The Influence of Photoperiod on the Regulation of Root and Callus Initiation of Perle Noir (<i>V. vinifera</i> L.): Expression of MADS-Box Gene

Abstract

To study the influence of photoperiod on roots differentiation in the Tunisian grapevine ( Vitis vinifera L.) cultivar Perle noir, roots and callus initiation were analyzed under three different conditions of day length: long day (LD), short day (SD) and darkness (D). The photoperiod influenced the number of callus and roots per cuttings; it has a significant effect on the roots and callus initiation. Expression profile analysis of six MADS-box genes ( VTM8 , VSEP 2, VAG 12, VAG 17-1, VAG 17-2 and VSOC 1.3) during root and callus development is in agreement with the above-mentioned observation. The expression of the MADS-box genes during root and callus development fluctuated in a tissue-dependent manner. These data suggest that all genes are expressed in roots under three photoperiods. Total darkness gives the number of the most important root per cutting compared to the other two conditions. This photoperiodic condition gave the most important expression of the studied genes VAG 12, VAG 17-2, VAG 17-1, VTM 8 and VSEP 2 transcripts were not found in callus grown in the dark or in LD conditions, respectively. VSOC 1.3 transcripts were not found in callus grown in the dark or in SD conditions, respectively. Transcript abundance of VTM 8 and VSOC 1 was highest in LD.