Analysis of obtained chloroplast transformants of tobacco (Nicotiana tabacum L.) plants with marker expression cassette of aadA au gene, changing the color of leaves

Abstract

Transplastomic tobacco Nicotiana tabacum cv. Petit Havana plants were obtained by ballistic transformation. The modified expression cassette aadA au was used as a marker, which confers the resistance to streptomycin and spectinomycin and causes the golden color of the leaf when planted in the soil after selection on selective medium. Plants were transferred into soil and screened for the golden leaf color. Molecular analysis was performed to confirm the transplastomic nature of the plants. The differences in plastid ultrastructure of mesophyll cells between the leaves of tobacco plants of wild-type (with green leaf fragments) and plastids with altered pigmentation (old leaves of wild-type and yellow pieces of the leaf with transformed chloroplasts) were analyzed by electron microscopy. It was shown that the ultrastructural organization of plastids of transplastomic plants with golden color had distinct differences from the chloroplasts of plants in the control group by the number and arrangement of thylakoids, the number and sizes of starch grains and plastoglobules. Decreased number of thylakoids and starch grain inclusions was marked in the mesophyll cells on a background of their increased number in the stroma and grana. There were also significantly more light areas of the stroma in transplastomic plants, which was typical for nucleoid areas.