Induction of tolerance to cryogenic protocols in Solanum tuberosum by salicylic acid is mediated by enzymatic antioxidant activity and hydrogen peroxide

ABSTRACT

Two applications of cryogenic protocols are cryotherapy and cryopreservation for virus cleaning and germplasm storage. They are based on exposing explants to ultra-low temperature (−196°C) in liquid nitrogen. Ultra-low temperature in cryogenics implies abiotic stress, leading to the production of reactive oxygen species (ROS), which are the main reason for the low survival and death of explants. Hydrogen peroxide (H₂O₂) is an important ROS produced by stress. Enzymatic antioxidants like catalase (CAT) and peroxidase (POX) are essential for avoiding damage due to H₂O₂, which is a primary signal against stress. Salicylic acid (SA) is involved in tolerance to stress-like cryogeny. Information about the relationship between SA-cryogeny-antioxidant enzymatic activity is scarce. The objective was to evaluate the induction of cryogeny tolerance by SA associated with antioxidant activities like CAT, POX, and H₂O₂ and proline accumulation in tissue, during cryogenic protocols in two clones of potato (Solanum tuberosum L.). SA-induced cryogenic tolerance in both clones, mediated by reducing CAT enzymatic activity, higher H₂O₂ content, proline accumulation and higher water potential before cryogeny. Enhanced CAT and POX activities after cryogeny were related to decreased H₂O₂ content and higher survival. Results suggest the signalling role of H₂O₂ in the induction of tolerance to cryogenic stress.

KEYWORDS:

• Catalase
• cryogeny
• hydrogen peroxide
• oxidative stress
• peroxidase
• potato

Acknowledgments

The authors are grateful for the grant of scholarship number 926485 to the lead author by the National Council of Science and Technology (CONACYT). All facilities were provided by the National Potato Programme of the National Institute of Forestry and Agricultural Research (INIFAP) and the Department of Botany, Postgraduate College.

Disclosure statement

No potential conflict of interest was reported by the author(s).