COMPARATIVE ANALYSIS OF THE N2-FIXING AND PHOSPHATE-SOLUBILIZING BACTERIAL COMMUNITIES ASSOCIATED WITH GREENHOUSE-TOMATO CROPS

VIO, SANTIAGO ADOLFO; GARCIA, SABRINA SOLEDAD; BERNABEU, PAMELA; RILLING, JOAQUÍN IGNACIO; PISTORIO, MARIANO; JORQUERA, MILKO ALBERTO; LUNA, MARIA FLAVIA

Valparaíso

Congreso; 1° ISME Latino América; 2019

The potential plant growth promotion functions of plant-associated bacterial communities have received significant attention in recent years. In this way, we assessed the bacterial functional diversity associated with greenhouse-tomato plants in two sites of the horticultural belt of La Plata, Argentina: Site-I, large story of tomato crops and Site-II, pristine land with its first tomato crop. Total DNA was obtained from samples of bulk soil (BS), rhizosphere (Rh) and surface-disinfected root (Rt), stem (St) and fruit (Ft) samples of tomato var. elpida. The diversity of nifH and phoD genes was assessed with PCR-DGGE. Total bacteria (16S-rRNA), phoD and nifH gene abundances were evaluated with qPCR. PCR-DGGE revealed differences in all communities from both sites. For phoD, all samples were different at 70%. For nifH gene, BS and Rh of both sites were different at 70%, whereas plant tissue samples presented large similarities between sites.qPCR revealed similar copy numbers between both sites total and phoD communities (~1014, ~1014, ~1010, ~109, and ~108 16S copies g-1 sample, and ~106, ~106, ~105, ~103 and ~103 phoD copies g-1 sample in BS, Rh, Rt, St and Ft, respectively). For nifH, both sites contained ~106 and ~107 copies g-1 sample in BS and Rh, respectively. Rt, St and Ft samples were not successfully quantified.Results suggest that (I) agronomic usage of soil in this crop modified the diversity of functional genes in all studied niches; (II) plant selection of its functional internal microbiome might occur; (III) the abundance of specialized bacterial communities remains constant.