Elicitors, SA and MJ enhance carotenoids and tocopherol biosynthesis and expression of antioxidant related genes in Moringa oleifera Lam. leaves.

Moringa oleifera Lam. leaves are rich source of
carotenoids (provitamin A) and a-tocopherol (vitamin E),
and there is a scope for their further enhancement, through
elicitor mediation, thereby a great potential for addressing
these vitamins deficiency. In the present study, we report
the efficacy of foliar administration of biotic elicitors,
carboxy-methyl chitosan and chitosan, and signaling molecules,
methyl jasmonate (MJ) and salicylic acid (SA) for
enhancement of major carotenoids and a-tocopherol.
Highest a-tocopherol content of 49.7 mg/100 g FW was
recorded upon foliar application of 0.1 mM SA after 24 h
of treatment, which represented a 187.5 % increase in
comparison to the untreated control. Similarly, a maximum
of 52.6 mg/100 g FW lutein, and 21.8 mg/100 g FW bcarotene
content were observed in leaves after 24 h of
treatment with MJ, which represented a 54.0 and 20.3 %
increase in comparison to the untreated control, respectively.
Among the major genes of carotenoid biosynthetic
pathway, the expression of lycopene b-cyclase (LCY-b)
was maximum influenced after treatment with elicitors and
signaling molecules, compared to phytoene synthase and
phytoene desaturase, suggesting the LCY-b-mediated
enhancement in the production of b-carotene in elicitor
treated M. oleifera leaves. Enhanced production of atocopherol
under respective elicitor treatment was further
supported by 2.0–2.7 fold up-regulation of c-tocopherol
methyl transferase, compared to untreated control. This is
the first report on elicitor-mediated enhanced production of
tocopherol and carotenoids in foliage of economically
important food plant.