Print version ISSN 1405-3195
SILVA-PEREZ, Viridiana et al. QTLs associated to carotene content in maize leaves (Zea mays L.). Agrociencia [online]. 2012, vol.46, n.4, pp. 333-345. ISSN 1405-3195.
Carotenoids are antioxidant pigments that capture photons from the visible spectrum and protect plant tissues against photo-oxidation, which is related to photosynthesis rate and crop yield. Biosynthesis of carotenoids occurs in plastids, where they are synthesized via the mevalonate-independent pathway, whit more than 10 enzymes and an unknown number of factors are involved. In order to identify chromosome regions of maize (Zea mays L.) associated with carotene content, carotenoids were measured in leaves from 200 maize recombinant inbred lines (RILs), developed from a B73×Mo17 cross and grown in Irapuato, México, during the 2009 spring/summer cycle. Quantitative trait loci (QTLs) found were associated with the following compounds: lutein, α-carotene, β-carotene, β-cryptoxanthin and zeaxanthin. β-carotene (80% of total) was the carotene present in the highest amount in the leaves and β-cryptoxanthin (0.2%) was the lowest. Twenty-one significant QTLs were located in chromosomes 1, 2, 4, 5, 6 and 8. A highly significant QTL (p≤0.001) was located in bin 1.07 with a high additive value for lutein (-89.16 µg g-1 DW, r2 ≅0.07 ), α-carotene (-25.41 µg g-1 DW, r2 ≅0.07 ) and β-carotene (-674.98 µg g-1 DW, r2 ≅0.09 ). A β-cryptoxanthin QTL was located in chromosome 8 using the psy2 marker which is a palarog gene to the phytoene synthase enzyme; another QTL coincided with an abscisic acid QTL related to the carotene dioxygenase gene. It is inferred that in the maize genome there are unknown factors related to carotene content in green leaves, and the QTLs located in this study could help to identify new genes or factors that determine the carotenoid content in maize leaves.
Keywords : Zea mays; QTLs; quantitative traits; carotenoids in leaves.