Physiological and molecular insights into the high salinity tolerance of Pongamia pinnata (L.) pierre, a potential biofuel tree species.
Soil salinity is gradually becoming a threat to the global economy by affecting agricultural productivity worldwide. Here, we analyze the salinity tolerance of Pongamia pinnata with an insight into the underlying physiological and molecular responses. Despite a reduction in net photosynthetic rate, P. pinnata efficiently maintained its leaf water potentials even at 500mM NaCl for 15days and displayed no visible stress symptoms. Na+localization analysis using CoroNa-Green AM revealed effective Na+sequestration in the roots when compared to leaves. Elemental analysis demonstrated that roots accumulated more of Na+while K+content was higher in leaves. At the molecular level, salt stress significantly induced the expression levels of salt overly sensitive1 (SOS1), SOS2, SOS3, high affinity K+transporter (HKT1), ABA biosynthetic and receptor genes (NCED and PYL4), guaiacol peroxidase (POD) exclusively in roots while tonoplast localized Na+/H+exchanger (NHX1) was significantly enhanced in leaves. Our results clearly demonstrate that leaves and roots of Pongamia exhibit differential responses under salt stress although roots are more efficient in sequestering the Na+ions. The present study provides crucial inputs for understanding salt tolerance in a tree species which can be further utilized for developing salt tolerance in higher plants.
Photosynthesis and Stress Biology Laboratory, Department of Plant Sciences, University of Hyderabad, Hyderabad 500046, India.
Sureshbabu
S
Marriboina
Photosynthesis and Stress Biology Laboratory, Department of Plant Sciences, University of Hyderabad, Hyderabad 500046, India.
Debashree
D
Sengupta
Photosynthesis and Stress Biology Laboratory, Department of Plant Sciences, University of Hyderabad, Hyderabad 500046, India.
Sumit
S
Kumar
Photosynthesis and Stress Biology Laboratory, Department of Plant Sciences, University of Hyderabad, Hyderabad 500046, India. Electronic address: attipalli.reddy@gmail.com.
Attipalli R
AR
Reddy
D056804:Biofuels; D002734:Chlorophyll / Q000378:metabolism; D018613:Microscopy, Confocal; D008855:Microscopy, Electron, Scanning; D033641:Millettia / Q000378:metabolism / Q000502:physiology* / Q000648:ultrastructure; D010788:Photosynthesis / Q000502:physiology; D045332:Photosystem II Protein Complex / Q000502:physiology; D018515:Plant Leaves / Q000502:physiology / Q000648:ultrastructure; D018526:Plant Transpiration / Q000502:physiology; D016133:Polymerase Chain Reaction; D055051:Salt-Tolerant Plants / Q000502:physiology*; D013052:Spectrometry, X-Ray Emission; D014197:Trees / Q000378:metabolism / Q000502:physiology* / Q000648:ultrastructure
D056804:Biofuels; D045332:Photosystem II Protein Complex; D002734:Chlorophyll
Na(+) localization; Photosynthetic performance; Pongamia pinnata; Roots; SOS pathway; Salt tolerance