Differential Role for Trehalose Metabolism in Salt-Stressed Maize.
Little is known about how salt impacts primary metabolic pathways of C4 plants, particularly related to kernel development and seed set. Osmotic stress was applied to maize (Zea mays) B73 by irrigation with increasing concentrations of NaCl from the initiation of floral organs until 3 d after pollination. At silking, photosynthesis was reduced to only 2% of control plants. Salt treatment was found to reduce spikelet growth, silk growth, and kernel set. Osmotic stress resulted in higher concentrations of sucrose (Suc) and hexose sugars in leaf, cob, and kernels at silking, pollination, and 3 d after pollination. Citric acid cycle intermediates were lower in salt-treated tissues, indicating that these sugars were unavailable for use in respiration. The sugar-signaling metabolite trehalose-6-phosphate was elevated in leaf, cob, and kernels at silking as a consequence of salt treatment but decreased thereafter even as Suc levels continued to rise. Interestingly, the transcripts of trehalose pathway genes were most affected by salt treatment in leaf tissue. On the other hand, transcripts of the SUCROSE NONFERMENTING-RELATED KINASE1 (SnRK1) marker genes were most affected in reproductive tissue. Overall, both source and sink strength are reduced by salt, and the data indicate that trehalose-6-phosphate and SnRK1 may have different roles in source and sink tissues. Kernel abortion resulting from osmotic stress is not from a lack of carbohydrate reserves but from the inability to utilize these energy reserves.
Department of Agronomy and Horticulture, University of Nebraska, Lincoln, Nebraska 68583-0915 (C.H., S.W.B., A.K., M.L.);Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, United Kingdom (C.A.G., M.J.P.); andAgrocampus-Ouest, Institut de Recherche en Horticulture et Semences (INRA, Agrocampus-Ouest, Université d'Angers), SFR 149 QUASAV, F-49045 Angers, France (S.S.).
Clémence
http://orcid.org/0000-0002-3782-3794
C
Henry
Department of Agronomy and Horticulture, University of Nebraska, Lincoln, Nebraska 68583-0915 (C.H., S.W.B., A.K., M.L.);Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, United Kingdom (C.A.G., M.J.P.); andAgrocampus-Ouest, Institut de Recherche en Horticulture et Semences (INRA, Agrocampus-Ouest, Université d'Angers), SFR 149 QUASAV, F-49045 Angers, France (S.S.).
Samuel W
SW
Bledsoe
Department of Agronomy and Horticulture, University of Nebraska, Lincoln, Nebraska 68583-0915 (C.H., S.W.B., A.K., M.L.);Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, United Kingdom (C.A.G., M.J.P.); andAgrocampus-Ouest, Institut de Recherche en Horticulture et Semences (INRA, Agrocampus-Ouest, Université d'Angers), SFR 149 QUASAV, F-49045 Angers, France (S.S.).
Cara A
http://orcid.org/0000-0001-5167-2606
CA
Griffiths
Department of Agronomy and Horticulture, University of Nebraska, Lincoln, Nebraska 68583-0915 (C.H., S.W.B., A.K., M.L.);Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, United Kingdom (C.A.G., M.J.P.); andAgrocampus-Ouest, Institut de Recherche en Horticulture et Semences (INRA, Agrocampus-Ouest, Université d'Angers), SFR 149 QUASAV, F-49045 Angers, France (S.S.).
Alec
A
Kollman
Department of Agronomy and Horticulture, University of Nebraska, Lincoln, Nebraska 68583-0915 (C.H., S.W.B., A.K., M.L.);Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, United Kingdom (C.A.G., M.J.P.); andAgrocampus-Ouest, Institut de Recherche en Horticulture et Semences (INRA, Agrocampus-Ouest, Université d'Angers), SFR 149 QUASAV, F-49045 Angers, France (S.S.).
Matthew J
MJ
Paul
Department of Agronomy and Horticulture, University of Nebraska, Lincoln, Nebraska 68583-0915 (C.H., S.W.B., A.K., M.L.);Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, United Kingdom (C.A.G., M.J.P.); andAgrocampus-Ouest, Institut de Recherche en Horticulture et Semences (INRA, Agrocampus-Ouest, Université d'Angers), SFR 149 QUASAV, F-49045 Angers, France (S.S.).
Soulaiman
S
Sakr
Department of Agronomy and Horticulture, University of Nebraska, Lincoln, Nebraska 68583-0915 (C.H., S.W.B., A.K., M.L.);Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, United Kingdom (C.A.G., M.J.P.); andAgrocampus-Ouest, Institut de Recherche en Horticulture et Semences (INRA, Agrocampus-Ouest, Université d'Angers), SFR 149 QUASAV, F-49045 Angers, France (S.S.) mlagrimini2@unl.edu.
L Mark
http://orcid.org/0000-0002-8588-1569
LM
Lagrimini
D050260:Carbohydrate Metabolism / Q000187:drug effects; D018506:Gene Expression Regulation, Plant; D005964:Glucosyltransferases / Q000235:genetics / Q000378:metabolism; D009997:Osmotic Pressure; D010744:Phosphoric Monoester Hydrolases / Q000235:genetics / Q000378:metabolism; D010788:Photosynthesis / Q000187:drug effects; D018515:Plant Leaves / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism; D012639:Seeds / Q000378:metabolism; D012965:Sodium Chloride / Q000494:pharmacology; D013312:Stress, Physiological; D013395:Sucrose / Q000378:metabolism; D013403:Sugar Phosphates / Q000378:metabolism; D014199:Trehalose / Q000031:analogs & derivatives / Q000378:metabolism*; D003313:Zea mays / Q000187:drug effects / Q000502:physiology*
D010940:Plant Proteins; D013403:Sugar Phosphates; C082722:trehalose-6-phosphate; D012965:Sodium Chloride; D013395:Sucrose; D014199:Trehalose; D005964:Glucosyltransferases; C023180:trehalose-6-phosphate synthase; C071570:SNF1-related protein kinases; D017346:Protein Serine-Threonine Kinases; C023178:trehalose-phosphatase; D010744:Phosphoric Monoester Hydrolases