Comparation of Fusarium verticillioides incidence and fumonisins content in maize grains from plants with female inflorescences covered and uncovered

SARTORI, MELINA; NESCI, A; ETCHEVERRY, M.

Mendoza

Conferencia; MYCORED ARGENTINA ISM 2011 Conference, Strategies to reduce the impact of mycotoxins in Latin Amrica in a global context; 2011

MYCORED ARGENTINA

Maize kernels are universally infected by Fusarium verticillioides (Sacc.) Nirenberg (Teleomorph: Gibberella moniliformis Wineland). Many infected plants are asymptomatic, but when the balance is altered stem and ears maize rot occurs. The rot in the ears of maize caused by F. verticillioides seriously affect yields in Argentina. Even when the grains are apparently healthy, could result in the accumulation of toxic metabolites such as fumonisin B1 (FB1) and B2 (FB2), which have a potential toxicity associated with harmful effects on animal and human health. F. verticillioides can invade maize plant in three infection pathways: i) Growth in root systems stem and leaf through seed transmission (vertically dissemination); ii) Infection of the ears through airborne transmission or splash of rain from microconidia or macroconidia crop residues (horizontal transmission); iii) Contamination of crops by insect vectors (horizontal transmission). Extrinsic factors of abiotic origin have included water availability and temperature. The aim of this study was to determine which the main route of infection of F. verticillioides is in maize plant, to determine the best way to apply a biological control agent of the pathogen. The assay was performed with three random blocks on plots of 3 x 7 m. EscucharLeer fonéticamente DiccionarioPaper bags permeable to moisture, were placed in the ears or female inflorescences, in ten plants per treatment per block, at the time of flowering and allowed to harvest the maize. In the harvested grain was determined F. verticillioides incidence. Fumonisins contents were analyzed by HPLC Although there was a higher count of F. verticillioides in the treatment of the ears covered with bags, all counts were in the order of 5 log. Apparently the bags did not prevent the infection of maize. Significant differences were observed in the content of FB1 and FB2 between treatments of the ears covered with respect to non-covered ears (p>0.0018), finding significant levels of these toxins in maize obtained from covered ears. Based on the results can be inferred that the main route of entry of spores of F. verticillioides in the plants analyzed is by vertical transmission through seeds and not horizontally, as has been observed that the pathogen was isolated from the harvested grain, even when the female inflorescences were covered from the time of flowering to harvest.