Differential gene expression in sugarcane roots infested by root froghopper

Abstract

Currently, sugarcane (Saccharum spp.) has been threatened by infestation of root froghopper (Mahanarva fimbriolata) and concern about its harmful effects is growing, due to the increase of envi­ronmental conditions favorable to the development of this pest, such as the harvest system expansion, in which there is no burning of sugarcane straw. The cDNA-AFLP technique was performed in order to identify the Differentially Expressed Fragments (DEF) in roots of sugarcane infested by root froghopper nymphs. Thus, plants of a susceptible variety (SP80-1816) and a resistant variety ("least infested") (SP83-5073) were grown and subsequently infested. Samples of roots were collected and frozen every 1, 2, 7 and 14 days of infestation. The subsequent analysis by cDNA-AFLP technique from seven combinations of primers allowed the observation of 37 fragments, which were sequenced and revealed similarities to proteins involved in various activities, such as DNA transposition, amino acid transport and gene transcription, in addition to other proteins without sequence similarity to proteins of known function. The alignments show similarities to expressed genes and it is possible to consider that the character of resistance is related to a combined action of several genes; in addition, some of the fragments obtained do not show similarities and may have important roles in the mechanism of resistance.