Expression of the aldehyde oxidase 3, ent-copalyl diphosphate synthase, and VIVIPAROUS 1 genes in wheat cultivars differing in their susceptibility to pre-harvest sprouting

The quality of wheat grains is often negatively affected by pre-harvest sprouting (PHS), a complex trait with a poorly understood genetic background. In this study two wheat cultivars differing in their susceptibility to PHS were used to investigate expression of three genes: AAO3 , CPS3 and VP1 . AAO3 is coding for aldehyde oxidase 3, an enzyme involved in the synthesis of abscisic acid. CPS3 codes for ent-copalyl diphosphate synthase which belongs to the pathway of gibberellic acid synthesis. The product of VP1 (VIVIPAROUS 1 ) is a transcription factor which controls expression of the former two genes. The study was carried out using both developing and sprouting-induced grains. In Piko, a wheat cultivar susceptible to PHS, accumulation of the AAO3 transcript was significantly decreased, during the last stages of grain development, in comparison to Slawa, a cultivar tolerant to PHS. In case of the CPS3 and VP1 transcripts, the differences between cultivars were especially evident from 17 th to 31 st day after pollination. In turn, after induction of sprouting within spikes, accumulation of the AAO3 and VP1 mRNA in the Slawa grains was lower in comparison to that observed in the Piko grains. Moreover, accumulation of the CPS3 transcript was significantly higher for Piko than for Slawa, both in sprouting and non-sprouting grains. According to our knowledge this report provides the first description of the AAO3 and CPS3 expression in the context of PHS, and in the future it would be valuable to correlate this information with the data on the accumulation of ABA and GA 3 .