OLIVEIRA-PAIVA, C. A.

SANTOS, V. L.

SILVA, U.

VIEIRA, J. A. C.

English

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MA-0423Maize endophytic bacteria and their potential as plant growth promotingVL Santos , JAC Vieira , U Silva , CA Oliveira Universidade Federal de Minas Gerais, Brazil. Embrapa Milho e Sorgo, BrazilThe colonization of plant roots, stem, leaves or fruits by beneficial microorganisms can protect plants fromdiseases, promote growth and enhance biomass. These features have made them valuable for improvingcrop performance. Maize (Zea mays L.) represents one of the main economic crops for food and energy inthe world, and its associated microbial communities have been intensively prospected focusing on theselection of plant growth promoter microorganisms (PGPM) and their use as biofertilizers. In this work,endophytic bacteria were isolated from roots of Pioneer 30F35 Herculex hybrid corn crops, cultivated withand  without  phosphorus  fertilization  for  to  evaluate  the  potential  as  plant  growth  promoting.  Afteridentification by partial sequencing of the 16S rDNA gene, a total of 178 bacteria was evaluated regardinginorganic  phosphate  (CaPO4)  solubilization,  antagonizing  bacterial  (Bacillus  subtilis  and  Pantoeaananatis)  and phytopathogenic fungal  growth (Fusarium verticillioides and Coletotrichum graminicola),mineralization of phytate, and IAA and siderophores production. There was an equal distribution of theisolates from Actinobacteria, Firmicutes and Proteobacteria clades, and only one isolate (Flavobacteriumacidificum RT3B- 41) of Bacteroidetes phylum was found. The main genera  found were Microbacterium,Bacillus, Staphylococcus, Pseudomonas, Lactococcus, Enterobacter and Curtobacterium. In the in vitroassays, 81% of the isolates showed at least one PGP attribute, being that 57% produced auxin (4.5 to 111μg/ml),  31% were  able  to  solubilize  CaPO4 (10  to  527  mg/l),  42% to  mineralize  phytate,   15  % ofantagonizing phytopathogenic bacteria and fungi, and 43%  produceD siderophores (0.4 to 7.45mM). Aninverse correlation between the CaPO4 solubilization levels and pH values was observed (r  = -0.56,p<0.05), suggesting the involvement of the acid production in the phosphate solubilization by bacteria.The  spectrum  of  activity  varied  among  isolates  in  the  study  belonging  to  genera  Bacillus  andPseudomonas  (the most  frequent),  and Arthrobacter,  Leucnostoc,  Microbacterium,  Pseudoclavibacter,Serratia and Staphylococcus. Of the 15 isolates with antibacterial activity, five were active only againstBacillus subtilis, seven antagonizing the both bacteria evaluated (RT2A-12, RT3C-11, RT3C-21 RP3C-01,RT2B-13, RT2C-11 and FP1A -13), and none showed activity only against P. ananatis,  gram-negativebacteria causing of the disease "white spot" of corn. Regarding the 20 isolates with activity against C.graminicola  or  F.  verticillioides,  causing  large  impact  of  disease  popularly  known  as  "corn  rots,"  15antagonized only C. graminicola, four antagonized the two tested fungi (RT2A-12 , RT3C-11, RT3C-21 E1936 RP3C-01) and ST3-116 antagonized only F. verticillioides.  This work demonstrates the potentialapplication of these isolates as PGPM, which may be still confirmed by in vivo and field tests.FinancialSupport: Fapemig, Capes, CNPq.1 1 1 212XXIII Congreso Latinoamericano de Microbiología http://alam-cam2016.posterselectronicos.com/Abstract/e2d64082-cf27...2 de 4 21/11/2016 10:42

Maize endophytic bacteria and their potential as plant growth promoting.

http://www.alice.cnptia.embrapa.br/bitstream/doc/1056666/1/Maizeendophytic.pdf

Maize endophytic bacteria and their potential as plant growth promoting.

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