The Cross Talk Between ROS and NO in The Viability Declination of Cryopreserved-Pollen From Paeonia Lactiflora

Abstract

Reactive oxygen species (ROS) and nitric oxide (NO), as two common active molecules, are both involved in the changes of viability after liquid nitrogen (LN) stored, but the relationship between these two molecules has not been involved in plant cryopreservation up to now. In this study, the pollen of Paeonia lactiflora 'Fen Yu Nu' with significantly decreased viability after cryopreservation as materials, by studied the effects of the two regulators on each other and their biosynthesis and scavenging indexes, to explore the interaction between ROS and NO in pollen cryopreservation and its mechanism.The results showed that: the contents of ROS and NO increased significantly with the decrease of pollen viability after cryopreservation, and regulated ROS and NO content had a significant effect on post-LN pollen viability; the changes of ROS content positively regulated the endogenous NO content, and had significant effects on the expression level of NOS-like enzyme regulation gene CSU2 and its activity; while regulated NO had a positive effect on ROS content, and significantly affected the expression of NADPH oxidase and its regulatory gene RBOHJ, and also significantly affected catalase (CAT) and the substrate related to ascorbic acid (AsA)- glutathione (GSH) antioxidant cycle system. These results indicate that there was a positive interaction between ROS and NO in the pollen cryopreservation, NOS biosynthesis pathway was one of the ROS regulated NO pathways, NADPH oxidase, CAT and AsA-GSH antioxidant cycle system were the key sites for NO regulated ROS content.