Mapping the ‘Two-component system’ network in rice

Abstract

Two-component system (TCS) in plants is a histidine to aspartate phosphorelay based signaling system. Rice genome has multifarious TCS signaling machinery comprising of 11 histidine kinases (OsHKs), 5 histidine phosphotransferases (OsHPTs) and 36 response regulators (OsRRs). However, how these TCS members interact with each other and comprehend diverse signaling cascades remains unmapped. Using a highly stringent yeast two-hybrid (Y2H) platform and extensive in planta bimolecular fluorescence complementation (BiFC) assays, distinct arrays of interaction between various TCS proteins have been identified in the present study. Based on these results, an interactome map of TCS proteins has been assembled. This map clearly shows a cross talk in signaling, mediated by different sensory OsHKs. It also highlights OsHPTs as the interaction hubs, which interact with OsRRs, mostly in a redundant fashion. Remarkably, interactions between type-A and type-B OsRRs have also been revealed for the first time. These observations suggest that feedback regulation by type-A OsRRs may also be mediated by interference in signaling at the level of type-B OsRRs, in addition to OsHPTs, as known previously. The interactome map presented here provides a starting point for in-depth molecular investigations for signal(s) transmitted by various TCS modules into diverse biological processes.

Contributions of Adaptive Plant Architecture to Transgressive Salinity Tolerance in Recombinant Inbred Lines of Rice: Molecular Mechanisms Based on Transcriptional Networks

“…This network of 244 genes appeared to be regulated primarily through the cytokinin signaling pathway as indicated by signature signaling genes such as OsRR23 (Os02t0796500-01; B-type response regulator) and OsHK5 (Os10t0362300-02; cytokinin signal receptor protein), biosynthetic genes such as OsIPT9 (Os01t0968700-02; Isopentenyl transferase), and deactivation genes such as N-glucosyltransferase (Os03t0824600-00; cytokinin conjugation enzyme; Supplementary Table 2). The OsIPT9, OsRR23, and OsHK5 have been reported to modulate adaptive morphology and growth under saline conditions, chemical toxicity, nutrient deficiency, and many biotic factors (Sharan et al, 2017;Ghosh et al, 2018;Nongpiur et al, 2019). The timely and robust expression of this cytokinin-mediated network in the transgressive super-tolerant FL510 is consistent with its unique adaptive morphology that may confer osmotic stress avoidance through regulated transpiration and robust photosynthesis (Figure 2).…”

Histidine kinase MHZ1/OsHK1 interacts with ethylene receptors to regulate root growth in rice

“…Two-component systems also participate in cytokinin signaling in Arabidopsis and similar mechanism may exist in rice 38,47,[60][61][62][63] . Considering that rice may have only two functional HPts (OsAHP1 and OsAHP2) for signaling 47,48 , it is hence possible that these two genes play roles in both ethylene signaling and cytokinin signaling in specific manners depending on distinct treatments, times, cell types, tissues and/or organs.…”

The Interaction Network and Signaling Specificity of Two-Component System in Arabidopsis

“…Since the discovery of the two-component multi-step phosphorylation system in plants, interaction relationships of the two-component elements were investigated to reveal the mechanisms of the phosphorelays, especially in Arabidopsis and hetero-and homodimers were largely screened based on the Y2H, BiFC, and phosphorelay assays. In addition, the protein interaction network was also mapped in rice and polar [125,126]. Here, we focus on the recent progress in the TCS protein interaction relationships, and an interaction network map was further depicted for the TCS elements in Arabidopsis (Figure 7).…”