Pré-tratamento de tunicamicina em sementes de feijão-caupi germinadas sob salinidade

Abstract

Cowpea (Vigna unguiculata L.) is one of the most cultivated legumes in Brazil, being one of the main sources of the sub-Northeast. Salinity is one of the major factors that reduces the productivity of cultivars around the world. In order to minimize the effects caused by plants, plants can develop different mechanisms to be able to survive and develop. Evidence indicates that the endoplasmic reticulum (ER) directly participates in secondary responses to saline stress in plant cells. Thus, this work evaluates whether the chemical pre-treatment of tunicamycin (TM), a specific inducer of ER stress, in cowpea seeds cv. TVu results in biochemical and metabolic adjustments that help plants thrive under saline conditions. On that occasion, the seeds were previously treated for a period of 8h with 0, 150, 250, 375, and 500 μg/mL of TM. Subsequently, they were germinated in vermiculite and 75mM salt (NaCl) solution. Then, 8 days seedlings were transferred to hydroponics with Clark's solution and NaCl 75 mM and they were kept at this condition for 15 days. After that, growth traits, inorganic ions, antioxidant enzymatic system and of the profile of metabolites of leaves and roots were assessed. There were no significant changes in the morphological parameters of the plants. Pre-treatment with TM showed higher content of photosynthetic pigments and lower content of Na+ and K+ ions compared to TM 0. In addition, the pre-treatment induced a positive modulation of metabolites in the leaves, including the amino acid proline, stress tolerance, as well as a negative modulation in the roots, in which sugars may be consumed to maintain energy levels. In general, the data contribute to the study cowpea under responses under salt stress. However, it is recommended to evaluate different conditions of priming, different times of plant growth and different salinity conditions.