Betaines and free amino acids in salt stressed vitroplants and winter resting buds of Populus trichocarpa X deltoides

Abstract

199LBetaines and free amino acids in salt stressed vitroplants and winter resting buds of Populus trichocarpa x de/ (oWra, Organic solutes, in particular glycine betaine and proline, have been detected as osmoprotective compounds in many microorganisms and herbaceous species. However, for woody plants, very little information is available on mechanisms of adaptation to salt stress. In the present study, effects of NaCI treatment on betaine and free amino acid contents in a clone of Populus trichocarpa x deltoides micropropagated vitroplants were analyzed using HPLC and silicate plate chromatography. The application during 12 days of 50 to 200' mM NaCl to vitroplants cultured on Murashige and Skoog medium (Murashige and Skoog 1962, Physioi, Plant. 15: 473-497) led to a progressive decrease of growth, leaf senescence, abscission, and apical necrosis, Populus trichocarpa x dehoides was characterized by the absence of glycine betaine and/oT proline accumulation. However, trigonelline was found to increase in vitroplants subjected lo 100 mM NaCI. Trigonelline was also' present in dormant buds harvested in natural conditions and missing in active buds. In vitroplants, the content of some amino acids was strongly modified by salt stress, A progressive accumulation of alanine and 7-amino butyrale was particularly significant in roots, whereas the relative concentration of glutamine was strongly enhanced in leaves. Leaf content of glutamate and ornithine attained maximum in the presence of 100 and 150 mM NaCl concentrations, and then deereased. Arginine and serine pools were not significantly modified by salt treatment. The variations in vitroplants were of small amplitude connpared to those obser\'ed in mature poplars where winter rest was associated with a very high arginine level and with a disappearance of nearly all other free amino acids. The results are discussed in relation to previous data obtained with herbaceous species and in relation to some metabolic pathways in poplars where trigoneiline could be considered as a sensitive stress indicator.

Effect of short‐term salt stress on the metabolic profiles of pyrimidine, purine and pyridine nucleotides in cultured cells of the mangrove tree, Bruguiera sexangula

“…5A). Trigonelline has been recognised in compatible solutes, and the content increased in some salt‐stressed plants (Bray et al 1991, Cho et al 1999, Tramontano and Jouve 1997). An increase in trigonelline synthesis with salt stress therefore appears to be closely related to the synthesis of osmoprotective compounds so as to prevent water loss when these mangrove cells are exposed to excess salt.…”

Defensive and secondary metabolism in plant tissue cultures, with special reference to nicotinamide, glutathione and oxidative stress

“…Increased trigonelline levels may also occur in response to salt stress (Bray et al 1991). Thus, it is tempting to speculate that PADPRPinduced NIC release is a connection between many stress conditions, especially oxidative stress, causing, for example, single strand breakage (SSB) in DNA and the induction of defensive metabolism, involving secondary metabolite biosynthesis, as well as activation of peroxide and free radical-degrading enzymes.…”

Chemical basis for differential acceptance of two sympatric rutaceous plants by ovipositing females of a swallowtail butterfly, Papilio polytes (Lepidoptera, Papilionidae)

“…However, trigonelline is not ubiquitous in the plant kingdom, and some plant species have been demonstrated to accumulate certain betaines including trigonelline in considerable concentrations in response to a variety of environmental stresses, particularly to salt stress (Bray et al 1991;Gorham 1995;Tramontano & Jouve 1997;Cho et al 1999;Sakamoto & Murata 2001). To our knowledge, this is the first report of trigonelline from rutaceous plants.…”