Physiological and proteomic analyses reveal cAMP ‐regulated key factors in maize root tolerance to heat stress

This study was designed to investigate cAMP roles in thermotolerance of maize root. Adenylyl cyclase (AC) cataly zes ATP to generate cAMP. For two identified maize AC genes,ZmRPP13-LK3 andZmPSiP, the predictive ABA response element was found in their promoter fragments. Both ABA and heat stress treatment increased the promoter activity ofZmRPP13-LK3 andZmPSiP. In the roots of maize ABA-deficient mutantvp5, the heat-caused increase of these two gene expression and cAMP content was obviously less than that in the roots of its wild-typeVp5. cAMP pretreatment decreased H2O2 and malondialdehyde content, but increased the activities of superoxide dismutase and ascorbate peroxidase in roots compared to no pretreatment under heat stress. By iTRAQ proteomics analysis, 268 cAMP-mediated differentially expressed proteins (DEPs) were identified from maize roots exposed to heat stress. The integrated analysis of these DEPs showed that cAMP was involved in many important biological processes, including ion uptake, protein degradation via autophagy or ubiquitin –proteasome system, a rapid delivery of stress-related cargo molecules by vesicle trafficking, and adaptation response by defense proteins. To determine whether the gene expression of these DEPs was regulated by cAMP and ABA, the gene expression of randomly selected 15 DEPs as ion transporters and heat shock proteins was analyzed, and the results indicated that cAMP and ABA pretreatment also enhanced the expression of their genes. ...
Source: Food and Energy Security - Category: Food Science Authors: Tags: ORIGINAL RESEARCH Source Type: research