Background and AimsPhosphorus deficiency is a major limiting factor for crop yield worldwide. Previous studies revealed that PHR1 and it homologues play a key role in regulating the phosphate starvation response in plants. However, the function of PHR homologues in common wheat (Triticum aestivum) is still not fully understood. The aim of the study was to characterize the function of PHR1 genes in regulating phosphate signalling and plant growth in wheat.MethodsWheat transgenic lines over-expressing a wheat PHR1 gene were generated and evaluated under phosphorus-deficient and -sufficient conditions in hydroponic culture, a soil pot trial and two field experiments.Key ResultsThree PHR1 homologous genes Ta-PHR1-A1, B1 and D1 were isolated from wheat, and the function of Ta-PHR1-A1 was analysed. The results showed that Ta-PHR1-A1 transcriptionally activated the expression of Ta-PHT1.2 in yeast cells. Over-expressing Ta-PHR1-A1 in wheat upregulated a subset of phosphate starvation response genes, stimulated lateral branching and improved phosphorus uptake when the plants were grown in soil and in nutrient solution. The data from two field trials demonstrated that over-expressing Ta-PHR1-A1 increased grain yield by increasing grain number per spike.ConclusionsTaPHR1 is involved in phosphate signalling in wheat, and was valuable in molecular breeding of crops, with improved phosphorus use efficiency and yield performance.

Light-regulated modules offer unprecedented new ways to control cellular behaviour with precise spatial and temporal resolution. Among a variety of bacterial light-switchable gene expression systems, single-component systems consisting of single transcription factors would be more useful due to the advantages of speed, simplicity, and versatility. In the present study, we developed a single-component light-activated bacterial gene expression system (eLightOn) based on a novel LOV domain from Rhodobacter sphaeroides (RsLOV). The eLightOn system showed significant improvements over the existing single-component bacterial light-activated expression systems, with benefits including a high ON/OFF ratio of >500-fold, a high activation level, fast activation kinetics, and/or good adaptability. Additionally, the induction characteristics, including regulatory windows, activation kinetics and light sensitivities, were highly tunable by altering the expression level of LexRO. We demonstrated the usefulness of the eLightOn system in regulating cell division and swimming by controlling the expression of the FtsZ and CheZ genes, respectively, as well as constructing synthetic Boolean logic gates using light and arabinose as the two inputs. Taken together, our data indicate that the eLightOn system is a robust and highly tunable tool for quantitative and spatiotemporal control of bacterial gene expression.

Hyperphosphorylation of tau occurs in preclinical and clinical stages of Alzheimer's disease (AD), and hyperphosphorylated tau is the main constituent of the paired helical filaments in the brains of mild cognitive impairment and AD patients. While most of the work described so far focused on the relationship between hyperphosphorylation of tau and microtubule disassembly as well as axonal transport impairments, both phenomena ultimately leading to cell death, little work has been done to study the correlation between tau hyperphosphorylation and DNA damage. As we showed in this study, tau hyperphosphorylation and DNA damage co-occurred under formaldehyde treatment in N2a cells, indicating that phosphorylated tau (p-Tau) induced by formaldehyde may be involved in DNA impairment. After phosphorylation, the effect of tau in preventing DNA from thermal denaturation was diminished, its ability to accelerate DNA renaturation was lost, and its function in protecting DNA from reactive oxygen species (ROS) attack was impaired. Thus, p-Tau is not only associated with the disassembly of the microtubule system, but also plays a crucial role in DNA impairment. Hyperphosphorylation-mediated dysfunction of tau protein in prevention of DNA structure from damage under the attack of ROS may provide novel insights into the mechanisms underlying tauopathies.

Heterotrimeric G proteins, which consist of G , G and G subunits, function as molecular switches to regulate a wide range of developmental processes in plants. In this study, we characterize the function of rice RGG2, which encodes a type B G subunit, in grain size and yield production. The expression levels of RGG2 are significantly higher than those of other rice G -encoding genes in all tissues tested, suggesting that RGG2 plays essential roles in rice growth and development. By regulating cell expansion, RGG2 overexpression in Nipponbare (NIP) leads to reduced plant height and decreased grain size. By contrast, two mutants generated by the clustered, regularly interspaced, short palindromic repeat (CRISPR)/CRISPR-associated 9 (Cas9) system in the Zhenshan 97 (ZS97) background, zrgg2-1 and zrgg2-2, exhibit enhanced growth, including elongated internodes, increased 1000-grain weight and plant biomass, and enhanced grain yield per plant (+11.8% and 16.0%, respectively). These results demonstrate that RGG2 acts as a negative regulator of plant growth and organ size in rice. By measuring the length of the second leaf sheath after gibberellin (GA ) treatment and the GA-induced α-amylase activity of seeds, we found that RGG2 is also involved in GA signaling. In summary, we propose that RGG2 may regulate grain and organ size via the GA pathway and that manipulation of RGG2 provides a novel strategy for rice grain yield enhancement. This article is protected by copyright. All rights reserved.

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Summary Plants maintain a dynamic balance between plant growth and stress tolerance to optimise their fitness and ensure survival. Here, we investigated the roles of a clade A type 2C protein phosphatase (PP2C)‐encoding gene, OsPP2C09, in regulating the trade‐off between plant growth and drought tolerance in rice (Oryza sativa L.). The OsPP2C09 protein interacted with the core components of abscisic acid (ABA) signalling and showed PP2C phosphatase activity in vitro. OsPP2C09 positively affected plant growth but acted as a negative regulator of drought tolerance through ABA signalling. Transcript and protein levels of OsPP2C09 were rapidly induced by exogenous ABA treatments, which suppressed excessive ABA signalling and plant growth arrest. OsPP2C09 transcript levels in roots were much higher than those in shoots under normal conditions. After ABA, polyethylene glycol and dehydration treatments, the accumulation rate of OsPP2C09 transcripts in roots was more rapid and greater than that in shoots. This differential expression between the roots and shoots may increase the plant’s root‐to‐shoot ratio under drought‐stress conditions. This study sheds new light on the roles of OsPP2C09 in coordinating plant growth and drought tolerance. In particular, we propose that OsPP2C09‐mediated ABA desensitisation contributes to root elongation under drought‐stress conditions in rice.

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