Investigation of Salinity Tolerance Mechanisms in the Halophyte, Clerodendrum inerme

Diverse ecotypes of saline tolerant Clerodendrum inerme were studied to investigate the morphological, physiological and genetic variations. Seashore, backwater and inland ecotypes of C. inerme recorded significant difference in morphological characteristics viz., leaf area, leaf thickness and midrib thickness. Physiological studies revealed chlorophyll a/b ratio, total chlorophyll and proline content was higher in seashore ecotype than backwater and inland ecotype. The genetic diversity analysis using Randomly Amplified Polymorphic DNA primers showed that seashore ecotype remained as a separate cluster whereas backwater and inland were clustered together. DD-RT-PCR strategy was adapted using in vitro derived plantlets for understanding the molecular basis of salinity tolerance in C. inerme. The molecular studies showed differential expression of nine cDNA frag ments of which, 300 bp and 100 bp cDNA were expressed in leaves of control plants (without NaCl) and 500 bp cDNA was expressed in leaves of 100 mM NaCl stressed plant. Sequencing of the differentially expressed cDNA and its in silico analysis using BLASTN revealed that there is significant similarity with Gossypium hirsutum clone MX152H12-jol, Theobroma cacao Ammonium transporter and Solanum lycopersicum chromosome ch10, respectively.