EFFECT OF PESTICIDES AND THE INOCULATION OF PHOSPHATE SOLUBILIZING BACTERIA ON THE COLONIZATION ABILITY OF NATIVE ARBUSCULAR MYCORRHIZAL FUNGI AND THE DEVELOPMENT OF PEANUT AND WHEAT PLANTS IN A CROP ROTATION SYSTEM

FERNANDEZ VALDEZ, PILAR; DALMASSO, ROMINA YANET; ANZUAY, MARÍA SOLEDAD; LUDUEÑA, LILIANA; TAURIAN, TANIA; ANGELINI, JORGE

Los Cocos

Congreso; XVII Congreso Argentino de Microbiología General; 2022

Sociedad Argentina de Microbiología General

Arbuscular mycorrhizal fungi (AMF) constitute the most common type of symbiosis in nature. AMFcolonize the roots of plants without causing harm, and through this intimate contact, the AMFreceives carbon fixed by the plant, in exchange for water and mineral nutrients, leading to a positiveimpact on plant growth. Agricultural ecosystems are dominated by this symbiosis, and agriculturalpractices can have varying effects on these fungi. The addition of pesticides can alter the fungalbiomass and their ability to provide nutrients to their host plant. Considering the importance ofphosphorus (P) on plant nutrition and its limited availability in soils, phosphate solubilizing bacteria(BSP) constitute one of the most important bacterial groups in agricultural soils. It has been proventhat some BSP can stimulate the establishment and growth of AMF. The objective of this work was to study the impact of the application of agrochemicals used on peanut (Arachis hypogaea L.) andwheat (Triticum aestivum) cultivation and the inoculation of the BSP Enterobacter sp. J49, on theability of native AMF to colonize roots and on the development of these plants, in a crop rotationsystem in a microcosm scale. For this purpose, 8 treatments with 5 repetitions each whereestablished: control pots without agrochemicals and non-inoculated seeds; pots withoutagrochemicals and inoculated seeds; pots with agrochemicals (commercial dose, half dose anddouble dose) and non-inoculates seeds; and pots with agrochemicals (commercial dose, half doseand double dose) and inoculated seeds. The level of AMF root colonization was determined as thenumber of root segments colonized divided by the total number of root segments, expressed aspercentage, at 40 and 100 days post-sowing. As growth parameters for both plants shoot length,fresh weight, dry weight and P content where measured. Result obtained indicate that on both plants at both times measured the percentage of root colonization by AMF was significantly higher in plants inoculated with the BSP and not treated with agrochemicals, with respect to all non-inoculated treatments. This parameter showed similar results in non-inoculated plants treated with agrochemicals and control plants. When all inoculated treatments where compared, plants treated with double dose of agrochemicals showed the lowest percentage of AMF root colonization. In terms of growth parameters of peanut and wheat at both times, results show that all inoculated plants had significantly higher values than non-inoculated plants. These results show that the addition of agrochemicals at commercial or half-dose has no negative effect on the ability of native AMF to colonize peanut and wheat plants, while the addition of double-dose of agrochemicals has a negative effect on this parameter. In regards to the inoculation of the BSP, our findings confirm the ability of Enterobacter sp. J49 to promote the growth of both plants at both time points measured.