Insights into the Mechanisms of Heat Priming and Thermotolerance in Tobacco Pollen |
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Authors: | Lavinia Mareri Claudia Faleri Iris Aloisi Luigi Parrotta Stefano Del Duca Giampiero Cai |
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Affiliation: | 1.Department of Life Sciences, University of Siena, Via P.A. Mattioli 4, 53100 Siena, Italy; (L.M.); (C.F.); (G.C.);2.Department of Biological, Geological and Environmental Sciences, University of Bologna, Via Irnerio 42, 40126 Bologna, Italy; (I.A.); (S.D.D.);3.Interdepartmental Centre for Agri-Food Industrial Research, University of Bologna, Via Quinto Bucci 336, 47521 Cesena, Italy |
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Abstract: | Global warming leads to a progressive rise in environmental temperature. Plants, as sessile organisms, are threatened by these changes; the male gametophyte is extremely sensitive to high temperature and its ability to preserve its physiological status under heat stress is known as acquired thermotolerance. This latter can be achieved by exposing plant to a sub-lethal temperature (priming) or to a progressive increase in temperature. The present research aims to investigate the effects of heat priming on the functioning of tobacco pollen grains. In addition to evaluating basic physiological parameters (e.g., pollen viability, germination and pollen tube length), several aspects related to a correct pollen functioning were considered. Calcium (Ca2+) level, reactive oxygen species (ROS) and related antioxidant systems were investigated, also to the organization of actin filaments and cytoskeletal protein such as tubulin (including tyrosinated and acetylated isoforms) and actin. We also focused on sucrose synthase (Sus), a key metabolic enzyme and on the content of main soluble sugars, including UDP-glucose. Results here obtained showed that a pre-exposure to sub-lethal temperatures can positively enhance pollen performance by altering its metabolism. This can have a considerable impact, especially from the point of view of breeding strategies aimed at improving crop species. |
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Keywords: | pollen heat priming heat stress response sugar metabolism antioxidant response calcium cytoskeleton |
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