Identification of suitable reference genes by quantitative real-time PCR for gene expression normalization in sunflower

PICARDI, L.A.; PICARDI, L.A.; OCHOGAVIA, A,; OCHOGAVIA, A,; NESTARES, GRACIELA; NESTARES, GRACIELA

PLANT OMICS

SOUTHERN CROSS PUBL

Año: 2017 vol. 10 p. 210 - 218

1836-0661

cetohydroxyacid synthase (AHAS) is the target site of several herbicides. This enzyme catalyzes the first step in the biosynthesis of branched chain amino acid. In sunflower, three genes coding for AHAS catalytic subunit were reported (ahas1, ahas2 and ahas3). The aim of this work was to study the expression pattern of ahas genes family and AHAS activity in sunflower. Different organs (leaves, shoots, roots, flowers and embryos) were evaluated at different developmental stages. The transcriptional profile was studied for the three genes through RT-qPCR. Ahas1 level was higher in vegetative tissues than in reproductive ones, while the opposite behaviour was observed for ahas2 and ahas3. This study confirmed that ahas1 higher expression was in leaves, where all the induced and natural gene mutations conferring herbicide resistance were found meanwhile . Ahas2 and ahas3 maximal expression was in immature flowers and embryos. A positive correlation was observed for ahas2 and ahas3 transcript amounts in reproductive tissues, with maximal levels in immature disc flowers and at 20 days post flowering seeds. The highest AHAS activity was found in leaves and immature embryos, and positive correlation was detected for ahas genes and AHAS activity in roots, flowers and embryos but no for green tissues. It can be concluded that differences in AHAS genes expression are tissue-specific and temporally regulated. Moreover, maintaining multiple AHAS isoforms in sunflower seems to be the result of variable expression requirements controlled by different regulatory mechanisms in diverse organs at specific developmental stages.