title: Heat Stress Decreases Levels of Nutrient-Uptake and -Assimilation Proteins in Tomato Roots.
abstract: Global warming will increase root heat stress, which is already common under certain conditions. Effects of heat stress on root nutrient uptake have rarely been examined in intact plants, but the limited results indicate that heat stress will decrease it; no studies have examined heat-stress effects on the concentration of nutrient-uptake proteins. We grewSolanum lycopersicum(tomato) at 25 °C/20 °C (day/night) and then transferred some plants for six days to 35 °C /30 °C (moderate heat) or 42 °C/37 °C (severe heat) (maximum root temperature = 32 °C or 39 °C, respectively); plants were then moved back to control conditions for seven days to monitor recovery. In a second experiment, plants were grown for 15 days at 28 °C/23 °C, 32 °C/27 °C, 36 °C/31 °C, and 40 °C/35 °C (day/night). Concentrations of nutrient-uptake and -assimilation proteins in roots were determined using protein-specific antibodies and ELISA (enzyme-linked immunosorbent assay). In general, (1) roots were affected by heat more than shoots, as indicated by decreased root:shoot mass ratio, shoot vs. root %N and C, and the level of nutrient metabolism proteins vs. less sensitive photosynthesis and stomatal conductance; and (2) negative effects on roots were large and slow-to-recover only with severe heat stress (40 °C-42 °C). Thus, short-term heat stress, if severe, can decrease total protein concentration and levels of nutrient-uptake and -assimilation proteins in roots. Hence, increases in heat stress with global warming may decrease crop production, as well as nutritional quality, partly via effects on root nutrient relations.
authors.affiliation: Department of Environmental Sciences, University of Toledo, Toledo, OH 43606, USA. anjugiri1@gmail.com.
authors.forename: Anju
authors.initials: A
authors.lastname: Giri
authors.affiliation: Department of Environmental Sciences, University of Toledo, Toledo, OH 43606, USA. scott.heckathorn@utoledo.edu.
authors.forename: Scott
authors.initials: S
authors.lastname: Heckathorn
authors.affiliation: Department of Environmental Sciences, University of Toledo, Toledo, OH 43606, USA. samishra@kean.edu.
authors.forename: Sasmita
authors.initials: S
authors.lastname: Mishra
authors.affiliation: U.S. Department of Agriculture, University of Toledo, Toledo, OH 43606, USA. charles.krause@ars.usda.gov.
authors.forename: Charles
authors.initials: C
authors.lastname: Krause
keywords: Solanum lycopersicum; heat stress; high temperature; nutrient-uptake proteins; nutrients; tomato