Comparative Adaptation Responses of Melon (Cucumis melo L.) Genotypes to Salinity Stress

The objective of this work was to understand the mechanisms of physiological, biochemical, and molecular responses to salinity stress of three Turkish melon genotypes (YYU ۱, YYU ۴ and CU ۱۹۶) and cv. Ananas. The study used Randomized Complete Block Design (RCBD) and pots were irrigated with Hoagland nutrient solution after two-leaf stage until harvesting by ۵۰ and ۷۵ mM NaCl concentrations. For evaluation of responses, chlorophyll and carotenoid content, total phenolic and flavonoid amount, proline variations, and nutrient elements were determined. Moreover, qRT-PCR analyses were performed to identify the expression level of six TF (Transcription Factors) genes (WRKY۲۴, TCP۱۵, CmHD-Zip, mTERF۲, Dof۳ and CmADH۲). Increase in salt application led to increase in chlorophyll content in the melon genotypes, but decrease (about ۵۵%) in cv. Ananas. Phenolic, flavonoid, and proline contents varied based on the melon genotypes, but generally increased in Ananas. Expression levels of TCP۱۵ and WRKY۲۴ showed more fold change at ۷۵ mM NaCl treatment. On the other hand, the expression of CmADH۲ and Dof۳ showed more fold change at ۵۰ mM NaCl treatment. Finally, according to adaptation mechanisms of melon genotypes, the study might help in selection and detection of the salt tolerant ones.

Keywords:

Biochemical responses , Salt stress , TF (Transcription Factors) genes.