Ultrastructural evidence for AMF mediated salt stress mitigation in Trigonella foenum-graecum.
The study unveils that inoculation with arbuscular mycorrhizal fungus (Glomus intraradices Schenck and Smith) prevents salt-induced ultrastructural alterations in fenugreek (Trigonella foenum-graecum L.) plants. Mycorrhizal (M) and non-mycorrhizal (NM) fenugreek plants were subjected to four levels of NaCl (0, 50, 100, and 200 mM NaCl). Salt-induced ultrastructural changes were captured using a Transmission Electron Microscope. Effects of salt on the ultrastructure of cells include shrinkage of protoplasm, widening apoplastic space between cell wall and cell membrane, disorganization of grana in chloroplast--swelling and reduction in the number of thylakoids, disintegration of chloroplast membrane, accumulation of plastoglobules, dilation of cristae and denser matrix in mitochondria, and aggregation of chromatin in nucleus. However, the extent of salt-induced ultrastructural damage was less in M plants as compared to NM plants. Lower lipid peroxidation and electrolyte leakage in M plants also indicated less membrane damage. This reduction of ultrastructure damage is a demonstration of enhanced tolerance in M plants to salt stress. The AMF-mediated lesser damage may be due to higher osmolyte (glycinebetaine, sugars) and polyamines concentration, and more and bigger plastoglobules (higher α-tocopherol concentration) in M plants as compared to NM plants. While lower Na(+) and Cl(-) ions assures less ionic toxicity, higher osmolytes and tocopherols ensure osmotic adjustment and better capacity to scavenge free radicals generated due to salt stress, respectively.
Applied Mycology Laboratory, Department of Botany, University of Delhi, Delhi 110 007, India. meevelin@gmail.com
Heikham
H
Evelin
Bhoopander
B
Giri
Rupam
R
Kapoor
D050260:Carbohydrate Metabolism; D002241:Carbohydrates; D002462:Cell Membrane / Q000187:drug effects / Q000502:physiology / Q000648:ultrastructure; D002467:Cell Nucleus / Q000187:drug effects / Q000502:physiology / Q000648:ultrastructure; D002473:Cell Wall / Q000187:drug effects / Q000502:physiology / Q000648:ultrastructure; D002736:Chloroplasts / Q000187:drug effects / Q000502:physiology / Q000648:ultrastructure; D055137:Glomeromycota / Q000187:drug effects / Q000502:physiology / Q000648:ultrastructure*; D058503:Mesophyll Cells / Q000187:drug effects / Q000502:physiology / Q000648:ultrastructure; D046529:Microscopy, Electron, Transmission; D008928:Mitochondria / Q000187:drug effects / Q000502:physiology / Q000648:ultrastructure; D038821:Mycorrhizae / Q000187:drug effects / Q000502:physiology / Q000648:ultrastructure*; D009995:Osmosis; D018515:Plant Leaves / Q000187:drug effects / Q000502:physiology / Q000648:ultrastructure; D018517:Plant Roots / Q000187:drug effects / Q000382:microbiology / Q000502:physiology / Q000648:ultrastructure*; D011073:Polyamines / Q000378:metabolism; D012492:Salts; D012965:Sodium Chloride / Q000494:pharmacology*; D013312:Stress, Physiological; D029910:Trigonella / Q000187:drug effects / Q000502:physiology / Q000648:ultrastructure*; D024502:alpha-Tocopherol / Q000378:metabolism
D002241:Carbohydrates; D011073:Polyamines; D012492:Salts; D012965:Sodium Chloride; D024502:alpha-Tocopherol