Differential metabolic responses of perennial grass Cynodon transvaalensis×Cynodon dactylon (C4) and Poa Pratensis (C3) to heat stress

Publication Type:Journal Article
Year of Publication:2011
Authors:Du, H, Wang, Z, Yu, W, Liu, Y, Huang, B
Journal:Physiologia Plantarum
Date Published:2011
ISBN Number:1399-3054

Differential metabolic responses to heat stress may be associated with variations in heat tolerance between cool-season (C3) and warm-season (C4) perennial grass species. The main objective of this study was to identify metabolites associated with differential heat tolerance between C4 bermudagrass and C3 Kentucky bluegrass by performing metabolite profile analysis using gas chromatography-mass spectrometry. Plants of Kentucky bluegrass (Poa Pratensis‘Midnight’) and hybrid bermudagrass (Cynodon transvaalensis×Cynodon dactylon‘Tifdwarf’) were grown under optimum temperature conditions (20/15°C for Kentucky bluegrass and 30/25°C for bermudagrass) or heat stress (35/30°C for Kentucky bluegrass and 45/40°C for bermudagrass). Physiological responses to heat stress were evaluated by visual rating of grass quality, measuring photochemical efficiency (variable fluorescence to maximal fluorescence) and electrolyte leakage. All of these parameters indicated that bermudagrass exhibited better heat tolerance than Kentucky bluegrass. The metabolite analysis of leaf polar extracts revealed 36 heat-responsive metabolites identified in both grass species, mainly consisting of organic acids, amino acids, sugars and sugar alcohols. Most metabolites showed higher accumulation in bermudagrass compared with Kentucky bluegrass, especially following long-term (18 days) heat stress. The differentially accumulated metabolites included seven sugars (sucrose, fructose, galactose, floridoside, melibiose, maltose and xylose), a sugar alcohol (inositol), six organic acids (malic acid, citric acid, threonic acid, galacturonic acid, isocitric acid and methyl malonic acid) and nine amino acids (Asn, Ala, Val, Thr, γ-Aminobutyric acid, IIe, Gly, Lys and Met). The differential accumulation of those metabolites could be associated with the differential heat tolerance between C3 Kentucky bluegrass and C4 bermudagrass.

Short Title:Physiologia Plantarum
Taxonomic name: 
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Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith