Contrasting transcriptional responses of PYR1/PYL/RCAR ABA receptors to ABA or dehydration stress between maize seedling leaves and roots

Abstract

BackgroundThe different actions of abscisic acid (ABA) in the aboveground and belowground parts of plants suggest the existence of a distinct perception mechanism between these organs. Although characterization of the soluble ABA receptors PYR1/PYL/RCAR as well as core signaling components has greatly advanced our understanding of ABA perception, signal transduction, and responses, the environment-dependent organ-specific sensitivity of plants to ABA is less well understood.ResultsBy performing real-time quantitative PCR assays, we comprehensively compared transcriptional differences of core ABA signaling components in response to ABA or osmotic/dehydration stress between maize (Zea mays L.) roots and leaves. Our results demonstrated up-regulation of the transcript levels of ZmPYLs homologous to dimeric-type Arabidopsis ABA receptors by ABA in maize primary roots, whereas those of ZmPYLs homologous to monomeric-type Arabidopsis ABA receptors were down-regulated. However, this trend was reversed in the leaves of plants treated with ABA via the root medium. Although the mRNA levels of ZmPYL1-3 increased significantly in roots subjected to polyethylene glycol (PEG)-induced osmotic stress, ZmPYL4-11 transcripts were either maintained at a stable level or increased only slightly. In detached leaves subjected to dehydration, the transcripts of ZmPYL1-3 together with ZmPYL5, ZmPYL6, ZmPYL10 and ZmPYL11 were decreased, whereas those of ZmPYL4, ZmPYL7 and ZmPYL8 were significantly increased. Our results also showed that all of the evaluated transcripts of PP2Cs and SnRK2 were quickly up-regulated in roots by ABA or osmotic stress; conversely they were either up-regulated or maintained at a constant level in leaves, depending on the isoforms within each family.ConclusionsThere is a distinct profile of PYR/PYL/RCAR ABA receptor gene expression between maize roots and leaves, suggesting that monomeric-type ABA receptors are mainly involved in the transmission of ABA signals in roots but that dimeric-type ABA receptors primarily carry out this function in leaves. Given that ZmPYL1 and ZmPYL4 exhibit similar transcript abundance under normal conditions, our findings may represent a novel mechanism for species-specific regulation of PYR/PYL/RCAR ABA receptor gene expression. A difference in the preference for core signaling components in the presence of exogenous ABA versus stress-induced endogenous ABA was observed in both leaves and roots. It appears that core ABA signaling components perform their osmotic/dehydration stress response functions in a stress intensity-, duration-, species-, organ-, and isoform-specific manner, leading to plasticity in response to adverse conditions and, thus, acclimation to life on land. These results deepen our understanding of the diverse biological effects of ABA between plant leaves and roots in response to abiotic stress at the stimulus-perception level.Electronic supplementary materialThe online version of this article (doi:10.1186/s12870-016-0764-x) contains supplementary material, which ...

Quantitative Proteomic Analyses Identify ABA-Related Proteins and Signal Pathways in Maize Leaves under Drought Conditions

“…These processes involve the expression of stress-response genes, many of which are regulated by ABA (Fan et al, 2016). Therefore, ABA as an important messenger regulates the adaptive response of plants to abiotic stress (Sah et al, 2016).…”

Peer Review #1 of "Genome-wide identification of ABA receptor PYL family and expression analysis of PYLs in response to ABA and osmotic stress in Gossypium (v0.1)"

“…Similar structures also exist in other plants. Furthermore, the expression patterns of PYL genes have been studied in tissues and in responding to exogenous ABA and diverse stresses in multiple plants (Saavedra et al, 2010;Boneh et al, 2012;Kim et al, 2012;Bai et al, 2013;González-Guzmán et al, 2014;Tian et al, 2015;Fan et al, 2016;Gordon et al, 2016;Yu et al, 2016;Chen et al, 2017;Zhang et al, 2017). These findings provide valuable information for researchers to further examine the functions of PYLs in ABA signaling in plants.…”

“…Accordingly, it is of great importance to enhance stress tolerance of cotton plants. One of the key strategies may be achieved via genetically engineering of PYL genes (Kim et al, 2014;Lee et al, 2015;Yu et al, 2016;Zhao et al, 2016;Chen et al, 2017;Liang et al, 2017). It is therefore essential for us to elucidate the functions and regulatory mechanisms of Gossypium PYLs.…”

The spatio-temporal specificity of PYR1/PYL/RCAR ABA receptors in response to developmental and environmental cues

“…1 Our recent results demonstrated that PYR1/PYL/RCAR ABA receptor genes in maize exhibit distinct expression patterns in response to abiotic stresses (or ABA) between roots and leaves, with isoforms that are upregulated in roots being down-regulated in leaves, and vice versa. 33 Except with the different downstream transcript factors, this receptor family themselves displays a clear development-specific features in transcription. PYL5 is the most highly expressed receptor at seed maturation, suggesting that it may play a major role in ABA response at this stage.…”