciência do Solo
SUMMARY:
Rhizobia are bacteria known to infect legume roots, forming nodules where they fix Rhizobia are bacteria known to infect legume roots, forming nodules where they fix atmospheric N more efficiently than the diazotrophic bacteria that colonize grasses. Several works report the presence of rhizobia inside the roots of grasses, as well as sugarcane. It is not known whether these organisms have beneficial functions for plants, but if they are capable of acting as growth-promoting bacteria, this association with grassy rhizobia may represent a great possibility for the development of technologies based on bioinputs or on more independent management of chemical fertilizers for the culture. The results obtained so far suggest that (brady)rhizobia and other non-nodulating bacteria phylogenetically related to them represent a group of microorganisms that should be better studied in the sense of their application to cultures of the Poaceae family. The objective of this work was to prospect and characterize populations of rhizobia associated with the most used variety of sugarcane in Northeast Brazil, cultivated in soil with a long history of sugarcane exploitation, and to evaluate the effect of intercropping with nodulating legumes on these populations, through isolation followed by genetic and functional characterization. An experiment was set up in the municipality of Carpina-PE, Zona da Mata de Pernambuco. The treatments were distributed in randomized blocks with four replications and the treatments corresponded to the single crop and the intercropping of sugarcane with different species of grain-producing legumes (cowpea, peanut and soybean). At 5 months after planting the sugarcane, non-lignified roots were collected, which were macerated in saline solution and the suspension was used as an inoculant in bait plant trials, using the same legumes of the consortia. The isolates obtained from the formed nodules were genetically characterized, through 16S-RNA sequencing, and phenotypically in YMA medium. The isolates were tested for their ability to promote growth and biomass production and to change morphoanatomical parameters of sugarcane roots, in a pre-sprouted seedling inoculation experiment of legume growth in a greenhouse experiment. In the first trial with bait plants, nodules were only formed in cowpea inoculated with the suspension prepared from the roots of sugarcane cultivated in consortium with this legume. This result indicates the lack of rhizobia populations capable of nodulating soybeans and peanuts in sugarcane tissues, as well as demonstrating that cowpea cultivation was necessary to stimulate the presence of their microsymbionts in grass roots, probably by stimulating populations naturally established in the soil. These nodules generated a collection of 20 authenticated rhizobia, with low phenotypic and genetic diversity, with 4 isolates classified as Bradyrhizobium and 7 as Rhizobium. Among all the isolates in the collection, 55% solubilize calcium phosphate and all are capable of producing AIA. The thickness of the canopy, cortex and vascular system, as well as the density and length of root hairs in the sugarcane root were positively influenced by inoculation.
BANKING MEMBERS:
Externo à Instituição - FELIPE JOSÉ CURY FRACETTO - UFRPE
Externa à Instituição - EMILIA CRISTINA PEREIRA DE ARRUDA - UFPE
Presidente - 457.055.504-72 - ANA DOLORES SANTIAGO DE FREITAS - UFRPE
Externo à Instituição - JAKSON LEITE - IFPA
Externo à Instituição - PAULO IVAN FERNANDES JÚNIOR - EMBRAPA