We tested for a tradeoff across species between plant maximum photosynthetic rate and the ability to maintain photosynthesis under adverse conditions in the unfavorable season. The ecotype ‘Falster’, adapted to cold climates, increased total fructan content and produced more fructans (DP˃7) in the roots than the variety ‘Veyo’, adapted to warmer climates suggesting that accumulation of fructans in roots, especially the high-DP fructans as an adaptive trait for plant recovery after abiotic stresses. Our results also show the accumulation and depolymerization of fructans with different DP, together with the induction of genes encoding fructosyltransferases and fructan exohydrolases in both ‘Veyo’ and ‘Falster’ during cold acclimation, supporting the hypothesis that fructan synthesis and depolymerization occurring simultaneously. The accumulation of fructans, DP˃50 was only apparent in the top tissues where the Lp1-FFT expression is higher compared to the roots in both “Veyo” and “Falster. We observed changes in fructan composition and induction of low-DP fructans, especially DP=4, in both the top and the roots of ‘Veyo’ and ‘Falster’ in response to low-temperature stress. The present study describes the analysis of the compositional changes in the full spectrum of fructan oligomers, fructan distribution between above ground biomass (top) and the roots, and the transcription of candidate genes involved in fructan metabolism during cold acclimation in perennial ryegrass variety ‘Veyo’ and ecotype ‘Falster’ from distinct geographical origins. Perennial ryegrass (Lolium perenne L.) produces high levels of fructans as a mixture of oligomers with different degrees of polymerization (DP). Results in this report demonstrate that cold-induced changes in FA profile represent a useful screening tool for early identification of differences in cold acclimation potential among rice accessions. Double-bond index analysis indicated that 18 carbons FAs DBI for roots might be a good screening tool for cold response in rice. Linolenic acid was reduced in the shoots of both Amaroo and Quila 66304, while oleic acid content was reduced in shoots of Amaroo and slightly increased in shoots of Quila 66304. Cold exposure also led to enhanced levels of palmitic acid in shoots of Amaroo and, in a smaller extent, in shoots of Quila 66304. Similarly, roots of cold-exposed line Quila 66304 also presented preferential accumulation of linolenic and linoleic FAs and reduction of palmitic and stearic FAs.
Cold exposure led to the preferential accumulation of the polyunsaturated linolenic and linoleic FAs and reduction of palmitic and stearic FAs, besides showing increased lignoceric acid content in roots of the variety. In this work, we evaluated changes in fatty acid (FA) composition as a potential screening tool to evaluate chilling sensitivity of rice accessions. Several reports have demonstrated that cold induce differential effects on the fatty acids profile of membranes in chilling-sensitive and chilling-tolerant plants.
Breeding programs aimed at increasing rice production are expected to reduce cold-imposed grain losses. Rice, a staple food for more than one half of the world’s population, is one of the most cold-sensitive cereals.