Apocarotenoid gene expression in saffron (Crocus sativus L.)

Saffron (Crocus sativus L.) is a triploid sterile plant characterized by its long red stigmas, which produce and store its chief carotenoid derivatives-safranal, crocin and picrocrocin. Saffron selections of Kashmir are heterogeneous for floral characteristics which are mainly attributed to the environmental factors, though genetic factors may have role with regard to its differential characteristics across various selections found in the area. Identification of high yielding selections using the existing gene pool of saffron may help in improving the productivity of this crop. The present study was conducted at Biotechnology Lab, Central Institute of Temperate Horticulture, Srinagar, India during 2012-2013 to find out the apocarotenoid gene expression in thirty-one morphogically distinct clones of saffron. Comparative apocarotenoid gene expression through Real Time PCR analysis revealed a significant variation in Zeaxanthin cleavage dioxygenase (CsZCD) and lycopene-β-cyclase (CsLYC) genes between the most divergent selections (CITH-S-107 and PAM-S-116) indicating a possible role of these genes for regulating the apocarotenoid production in stigma. Significant variation was observed with respect to stigma length (2.86 to 4.84 cm) across thirty-one selected saffron clones. Although some clones showed variation with respect to stigma number, in addition to normal trifid stigmas, some clones produce tetrafid stigmas as well but this character was not heritable. Our study provides sufficient knowledge to identify clones with better stigma characteristics and higher apocarotenoid biosynthetic potential for further crop improvement programs.