Molecular, morphological, and biomolecular characterization of ethyl methanesulfonate-induced mutations in Aerides odoratum, an orchid

Abstract

Aerides odoratum L. is a medicinal and ornamental orchid of the Eastern Himalayas, India. Its uses in pharmacology are nought because of its rare occurrence, longer life cycle, and lack of artificial methods for large-scale propagation. Protocorms (60 days old) were treated with various concentrations of ethyl methanesulfonate ranging from 0.025% to 0.5% for different durations (2, 5, 7, and 10 days) during M0 (treatment) in vitro generation. The survival of these protocorms and the generation of shoots and roots were noted. 10–20 plantlets of each treatment showing variation in the number and weight of shoots in M0 generation (treatment generation) were maintained for three subsequent generations. M3 (third generation) axenic plantlets were hardened in the orchidarium with a 75% survival frequency. Four mutant lines (M3V1–M3V4) were established based on RAPD analysis of the leaf DNA of 300-day-old plants. M3V-1 was noted as the best among all mutant lines based on morphological analysis, whereas M3V-2 was noted as the most superior in terms of having the highest quantity of osmolytes, pigments, stomata, and phenol. M3V-3 had maximum root length, leaf breadth, and carotenoids. M3V-4 showed the viridis chlorophyll spectrum as the most distinguishing factor. Hence, this standardized protocol can be used for the genetic improvement of A. odoratum.